'Pineapple Express' pattern for drought stricken California is shaping up – how long will it last?

From NASA JPL, video animation follows.

pineapple_express

Wet weather is again hitting drought-stricken California as the second and larger of two back-to-back storms makes its way ashore. The storms are part of an atmospheric river, a narrow channel of concentrated moisture in the atmosphere connecting tropical air with colder, drier regions around Earth’s middle latitudes.

The storm that arrived on Feb. 26, 2014, and the one about to hit, are contained within the “Pineapple Express,” an atmospheric river that extends from the Pacific Ocean near Hawaii to the Pacific coast of North America, where it often brings heavy precipitation. This next storm is expect to be the largest rain producer in Southern California in three years.

This animation, created with data acquired by the Atmospheric Infrared Sounder (AIRS) instrument on NASA’s Aqua satellite, shows the total amount of water vapor contained in the atmosphere for most of the month of February if it were all to fall as rain. Typically, the atmosphere over Southern California and most of the continental U.S. in winter holds only about 0.4 inch (10 millimeters) or less of water vapor. However, much wetter air lies tantalizingly close in regions to the south and west. The largest amounts of atmospheric moisture, up to 2.4 inches (60 millimeters), are associated with a persistent band of thunderstorms circling the tropics. These thunderstorms are the source of several atmospheric rivers apparent in this animation. One atmospheric river arises near Hawaii around Feb. 10 and comes ashore in Central California a few days later, bringing the largest Sierra Nevada snowfall of the season to date. Other atmospheric rivers can be see originating in the Gulf of Mexico and extending into the Atlantic on the right side of the movie; the northward movement of tropical water vapor is important in winter storms in the eastern U.S. and Europe. The animation concludes with the current Pineapple Express. Moisture from around Hawaii has surged northeast, and the persistent, dry air immediately west of Baja California has been replace by air with up to 1.6 inches (40 millimeters) of water vapor. The next storm will bring that moisture ashore, where it will be forced upward by coastal mountains to fall as heavy rain. Up to 8 inches (20.3 centimeters) of rain is predicted in some parts of the Los Angeles area by March 2, bringing possible flooding and landslides to recent wildfire burn areas.

The recent cold conditions in the eastern U.S. are also apparent in this movie as very dry regions. Because cold air can hold relatively little water (less than 0.4 inch or 10 millimeters), cold region are always dry. So, the eastern U.S. has some of the driest air in this animation. However, high pressure systems also dry the atmosphere by forcing down air from above.

That descending air expands and warms, but retains the low moisture amounts it had when it was higher and cold. So, cold Minnesota and warm Mexico have similar water vapor amounts in this movie.

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Larry Hamlin

Obviously Obama’s visit to California where falsely claimed that our states drought was caused by man made climate change has taken on the “Gore effect” outcome. Perhaps Obama should make more visits to naturally occurring drought areas and make similar flawed claims as in California so these areas could receive help from Mother Nature.

Looking at the GOES water vapor loop from NOAA, you will see almost an eye-like structure in the storm currently headed to shore.
http://www.ssd.noaa.gov/goes/west/nepac/flash-wv.html

It does a good job of showing how California gets its reputation. But I guess due to the short duration, it does not show how the NW is just the opposite.

That’s Obama’s place in history then, The Man Who Made It Rain In California.

Latitude

bets on whether they miss-manage this water too….

Lots of moisture in the Gulf of Mexico poised to come north as this storm rolls across the USA. Rain to the south, but where it collides with cold air to the north there will be little talk of spring, and much muttering as people shovel themselves out.. In its wake the storm may well drag down cold air that will set records.

Bob Koss

Journalists are feverishly reviewing their articles from past years so they’ll be ready to write more woeful articles about the devastating mudslides which will be caused by the rains they were recently complaining hadn’t come.

hunter

Well, the President did promise to improve the weather…………

Tim Clark

Caleb says:
February 28, 2014 at 12:20 pm
Wichita, KS
Sunday, 3/2
11 | -1 °F
Ice Pellets
Within 1 degree of the all-time, never in recorded history record.

