Extended Forecasts are Not Reliable

Reposted from the Cliff Mass Weather and Climate Blog

We are constantly exposed to extended forecasts in the media and online, with predictions extending through the next month and more.

Can you rely on such predictions?    Are they really worth paying attention to?

Quite honestly, probably not–and if you do consider them, do so with the knowledge that their skill is marginal at best.

Take this month (October) for example.  The official NOAA Climate Prediction Forecast for October temperatures, made on Sept. 19th, was for warmer than normal conditions over the west and MUCH above normal over the southwest U.S.

What actually happened?  Nearly the entire west was much colder than normal, with the northern parts MUCH, MUCH colder than normal.  A miss.  In fact, a big miss.

Or the official 3-4 week forecast, made on October 4th?   Warmer than normal over the west.

Such poor forecasts even a month out are not unusual.   UW graduate student Nick Weber and I evaluated the skill of the main U.S. long-term forecasting model (the CFSv2) and found that skill is typically lost after roughly 2 weeks (see below and published in the peer-reviewed literature).  This figure shows the forecast error (root mean square error) at 500 hPa—about 18,000 ft, a good level to view atmospheric predictability.  The situation is the same over Washington, the western U.S., the continental U.S. or global.  Skill is rapidly lost the second week out.

While meteorologists struggle to produce improved forecast skill past two weeks, we have gained a great deal of skill at the shorter time ranges, particularly for days 3-8.

So why is our skill improving rapidly for the shorter periods, but not the longer ones?

Because the forecasting problem is very different at the different temporal scales.

For the short periods, forecasting  is an initial value problem.  We start with a good description of the 3D atmosphere and our models simulate how things evolve.   Because of weather satellites and other new data sources, our initial description of the atmospheric has gotten MUCH better.  And our models are much better:  higher resolution, much better description of key physical processes, and more.  That is why a plot of the skill of  skill of the 1-10 day forecasts of the European Center has improved greatly over the past decades (see below)

But small errors in the initial description of the atmosphere and deficiencies in our models inevitably lead to growing errors, and by 2 weeks such errors swamp the forecast.  The forecasts are not much better than simply using the average conditions (or climatology).

There is hope for some skill beyond two weeks, by taking advantage of the forecast skill available from aspects of the environment that are changing slowly (such as sea surface temperatures, sea ice extent, snow extend, soil moisture).    These aspects influence the atmosphere and potentially can torque the atmosphere one way or the other.  Essentially, the forecast problem has changed from an initial values problem to a boundary-forced problem (the boundary being the surface characteristics that can influence weather).

But the skill that might be available from the boundary conditions is different—not about the conditions at a specific time, but for the average conditions over a month or season.   A good example of such skill is the relationship of the warmer (El Nino) or colder (La Nina) temperatures of the tropic Pacific sea surface and weather around the world.    There is some skill there, but it is relatively modest.

Unfortunately, our models still have key deficiencies (such as poor description of thunderstorms) that make it difficult for us to derive all the potential skill that should be available from the slowly changing boundary conditions.   A lot of work is needed, but I am hopeful that eventually forecast skill beyond two weeks will improve.

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Ron Long
October 31, 2019 6:10 pm

Weather forecasting for dummies: when you get up in the morning look out the window. If you fancy yourself an intellectual look at the wind direction and see if there are weather signals upwind. That having been said the introduction of weather satellites has done a lot for some increase in forecast accuracy, and some weatherpersons actually seem to combine common sense and satellite data to produce better forecasts. Fun fact: At Roseburg, Oregon they regularly report things like “goats high and scattered” or “goats bunched up and descending”, which is what the wild (ferral) goats on the mountain are doing. High and scattered is great weather and bunched up and descending is deteorating weather.

Walter Sobchak
Reply to  Ron Long
October 31, 2019 8:28 pm

Matt. 16

2 [Jesus] answered and said unto them, When it is evening, ye say, It will be fair weather: for the sky is red.
3 And in the morning, It will be foul weather to day: for the sky is red and lowering.

Bryan A
Reply to  Walter Sobchak
October 31, 2019 9:08 pm

Red sky in the morning, sailor take warning. Red sky at night, sailors delight

Richard Patton
Reply to  Bryan A
October 31, 2019 11:37 pm

It’s just the opposite in the tropics as the prevailing flow is just the opposite.

Reply to  Bryan A
October 31, 2019 11:46 pm

Red Sky at Night, VietCong delight
Red sky in the morning, napalm bomb warning.

From ‘The “Vietnamese Archers”, an every day story of country folk’

Reply to  Bryan A
November 1, 2019 1:57 am

It’s shepherds in England – or an alternative:
Red sky at night means the castle’s alight.
The shepherd’s delighted, the earl has ignited.

Richard of NZ
Reply to  Bryan A
November 1, 2019 3:06 am

Mares tails and mackerel scales
Cause tall ships to carry small sails.

Alternative regarding marine winds.

Samuel C Cogar
Reply to  Bryan A
November 1, 2019 3:53 am

If the cows are lying down in the field chewing their cud during the day, its a sign of impending rain.

Gerry, England
Reply to  Samuel C Cogar
November 1, 2019 6:49 am

I think that has been shown to be just that their legs are tired.

Jeff Alberts
Reply to  Samuel C Cogar
November 1, 2019 4:08 pm

My wife keeps insisting on this, but “impending” seems to mean “within 2 weeks”. Not very helpful. Although, it could be that they’re lying down due to a cold front moving in, and their bellies and udders are cold.

Samuel C Cogar
Reply to  Samuel C Cogar
November 2, 2019 4:32 am

I think that has been shown to be just that their legs are tired.

Yeah, ….. right, ….. a whole herd of cows whose legs get tired at the same time. “DUH”, I should have thought of that.

Cows will lie down when chewing their cud, …. and lying down on a dry, warm spot beats the ell out of lying down on cold, soaking wet ground.

Cows are smarter than some people. I useta raise beef cattle, I know.

