Record Atlantic SSTs continue in the hurricane Main Development Region
Sea Surface Temperatures (SSTs) in the Atlantic's Main Development Region for hurricanes had their warmest April on record, according to an analysis of historical SST data from the UK Hadley Center. SST data goes back to 1850, though there is much missing data before 1910 and during WWI and WWII. The area between 10°N and 20°N, between the coast of Africa and Central America (20°W - 80°W), is called the Main Development Region (MDR) because virtually all African waves originate in this region. These African waves account for 85% of all Atlantic major hurricanes and 60% of all named storms. When SSTs in the MDR are much above average during hurricane season, a very active season typically results (if there is no El Niño event present.) SSTs in the Main Development Region (10°N to 20°N and 20°W to 85°W) were an eye-opening 1.46°C above average during April. This is the third straight record warm month, and the warmest anomaly measured for any month--by a remarkable 0.2°C. The previous record warmest anomalies for the Atlantic MDR were set in June 2005 and March 2010, at 1.26°C.
Figure 1. The departure of sea surface temperature (SST) from average for May 13, 2010. Image credit: NOAA/NESDIS.
What is responsible for the high SSTs?
As I explained in detail in a post on record February SSTs in the Atlantic, the Arctic Oscillation (AO) and its close cousin, the North Atlantic Oscillation (NAO), are largely to blame for the record SSTs. The AO and NAO are climate patterns in the North Atlantic Ocean related to fluctuations in the difference of sea-level pressure between the Icelandic Low and the Azores-Bermuda High. If the difference in sea-level pressure between Iceland and the Azores is small (negative NAO), this creates a weak Azores-Bermuda High, which reduces the trade winds circulating around the High. During December - February, we had the most negative AO/NAO since records began in 1950, and this caused trade winds between Africa and the Lesser Antilles Islands in the hurricane Main Development Region to slow to 1 - 2 m/s (2.2 - 4.5 mph) below average. Slower trade winds mean less mixing of the surface waters with cooler waters down deep, plus less evaporational cooling of the surface water. As a result, the ocean heated up significantly, relative to normal, over the winter. Negative AO/NAO conditions have been dominant much of this spring as well, resulting in further anomalous heating of the MDR waters. This heating is superimposed on the very warm global SSTs we've been seeing over the past few decades due to global warming. Global and Northern Hemisphere SSTs were the 2nd warmest on record this past December, January, and February, the warmest on record in March, and will likely be classified as the warmest or second warmest on record for April, since NASA just classified April as the warmest April on record for the globe. We are also in the warm phase of a decades-long natural oscillation in Atlantic ocean temperatures called the Atlantic Multi-decadal Oscillation (AMO). This warm phase began in 1995, and has been partially responsible for the high levels of hurricane activity we've seen since 1995.
What does this imply for the coming hurricane season?
The high April SST anomaly does not bode well for the coming hurricane season. The three past seasons with record warm April SST anomalies all had abnormally high numbers of intense hurricanes. Past hurricane seasons that had high March SST anomalies include 1969 (0.90°C anomaly), 2005 (1.19°C anomaly), and 1958 (0.97°C anomaly). These three years had 5, 7, and 5 intense hurricanes, respectively. Just two intense hurricanes occur in an average year. The total averaged activity for the three seasons was 15 named storms, 11 hurricanes, and 6 intense hurricanes (an average hurricane season has 10, 6, and 2.) Both 1958 and 2005 saw neutral El Niño conditions, while 1969 had a weak El Niño.
The SSTs are already as warm as we normally see in July between Africa and the Caribbean, and we have a very July-like tropical wave approaching the Lesser Antilles Islands this weekend. However, wind shear is still seasonably high, and the tropical waves coming off of Africa are still too far south to have much of a chance of developing. The GFS model is indicating that shear will start to drop over the Caribbean the last week of May, so we may have to be on the watch for tropical storms forming in the Caribbean then.
For those of you interested in a more detailed look at the early season tropical weather outlook, consult the excellent wunderblogs of StormW and Weather456. I'll be back with a new post on Monday.
