From Judith Curry’s Climate Etc.
Posted on June 4, 2019 by curryja
by Judith Curry and Jim Johnstone
CFAN predicts an active North Atlantic hurricane season season.
The Atlantic hurricane has begun. We are off to an early start with one wimpy subtropical storm that lasted less than a day, and a small system that is trying to spin up in the Bay of Campeche.
Other forecast providers have begun issuing forecasts:
- NOAA predicts a near normal season with 4-8 hurricanes.
- Tropical Storm Risk predicts slightly below normal activity, with 6 hurricanes and ACE of 88.
- Colorado State University predicts near normal season: 6 hurricanes and ACE of 100
Climate Forecast Applications Network (CFAN) is going bold, see below. [link] to forecast report.
CFAN’s seasonal forecast
Table 1. Current (May) 2019 hurricane forecasts of North Atlantic ACE, North Atlantic total hurricanes, U.S. landfalling hurricanes. 
Introduction
Indices of North Atlantic hurricane activity display substantial interannual variations (Fig. 1), in addition to prominent multidecadal changes that are positively associated with basin-scale sea surface temperature (SST) changes known as the Atlantic Multidecadal Oscillation (AMO). North Atlantic Accumulated Cyclone Energy (ACE), an integrative metric based on tropical cyclone wind speeds, approximately doubled with an abrupt 1995 shift toward warmer North Atlantic surface conditions.
Figure 1. North Atlantic hurricane indices, 1970-2018. Top: North Atlantic hurricane totals (red) and U.S. landfalls (blue). Center: Major hurricanes and U.S. landfalls. Bottom: North Atlantic Accumulated Cyclone Energy (ACE). Hurricanes, major hurricanes, and ACE increased abruptly in 1995 with a shift toward higher North Atlantic sea surface temperatures associated with the Atlantic Multidecadal Oscillation.
CFAN develops seasonal to annual climate forecasts using an innovative data mining approach guided by climate dynamics analysis. CFAN’s late-May seasonal forecast for the 2019 Atlantic hurricane season is based on climate conditions and tendencies observed in data from January 1 through May 17, 2019.
Recent climate anomalies and ENSO update
Overall, there is little change relative to CFAN’s ENSO forecast report in March 2019, although there is growing support for an El Niño Modoki in autumn. Expected summer sea surface temperature (SST) conditions in the tropical Pacific were assessed in CFAN’s March 2019 ENSO forecast. CFAN’s March ENSO forecast called for weakening eastern Pacific El Niño conditions during spring but a partial regrowth of central Pacific El Niño Modoki warmth during July-August-September (JAS), overlapping with the early part of the hurricane season. Forecasts suggest largely neutral anomalies of North Atlantic Arc SSTs.
CFAN’s ENSO forecast plumes from ECMWF (initialized March 1) are shown in Figure 2, for Niño1.2, Niño 3, Niño4, and the Modoki Index. ECMWF shows a continued decline of Niño 3 and Niño 1.2 through fall. Niño 4 and Modoki values increase through mid-summer, with moderate Modoki conditions through fall. NOTE: ECMWF’s June seasonal forecast will be available June 5 (tomorrow evening).
Figure 3: CFAN’s analysis of ENSO forecasts from ECMWF seasonal forecast system (SEAS5), initialized 5/1/19.
Hurricane Predictors
CFAN’s forecast method identifies precursors of Atlantic hurricane activity from seasonal patterns of anomalies and tendencies in globally-gridded sea surface temperatures (SSTs) and numerous dynamical and thermodynamic variables based on NCEP-NCAR Reanalysis data at 17 tropospheric and stratospheric levels. While simple patterns of spring-summer climate anomalies offer direct indications of expected hurricane activity, predictions at longer leads involve interactions of slow seasonal to interannual climate processes, including those related to ENSO and the Quasi-biennial Oscillation (QBO) of equatorial stratospheric winds, which tend to undergo rapid phase transitions during spring.
The actual predictors used are not described in the publicly-issued forecast report; more details are provided to our clients.
Forecast models
Figure 5 illustrates the historical leave-one-out forecasts by the most skillful models (gray lines), and overall annual forecast values (blue lines) based on the ensemble means. Forecast model results are shown in Table 1 and Figure 5. In Table 1, forecast uncertainty is reflected in the range of model predictions, and the mean absolute error (MAE) in leave-one-out tests.
Figure 5. Model hindcast hurricane estimates (blue) and observed historical metrics (red). Fine gray lines depict individual model estimates and blue lines reflect model means. A. North Atlantic ACE. B. North Atlantic hurricane totals. C. US hurricane landfalls. D. Florida hurricane landfalls. Values in the lower right of each panel reflect the expected 2019 index value based on the mean of individual model estimates and the ±1 standard deviation spread. Lower left values display index means over the 1995-2018 period.
Potential 2017 analogue
Our forecast issued in November 2018 suggested above-average hurricane activity in 2019, reflected by ACE forecast of 163 (1995-2018 mean: 132). High activity in 2019 was further suggested by Atlantic-sector atmospheric patterns in August-October (ASO) 2018 that closely matched those of ASO 2016, which preceded by one year the high-activity season of 2017 (ACE 226).
Currently, we find additional indications of atmospheric behavior that suggest a potential replay of 2017 conditions in 2019. Figure 6 compares 2019 (left) and 2017 (right) anomalies of global sea level pressure (SLP) (1st row, spatial correlation r = 0.5), NH SLP (2nd row, r = 0.5) and zonal-mean geopotential heights (3rd row, r = 0.7) and zonal (westerly) winds (4th row, r = 0.4).
Figure 6. Comparison of April-May atmospheric anomalies during 2019 (left) and 2017 (right), based on data from April 1-May 17. Top row: Global sea level pressure (SLP). 2nd row: NH SLP. 3rd row: Zonal-mean geopotential heights, by latitude (x-axis) and height (y-axis). 4th row: Zonal-mean U (westerly) winds.
Global April-May SLP anomalies during both years (Fig.6, 1st row) feature a wide zone of high pressure over the tropical Indo-Pacific and an Arctic high centered over Iceland-Greenland, while negative SLP anomalies prevail over a midlatitude band stretching from western Asia to the North Atlantic. In the Southern Hemisphere, similarly-structured zones of negative SLP anomalies cover most of the Antarctic and South America.
A polar perspective (Fig. 6, 2nd row) also highlights the similar NH SLP anomaly structures during 2017 and 2019, including a Greenland high that extends southward over Europe and the Indian Ocean. Zonal-mean (east-west) anomalies of geopotential heights (Fig. 6, 3rd row) share coherent positive anomalies from the surface to the 20 hPa pressure level in the tropical-subtropical lower stratosphere, in contrast to negative height anomalies over the NH midlatitudes and Antarctica. Zonal wind anomalies (Fig. 6, 4th row) display coherent positive (westerly) anomalies involving all vertical levels from 1000 to 10 hPa around 30°N and 50°S, while anomalous easterly flow is seen at tropospheric levels (1000 to 200 hPa) in the Southern Hemisphere around 15°S. Similar states of the stratospheric Quasi-biennial Oscillation (QBO) are indicated by positive zonal wind anomalies from 20 to 70 hPa during April-May 2017 and 2019. April-May patterns generally indicate strong vertical coupling of tropospheric and stratospheric pressure and circulation anomalies in spring 2017 and 2019.
Disparities between 2017 and 2019 conditions include a recent zone of low pressure in the tropical NE Pacific during April-May 2019 (not present in 2017) that is associated with the stronger April 2019 El Niño conditions relative to 2017. Strong hurricane activity in 2017 followed an unusually rapid early-summer transition toward La Niña conditions. Our retrospective analysis of the 2017 hurricane season identified additional factors as well, including pronounced southerly flows of low-level winds and moisture toward the Gulf of Mexico from south of the equator, part of a ‘meridional mode’ (north-south) pattern involving tropical ocean-atmosphere anomalies in both hemispheres.
Discussion
Relative to average Atlantic tropical cyclone activity since 1995, our current forecasts call for above normal North Atlantic ACE and near normal North Atlantic hurricane frequency in 2019. These estimates are similar to our November forecasts, but somewhat higher than our March forecasts that were largely neutral relative to the mean activity since 1995 due to a prevalence of conflicting positive and negative indicators.
Recent indicators of high activity feature many related Arctic circulation anomalies related to positive SLP and geopotential height anomalies over the North Pole from April 1 to May 17. Arctic hurricane precursors are generally most robust during the yet-completed April-June window, and warrant close ongoing attention.
