TSR predicts very active hurricane season; Atlantic May MDR SSTs warmest on record

By: Dr. Jeff Masters , 13:51 GMT le 10 juin 2010

Share this Blog
4
+

The British private forecasting firm Tropical Storm Risk, Inc. (TSR) has joined the ranks of NOAA and Colorado State University in calling for an exceptionally active 2010 Atlantic hurricane season. The latest TSR forecast issued June 4 calls for 17.7 named storms, 9.5 hurricanes, 4.4 intense hurricanes, and an Accumulated Cyclone Energy (ACE) 181% of average. These numbers are much above the 50-year average of 10 named storms, 6 hurricanes, and 2 intense hurricanes, and are an increase from their April forecast of 16.3 named storms, 8.5 hurricanes, and 4 intense hurricanes. The TSR June forecast numbers are the highest they've ever gone for in the eleven years they've been issuing Atlantic hurricane season forecasts. TSR predicts a 85-90% chance that activity will rank in the top 1/3 of years historically, and a 85% chance that U.S. landfalling activity will be above average. TSR rates their skill level as 20-34% higher than a "no-skill" forecast made using climatology, though an independent assessment by the National Hurricane Center (Figure 1) gives them somewhat lower skill numbers.

TSR projects that 5.7 named storms will hit the U.S., with 2.5 of these being hurricanes. The averages from the 1950-2009 climatology are 3.2 named storms and 1.5 hurricanes. They rate their skill at making these June forecasts for U.S. landfalls at 10 - 17% higher than a "no-skill" forecast made using climatology. In the Lesser Antilles Islands of the Caribbean, TSR projects 1.8 named storms, 0.8 of these being hurricanes. Climatology is 1.1 named storms and 0.5 hurricanes.

TSR cites two main factors for their forecast of an exceptionally active season:

1) Their model predicts that sea surface temperatures will be 0.6°C warmer than average in August and September over the Main Development Region (MDR) for Atlantic hurricanes. This is the area between 10°N and 20°N, between the coast of Africa and Central America (20°W - 80°W). It is called the Main Development Region 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.)

2) Their model predicts slower than normal trade winds in August and September over the Main Development Region (MDR). Trade winds are forecast to be 1.2 meters per second (about 2.7 mph) slower than average. This would create more spin for developing storms, and allow the oceans to warm up, due to reduced mixing of cold water from the depths and lower evaporational cooling.


Figure 1. Comparison of the percent improvement over climatology for May and August seasonal hurricane forecasts for the Atlantic from NOAA, CSU and tropicalstormrisk.com (TSR) from 1999-2009 (May) and 1998-2009 (August), using the Mean Squared Error. Image credit: Verification of 12 years of NOAA seasonal hurricane forecasts, National Hurricane Center.

2010 hurricane season forecasts from CSU and NOAA
NOAA's 2010 Atlantic hurricane season forecast, issued May 27, called for 18.5 named storms, 11 hurricanes, 5 major hurricanes, and an ACE index 210% of normal (using the mid-point of their range of numbers.) The 2010 Atlantic hurricane season forecast from Colorado State University (CSU) issued on June 2 called for 18 named storms, 10 hurricanes, and 5 intense hurricanes. So, the consensus forecast from NOAA, CSU, and TSR is 18 named storms, 10 hurricanes, and 5 intense hurricanes. The June forecast numbers from all three groups were the highest they've ever gone for in their history of issuing Atlantic hurricane season forecasts.

May SSTs in the tropical Atlantic set a new record
Sea Surface Temperatures (SSTs) in the Atlantic's Main Development Region for hurricanes had their warmest May 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. SSTs in the Main Development Region (10°N to 20°N and 20°W to 80°W) were a remarkable 1.51°C above average during May. This is the fourth straight record warm month, and the warmest anomaly measured for any month. The previous record warmest anomaly for the Atlantic MDR was 1.46°C, set last month. Third place goes to June 2005 and March 2010, with a 1.26°C anomaly. 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, though global warming and Atlantic Multidecadal Oscillation (AMO) also play a role. However, trade winds over the tropical Atlantic have increased to near-normal speeds over the past week, since the Bermuda-Azores High has strengthened to near-normal pressures. The Bermuda-Azores High and its associated trade winds are forecast to increase to above average strength during mid-June, according to the latest runs of the GFS model. This means that Atlantic SST anomalies have probably peaked for the year, and we can anticipate that the June SST anomaly in the MDR will not be as great as the May anomaly--and may even fall below the June record set in 2005.


Figure 2. The departure of sea surface temperature (SST) from average for June 10, 2010. Image credit: NOAA/NESDIS.