Reply to  Bryan A
November 1, 2019 1:31 pm

Train whistles tend to sound different (mournful?) when rain is imminent.

Samuel C Cogar
Reply to  PaulH
November 3, 2019 4:05 am

High humidity and Doppler effect.

D Anderson
Reply to  Walter Sobchak
November 1, 2019 8:50 am

Robins have a kind of warbling song before it rains. My dad use to say the robins are singing for rain.

Reply to  Ron Long
October 31, 2019 9:03 pm

It was autumn, and the Indians on the remote reservation asked their new Chief if the winter was going to be cold or mild. Since he was an Indian Chief in a modern society, he had never been taught the old secrets.

When he looked at the sky, he couldn’t tell what the weather was going to be. Nevertheless, to be on the safe side, he replied to his tribe that the winter was indeed going to be cold and that the members of the village should collect firewood to be prepared.

Also, being a practical leader, after several days he got an idea. He went to the phone booth, called the National Weather Service and asked, “Is the coming winter going to be cold?”

“It looks like this winter is going to be quite cold indeed,” the meteorologist at the weather service
responded. So the Chief went back to his people and told them to collect even more wood in order to be prepared.

A week later, he called the National Weather Service again. “Is it going to be a very cold winter?”

“Yes,” the man at National Weather Service again replied, “it’s definitely going to be a very cold winter.” The
Chief again went back to his people and ordered them to collect every scrap of wood they could find.

Two weeks later, he called the National Weather Service again. “Are you absolutely sure that the winter is going to be very cold?”

“Absolutely,” the man replied. “It’s going to be one of the coldest winters ever.”

“How can you be so sure?” the Chief asked.

The weatherman replied, “The Indians are collecting wood like crazy.”

Reply to  Streetcred
November 1, 2019 4:52 am

Still a good tale. It’s the one that came to mind when I read about the goats!

Reply to  Streetcred
November 1, 2019 9:28 am

This is called the perfect positive feedback!

Rick Scheck
Reply to  JaKo
November 1, 2019 5:07 pm

Precisely the factor at play both in the CO2 “tipping” point trope as well as in the herd mind of its adherents.
Outside of that, positive feedback is rare in natural processes and a trap for buying into the CAGW mania.

Reply to  Streetcred
November 1, 2019 11:49 am

The one that I heard was about the New England Weather Forecast office who had a terrible reputation for producing consistently inaccurate forecasts. One day the lead forecaster noticed that the local newspaper was putting out incredibly accurate daily forecasts. After studying the newspaper forecasts for several weeks, he anonymously contacted the editor and asked him how they managed to produce such spot-on forecasts. “It’s easy”, replied the editor. “We just look at whatever the Weather Service says, and we print the exact opposite of their forecasted weather”.

Y. Knott
Reply to  Ron Long
November 1, 2019 4:24 am

There’s an actual statistic for the accuracy of forecasts, from the aviation community. Every forecast is 98% accurate – for the first hour after it’s issued – then it goes rapidly downhill.

But the GWAlarmists can forecast weather out over twelve years, yep…

Bruce Ranta
October 31, 2019 6:12 pm

Model schmodel. Repeat ad nauseam.

“All models are wrong. Some are useful.” A quote from one of the best modelers the Ontario government has ever had. I’d give his name, but it might cost him dearly.

Reply to  Bruce Ranta
October 31, 2019 9:23 pm

The models all agree. The observed data is wrong. Not mine but still funny

Ed Fix
October 31, 2019 6:15 pm

I always tell my friends that the weather is under no obligation to read or follow the forecast. Climate even less so.

I think maybe my friends are getting tired of hearing that joke.

Joel O'Bryan
Reply to  Ed Fix
October 31, 2019 6:50 pm

“But small errors in the initial description of the atmosphere and deficiencies in our models inevitably lead to growing errors, and by 2 weeks such errors swamp the forecast. “

Cliff Mass’s observation about long-range forecasting and it’s explosion of error propagation into junk sails right over the heads of the Climate Change congregation and it’s priesthood.

And yet Nick Stokes, Mosher, even Dr Spencer still seem to “believe” supercomputer GCMs have some kind of value projecting a set of wiggly line temps to 2080 and beyond. That some GCMs might better project the number of angels on the pinhead than others. That is, that uncertainty and statistical error propagation cease simply because it is a “climate model” and not a “weather model.” And a belief that some do it better than others. News Flash: They’re all junk.

The climate modeler community — all just a bunch of Self-Licking Ice Cream cones, that is a jobs program for scientists, computer engineers and programmers paid for with tax dollars. The only utility they provide is supporting a politically-driven policy narrative. Science they are not most assuredly. The sooner most folks admit that obvious conclusion, the sooner science can begin a Road to Redemption.

nw sage
Reply to  Joel O'Bryan
October 31, 2019 7:04 pm

Everything derives from the set of conditions that exist NOW. If we knew enough (everything) about the NOW we would be able to tell with certainty what NOW + 1 would be. We can’t, we won’t and we never will be able to know enough.

Joel O'Bryan
Reply to  nw sage
October 31, 2019 10:00 pm

It’s not just knowing perfectly the initial conditions. The structural models in GCM equations are wrong since they parameterize so many important energy flow processes, which itself leads to its own unknowable propagating errors even if the IC’s were perfect. Judith Curry made that point clear in her recent blog post re-posted here yesterday.

Samuel C Cogar
Reply to  nw sage
November 1, 2019 4:14 am

nw sage October 31, 2019 at 7:04 pm

Everything derives from the set of conditions that exist NOW.

And 30 seconds (or whatever) from NOW ……. becomes the “new” NOW, …… right?

As Willis E. might say, …… an Emergent Phenomena might prove you wrong every time you predict something.

Larry in Texas
Reply to  Joel O'Bryan
October 31, 2019 7:56 pm

Another example of the dangers inherent in the science-government complex that Eisenhower warned about in his Farewell Address. This is a nefarious, interconnected mutual admiration and reward society.