Forecast estimates of U.S. landfalls are close to 1995-2018 averages and have greater forecast uncertainties than North Atlantic ACE and hurricane totals. We will issue a late-June follow-up report on developing conditions relevant to all hurricane metrics discussed here, with a particular emphasis on those relevant to U.S. and Florida hurricane landfalls.
Forecasts in late May are driven by the needs of the reinsurance industry. Circulation patterns of relevance to Atlantic hurricanes generally are in place by the end of June. In a few months, we will know which forecasting group has read the tea leaves correctly.
This is one forecast where I hope we are wrong; we really don’t need another active hurricane season. The key issue of importance is landfalls; we won’t have a good reading on that until the end of June.
“CFAN predicts an active North Atlantic hurricane season season.”
season season.”? It must be twice as bad as we thought.! lo
Perhaps it’s just well salted?
Thank you, Judy. As always, you add great texture to this discussion, along with world-class expertise, and always, a humble word-smithing.
For U.S. landfalls, I’d guess 0-10 and I would be correct at least 95% of the time.
Should have never been named. One visit by the hurricane hunters with marginal TS windspeeds with no other fly throughs showing such, a named TS should not make. They are and have been skewing the record by naming storms that in the past would not have been named.
BTW, as I write this there is not a tropical storm or cyclone in evidence anywhere on earth. Unusual for this time of year.
rah
“Unusual at this time of year”.
No, not really. Low tropical convection causes late start to season. Should remain soft for a while yet. In 2005 accumulated convection started noticible atmospheric reaction on 18th May.
Regards
Not a thing in the Indian Ocean since Fani over a month ago.
Atlantic: Marginal TS Andrea.
Pacific: Typhoon Wutip (Betty) in feb. and since then only TDs.
Philip Klotzbach
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The globe has had no #hurricane-strength tropical cyclones since May 3. Only once since 1990 has the globe had 0 hurricanes from May 4 through June 5 – in 2016. Currently no areas are being monitored for imminent tropical cyclone development.
https://twitter.com/philklotzbach/status/1136292874838896642
They are naming storms that in the past would not have been found.
I can predict with 100% accuracy that any and all US landfalling, Caribbean Island hitting, or Mexico-Yucatan hitting hurricane during the peak season: mid-August to End-October, will be due to Climate Change, per Al Gore and the rest of his Klimate Krew Krazies.
Mecahnism: Apparently according to the Ministry of Klimate Truth, hurricanes never a happened before human’s starting burning fossil fuels.
Good one.
Al Gore has some profound rules for hurricanes:
Rule 1. Every hurricane from now on is due to global warming.
Rule 2. Refer to Rule 1.
Rule 3. Reger to Rule 1.
I can predict with 100% accuracy that any and all US landfalling, Caribbean Island hitting, or Mexico-Yucatan hitting hurricane during the peak season: mid-August to End-October, will be Made Worse due to AGW – because that’s what warmer SSTs do. Y’know, physics.
There fixed it for you.
Prove it.
Apparently an average to you means that any deviation above the average is unusual. Statistics is not your strong suit I assume Loydo.
Galveston 1900 ?
Great Maimi hurricane of 1926?…
All those colonial New World Spanish galleons and fleets bearing gold booty from South America laying on the Carribean and Gulf of Mexico floors from unknown hurricane disasters 400 years ago?
Loydo?
August 24, 1814 – The British burned Washington DC in revenge for the war of 1812. That night, a tornado embedded in a hurricane puts the fire out. When was the last hurricane to hit Washington DC?
August 20, 1886 – A strong hurricane strikes Indianola, Texas. The 8th strongest on record. On September 30, another hurricane came very close to Indianola. The town was then abandoned because of these two hurricanes.
1935 Labor Day hurricane – Went from a tropical depression to the strongest landfalling hurricane in US history in 30 hours. When was the last hurricane to go from a depression to category 5 in 30 hours?
August 31, 1954 – Hurricane Carol hit Connecticut as a category 3 hurricane. When was the last cat-3 to make a direct landfall in New England.
September 11, 1954 – Hurricane Edna made landfall within 100 miles of Carol as an almost category 3 hurricane. When was the last time two strong hurricanes have made landfall very close to each other in under two weeks?
October 15, 1954 – Hurricane Hazel made just north of the North Carolina/South Carolina border as a category 4 hurricane. When was the last cat-4 to have a direct strike on North Carolina?
