Atlantic Sea Surface Temperatures and Anomalies

[KWT]

It'll be interesting to see if that reverses Wxman57, we've had a super condusive pattern for a weak Subtropical belt but that has gone on for 3 months more or less, I can't imagine that pattern can keep repeating into the summer so that maybe one good chink of light...

Will be interesting to see if March's ECM update is as positive as its Feb forecast, one thing I'm sure about, the ENSO forecast will not be as agressive, not with Feb holding firm and the subsurface warming up again, the CFS forecast for borderline El nino looks very good IMO.

[gatorcane]

Here is another comparison from 2009 and now at this time. Huge difference.

Perhaps we will see an early start to the Cape Verde season.

Mar. 1st, 2010:


Mar. 2nd, 2009:

[Ivanhater]

As we saw in 2009, SSTs are only part of the equation. If you remember, the Gulf of Mexico SSTs were well above normal, even higher than in 2005. Fortunately, wind shear was also high in the Gulf, so we saw no big storms. I'm afraid this year will be different in that the wind shear will likely be much lower than 2009, and not just because El Nino will be gone. It's the lower pressures in the MDR due to a weakened Bermuda High that are resulting in lower easterly trade winds and less low-level shear (and less dry air).

Wow, this is the first thing I have heard about this upcoming season, after spending the winter in the winter forum. This is quite a bold statement coming from wxman, kind of gave me chills

[WeatherLovingDoc]

The Euro with four month lead. At least you get the idea sans subscription. Perhaps "There'll be a hot time in the old town tonight!" (American ragtime song, composed in 1896 by Theodore August Metz with lyrics by Joe Hayden).


[img]URL=http://img715.imageshack.us/i/seasonalchartspublic2tm.gif/][/URL][/img]

[HURAKAN]

Impressive anomalies in the Cape Verde region

[Blown Away]

The lower pressures in the MDR is due to a weakened Bermuda High that are resulting in lower easterly trade winds and less low-level shear (and less dry air).

In past years when there was a weak winter BH, does it usually carry over into the hurricane season? Maybe we will see more recurve's this year and higher chances of a storm for the Carolinas/NE CONUS? The above average MDR SST's may not bode well for the Caribbean. We shall see.

[KWT]

The 2004 season had a very weak ridge indeed but powered up for the mean of the season as we all know, so I'd imagine there isn't a huge synoptic comprasion to be had, esp when the main reason for the weak upper high was an utter monster of a -ve AO, the strongest ever negative AO for Feb, once that eases off the Sub tropical belt may strengthen back somewhat again.

[cycloneye]

Some cooling in the far Eastern Atlantic on the past couple of days.

[KWT]

I suspect it maybe because a strong upper high has formed near the UK, which is probably helping to strengthen the easterlies a little over N.Africa as the jet deflects back northwards.

Still it doesn't take away from some very impressive anomalies elsewhere in the basin!

[cycloneye]

Analisis by Dr Jeff Masters of the warm anomalies in MDR area

Interesting observations by Dr Masters.

Posted by: JeffMasters, 4:52 PM GMT on March 08, 2010

Sea Surface Temperatures (SSTs) in the Atlantic's Main Development Region for hurricanes were at their highest February level on record last month, 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 region between 10°N and 20°N, between the coast of Africa and Central America, 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 1.02°C above average during February. This easily beats the previous record of 0.83°C set in 1998. SSTs in the Main Development Region are already warmer than they were during June of last year, which is pretty remarkable, considering February is usually the coldest month of the year for SSTs in the North Atlantic. The 1.02°C anomaly is the 6th highest monthly SST anomaly for the MDR on record. The only other months with higher anomalies all occurred during 2005 (April, May, June, July, and September 2005 had anomalies of 1.06°C - 1.23°C).

What is responsible for the high SSTs?

Don't blame El Niño for the high Atlantic SSTs. El Niño is a warming of the Pacific waters near the Equator, and has no direct impact on Atlantic SSTs. Instead, blame the Arctic Oscillation (AO) or its close cousin, the North Atlantic Oscillation (NAO). 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. They are some of the oldest known climate oscillations; seafaring Scandinavians described the pattern several centuries ago. Through east-west oscillation motions of the Icelandic Low and the Azores-Bermuda High, the AO/NAO controls the strength and direction of westerly winds and storm tracks across the North Atlantic. A large difference in the pressure between Iceland and the Azores (positive NAO) leads to increased westerly winds and mild and wet winters in Europe. Positive NAO conditions also cause the Icelandic Low to draw a stronger south-westerly flow of air over eastern North America, preventing Arctic air from plunging southward. In contrast, if the difference in sea-level pressure between Iceland and the Azores is small (negative NAO), westerly winds are suppressed, allowing Arctic air to spill southwards into eastern North America more readily. The winter of 2009 - 2010 has seen the most negative AO and NAO patterns since record keeping began in 1950, which caused a very cold winter in Florida and surrounding states. A negative AO/NAO implies a very weak Azores-Bermuda High, which reduces the trade winds circulating around the High. During December - February, trade winds between Africa and the Lesser Antilles Islands in the hurricane Main Development Region were 1 - 2 m/s (2.2 - 4.5 mph) below average (Figure 2). 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 has heated up significantly, relative to normal, over the winter. This heating is superimposed on the very warm global SSTs we've been seeing over the past decade, leading to the current record warmth. Global and Northern Hemisphere SSTs were the 2nd warmest on record in both December and January.