Reply to  Joel O'Bryan
October 31, 2019 10:24 pm

“Cliff Mass’s observation about long-range forecasting and it’s explosion of error propagation into junk sails right over the heads of the Climate Change congregation and it’s priesthood.”

Mmm, right over their heads…

You should ask Cliff to explain the difference between short term weather forecasts and climate simulations. Because judging by your post you seem to think they are the same thing.

James R Clarke
Reply to  Loydo
October 31, 2019 11:26 pm

They are not the same thing. They are worse! At least the forecast models start of with good observations and decent equations of the fluid dynamics of the atmosphere. Climate models don’t really start with initial conditions as much, but they also don’t have good equations that describe the climate dynamics. Consequently, their output is really a function of the assumptions that go into them, and has very little to do with reality.

There are no real world observations that support the assumptions (or conclusions) of the climate models, unless you cherry-pick very specific time periods where the curves match up for a brief time.

Richard S Courtney
Reply to  Loydo
November 1, 2019 1:06 am


You display your ignorance when you fail to understand the problem of “error propagation” in climate models. And that is merely the start of the profound problems of climate models.

There are no existing models of global climate that are capable of providing reliable predictions of future climate, and there are good reasons to suspect such models will not be capable of development within the lifetime of anybody now alive.
I provide the following theoretical and pragmatic explanations of these assertions.

No model’s predictions should be trusted unless the model has demonstrated forecasting skill. Climate models which existed 25 years ago have been altered (because they proved inadequate) so now do not exist. In other words, existing climate models have not existed for 25, 50 or 100 years so it is not possible to assess their predictive capability on the basis of their demonstrated forecasting skill; i.e. they have no demonstrated forecasting skill and, therefore, their predictions are unreliable.

Put bluntly, predictions of the future provided by existing climate models have the same degree of demonstrated reliability as has the casting of chicken bones for predicting the future.

The ability of a computer model to appear to represent existing reality is not a guide to the model’s predictive ability. For example, the computer model called ‘F1 Racing’ is commercially available. It is based on physical principles (if it were not then the racing cars would not behave realistically), and ‘F1 Racing’ is a much more accurate representation of motor racing than any GCM is of global climate. But the ability of a person to win a race as demonstrated by ‘F1 Racing’ is not an indication that the person could or would win the Monte Carlo Grande Prix if put in a real racing car. Similarly, an appearance of reality provided by a GCM cannot be taken as an indication of the GCM’s predictive ability in the absence of the GCM having any demonstrated forecasting skill.

Furthermore, the climate models are based on assumptions that may not be correct. The basic assumption used in the models is that change to climate is driven by change to radiative forcing. And it is very important to recognise that this assumption has not been demonstrated to be correct. Indeed, it is quite possible that there is no force or process causing climate to vary. I explain this as follows.

The climate system is seeking an equilibrium that it never achieves. The Earth obtains radiant energy from the Sun and radiates that energy back to space. The energy input to the system (from the Sun) may be constant (although some doubt that), but the rotation of the Earth and its orbit around the Sun ensure that the energy input/output is never in perfect equilibrium.

The climate system is an intermediary in the process of returning (most of) the energy to space (some energy is radiated from the Earth’s surface back to space). And the Northern and Southern hemispheres have different coverage by oceans. Therefore, as the year progresses the modulation of the energy input/output of the system varies. Hence, the system is always seeking equilibrium but never achieves it.

Such a varying system could be expected to exhibit oscillatory behaviour. And, importantly, the length of the oscillations could be harmonic effects which, therefore, have periodicity of several years. Of course, such harmonic oscillation would be a process that – at least in principle – is capable of evaluation.

However, there may be no process because the climate is a chaotic system. Therefore, the observed oscillations (ENSO, NAO, etc.) could be observation of the system seeking its chaotic attractor(s) in response to its seeking equilibrium in a changing situation.

Very, importantly, there is an apparent ~900 year oscillation that caused the Roman Warm Period (RWP), then the Dark Age Cool Period (DACP), then the Medieval Warm Period (MWP), then the Little Ice Age (LIA), and the present warm period (PWP). All the observed rise of global temperature in the twentieth century could be recovery from the LIA that is similar to the recovery from the DACP to the MWP. And the ~900 year oscillation could be the chaotic climate system seeking its attractor(s). If so, then all global climate models and ‘attribution studies’ utilized’ e.g. by IPCC and CCSP are based on the false premise that there is a force or process causing climate to change when no such force or process exists.

But the assumption that climate change is driven by radiative forcing may be correct. If so, then it is still extremely improbable that – within the foreseeable future – the climate models could be developed to a state whereby they could provide reliable predictions. This is because the climate system is extremely complex. Indeed, the climate system is more complex than the human brain (the climate system has more interacting components [e.g. biological organisms] than the human brain has interacting components [e.g. neurones} ), and nobody claims to be able to construct a reliable predictive model of the human brain. It is pure hubris to assume the climate models are sufficient emulations for them to be used as reliable predictors of future climate when they have no demonstrated forecasting skill.


Phil Rae
Reply to  Richard S Courtney
November 1, 2019 3:49 am


Some good analogies & explanations that make way more sense than the drivel from the CAGW zealots.

Reply to  Richard S Courtney
November 1, 2019 5:05 am

”There are no existing models of global climate that are capable of providing reliable predictions of future climate …”

I seem to recall that one member of the “climatology community” (can’t remember which one) admitted that even the starting point for models doesn’t reflect reality either!

Reply to  Loydo
November 1, 2019 3:25 am

Look up the special pleading fallacy.

I reckon you know that weather and a double pendulum are quite different, too…

Jeff Alberts
Reply to  Ed Fix
November 1, 2019 4:15 pm

I would be happy to see a 2 day forecast that was consistently right. Doesn’t happen.

Mark Broderick
October 31, 2019 6:16 pm


“That is why a plot of the skill of skill of the 1-10 day forecasts of the European Center has improved greatly over the past decades.”

Great post…

Joel O'Bryan
October 31, 2019 6:31 pm

This is exactly why I only post images in the comments of the 6-10 outlook. It is pretty reliable out to 10 days in my experience watching for about 10 years. Beyond 8 days, I had seen the NOAA/NCEP 8-14 day outlook fail numerous times.

Here’s the current 6-10 day outlook (10/31/2019). Bundle up Great Lake-Midwest to Texas.

the NOAA/NCEP URL to bookmark is:

October 31, 2019 6:48 pm

“Quite honestly, probably not–” what probably not?

….they can’t even get our daily forecast right….on the day it’s happening

David Guy-Johnson
Reply to  Latitude
November 1, 2019 1:21 am

Latitude. That’s a silly comment because the vast majority of the time daily forecasts are correct. The FACTS prove that.

Reply to  David Guy-Johnson
November 1, 2019 4:43 am

“ vast majority”
I am with Latitude…when the weather is fairly consistent they are accurate but when a big change is about to occur…wellllll

Right-Handed Shark
Reply to  David Guy-Johnson
November 1, 2019 5:51 am

The weather app on my smartphone, provided by AccuWeather, tells me it’s raining in my area right now. It isn’t.

Gerry, England
Reply to  David Guy-Johnson
November 1, 2019 6:52 am

A classic on the text comment stream at a test match a year or so ago where the start was being delayed.
‘well that forecast is quite different to the one they gave us an hour or so ago’ LOL

John Endicott
Reply to  David Guy-Johnson
November 1, 2019 11:28 am

I don’t know that I’d go so far as to say the vast majority of the time. Daily forecasts have proven to be more accurate than they use to be but they still get it wrong quite often. Part of the problem is that forecasts cover a large area. For example a forecast for rain or a high of 60 could be accurate in one location but be inaccurate just a few short miles away (but well within the forecast area).

Jeff Alberts
Reply to  David Guy-Johnson
November 1, 2019 4:20 pm

I’m with Latitude as well. Of course we need to define “right”.

I still have a screen capture of a local forecast from Accuweather I think it was, which showed sunny and clear right then, when in reality it was overcast from horizon to horizon.

I used to track these, and got tired of keeping up, but it was pretty horrific.

October 31, 2019 6:55 pm

My favorite put down of weather forecasting involves a “disaster” report by a cute little blonde anchorette back before the 6 second delay was imposed. She wasn’t reporting on a disaster, her reporting became a disaster.

When it came time to introduce the Meteorologist to give the nightly forecast, she really pulled a boner…er, uh,…made a boo boo. Apparently he had predicted a large snow the previous day, but it didn’t materialize. She looked at him, and with a stern look asked, “So, where’s that 10 inches you promised me last night?”

As the weather guy and the sports guy did a double face-palm and almost fell off their stools trying to stifle laughter, she got that “deer in the headlights” look, realizing how that must have sounded. The station quickly faded to a commercial.

Reply to  TEWS_Pilot
October 31, 2019 8:32 pm

I once had an LP (lost it sometime over the years) called, “Pardon My Bloopers,” compiled by Kermit Shafer. It was hilariously ribald at the time it was produced; rather mild today. There were several weather-related bloopers. They included, “Helena got six inches during the night. Uh, Helena, MONTANA, got six inches OF SNOW during the night.”
An Alaskan radio DJ, “Let’s take a leak out the window, and see if it’s freezing.”
And somewhere on the east coast, “the fog was as thick as sea poop.” ( pea soup).

I’m afraid many of the bloopers would be declared offensive, today.

Rick Scheck
Reply to  TEWS_Pilot
November 1, 2019 5:18 pm

Live television is glorious. Nothing else separates the “readers” from the pros.

October 31, 2019 6:57 pm

Where I live we are daily given both 7-day and 10-day forecasts. I have learned from experience that both fall below 50% accuracy more than two days out. Get those up to near 100% and then I’ll consider “climate forecasts.”

Clarky of Oz
October 31, 2019 6:57 pm

I prefer an old piece of rope hanging from a gum tree.
If it is swinging back and forth it is windy.
If is wet it is raining.

Lorne Newell
Reply to  Clarky of Oz
October 31, 2019 7:16 pm

You obviously qualify for a forecasting certificate. Now buck-up and get adegree.

Reply to  Clarky of Oz
November 1, 2019 3:20 pm

In Swansea, in South Wales, there are two forecasts.
If you can’t see the Mumbles [local hill/headland] – it’s raining.
If you can see the Mumbles – it is about to rain.


steve case
October 31, 2019 6:59 pm

Kip Hansen posted this double pendulum example a while back:
After about five or six swings the divergence becomes obvious.

Joel O'Bryan
October 31, 2019 7:03 pm

Another point to make concerning even Dr Mass’s El Nino-La Nina atmospheric zonal-meridonal flow graphs above.

Winter 2018-2019 was wet across the western US. We saw that in the flooding leading to late plantings due to wet fields from Washingston State barly and oats to the Midwest cornfields. But what was the Winter 2018-2019?… El Nino. What does the ENSO meter over to the right on this page say (+0.6), we’re into El Nino territory again, but where has the moisture and flow been recently (a meridonal pattern – October snow and cold records from Montana to Texas).

And what was the West Coast atmospheric flow to bring in all that moisture last winter-spring (January-March) and now? Last January-March it was a La Nina type meridonal flow bringing moisture to the Northwest and cold air and moisture to the MidWest in Arctic polar vortex excursions. It was not a warm-dry Zonal El Nino flow pattern to the northern US last January-March even though El Nino conditions existed in the tropical Pacific. So even that long-range forecasting “paradigm” breaks down.

Jeff Alberts
Reply to  Joel O'Bryan
November 1, 2019 4:36 pm

To say that El Nino/La Nina produce specific weather patterns in specific areas is largely false. They can give all kinds of different weather.

Lorne Newell
October 31, 2019 7:08 pm

I am really perplexed why this goes on and on. Seldom and mostly never are the predictions rights but it gets swallowed without challenge retractions never make the news. The Brasil fires are a prime example. Common sense tells that it the early eco-terrorist statements were suspect and not logical and graphs were readily available to refute those claims but it just kept rolling along.

Samuel C Cogar
Reply to  Lorne Newell
November 1, 2019 8:10 am
October 31, 2019 7:17 pm

The author wrote that the weather models are not very accurate! That’s a first and is to be commended but to say accurate out to 8 – 10 days is total bullshit. Admission of only two days out with 50% accuracy would have made a winning/truthful reading.

Nevertheless, it is better than anything I have read for quite some time on weather related models. Politicians, weather forecasters, and so-called “climate scientists” seem to be the only ‘species’ that get a free ride with less than a coin flip of being correct.

John F. Hultquist
October 31, 2019 7:37 pm

The New England Weather Stick does not work well when placement is in the lee of a mountain range; central Washington State being an example.
comment image

A friend in Western Pennsylvania — up slope winds — finds hers quite accurate.

~ ~ ~ ~ ~
National Weather Service forecasts are for large areas. Just because there is a 60% chance of rain in the forecast does not mean much at a specific place. Reminds me of the song line “it’s 5 o’clock somewhere.”

Jeff Alberts
Reply to  John F. Hultquist
November 1, 2019 4:44 pm

“National Weather Service forecasts are for large areas. Just because there is a 60% chance of rain in the forecast does not mean much at a specific place. Reminds me of the song line “it’s 5 o’clock somewhere.””

So we’re down to large-area vague forecasts. I don’t see much use there.

October 31, 2019 7:38 pm

1. The ‘official’ prognosticators can’t even get tomorrow correct – BoM in Australia is often 3°C wrong in their guess for the next day even as late as 10 PM. Today I woke to a ‘possible thunderstorm’ that wasn’t even on the map last night.

2. Long range weather forecasters actaully do exist and are quite accurate – they just aren’t paid for by the public purse. Inigo Jones, Farmers’ Almanac and others have a long history of getting long range pretty well nailed across decades.

John Robertson
October 31, 2019 7:43 pm

“Extended Forecasts are Not Reliable
Can you rely on such predictions? Are they really worth paying attention to?”
Geez Charles I figure the extended forecast is damn near always reliably wrong.
Just as the predictions of Doom from CAGW have all been consistently wrong.
There is some kind of consistency and reliability here.
Of course the weather channel day 3 is always promising better weather than ever occurs.

Clyde Spencer
October 31, 2019 7:53 pm

“So why is our skill improving rapidly for the shorter periods, but not the longer ones?”

Well, we have geosynchronous weather satellites viewing the clouds and measuring temperatures, and Doppler radar tracking precipitation and winds is ubiquitous in the US. Neither were available when I was young. And, we keep making technological improvements in those two technologies. Extrapolation on fronts isn’t too theoretically challenging for 2 or 3 days out.

The money being wasted on climatology would be better spent on improving the theory of meteorology forecasts.

Alan Webb
October 31, 2019 8:02 pm

In 2017, I planned a trip to Missouri for the Great American Eclipse. The first long range forecast for eclipse day was: cloudy, 60% chance of rain. We went anyway, the weather was 99% perfect.

October 31, 2019 8:43 pm

So the experts can’t tell me what temp and other conditions are going to be in 15 days in my immediate location, but the experts can tell me what the climate (which is essentially temps and other conditions) are going to be WORLDWIDE in 50 years. I have some bridges I could sell you.

October 31, 2019 8:54 pm

” … we have gained a great deal of skill at the shorter time ranges, particularly for days 3-8.”

I beg to differ, our BoM here in Australia struggles within the forecast period of 24 hours ahead.

October 31, 2019 8:55 pm

In all fairness to weather forecasters, some conditions add great complexities to their attempt to forecast.

I live north of Atlanta. Our weather genetally comes from the northwest during winter (southwest in summer). But there is a problem forecasting winters. The Appalachian mountian range is just north of us, angling from the southwest to the northwest. Air coming from the northwest must flow over the mountains to reach us. Some cold fronts manage to do this; some don’t. The cold air wants to hug the base of the mountain, and a sufficient volumn of air must pile up at the base, for it to get over the mountains. They clearly have a problem with their ability to predict if a cold front is going to reach Atlanta, and if so, just how cold the coldest air getting over the mountains will be.

This is the situation as I write this. Last week, tonight’s low temperature was forecast to be 38 degrees F. This morning, they were saying 32. Right now (close to midnight), it’s suppose to drop to 29.

Forecasting for the short-term is difficult; for the long-term, impossible. I don’t see that changing much in the future.

Jeff Alberts
Reply to  jtom
November 1, 2019 4:46 pm

Those darn mountains keep moving around, screwing up the forecasts.

October 31, 2019 9:07 pm

Mods, why are all of my posts disappearing down the worm-hole ?

Jeff Alberts
Reply to  Streetcred
November 1, 2019 4:46 pm

Worms need to eat too.

Patrick MJD
October 31, 2019 9:35 pm

Models are not reliable for extended forecasts? Ya think!

This is the whole problem with weather and climate “forecasting” it’s all BS. I see comments that in many threads about weather and climate that weather/climate models are just in need of more computing power to improve resolution and thus improve forecast reliability. Which, of course, is totally bogus. I just do not see how computer models that have so limited variable inputs can in anyway predict extended “weather” patterns. In my experience most “forecasts” have be wrong, 48% of the time.

Clyde Spencer
Reply to  Patrick MJD
November 1, 2019 12:17 pm

Patrick MJD
One has to be careful about what is called “wrong.” There are false positives and false negatives. It is my impression that, with respect to precipitation, false positives — that is, forecast precipitation that doesn’t materialize — are common, whereas surprise precipitation (false negative) is rare. So, for some areas, such as coastal California with a Mediterranean Climate (two seasons) with broad cloud cover in the rainy season, false positive are probably more rare than in the Appalachians.