Shall I go on? I can. I left off the 1938 Long Island Express hurricane, the storm that inspired Shakespeare’s play The Tempest, the 1821 Norfolk-Long Island hurricane, and many more. Weather history is the mortal enemy of the environmental movement.
Made worse due to alarmist, activist scientists making hurricanes appear more powerful than they really are, like hurricane Michael that was upgraded to a category 5 based on one dubious wind measurement, even though Michael didn’t cause the extent of damage that would justify a category 5 rating. That’s my prediction for this year and beyond.
Loydo, exactly how much does 0.01C increase the strength of a hurricane.
PS: How exactly do you use a a few dozen sensors with a sensitivity of 0.1C to measure a 0.01C increase in temperature of the entire ocean?
You heard him – “y’know, physics’.
Apparently, his sense of scale isn’t his strong suit, either.
Er…prove the higher SSTs are due to man-made CO2.
That’s like, the whole argument you see.
You are simply Begging the Question, a logical fallacy. There, fixed it for you.
My prediction is that one or more hurricanes will make landfall, maybe in the U.S. or maybe in the Caribbean, causing a lot of devastation and sadly some loss of life. This will be blamed on climate change and the usual suspects e.g. Micheal Mann will take to twitter saying how climate change has made it 30% worse or 30% more likely or whatever.
My prediction for next year is that one or more hurricanes will make landfall somewhere, causing a lot of devastation which will be blamed on climate change. Micheal Mann will take to twitter claiming blah, blah, blah.
My prediction for 2021 is that one or more hurricanes will make landfall somewhere etc. etc.
My prediction for 2022 etc. etc. etc.
“Should the worst-case scenario of rainfall from a budding tropical feature in the western Gulf of Mexico become involved, levels on the lower Mississippi could approach that of the Great Flood of 1927.”
High pressure in the Eastern Pacific may increase the amount of tropical storms in the Gulf of Mexico.
http://tropic.ssec.wisc.edu/real-time/mtpw2/product.php?color_type=tpw_nrl_colors&prod=conus×pan=24hrs&anim=html5
In late September, 1915, a rare hurricane and high river combined, causing a full river bank south of New Orleans (Cline, I. M. 1926. Tropical Cyclones. Macmillan); also a reverse river flow with a 15 foot rise occurred in 1722 reported by du Pratz, 1774. Probably coincidence but this year seems to be starting like 1985, late mid- October hurricane (Juan) in Gulf hit central Louisiana but covered large area.
“To complicate matters, heavy rainfall over the Central states and melting snow from the Rockies has created a surge of water from the Missouri and Arkansas rivers that is emptying into the Mississippi River and flowing southward.
Over the lower part of the Mississippi Valley, this surge of water may occur at nearly the same time that heavy rain falls.
The combination thereof could result in record-challenging high water on the lower Mississippi River, especially where the water levels are not mitigated by spillways toward the middle and into the latter part of June.”
https://www.accuweather.com/en/weather-news/tropics-to-play-role-in-torrential-rain-enhance-flood-risk-in-south-central-us/70008459
Thunderstorms in Texas and Louisiana will last for several days.
Circulation in the Niño 1.2 region does not change.
http://tropic.ssec.wisc.edu/real-time/mtpw2/product.php?color_type=tpw_nrl_colors&prod=samer2×pan=24hrs&anim=html5
The current practice of naming any breeze with sufficient force to ruffle your hair is not something the climate alarmist industry has done by accident.
The opportunity to claim each and every breeze is bigger or more common now that in past periods is the reason to name so called storms when they are just normal air currents that would in the past have been described as a good drying day to hang out the washing.
The snowflakes need storm names to maintain their level of angst, or maybe it’s just to help them try and convince “normal” people, there is something spooky happening with the weather patterns when there is not.
The downpours over Louisiana will last several days.
Tropical depression over the Gulf of Mexico.
https://www.tropicaltidbits.com/sat/satlooper.php?region=gom&product=ir
CFAN predicts an active North Atlantic hurricane season ….. This is one forecast where I hope we are wrong
If the above means that the current Hurricane season may be well above average the hypothesis based on a degree of correlation between ACE – Accumulated Cyclone Energy and Arctic (far N. Atlantic) Atmospheric Pressure would suggest that probability of the forecast indeed is likely to be wrong, as shown here:
http://www.vukcevic.co.uk/ACE4.htm
In the above the‘Normal’ bandwidth is set by an arbitrary deviation from the value of 100. The original graph (in blue) is from 2011 and subsequently updated (green).