Tim Clark

Bit of wind chill on tthe side.
19 mph NNE

timetochooseagain

There is a weak association between El Nino and slightly wetter than average conditions in Coastal and Northern California. Maybe if the predictions of an El Nino are correct, the drought plagued state will get some much needed relief. This could be a sign of that.
On the other hand, there is no guarantee it will work out that way.

Curt

As the old joke goes, there are four seasons in California: earthquake, fire, drought and flood.
I got 3 inches of rain overnight in the LA hills. It looks like a lot more to come.

Sun Spot

The “Dirty Thirties” encompassed a decade of drought. There was never a reason to think it wouldn’t happen again.

Robert Wykoff

So since the drought is caused by global warming, will the mudslides also be caused by global warming?

brians356

In 2010 / 2011 there were unbelievably wet months of March, April, and May in the Sierra Nevada, now called “The March Miracle” by Tahoe are ski resorts. At the 8000 ft elevation, Squaw Valley USA had a total of 454 inches of cumulative snowfall for the season entering March, and by the end of March it was up to 691″, and by 6 June it was 810″, a new all-time record for Squaw.
I hope we are looking at another March Miracle, as currently Squaw’s seasonal snowfall total stands at only 168 inches, less than 1/4 of what they had received on this date three years ago.

“That descending air expands and warms”
I’m sorry to have to ask what may be a rather basic question, but by why mechanism does the descending air expand? I had always been under the impression that the atmosphere was arranged with the denser air closer to the earth’s surface.
Also, it would seem to me that expanding air would cool, wouldn’t it?
Please would some kind soul help me understand?
Thank you.

brians356

Oops, “less than 1/2 what they had … “

Michael D

Cool animation. The atmospheric river looks like a loose firehose flapping up and down the West Coast. You’ll note that it was pointed at Vancouver/Seattle a few days ago, and yes we got wet.
After such a long dry spell, the dangers of flash flooding in California is a concern. Hopefully the small rains they had a few days ago will have opened up the soil a bit.

Joseph Bastardi

There is no connection to Hawaii moisture, their precipitable waters are well BELOW NORMAL and a look at the evolution reveals this is coming out of the northern branch, from the west northwest . What are we growing pineapples south of Alaska now.
Its nonsense. SST are very warm in North Pacific and helping, I am posting on weatherbell.com now to show what nonsense this is as a look at past 48 hours reveal this coming from the wnw with no connection to tropics, since precipitable water is BELOW NORMAL
Typical lump something together under a convenient idea. Weather much more complex than that

Michael D

Kate, I think you’re right. Maybe the writer meant “as time goes by, the dry region expands…”

Michael D says:
February 28, 2014 at 1:13 pm
Oh, I see. That’s a plausible explanation.
Thank you!

redc1c4

we got about 2 1/2′ overnight here in my part of The Valley…
we’ll have to wait & see what the rest of “Rain-pocalypse 2014” brings us.

eyesonu

This may be extremely interesting from my point of view. I need to digest it when I get time. Reminds me of a question I had when the hurricane/TD (Debbie maybe) parked itself off the west coast of Florida at the time of the Republican Convention in 2012. That atmospheric river was clearly visible for quite a while flowing north along the eastern US coast.
I’m going to need to put off some pressing issues while I take this opportunity to add to my vast wealth of economically (my point of view) useless knowledge.
Some things are priceless.

crosspatch says:
February 28, 2014 at 11:57 am

Looking at the GOES water vapor loop from NOAA, you will see almost an eye-like structure in the storm currently headed to shore.
http://www.ssd.noaa.gov/goes/west/nepac/flash-wv.html

I think that loop does a good job showing what Joe Bastardi means with:

SST are very warm in North Pacific and helping, I am posting on weatherbell.com now to show what nonsense this is as a look at past 48 hours reveal this coming from the wnw with no connection to tropics, since precipitable water is BELOW NORMAL

The water vapor loop shows a large area of dry air all around Hawaii and over to a couple lonely Tstrms below Baja California.