Gerald Browning
October 31, 2019 9:36 pm

The weather models go off the rails in 1-2 days without new infusions of observational data every 6-12 hours.
See Sylvie Gravel’s manuscript (search google scholar or see Climate Audit) on the explosive growth of mathematical relative l_2 errors at each level for the Canadian weather model compared to radiosondes over the US. Skill scores are misleading unless one knows the magnitude of the deviations at a given level. Relative errors provide percentage errors so are easily understoo.


Michael S. Kelly LS, BSA Ret.
October 31, 2019 9:48 pm

We live in northern Virginia, not far from Washington DC. This area is apparently on the interface of two major weather cells. That interface can change location to the north or south very rapidly, and in an unpredictable manner. Eight to ten day forecasts for this region are surprisingly good in one sense, and very poor in another; the weather that they forecast will pass through in pretty much the way the weathermen say, but not exactly where they say it will. Storms are the most noticeable phenomena, and predictions of timing and amount of precipitation are generally good. It’s just that they don’t happen along the expected path, but a little north or south of it.

Weather forecasting is an art, one informed by science, but one ultimately based on judgement and experience. Meteorologists have been getting better at understanding the sources of uncertainty, and either try to mitigate them, or caveat their forecasts appropriately. But it is still an art.

November 1, 2019 12:09 am

I discussed this with two meteorologists from TWC back in 2002. Basically the computer “model” software that’s been used has NEVER been reliable and they have had to do stage (18 to 30 hour segments) with resets of input data between. This is why the predictions past 24 hours are almost always garbage.

It would literally be 190°F in Pittsburgh in 2 days if you let the software run because it was worse than garbage.

Jacques Lemiere
November 1, 2019 12:36 am

well even for short forecasts…what is the actual uncertainty?
short forecasts are useful..because they have been proven useful essentially empirically..

you have to make assumptions..such as the ensemble of models runs contains reality..
that s not even sure, certainly not proven.

Jeff Alberts
Reply to  john
November 1, 2019 4:50 pm

The result, off-topic.

November 1, 2019 2:15 am

Here in the Netherlands the forecasts are very detailed, suggesting high accuracy. But often the sequential forecasts for a particular day are as variable as the weather itself.

November 1, 2019 2:22 am

I’m curious as to whether the errors are randomly distributed around the actual value or have a bias?

I tracked the forecast for London from the BBC for a while, and there was a significant warm bias to the errors. Indeed, the longer range forecast tended to become cooler the close in they got.

November 1, 2019 2:30 am

In my opinion, the NWS uses the wrong methodology so they get erroneous long-term forecasts. My friend Joe D’Aleo and his colleagues at WeatherBell use a different methodology, and in my experience they get much more reliable long term forecasts. Joe’s long-term Winter forecast will appear in November. I believe I understand their general methodology, but it’s not up to me to give away their secrets.

Regards, Allan

This is the second paper I’ve written with veteran meteorologist Joseph D’Aleo:
By Allan MacRae and Joseph D’Aleo, October 26, 2019

Our first paper was published in 2015 on Excess Winter Mortality:
By Joseph D’Aleo and Allan MacRae, September 4, 2015

Joe is one of the best meteorologists on the planet – this story illustrates how very competent he and the team at Weatherbell are, based on their strong predictive track record.

The U.S. National Weather Service (NWS) forecast a warm winter for 2014-15, and Joe called me in October 2014 to say he was concerned that the NWS forecast was seriously incorrect, and that the next winter would be particularly cold and snowy, especially in the populous Northeast. This was the second consecutive year that the NWS has made a very poor (excessively warm) Winter forecast.

Joe and I had been working together on a paper on Excess Winter Mortality, and we agreed that this incorrect “warm winter” NWS forecast was dangerous, especially if the country and its people were unprepared.

I proposed an approach, and we sent a presentation for my friend at the US Energy Information Administration (EIA). At the EIA’s request, Joe prepared his own monthly Winter Forecast by region for the EIA, who re-ran their winter energy demand calculations. Using Joe’s forecast, the EIA projected 11% more winter energy required for the USA than the “warm” NWS forecast had projected.

After that brutally cold and snowy winter, the actual energy used was 10% more than the EIA had projected using the warm NWS forecast, and just 1% less than Joe’s forecast projection. That is a huge amount of energy for the entire USA. I’m not sure if we saved any lives, but we definitely did a good deed.

Regards, Allan MacRae

November 1, 2019 3:08 am

The ability to predict is probably the best objective measure of scientific and technical competence. Note that every scary global warming prediction made by the climate alarmists has failed to materialize. Nobody should believe them.

To heck with 10-day forecasts or even seasonal forecasts – here is a successful 17-YEAR forecast.

The last of my three climate-and-energy predictions made in 2002 has now come true. There it is – the perfect Trifecta – my work here is done.

Best regards, Allan MacRae

In 2002 co-authors Dr Sallie Baliunas, Astrophysicist, Harvard-Smithsonian, Dr Tim Patterson, Paleoclimatologist, Carleton, Ottawa and Allan MacRae wrote:

1. “Climate science does not support the theory of catastrophic human-made global warming – the alleged warming crisis does not exist.”

2. “The ultimate agenda of pro-Kyoto advocates is to eliminate fossil fuels, but this would result in a catastrophic shortfall in global energy supply – the wasteful, inefficient energy solutions proposed by Kyoto advocates simply cannot replace fossil fuels.”

Allan MacRae published on September 1, 2002, based on a conversation with Dr. Tim Patterson:

3. “If [as we believe] solar activity is the main driver of surface temperature rather than CO2, we should begin the next cooling period by 2020 to 2030.”

Allan MacRae modified his global cooling prediction in 2013:

3a. “I suggest global cooling starts by 2020 or sooner. Bundle up.”

By Allan M.R. MacRae and Joseph D’Aleo, October 26, 2019

October 31, 2019 by Michael Snyder


November 1, 2019 4:06 am

Forecasts, shmorecasts: I’m more concerned about how much rain (or snow) we’re going to get, because the local watershed is loaded nearly to the. 35 miles north of Chicago, Lake Michigamu is pounding the lake shores good and hard, and the rivers are full to the brim from rains to the north of me back in August and September.

The rivers, creeks, flood catchment zones – all of it – are full to the brim and there is little to no room for any more. Where there was flooding on the Chicago River’s tributaries last summer and fish were swimming in the streets, that hasn’t gone down yet.

I’ve asked this before and not gotten an answer: why is no one looking at the humidity levels in the atmosphere? That is as important as temperature? Humid summer: nothing unusual. But a humid winter? The snow that fell yesterday was large, wet flakes, sometimes in clumps. Snap out of it, people. Go look at the snow when it falls. Large clumpy snowflakes mean more moisture in the air. (Fewer upper respiratory issues, too.)

More moisture in the air more precipitation. Temperatures only determine what form it takes when it falls out of the clouds.

Reply to  Sara
November 1, 2019 8:22 am

Sara – I saw your previous question but I have not studied this issue, so made no comment.

Reply to  Sara
November 1, 2019 9:57 am

Thanks, Alan. I think it’s a valid thing to study. It does have a direct effect on the weather.

Reply to  Sara
November 1, 2019 12:20 pm

Correction for Sara:

I did study humidity here, in Section 6 of this paper.

by Allan M.R. MacRae, B.A.Sc., M.Eng., June 15, 2019
Excel: https://wattsupwiththat.com/wp-content/uploads/2019/07/Rev_CO2-Global-Warming-Climate-and-Energy-June2019-FINAL.xlsx

6. The sequence is Nino34 Area SST warms, seawater evaporates, Tropical atmospheric humidity increases, Tropical atmospheric temperature warms, Global atmospheric temperature warms, atmospheric CO2 increases (Figs.6a and 6b).

Other factors such as fossil fuel combustion, deforestation, etc. may also cause significant increases in atmospheric CO2. However, global temperature drives CO2 much more than CO2 drives temperature.

Tim Gorman
November 1, 2019 5:30 am

Think about it. The wx models go screwy after a few days. Hurricane predictions have *wide* path uncertainties and landfall is unpredictable until landfall is actually happens. Both of these are based on predictions from “initial conditions” that are measured quite precisely. None of these models can predict weather a year into the future.

Yet the climate models claim to be able to do so. The prediction for the end of Year0, based on initial conditions at the start of Year0, becomes the input for the start of Year1, etc, etc, etc.

We continually hear the excuse from the climate alarmists – “weather is not climate and climate is not weather”. And yet there is a *direct* relationship between the two. When it is wet it is cooler, when it is dry it is hotter. This is all based on things like albedo, evapotranspiration, humidity, etc. If the climate models can’t get all of this right then no amount of parameterization and fudge factors can fix them. And as Pat Frank has shown, the models are all nothing more than a complex way of representing a linear equation, y=mx+b. And yet, as Richard Courtney demonstrated so well, the Earth’s climate has long term cycles associated with it – none of which are adequately represented in the linear equation outputs of the models.

If you can’t trust the weather models past about 10 days then there is no reason to trust today’s climate models all. The physics are just too complicated to reliably model using our present knowledge level.

Jeff Alberts
Reply to  Tim Gorman
November 1, 2019 4:53 pm

“The wx models”

Why is weather abbreviated as “wx”? I don’t get it.

Tim Gorman
Reply to  Jeff Alberts
November 1, 2019 5:22 pm

When I was doing high-speed morse code on the amateur radio bands 50 years ago, wx was the abbreviation used for “weather”. I suspect it came from usage on the old landline telegraph systems 150 years ago. It’s the same kind of abbreviation as TX for transmitter and RX for receiver.

Clyde Spencer
Reply to  Tim Gorman
November 1, 2019 8:50 pm

And “DX” for long Distance.

November 1, 2019 7:21 am

Joe Bastardi points this out all the time. EVERY long-term forecast is mostly above avg. Only until the time comes very close (couple weeks away) does it change to a more reasonable forecast.

Rhetorical questions:

What does this say about trying to forecast even beyond a month or two (like decades into the future)?
Why are forecasts beyond a couple weeks ALWAYS too warm?
How can the model-sychophants not acknowledge these severe/obvious model-issues?

November 1, 2019 8:34 am

So the world may not end in 12, 100, 5000 or more years. 12 years was a weather forecast or was it a wish?
I still rely on the forecast even if it is not always right at my location.

Johne Morton
November 1, 2019 8:46 am

I’ve been noticing this for years. Notice how the longer range forecasts rarely ever show large swaths of the country as predicted to have below or much below average temperatures. The forecasts are almost always for above average temperatures. This despite the fact that significant cold events still occur on a regular basis (usually explained by a “polar vortex” due to climate change…).

November 1, 2019 9:36 am

This is called the perfect positive feedback!

Rick Scheck
Reply to  JaKo
November 1, 2019 5:12 pm

Precisely the factor at play both in the CO2 “tipping” point trope as well as in the herd mind of its adherents.
Outside of that, positive feedback is rare in natural processes and a trap for buying into the CAGW mania.

November 1, 2019 11:37 am

Environment Canada provides the forecasts I usually depend on. Current Conditions are usually pretty close but not perfect as I live 25 miles from either local weather stations.
Summer thunderstorms can develop within just a few miles in this area so are impossible to predict accurately. They can only state possibilities.
Forecasts of highs and lows are usually only somewhat accurate for the current day and the next.
We are on the prairies in the lee of the mountains so the difficulties of accurate predictions are immense.
That does not mean they do not have value as very large weather systems can be fairly accurately tracked and future movements predicted. The timing is often considerably off, however.
They provide real time satellite and radar imagery and with a little practice we can use them plus a knowledge of local conditions to be reasonably accurate in predicting conditions in our own locality for a few hours. Usually that is all you really need to be prepared for what the weather brings.
As for long term climate models, I cannot see how there is any possibility of them being accurate. I think it is going to get colder because white men are building warmer houses.
I did not install my window AC this year because I predicted a cool summer. Was I ever right. I think the same trend will continue and we will have a cold winter. I put my winter tires on a month earlier than usual and was I ever right again. Three snowstorms before Halloween. It would have been nice to have been wrong.