The graph is not a forecast but a decadal (15 years ahead) estimate of a future trend.
Estimating the possible range of the ACE – Accumulated Cyclone Energy level is first essential step towards more credible forecasting. Dr. Curry as the principal factor employs the multidecadal changes that are positively associated with basin-scale sea surface temperature (SST) changes known as the Atlantic Multidecadal Oscillation (AMO).
This is as good as it goes, but the hypothesis depicted in the link above is based on the longer term fundamental properties of the N. Atlantic currents circulation as outlined here:
The North Atlantic currents are essential components of the Meridional Overturning Circulation (MOC) that transport large amounts of heat from the tropics toward the Arctic at same time losing heat and moisture to the atmosphere. By the time the current reaches the North Atlantic and near Arctic, its water is saline and cold, it sinks to produce north Atlantic Deep water current (NADW). It completes its circulation by flowing back towards the tropics or further into other ocean basins at depth, and then subsequently up-welling through a variety of mechanisms and locations. The time scale of this overturning varies between 600 and 1000 years depending where partial up-welling takes place.
The heat being transferred from the ocean surface back into the atmosphere at high latitudes can be 100W/m2 or more, depending on the strength of the westerly cold winds blowing at the high latitudes. By using atmospheric pressure as a rough guide it is possible to estimate trend in the heat loss. More heath is taken out, faster and deeper is down-welling.
It should be pointed out that the sinking current velocity has short term (in time and distance) vertical component directly proportional to its salinity but subsequently it has by far much longer term (in time and distance) horizontal component that is inversely proportional to the depth at which current flows. In another words colder and more saline water is, it sinks faster and deeper, but closer it is to the sea floor the lower is its onward velocity.
One part of the return current up-wells some 15 or so years later in the North Atlantic’s tropics along the west coast of North Africa, the area where the N. Atlantic hurricanes are initiated. Greater the temperature differential between the up-welling and the surface waters in this area, higher values for the ACE are likely, but due to variability in the velocity of the deep ocean current any individual year (as in 2017 case) may considerably deviate from the more general trend.
Another problem is the tropical storms in the Gulf of Mexico. High pressure in the Eastern Pacific (circulation in the region of Nino 1.2) directs storms over the US.
The flow of ozone shows the circulation in the upper troposphere.
You can see high in the eastern tropical Pacific.
ren
“The flow of ozone shows the circulation in the upper troposphere”.
Spot on ren. It is one of the most accurate indicators available. Ozone tells us absolutely nothing about CFC’s, but everything about atmospheric transport and temperature gradients.
Regards
Hurricanes are regular annual events that normally accompanied by ‘extreme weather conditions’ so this announcement is a welcome news.
“The company Thales Alenia Space in Cannes, France has announced that the Meteosat Satellites currently under construction have passed the stage of structural testing and will be put into orbit by the end of 2021. The system which is set to “revolutionise European meteorology” mark the next and third generation of Meteosat satellites in the hope of obtaining a rapid prediction of extreme weather conditions.”
From Global Weather Oscillation (David Dilly, Feb. 2019)
“An average hurricane season has 12 named storms and 6 hurricanes. Professor David Dilley’s prediction for the upcoming 2019 hurricane season calls for a near average season when it comes to the number of named storms (13) and hurricanes (6). However – due to the continuance of very warm ocean water and the 70-year hurricane landfall cycle – the upcoming 2019 season will likely be just as destructive and costly as the 2017 and 2018 hurricane seasons. GWO expects two major impact hurricanes to strike the United States this year – with a potential major hurricane also threatening portions of the Caribbean. GWO urges everyone to monitor the upcoming season closely via GWO’s webinars and our 13 zone predictions – this is not a year to be complacent.”
http://www.prweb.com/releases/2019_hurricane_predictions_2_major_u_s_impact_storms/prweb16120373.htm
“Model hindcast hurricane estimates (blue)”
…oh good grief…they got nothing right
Who knew that settled science would give such a wide range of predictions? I’d hate to see unsettled science!
It’s worse than we thought!
Think of the children!
My guess is it will be a little below average looking at everything.
My guess it that it will be in the range of natural variability.
My guess is that “natural variability” can never be responsible for anything at all in the warmista world…
In the period of low solar activity, the circulation is inhibited. That’s why a small tropical depression can be a big rain.