Box of Rocks

Kenny T is that your missing heat by chance???????

BTW, “eye-like structures” (I think that’s the semi-official term) sometimes show up on extremely strong east coast nor’easters. One of the best for its time was from the Blizzard of ’78, see http://www.boston.com/news/weather/weather_wisdom/2014/02/the_meteorology_behind_the_bli.html
They tend to be rather short-lived structures, I suspect that they arise much like a hurricane eye but don’t have the support to maintain them for very long. I’d love to see a hurricane hunter plane investigate one, though it would be tough to time and the icing might be horrendous.

eyesonu

Ric Werme says:
February 28, 2014 at 1:36 pm
crosspatch says:
February 28, 2014 at 11:57 am
==================
Are the two graphics showing the same thing or related? Would the low pressure be pulling an atmospheric river in from the southern boundary as shown in the lead post? Are both correct? I’m all eyes and ears.
This is interesting.

@ Kate Forney,
This link explains how descending air warms.
http://meteora.ucsd.edu/cap/santa_ana.html

@Roger Sowell
Thank you, Roger. I had expected that descending air would warm — I have a vague understanding of adiabatic heating. The article says “descending air expands”, which is what I did not expect, and does not seem to be consistent with my meager grasp of thermodynamics.
@Gary
Thanks, Gary. I read a little on Hadley cells, but I couldn’t discern how those might explain how descending air could expand. Such an event would seem to imply, at least to my simple mind, that the pressure was lower below than it was above. Were such a situation to occur, would it not be resolved very quickly by air rushing into the hole from all sides?

Gary

Kate, look up Hadley cells – may be the answer. (only explanation I have found)

eyesonu

Look at the wind map. http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-138.84,33.47,455
What’s current today started a couple of days ago with regards to atmospheric moisture and it’s transport.

Peter Miller

But what does the Distinguished Professor of Meteorology have to say about the current Californian weather/climate?
That will be an opinion which can be relied upon.
Yeah right.

Royaul43

Joseph Bastardi says:
February 28, 2014 at 1:11 pm
There is no connection to Hawaii moisture, their precipitable waters are well BELOW NORMAL and a look at the evolution reveals this is coming out of the northern branch, from the west northwest . What are we growing pineapples south of Alaska now.
Its nonsense. SST are very warm in North Pacific and helping, I am posting on weatherbell.com now to show what nonsense this is as a look at past 48 hours reveal this coming from the wnw with no connection to tropics, since precipitable water is BELOW NORMAL
Typical lump something together under a convenient idea. Weather much more complex than that
Joe-
I showed my 9th grade Earth Science students the satellite pics 3 and 2 days ago, pointing out the moisture trail from Hawaii up into the storm. Then I explained to them about the Pineapple Express, and what happened in CA in 1969. I then told them that it looked like this moisture would get sucked in and rotate around and nail us Fri. We just got .25 inches last night, and another .28 inches in 40 minutes right after lunch today. Watched it come in on the satellite view the whole time Since Wed.
In 1969 a large part of the Central Valley flooded when repeated Pineapple Express storms throughout the month of April washed near record snows down from the Sierras.
Hopefully we’ll get something like that pattern again this year.

As I understand it, when California does not get enough water then that is Climate; and if it does get a bunch of rain or snow then that is weather. Do I have my definitions right?

Dan in California

From the article: “The recent cold conditions in the eastern U.S. are also apparent in this movie as very dry regions. Because cold air can hold relatively little water (less than 0.4 inch or 10 millimeters), cold region are always dry.”
—————————————————–
This is sloppy thinking or sloppy writing. Air doesn’t “hold” the water, any more than the nitrogen “holds” the oxygen or CO2. It’s the volume and temperature that “hold” the water.

