El Niño is done; Haiti at risk of heavy rains next week; oil spill update

By: Dr. Jeff Masters , 8:09 PM GMT on May 19, 2010

Share this Blog
3
+

El Niño rapidly weakened during late April and early May, with sea surface temperatures over the tropical Eastern Pacific in the area 5°N - 5°S, 120°W - 170°W, also called the "Niña 3.4 region", falling a significant 0.65°C in just one month. Temperatures in the region are now in the "neutral" range, just 0.18°C above average, and well below the 0.5°C threshold to be considered an El Niño, according to the Australian Bureau of Meteorology. The speed of the collapse of El Niño makes it likely that a La Niña event is on its way this summer. This is what happened during the last strong El Niño event, in 1998--El Niño collapsed dramatically in May, and a strong La Niña event developed by hurricane season. Six of the sixteen El Niño models (updated as of April 15) are predicting La Niña conditions for hurricane season, and I expect more models will jump on the La Niña bandwagon when the May data updates later this week. The demise of El Niño, coupled with sea surface temperatures in the tropical Atlantic that are currently at record levels, have prompted two major hurricane forecasting groups (tropicalstormrisk.com and Colorado State University) to predict a significantly above average 2010 Atlantic hurricane season. Over the full 160-year period we have records of Atlantic hurricanes, La Niña years have typically had more hurricanes, and more strong hurricanes, compared to neutral years. However, since 1995, there hasn't been any difference between neutral and La Niña years in terms of hurricane activity. La Niña conditions typically cause cool and wet conditions over the Caribbean in summer, but do not have much of an impact on U.S. temperatures or precipitation.


Figure 1. Oil spill edge over the Gulf of Mexico on Wednesday, May 19, as seen from NASA's M ODIS instrument. Note that a band of cumulus clouds formed along the edge of the oil spill. I theorize this is because the low level wind flow out of the southeast moves faster over the oil, since the oil suppresses wave action. As the winds cross the spill boundary into rougher, clean water, they slow down, forcing the air to pile up and create updrafts that then spawn cumulus clouds. See my post on what oil might do to a hurricane for more information on how oil reduces wave action.

Oil spill update
Clouds over the Gulf of Mexico have again foiled satellite imaging of the extent of the Deepwater Horizon oil spill, though through breaks in the clouds it appears that a significant amount of the oil that was pulled southwards towards the Loop Current is now caught in a counter-clockwise rotating eddy just to the north of the Loop Current. However, some oil has escaped this eddy and is on its way south towards the Florida Keys. According to the latest trajectory forecasts from NOAA, the tongue of oil flowing southwards has at most "light" concentrations. The oil will grow more dilute as it travels the 500 miles to the Florida Keys. My present expectation is that the oil entering the Loop Current this week will cause only minor problems in the Keys next week. However, there is a lot of uncertainty about what the oil may do to the fragile Keys ecosystem. See my post yesterday for answers to many of the common questions I get about the spill.

Oil spill resources
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA trajectory forecasts
Deepwater Horizon Unified Command web site
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Surface current forecasts from NOAA's HYCOM model
HYCOM ocean current forecasts from LSU


Figure 2. Precipitation forecast from today's 8am EDT run of the NAVY NOGAPS model, valid 7 days from now. Precipitation amounts in excess of 70 mm (2.8") in 12 hours are predicted over Haiti, due to a tropical disturbance in the Western Caribbean. Image credit: U.S. Navy.

Potential serious rainfall threat to Haiti next week
Long-range forecasts from the GFS and NOGAPS models over the past few days have consistently been predicting an increase in moisture and decrease in wind shear over the Western Caribbean 5 - 7 days from now, and I expect that a tropical disturbance with heavy rains will develop in the Western Caribbean early next week. A strong subtropical jet stream over the southern Gulf of Mexico will steer the disturbance to the north and east, and the NOGAPS model shows heavy rains in excess of six inches impacting Haiti Wednesday through Thursday of next week. Rains of this magnitude are capable of causing a serious emergency with high loss of life in earthquake-shattered Haiti, and all interests in that nation should closely monitor the situation over the coming week. It is too early to speculate on the possibility of the disturbance becoming a tropical depression. The wunderblogs of StormW and Weather456, who are now featured bloggers for the coming hurricane season, have more information on this potential development, plus the possible development of a subtropical storm between Florida and Bermuda next week.