B d Clark
November 1, 2019 1:00 pm

My prediction for tonight,(after having pulled two teeth today) tonight is going to be a long one possibility of a anomolus high temperature certainly uncomfortable, the next few days will be sore with periods of relief from a mixture of fluids mixed with Panadol,with experience the forecast for the next few days is pointless with the ever threat of a high pressure knock to the side of my face resulting in a chaotic unpredictable few days.

You’ll excuse me if I dont care about the weather for one night at least.

Jeff Alberts
Reply to  B d Clark
November 1, 2019 4:55 pm

50% chance of precipitation means that if 100 things fall out of the sky, 50 of them will be rain. 🙂

Ulric Lyons
November 1, 2019 6:09 pm

My long range solar based prediction for the Arctic Oscillation, was AO turning positive from the 2nd October, turning negative from the 16th October, and turning positive again from the 27th October. November is negative from the 5th, turning positive from the 15th. December strongly negative from the 12th, turning positive from the 22nd. And watch out for the very cold February, especially the first half.


Joe Armstrong
November 2, 2019 10:46 am

In business, we have known about the forecast trumpet, sometimes called the “trumpet of doom” for some time.

Bottom line. The further out the forecast, the more it is unreliable.


Mike Maguire
November 2, 2019 2:36 pm

Nice article by Cliff to clarify something many folks don’t understand.

As an operational meteorologist for 37 years, I’ve made over 10,000 weather forecasts. The first of many lessons learned was to not get married to your forecast or the model output it’s based on. On tv the first 11 years, that meant not being overly confident in many situations that you were fairly confident about but could see the outside chance of being wrong with.
When/if you are right 9 times out of 10 people will remember the one time that you were wrong.
Fresh out of college and feeling over confident in models and my ability to interpret them……and the human weakness of having cognitive bias, i hung my hat on a few forecasts that in later years would have been revised much quicker.
After experiencing the real world, the objective is NOT to be right. The objective is to recognize when you are wrong ASAP or even might be wrong…..then adjust the previous forecast to dial in the changes.
Be very humble. When you are wrong, which happens a lot, you have to be careful about explaining why. The real reason is almost always because you believed the weather models. If your explanation seems to blame something other than yourself, it can come off the wrong way but do try to explain it vs pretending it didn’t happen or acting like you were right if partly wrong.
The best meteorologists are experts at paternities recognition. I note in today’s world with models much improved that almost all local NWS forecasts are just regurgitating hourly numerical weather output for that spot…….even going out days in advance.
Something like “rain likely between 4-7am, then chance of rain between 7-10am, followed by a chance of showers and a possible thundershower.
I understand that this gives some value to people who want to know exact times if they have an outdoor event but often, it suggests our ability to time weather with much mote precision than possible.
A forecast like that, which is common, tells me the forecaster is only passing on the model data and may not be actually looking at the pattern and recognizing some things that can assist him or her in beating the models.
Different models have different bias and most models will vary from the other ones, especially in the week 2 period.
Giving the numerical output from just the US model in a forecast 7 days from now is a recipe for a lot of busted forecasts.
Looking at the overall pattern, spacing between large scale features, the value of indices of things like the NAO or AO, consistency of solutions and between models are all considerations.
Despite the difficulty of getting it right after 1 week, there are plenty of fairly high confidence week2 forecasts. Not with exact timing of a storm on day 10 for instance….with rain but like what cliff stated…..the average and very likely chance for it to be wet or very warm during that period. It may rain on days 8-9-11 and temperatures 10 degrees above average but your daily forecast for rain on day 10 will be wrong.
If day 10 is a Saturday and somebody has a huge event planned outside, that may be the only day they care about.
You could come in the next day and tell them that it will rain that day and not the next.

Mike Maguire
November 2, 2019 5:01 pm

Despite the implied weather model weaknesses, weather models are the main reason that meteorologists can get most of the weather right for the first week display enough skill to be useful out to 2 weeks. In some cases, even beyond that.
I have enjoyed every hour of every day analyzing developing weather patterns since 1982….all thanks to weather models.

It’s like having a magic crystal ball that allows us to peer into the future and see weather patterns, features and the resulting consequences that will happen in form of the wind, snow, temperature or other things affected which we will experience.

And every new day results in a fresher sampling of initial conditions and an opportunity to fine tune yesterday’s forecast. The more extreme the weather pattern, the bigger the adrenaline rush in appreciating the enormity of the physical laws and powerful forces at play.
Despite loving the most extreme weather patterns the most, our job is to do the best possible in alerting people to the risk of high end, life threatening events……which sometimes can be seen in a week 2 forecast period with a high risk outlook.

Heat waves and cold outbreak risks can be seen with high risk and decent confidence for a large area in week 2. They are huge air masses that may be over 1,000 miles wide. They can change a bit but the forecast often is still good.
Excessive rain or severe weather events are tough to pinpoint at that time frame because they may be targeting a more limited geographic area…..with small changes having big impacts.

Hurricane forecasting skill has improved a great deal but obviously the skill drops off fast after the first few days.

Mike Maguire
November 2, 2019 5:23 pm

Speaking of extreme weather. I have not observed an increase in most of it the last 4 decades. In fact, warming the highest latitudes the most and decreasing the meridianal temp gradient has decreased some extreme weather as in violent tornadoes.

However, the atmosphere holding more water vapor has increased high end rain events and amounts. Heat waves in some places are slightly worse too….dough. If the planet is warmer this has to be true.

Regardless as somebody that estimates crop production/yields and energy use for heating and cooling for a living, the benefits from the modest warming and especially the massively beneficial increase in CO2 and in other areas outweighs the negatives for most of life on this greening planet during the current climate optimum…..by a wide margin.

I have spent the last 37 years observing it.

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