Jeff Masters
Reader Comments
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And MAnhattan and Miami are well..just awaiting their turn.
Shoot,,Fla builds trailer parks and called them Houses at the beach..
Ever seen what Andrew did to those things?
I did.
the gfs, imo
right, Mississippi was devestated. Biloxi was a mess.
GFS and ECMWF
Latest Information
May 17, 2010
Identifying oil in Mississippi, Alabama and Florida
May 17, 2010
Identifying oil in Louisiana
May 17, 2010
Unified Area Command to hold press briefing in Robert, La.
May 17, 2010
Current Operations and Ongoing Response
May 17, 2010
PHOTO RELEASE: Bird cleaning at FT JACKSON, La.
May 17, 2010
DHR: Vessels of Opportunity Program
May 17, 2010
Situation Status Map - May 17, 2010
Good morning, thought of you as 5" of rain fell over Houston/Galveston over the weekend. And you are all still 2-3 " below normal for the year!!
They probably will never mover NOLA, although they should slowly move portions of the city to higher ground, away from the MS River delta area. Considering half of NOLA is below sea level and they're at a high risk of a major hurricane in any given season.
I understand the NOLA residents love their city, like Patrap, I respect that. Blame it all on the folks who busted up that log-jam on one of the area rivers in the 1860's. That started this mess, and it will not finish until:
A) The Army Corp of Engineers "engineer" a way to tame the MS River, which is not likely.
or
B) Mother Nature wins and NOLA is reclaimed by natural forces.
They sure were, which flooded NOLA, it did not DEVESTATE NOLA. I am not saying Katrina did not "hit" NOLA but realistically it did not DEVESTATE NOLA. It is symantics I know, I just have seen real devestation and NOLA was not it.
Drak what site do you use.....the Navy was pretty good.
I was there and that was DEVESTATION
Link
Link
Hey man!
I received 1.90" total outta the 2 days. But just 10 miles to my east received some 5". Ground sucked it up too. yards are greener and we really needed that. Hope more comes this week as forecasted
Ya really...bro you got that right...OUCH
nicely played
Seems we now have gotton to the root of things.
Disaster jealousy 101.
A fine Florida trait expressed daily here.
Im off to savor the Shrimps,..
Enjoy the new entry..it will be out shortly.
Toodles..
."Calamity knows NO borders,only mens minds and Map's do"..
Pat i normally agree with you however I find this insulting. I do not envy ANYONE as I have been in one of if not the worst Hurricane ever. I am from Florida and the idea of another Andrew freaks me out. The majority of hurricanes hit Florida so why would anyone else here be envious of any disaster. The only NOLA thing I envy is thier Super Bowl win last year
We may have some photos of an historical past if the oil gets in the loop.
WTIO21 PGTW 171500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 11.3N 89.6E TO 14.0N 84.8E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT IM-
AGERY AT 171200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 11.7N 88.6E. THE SYSTEM IS MOVING NORTHWARD AT 06 KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 11.1N
87.7E IS NOW LOCATED NEAR 11.7N 88.6E, APPROXIMATELY 495 NM EAST OF
CHENNAI, INDIA. CONVECTION CONTINUES TO ORGANIZE AROUND A DEVELOPING
LOW LEVEL CIRCULATION CENTER (LLCC). AN EARLIER 170315Z ASCAT PASS
CONFIRMS THAT A WELL-DEFINED 20 TO 25 KNOT CIRCULATION HAS FORMED.
A 171108Z SSMI MICROWAVE IMAGE INDICATES MARKED CONSOLIDATION HAS
OCCURRED WITHIN THE PAST FEW HOURS WITH DEEP CONVECTION RINGING AN
EASILY IDENTIFIABLE LLCC. SEVERAL BANDS HAVE ALSO BEGUN TO WRAP
TOWARDS THE CENTER. THE SYSTEM LIES IN CLOSE PROXIMITY TO THE UPPER
RIDGE AXIS IN A REGION OF LOW VERTICAL WIND SHEAR AND FAVORABLE
MULTIDIRECTIONAL VENTING. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 25 TO 30 KNOTS, AND MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1001 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
181500Z.//
NNNN
Hey Oz, her ya' go, if you're up to another chase, actually the TX Panhandle is pretty busy right now:
However later today
MESOSCALE DISCUSSION 0589
NWS STORM PREDICTION CENTER NORMAN OK
1016 AM CDT MON MAY 17 2010
AREAS AFFECTED...NWRN TX
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 171516Z - 171615Z
TSTM CLUSTER OVER THE S PLAINS OF W TX HAS PRODUCED WIND GUSTS OF
70-80 MPH RECENTLY JUST EAST OF KLUB. LATEST NAM SUGGESTS THAT THE
STORM CLUSTERS WILL CONTINUE ESE INTO CNTRL TX THROUGH THE AFTN.