InMAGICn

Markstoval
You are correct. Unless you’re in Britain where flooding rains are climate but massive Scottish snow is weather.
Or something…

eyesonu

Did this thread hit a pause? Let’s roll.

SineWave

Joe Bastardi – Your article showing “what nonsense this is” is paywalled at weatherbell.com. If you’re refuting something on a free website in a free public forum, don’t make us pay to see what you say. You might as well just keep your comments to yourself.

It is the wettest drought ever.

Robert Wykoff says:
February 28, 2014 at 12:53 pm
So since the drought is caused by global warming, will the mudslides also be caused by global warming?
——————————————-
Naturally!!!

charles nelson

The climate business seems to be full of poor analogies.
‘The Greenhouse Effect’ being the cardinal one for its power to mislead and confuse but I have to say ‘Atmospheric Rivers’ is right up there in the pantheon of $hit analogies…
a river by definition is a body of water that normally flows within boundaries. There are no fixed boundaries in the atmosphere. There a no ‘rivers’ in the atmosphere.
How can we educate people if we use language like this?

eyesonu says:
February 28, 2014 at 1:58 pm

Ric Werme says:
February 28, 2014 at 1:36 pm
crosspatch says:
February 28, 2014 at 11:57 am
==================
Are the two graphics showing the same thing or related? Would the low pressure be pulling an atmospheric river in from the southern boundary as shown in the lead post? Are both correct? I’m all eyes and ears.

Both low pressure systems are pulling in surrounding low level air and convection and structure aloft lifts the air in the center. There are major differences between tropical storms, driven mainly be vertical temperature differences and extratropical storms, driven by horizontal temperature differences and fronts extending from the low.
The current Pacific storm isn’t pulling in much moisture from the south. Instead, it’s getting moisture from the north and northwest (on the other side of that dry slot). Then it’s wrapping it around to the south and up into California.
You can see the anomalously warm water in the northern Pacific at http://www.ospo.noaa.gov/data/sst/anomaly/2014/anomnight.2.27.2014.gif
There are some impressive photos of tropical feeds into both Pacific and Atlantic storms, and they produce a lot of precip when their winds lift over hills or fronts.
http://www.theweatherprediction.com/weatherpapers/009/ may describe the Pineapple Express well and has a satellite photo showing a feed into Seattle.
http://addins.wrex.com/blogs/weather/2010/02/east-coast-blues shows a nor’easter and its cold front that I think is also feeding the storm from the tropics.

Here is a piece of a comment which I left 6 days ago at the Telegraph, a UK msm.
“I live in No California. Out here we sometimes have what is known as a Pineapple Express. That is where conditions set up where a string of storms head from Hawaii and into the state. This generates some of the biggest floods for the state. This almost seems to be your version of it. This could also mean that in the next year that California may get a strong series of storms coming through. I have noticed that historical records show a one year offset for weather events between your coast and ours. In the case of California and the current drought, then the rain will be welcome, unless of course it turns into an inundation of large proportions.”
I did notice an offset between Atlantic storms producing large events and Pacific storms producing large events, while observing historical data records. I should have made notes when the thought first came to mind. I am not sure about the one year aspect, completely. There is some level of an offset though.
In the current case, there is a lot of dry air showing below 40N in the Pacific. It doesn’t look like a huge event for the northern part of California. Although for the southlands it might be more productive. There has been only a smattering of rain in the Trinity Co area so far from any of these recent storms. My assumption is that next year could be wetter up here, if the Pacific follows the Atlantic as past records show. Overall, I expect the next large flood for No California and areas further north to hit in the winter of 2016/17.