Major severe weather outbreak over Oklahoma expected tonight
NOAA's Storm Prediction Center has put much of Oklahoma in its High Risk region for severe weather today, warning that "The setup appears most favorable for large, relatively slow moving intense storms with large hail. A couple strong tornadoes also may occur."

I'll be back with a new post Thursday morning.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 111 - 61

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18Blog Index

Quoting Drakoen:


After looking at the 12z cyclone phase diagram, there is the possibility for subtropical development east of the Bahamas. The models don't agree on the track of the system so it's difficult to predict more accurately what will happen. The GFS takes it out the east, the ECMWF keeps it going west, the CMC has it going north.

One thing that is interesting on the ECMWF is its forecast for the core temperature to be warmer than the surrounding environment even though the system is largely embedded within the 500mb trough axis.


Figure1. ECMWF 850mb temperature forecast


The ECMWF appears to transition the system to fully warm-core right at the end of the forecast run at 240 hours just off the east coast of Florida.
Member Since: Posts: Comments:
Quoting Weather456:


Yep but ENE?


My bad, between north or northeast
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Quoting wunderkidcayman:
New surface map new surface map!!!!!!!!!!!!!!

18Z SURFACE MAP



OLD SURFACE MAP 12Z

Interesting... We have a low over Belize.
Quoting CybrTeddy:


Each season it gets more insane as more of the old crew leave.. we've now lost Press to boot.
Presslord is gone?
Member Since: Posts: Comments:
Could make it way to the Karolina's..

Im not saying it will..but one has to have a point of reference..
Member Since: Posts: Comments:
Quoting Drakoen:


After looking at the 12z cyclone phase diagram, there is the possibility for subtropical development east of the Bahamas. The models don't agree on the track of the system so it's difficult to predict more accurately what will happen. The GFS takes it out the east, the ECMWF keeps it going west, the CMC has it going north.
BR>One thing that is interesting on the ECMWF is its forecast for the core temperature to be warmer than the surrounding environment even though the system is largely embedded within the 500mb trough axis.


Figure1. ECMWF 850mb temperature forecast
</blockquote>

Levi and I was pointing to that earlier.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Surface pressures have been falling during the past 5 days in the western Caribbean and the Bahamas. This is a sign of the overall pattern starting to favor lower pressures over the entire SW Atlantic.

Caribbean buoy:



Bahamas Buoy:

Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
How about the hybrid system east of the Bahamas?


After looking at the 12z cyclone phase diagram, there is the possibility for subtropical development east of the Bahamas. The models don't agree on the track of the system so it's difficult to predict more accurately what will happen. The GFS takes it out the east, the ECMWF keeps it going west, the CMC has it going north.

One thing that is interesting on the ECMWF is its forecast for the core temperature to be warmer than the surrounding environment even though the system is largely embedded within the 500mb trough axis.


Figure1. ECMWF 850mb temperature forecast
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Quoting Stormchaser2007:


Moderate sub tropical storm or strong?


anything above 60 is strong. I'll go with moderate but the ECMWF is showing something stronger.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Levi32:


That model is the same as the CMC. Just two different names for the same model.
Oh! Thanks.
Member Since: Posts: Comments:
Now we can also sing the "El Nino is gone" song!!

Interesting, as the El Nino withers away, the tornado and severe storm activity continues o uncrease, back towards "normal"

Below is a picture fro TWC, the first tornado of the day, just outside Leedey, OK:
Member Since: Posts: Comments:
Quoting Levi32:


That model is the same as the CMC. Just two different names for the same model.

Correct!
Member Since: August 16, 2007 Posts: 6 Comments: 12461
New surface map new surface map!!!!!!!!!!!!!!

18Z SURFACE MAP



OLD SURFACE MAP 12Z

Member Since: Posts: Comments:
Quoting Levi32:


One more is hinting at it. The JMA (Japanese model) forecasts a trough to develop near the Bahamas in 24-48 hours, doesn't do much with it, and then it shows up again east of Florida on Day 8 after meandering around for several days.

Also notice no Caribbean low.

48 hours:



192 hours:



Can I assume that the JMA plots at Accu are behind an impenetrable paywall?

If not, a link? Please?

The JMA NICAM model (if it were available) would be an excellent addition...I might even drop a couple of others completely should it preform as well as I hope it will.
Member Since: August 16, 2007 Posts: 6 Comments: 12461
Quoting atmoaggie:

Dat's what I'm holding out for. Model consensus for a few cycles in a row leading up to the 96 hours out time frame (at a maximum).


What is interesting is that the models have already been correct thus far with the components that will induce the hybrid low so needless to say, its very valid consensus at this point.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Acemmett90:
oh yah this season this blogs gonna be a picture perfect remake of one flew over the Cookooes nest


Each season it gets more insane as more of the old crew leave.. we've now lost Press to boot.
Member Since: July 8, 2005 Posts: 259 Comments: 23015
Quoting Patrap:
Itsa Big Juicy WAVE

WV
LOL!
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
And we have the GGEM too.


That model is the same as the CMC. Just two different names for the same model.
Member Since: Posts: Comments:
thanks Pat, and Fish.
Member Since: Posts: Comments:
MESOSCALE DISCUSSION 0624
NWS STORM PREDICTION CENTER NORMAN OK
0320 PM CDT WED MAY 19 2010

AREAS AFFECTED...OK

CONCERNING...TORNADO WATCH 190...

VALID 192020Z - 192145Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 190 CONTINUES.

20Z MESOANALYSIS PLACES A LOW JUST S OF KGAG WITH A WRMFNT ESE
ACROSS DEWEY...BLAINE...KINGFISHER...OKLAHOMA COUNTIES...THEN SEWD
TO CHOCTAW COUNTY. A DRYLINE EXTENDED S FROM THE LOW INTO THE ALTUS
AREA.

TSTMS WERE INCREASING OVER WCNTRL OK NEAR THE TRIPLE POINT AND WILL
LIKELY BUILD SWD ALONG THE DRYLINE THROUGH LATE AFTN. OTHER STORMS
WILL CONTINUE TO GROW ALONG THE WRMFNT FROM JUST W OF KOKC WNW INTO
BLAINE/MAJOR COUNTIES. YET A THIRD REGION OF INITIATION...PER
LATEST RAPID REFRESH AND RECENT TCU DEVELOPMENT...WILL BE ACROSS
SERN OK TO THE SW THROUGH NW OF KMLC ALONG A POSSIBLE GRAVITY WAVE.

AS STORMS MATURE INTO SUPERCELLS THEY WILL MOVE 250/30 KTS WITH THE
TORNADO THREAT MAXIMIZED INVOF THE WRMFNT...PARTICULARLY FROM
KINGFISHER ESE THROUGH OKC METRO AND INTO SE OK NEAR KMLC. THIS
ZONE WILL MAINTAIN ESELY LLVL FLOW VEERING QUICKLY TO SW ABOVE 2-3
KM AMIDST LOW LCLS. VERY LARGE HAIL CAN ALSO BE EXPECTED.

..RACY.. 05/19/2010
Member Since: Posts: Comments:


LET THE GAMES BEGIN
Member Since: Posts: Comments:
Quoting Levi32:


One more is hinting at it. The JMA (Japanese model) forecasts a trough to develop near the Bahamas in 24-48 hours, doesn't do much with it, and then it shows up again east of Florida on Day 8 after meandering around for several days.

Also notice no Caribbean low.

48 hours:



192 hours:


And we have the GGEM too.
Member Since: Posts: Comments:
Quoting Weather456:
The hybrid low seems will be the strongest of the two.


Moderate sub tropical storm or strong?
Member Since: June 9, 2007 Posts: 4 Comments: 15718
Someone on here earlier was dissing the Tampa and Melbourne NWS offices for predicting a lot too little rainfall in central florida, and predicted that there would actually be widespread rainfall. Well, turns out, the NWS was right and maybe even wet-biased today.
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
I'm going with a 70% chance of Alex next week.



I'll go with 85% of TS Alex forming
Member Since: Posts: Comments:
Quoting Floodman:


Agreed...however, it needs to be said that model consensus 5-7 days out rarely results in model consensus at 4-5 days out...when it does happen, it's time to throw up the shutters

Dat's what I'm holding out for. Model consensus for a few cycles in a row leading up to the 96 hours out time frame (at a maximum).
Member Since: August 16, 2007 Posts: 6 Comments: 12461
Quoting CybrTeddy:


For those who are new to this game this year, this is EXACTLY what you would want to see for development. It is interesting to note after a season of ghost storms last year that if this develops the GFS would have once again nailed TS genesis weeks in advance, such as it did in 2008 with several if not most of our systems. For now however, it is all wait and see. If model support continues to be as strong as we close in.. the chances go up drastically every day.
Exactly!
Quoting masonsnana:

Which one?? and headed where??
Just general development.
Member Since: Posts: Comments:
NEXRAD Radar
Enid/Vance AFB, Base Reflectivity 0.50 Degree Elevation Range 124 NMI

Member Since: Posts: Comments:
Thanks Ace.
Member Since: Posts: Comments:
If the SW Caribbean low can induce enough outflow it can alter the subtropical jet to its favor. This is the solution seen on the CMC and NOGAPS.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Acemmett90 .nice image.
Member Since: Posts: Comments:
Quoting CybrTeddy:


For those who are new to this game this year, this is EXACTLY what you would want to see for development. It is interesting to note after a season of ghost storms last year that if this develops the GFS would have once again nailed TS genesis weeks in advance, such as it did in 2008 with several if not most of our systems. For now however, it is all wait and see. If model support continues to be as strong as we close in.. the chances go up drastically every day.


Agreed...however, it needs to be said that model consensus 5-7 days out rarely results in model consensus at 4-5, or 3-4 days out...when it does happen, it's time to throw up the shutters
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Itsa Big Juicy WAVE

WV
Member Since: Posts: Comments:
The hybrid low seems will be the strongest of the two.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting pottery:
Anyone have a link for a loop showing the CAtl Wave?> Not the cen.alt or East Atl Rainbows, neither shows the entire wave.
Thankee.


You could go here

I also have more links to other satellite imagery and computer model stuff here
Member Since: Posts: Comments:
From the doc's blog on the effect of the spill on Hurricanes:

"Oil reduces evaporation
Hurricanes are sustained by the heat liberated when water vapor that has evaporated from warm ocean waters condenses into rain. If one can reduce the amount of water evaporating from the ocean, a decrease in the hurricane's strength will result. Oil on the surface of the ocean will act to limit evaporation, and could potentially decrease the strength of a hurricane. However, if the oil is mixed away from the surface by the strong winds of a hurricane, the oil will have a very limited ability to reduce evaporation. According to a 2005 article in Popular Science magazine, Dr. Kerry Emanuel of MIT performed some tests in 2002 to see if oil on the surface of water could significantly reduce evaporation into a hurricane. He found that the slick quickly dissipated under high wind conditions that generated rough seas."


Any effect would be greatly lessened by the fact that the spill would "run" in front of the winds and high seas...dispersal would lessen the immediate impact on the beaches by spreading the oil out over a wider area
Member Since: Posts: Comments:
Quoting pottery:
Anyone have a link for a loop showing the CAtl Wave?> Not the cen.alt or East Atl Rainbows, neither shows the entire wave.
Thankee.


Atlantic Viz animated

ESL by LSU
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Now we have the UKMET, GFS, CMC, NOGAPS, and ECMWF forecasting development for next week. Let's see what unfolds...


For those who are new to this game this year, this is EXACTLY what you would want to see for development. It is interesting to note after a season of ghost storms last year that if this develops the GFS would have once again nailed TS genesis weeks in advance, such as it did in 2008 with several if not most of our systems. For now however, it is all wait and see. If model support continues to be as strong as we close in.. the chances go up drastically every day.
Member Since: July 8, 2005 Posts: 259 Comments: 23015
Quoting MiamiHurricanes09:
I'm going with a 70% chance of Alex next week.


Which one?? and headed where??
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Now we have the UKMET, GFS, CMC, NOGAPS, and ECMWF forecasting development for next week. Let's see what unfolds...


One more is hinting at it. The JMA (Japanese model) forecasts a trough to develop near the Bahamas in 24-48 hours, doesn't do much with it, and then it shows up again east of Florida on Day 8 after meandering around for several days.

Also notice no Caribbean low.

48 hours:



192 hours:


Member Since: Posts: Comments:
and I think that the shear won't be a problem
Member Since: Posts: Comments:
Quoting MiamiHurricanes09:
Now we have the UKMET, GFS, CMC, NOGAPS, and ECMWF forecasting development for next week. Let's see what unfolds...


The problem is the GFS does not foresee the development of a hybrid low. It kicks it out to see. It is likely, the GFS remains the the outsider.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting Acemmett90:

lol my fault should have check the date

Hey, is that the Ex-Ida Nor'easter? I think it might be...why, yes, it is.
Member Since: August 16, 2007 Posts: 6 Comments: 12461

Viewing: 111 - 61

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.