What does this imply for the coming hurricane season?

According to Dr. Phil Klotzbach of the University of Colorado, February temperatures in the MDR are not strongly correlated with active hurricane seasons. The mathematical correlation between hurricane season Accumulated Cyclone Energy (ACE) and February SSTs is only 0.26, which is considered weak. Past hurricane seasons that had high February SST anomalies include 1998 (0.83°C anomaly), 2007 (0.71°C anomaly), and 1958 (0.68°C anomaly). These three years averaged 13 named storms, 8 hurricanes, and 3 intense hurricanes, which is considerably higher than the average of 10, 6, and 2. The big question is, how long will the strong negative AO/NAO conditions keep the Azores-Bermuda High weak? Well, the AO has risen to near-neutral values over the past week, and the latest 2-week forecast from the GFS model show that the AO and NAO will not be as strongly negative during March. This should allow the Azores-Bermuda High to strengthen some this month and increase the trade winds over the MDR. However, I still expect we'll set a record for warmest-ever March SSTs in the Main Development Region. Longer term, the crystal ball is very fuzzy, as our ability to predict the weather months in advance is poor. The long-range NOAA CFS model is predicting SSTs in the Atlantic MDR will be about 0.70°C above average during the peak months of hurricane season, making it one of the top five warmest years on record--but not as warm as the unbelievable Hurricane Season of 2005, which averaged 0.95°C above normal during August - October

[drezee]

Great Article: I will say that this is a bit alarming, given that 2005 is basically our benchmark. I honestly beleived that we would never see analmolies like that again in my lifetime. I smell case study...

http://www.aoml.noaa.gov/phod/dataphod1 ... 6atsst.png


http://www.aoml.noaa.gov/phod/dataphod1 ... 6atsst.png

[drezee]

if you look at purely the MDR, it is warmer than May 1 of last year...

[drezee]

Buoy Point Analysis in MDR: more to come

Buoy 41041
Location: 14.357 N 46.008 W (14°21'24" N 46°0'30" W)
SST is 26.5C

In years past, first day it hit 26.5 after the winter minimum:

2006 05 06 16 00 91 5.4 6.6 1.79 8.33 6.10 999 1014.7 25.5 26.5 22.0 99.0 99.00

2007 06 05 17 00 80 6.5 7.8 1.74 8.33 5.07 999 1017.2 25.7 26.5 21.6 99.0 99.00

2008 07 01 16 50 73 6.2 7.2 1.63 7.14 5.11 999 1015.5 26.1 26.5 22.0 99.0 99.00

2009 06 26 13 50 66 5.4 6.5 1.78 7.69 5.36 999 1017.9 25.9 26.5 999.0 99.0 99.00

Average day June 9th (2005 data not available)

Buoy 41040
Location: 14.477 N 53.008 W (14°28'38" N 53°0'28" W)
SST 27.4C (buoy actually hit 27.9 on light winds on Feb 27, but that is an outlier)

2006 05 20 19 00 78 6.5 7.7 1.93 6.67 5.40 999 1015.3 27.5 27.4 22.4 99.0 99.00

2007 05 26 20 00 82 7.9 9.2 1.83 6.67 5.18 999 1012.9 26.7 27.4 21.0 99.0 99.00

2008 07 03 15 50 61 4.7 5.8 1.48 6.67 5.13 999 1016.8 26.6 27.4 21.6 99.0 99.00

2009 06 02 17 50 88 5.6 7.3 1.69 7.69 5.50 999 1015.2 26.8 27.4 22.7 99.0 99.00

Average day June 5th (2005 data not available)

[drezee]

Another interesting tidbit, 2008 was coolest in MDR...we had 0.5 hurricane days East of 60W and South of 20N...

2009 had 3.5
2007 had 1.5
2006 had 1

[KWT]

Worth noting as I've said several times a BIG change occuring in the Atlantic, with the models starting to develop a strong upper high over the subtropics so we may see some slight cooldown occuring in the SSTA's in the next couple of months if that holds for any length of time.

[cycloneye]

This graphic updates daily so the members can follow how the ssta's are doing in the MDR area.They continue to be above average.

[drezee]

Quick update on 41041:

SST is 26.9

previous earliest to 26.9 2006 on May 12...Two months ahead of schedule...Man, I wish I had 2005 data!!!!!!!!!

[KWT]

Yep no doubt they are warm, the 12z models thus far seem to be less keen on the Bermuda/Azores high strengthening as they were a few days ago, which is never a good thing given how warm the SST's are already.

Looks like things are much faster then normal.

[drezee]

4140 is at 27.6 on March 12th

previous record earliest to 27.6 May 26th 2006....

BTW in 2008 that buoy didn't hit 27.6 until July 4th...

[Cainer]

Just thought I'd post this to show the huge difference in SST's between this time last year and now.

March 13, 2009:


March 13, 2010: