El Niño is done; Haiti at risk of heavy rains next week; oil spill update
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
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been watching every video I can. At the beginning, the oil was coming out, and flowing almost straight up, in big pooofs. Now, the most recent video, shows the oil going further out horizontally, before curving upwards.
My thinking is either the pressure behind the flow has increased, or the oil itself has changed to a thicker, heavier type.
Really cool to see Dr. Masters get a lot of press this year and hope that we have a "nice" and informative discourse on the Blog this year as opposed to bikering and troll activity. We will probably have more folks on here looking at Dr. M's blog as the result of the press exposure....Kudos to Dr. M for his work and giving us this great forum to discuss the issues.
Adrian, you think we will have Alex from the area north of Bahamas subtropical or fully tropical?
You're asking for a lot on here. I can already see it simmering and it hasn't even started yet.
From Morehead City,NC....
"LONG TERM /SUNDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
AS OF 300 AM THURSDAY...THE SHORTWAVE WILL CLOSE OFF INTO A CUTOFF
UPPER LOW SUNDAY OFF THE SE COAST. THE UPPER LOW WILL THEN INTERACT
WITH A BROAD/WEAK SURFACE LOW NE OF THE BAHAMAS BECOMING VERTICALLY
STACKED MONDAY AND RETROGRADING TOWARD THE SE COAST MONDAY-THROUGH
WEDNESDAY AS AN UPPER HIGH OVER THE GREAT LAKES REGION BLOCKS ANY NE
TRACK. ALL OF THE 00Z GUIDANCE (NAM/GFS AND ECMWF) BRINGS SOME IMPACTS
TO EASTERN NC IN THE FORM OF SOUTHEASTERLY SWELL AND CHANCES FOR RAIN.
WHILE THERE ARE STILL DIFFERENCES IN THE MODELS...THE CONSENSUS
SUGGESTS THAT THE FORECAST EARLY TO MID NEXT WEEK COULD BE WETTER
AND COOLER THAN PREVIOUSLY FORECAST. NO CHANGES WILL BE MADE TO THE
EXTENDED FORECAST AT THIS TIME BUT IF THESE TRENDS CONTINUE IN THE
12Z MODELS THEN OUR FORECAST WILL NEED TO BE ADJUSTED ACCORDINGLY.
-- End Changed Discussion --"
What happens if Haiti floods from a weak disturbance? There is no bogus low. It is a real possibility that a disturbance will be heading for Hispaniola next week as indicated by not 1 model, but several. It is by far more dangerous than the subtropical low because of its potential to affect an already struggling country.
I can can only hope, but, that's one of the reasons I like the Blog early in the morning...the trolls like to sleep late I think.......... :)
CBS has footage of their reporters being turned away from a public beach in Louisiana where they were filming oil washing up on shore.
"This is BP's rules, it's not ours," someone aboard the boat said. Coast Guard officials told CBS that they're looking into it. "
Now..since the Coast Guard is a branch of the military, you gotta wonder how closely the government and BP are working together to keep the public from seeing this. I dont even understand how they think that's possible.
LOL...smart man...you're exactly correct.
I doubt admin will allow a lot starting soon. The "time outs" will start.
I think it will be fully tropical 60-mph storm
i'm not Adrian,but I have to give you my opinion
They postponed it to the 27th.
Obviously the potential for flooding down in the tropics this time of the year always exist. Almost gave in to the trigger happy gfs. The system of the southeast is cold-core in general with some chance at being named sts.
Not to different from andrea back in 07.
It was rescheduled to next Thursday.
This time 5 years ago...
This year really makes 2005 look small in terms of SSTs.
Its a good thing I bought my EATON emergency radio. (Gainesville Fl)
the watar is getting warmer VERY fast
Wait until the kids are out of school for summer.
It really does and from here on out the only way is up.
I see the increased rain chances for here early next week. Probably will be higher then what they have listed now.
What happens if Haiti floods from a weak disturbance?
Many will die...it's as simple as that...the situation there is dire...hundreds of thousands still living in refugee camps...violence is epidemic...especially against women, as well as children, people with disabilities and the elderly...
6z NOGAPS
So the history of Audrey(1957)can be repeated
For better analysis:
Some of the Tampa mets are already doing informal "tropical updates" almost nightly because the gulf is so warm.
I see much concern around the gulf, is the Atlantic warmer than normal?
Just updated a few minutes ago...
The whole basin is above normal:
Viewing: 701 - 751
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