VWP FROM LUBBOCK SHOWS AROUND 30-35 KTS OF MID-LVL FLOW AND AS THE
BOUNDARY LAYER CONTINUES TO HEAT AHEAD OF THE STORM CLUSTER...STORMS
SHOULD CONTINUE TO REMAIN RATHER STRONG WITH LARGE HAIL AND DMGG
WIND GUSTS THE PRIMARY SVR THREATS. AREA IS BEING MONITORED FOR A
WW.
..RACY.. 05/17/2010
Oz, have you or T Dude intercepted a live tornado yet?
I was actually just talking to tornadodude and he is chasing in the area for the next few days. Looks like he's going to get some action!
The Bay of Bengal will be very BUSY this year, as the SST are off the charts in that area, plus the available energy in the Bay of bengal is also very high. The MJO moved through that area sparking several very healthy looking waves.
Might be ready to wake up as it usually does. We might be seeing the beginning of the giant that is to come.
Gfs shows it somewhat on the tail of the storm rolling up the coast of the Northeast in about 3 days.. GFS has been having a hard time with this developing Noreaster.. Shear is dropping a little in the area the gfs & nogaps hint at, so something is trying there. I think we will see the soon to be developing storm in the GA/Carolina's coastline area be strong enough to pull in & eat that bit of energy making it that much a more event for the NE..
GLOBAL MODEL DATA TIME 00UTC 17.05.2010
NEW TROPICAL STORM FORECAST TO DEVELOP AFTER 48 HOURS
FORECAST POSITION AT T+ 48 : 12.5N 86.5E
VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
00UTC 19.05.2010 12.5N 86.5E WEAK
12UTC 19.05.2010 13.2N 84.4E WEAK LITTLE CHANGE
00UTC 20.05.2010 15.1N 84.2E WEAK LITTLE CHANGE
12UTC 20.05.2010 16.7N 85.0E WEAK LITTLE CHANGE
00UTC 21.05.2010 18.6N 86.3E WEAK LITTLE CHANGE
12UTC 21.05.2010 20.2N 88.9E WEAK LITTLE CHANGE
00UTC 22.05.2010 21.6N 90.8E STRONG INTENSIFYING RAPIDLY
12UTC 22.05.2010 22.1N 92.0E MODERATE WEAKENING RAPIDLY
00UTC 23.05.2010 BELOW TROPICAL STORM STRENGTH
THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT
MET OFFICE, EXETER, UK
TOO 170455
New SST anomaly map today shows the Pacific continuing to cool very rapidly, with already a La Ninish look appearing in the Nino 3.4 region.
Caribbean SSTs have cooled somewhat over the last week due to a burst of stronger than normal easterly trade winds, thanks to strong high pressure off the SE US tightening the pressure gradient over the Caribbean.
Lame? Watching 200+hr model forecast and tw's of africa in may is amusing. Projected upper winds by the gfs don't look to friendly.
upper winds is one thing...but the area of low pressure we are referring to in the SW Caribbean is non-frontal.
skye,none of the local mets are playing this storm up much except that it will be raining Tuesday night into Wednesday.
Link
Good morning Tampa, it's a beautiful, sunny, humid, late spring day in Arlington, TX.
It's about 80F, light E winds at 5-10MPH, RH about 65%. Prime conditions for our area of instability in the TX Panhandle to move SE and wreak havoc, with strong 70-80MPH straight-line winds in NW TX!
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