Dan in California says:
February 28, 2014 at 3:05 pm

From the article: “The recent cold conditions in the eastern U.S. are also apparent in this movie as very dry regions. Because cold air can hold relatively little water (less than 0.4 inch or 10 millimeters), cold region are always dry.”
—————————————————–
This is sloppy thinking or sloppy writing. Air doesn’t “hold” the water, any more than the nitrogen “holds” the oxygen or CO2. It’s the volume and temperature that “hold” the water.

The pedant in me agrees with you, but for atmospheric phenomena, there’s always air, and that has a lot to do with the temperature, especially as water evaporates or condenses around clouds. Until someone comes up with a line that reads as well as “warm air can hold more water”, I’ll fall back on it. (“Warm air permits more water vapor to mix before condensation sets it” just doesn’t read well.)
Your “volume and temperature” is excessively vague and provides no guidance to people who don’t realize a vacuum doesn’t have a temperature. Also, while I wouldn’t say nitrogen holds oxygen and water vapor, I have no trouble saying air holds any or all of its components. Air contains (and holds) N2, O2, Ar, H2O, CO2, etc.

Brian… the original “Miracle March” was actually back in 1991, when we went into the month at about 19% of average snowpack. We finished the month up at about 70% of average for that time of year…. a huge boost at the time, especially as we were in the midst of a multi year drought at the time. They sort of stole the phrase in 2011… and although it was a good wet spring, the two Marches really didn’t compare.
And there are some similarities to the climactic patterns this year and that, although there’s really no way to tell if our new-found wetter pattern will last throughout the month.
And I think Joe Bastardi is right…at least technically. This latest storm over CA/NV right now isn’t an atmospheric river, although you can make a case that the PW wrapped up in the current closed low was initially fed by an AR. But the direct tap from the tropics has been cut off, and it shouldn’t be described as an AR at this time.

charles nelson says:
February 28, 2014 at 4:27 pm
a river by definition is a body of water that normally flows within boundaries. There are no fixed boundaries in the atmosphere. There a no ‘rivers’ in the atmosphere.
——————————————————————————————-
Yet, NOAA points out that these ‘skyrivers’ can hold water equal to 30 times the flow of the Mississippi River. That is a large volume of water. I like the term ‘skyrivers’. Yes, these flows can meander and shift as they travel.

Here’s another good post (if you ignore the Nemo graphic) of the 2013 blizzard. There are photos showing the connection down to Bermuda and also the eye-like structure that sure looks like an eye.
http://www.washingtonpost.com/blogs/capital-weather-gang/post/incredible-imagery-from-the-february-8-9-2013-new-england-blizzard/2013/02/11/b51df444-73f1-11e2-aa12-e6cf1d31106b_blog.html

Mario Lento

Kate Forney says:
February 28, 2014 at 1:04 pm
“That descending air expands and warms”
I’m sorry to have to ask what may be a rather basic question, but by why mechanism does the descending air expand? I had always been under the impression that the atmosphere was arranged with the denser air closer to the earth’s surface.
Also, it would seem to me that expanding air would cool, wouldn’t it?
Please would some kind soul help me understand?
+++++++++++
Gravity is what causes the pressure to be higher near the surface. The column of air from the ground to the troposphere has weight to it and it causes pressure.
Air is colder up high away from the relatively warm surface of the earth. So a high pressure system will push that colder air downward. When it falls downward is does get denser – but it also expands because it warms. Air which contains “x” amount of water at some given temperature, will be drier at a higher temperature because warmer air can hold more water. That makes it harder to precipitate.
You might notice in CA, when it cold outside, we could have 60 or 70% humidity at 30 degrees F. When you warm that air in your home, it’s very dry – nose bleed dry at 70 degrees F.

Mario Lento

Sorry – Kate: I made a mistake when I wrote 30 degrees below:
You might notice in CA, when it cold outside, we could have 60 or 70% humidity at 30 degrees F. When you warm that air in your home, it’s very dry – nose bleed dry at 70 degrees F.
I should have written 33 degrees since 30 degree air would be dry at sea level atmospheric pressure. But the point still holds 🙂