Oil spill update
Light southeast or south winds of 5 - 15 knots will blow today through Tuesday, according to the latest marine forecast from NOAA. These winds will keep oil near the beaches of Alabama, Mississippi, and the extreme western Florida Panhandle, according to the latest trajectory forecasts from NOAA and the State of Louisiana. The latest ocean current forecasts from the NOAA HYCOM model are not predicting eastward-moving ocean currents along the Florida Panhandle coast this week, and it is unlikely that surface oil will affect areas of Florida east of Pensacola. Long range surface wind forecasts from the GFS model for the period 8 - 14 days from now show a southeasterly wind regime, which would prevent any further progress of the oil eastwards along the Florida Panhandle, and would tend to bring significant amounts of oil back to the shores of eastern Louisiana next week. If you spot oil, send in your report to http://www.gulfcoastspill.com/, whose mission is to help the Gulf Coast recovery by creating a daily record of the oil spill.


Figure 3. The oil spill as imaged on June 9, 2010, by NOAA's Terra satellite. The spill appears highly reflective in the sunglint portion of the image.

Oil spill resources
My post, What a hurricane would do the Deepwater Horizon oil spill
NOAA's fact sheet on Hurricanes and the Oil Spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
Oil trajectory forecasts from NOAA
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
Synthetic Aperture Radar (SAR) imagery from the University of Miami

I'll have a new post on Friday. The tropical Atlantic is quiet right now, with no models predicting tropical cyclone development over the next seven days.

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: 1500 - 1450

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30Blog Index

1500. cg2916
17:30 GMT le 11 juin 2010
NEW BLOG!!!
Member Since: 21 décembre 2007 Posts: 13 Comments: 3026
1499. cg2916
17:29 GMT le 11 juin 2010
New blog!
Member Since: 21 décembre 2007 Posts: 13 Comments: 3026
1498. stillwaiting
17:07 GMT le 11 juin 2010
Quoting Levi32:


One good reason why it won't, among other things, is that surface pressures are over 1018mb in the area, and will be rising to over 1020mb during the next day or so. Nothing will develop under that kind of high pressure.




what about 100-200 miles east of the bahamas????possible???
Member Since: 5 octobre 2007 Posts: 20 Comments: 4970
1497. AussieStorm
16:36 GMT le 11 juin 2010
Quoting Chicklit:
Good morning/afternoon.
Wondering if something can spin up around 33/75 near the Carolinas.
Loop

More of it
here
here
and here
Member Since: 30 septembre 2007 Posts: 9 Comments: 15750
1496. indianrivguy
16:35 GMT le 11 juin 2010
Quoting errantlythought:


Oh good lord, conspiracy moar elsewhere. Also try actual sources, not worthless blogs.

Especially when said worthless blogs report the story a month late to make it appear this is magically happening now.


no need to be so rude.. Orca is a respected and well liked member here.
Member Since: 23 septembre 2006 Posts: 1 Comments: 2428
1495. ElConando
16:33 GMT le 11 juin 2010
New BLOG!
Member Since: 6 septembre 2009 Posts: 2 Comments: 3709
1494. IKE
16:30 GMT le 11 juin 2010
NEW BLOG!
Member Since: 9 juin 2005 Posts: 23 Comments: 37858
1493. cyclonekid
16:29 GMT le 11 juin 2010
Hmmmm...this is just a random area that I saw. An area in the CPAC...too low in latitude for anything to develop but certainly interesting.



But in the meantime...here's what i'm looking at in the atlantic.



**ALL IMAGES MADE BY CYCLONEKID**
Member Since: 14 juillet 2009 Posts: 51 Comments: 1715
1491. NCHurricane2009
16:16 GMT le 11 juin 2010
Quoting Levi32:


24 hours....heavily baroclinic. From there it gets kicked out to the northeast. No chance of acquiring tropical characteristics of any kind. Not every wrapped up occluded system will get them.



http://www.ssd.noaa.gov/goes/east/nwatl/flash-vis.html

Satellite animation shows the low heading ESE right now. Clicking on the check box HDW-high shows upper-level winds NWerly, its caught on the back side of its parent upper trough, which is why its heading ESE.

Maybe later it will track NE if its get caught back into the east side of its parent upper trough. Not really excited about this system yet either until I see some convection at the center.

EDIT: I think the most baroclinic part is off to the east now that its occluded. But it is true that not all deeply-occluded systems become tropical because they often don't run into enough atm. instability (warm enough SSTs coupled with cold enough upper low/trough) to develop convection.
Member Since: 15 septembre 2009 Posts: 391 Comments: 3519
1490. SouthALWX
16:15 GMT le 11 juin 2010
Quoting StormW:


Here's a little something that explains how the QBO MAY affect Atlantic storms. From one of Dr. Grey's seasonal forecasts. In my research, found the QBO affects only the region as far N-S as 15 deg. max. Again, the QBO may not have much in a warm AMO, but then again in 2005, the majority of systems either developed, or gained strength at or above 15N

2. QBO winds as a long-range predictor of hurricane activity

a. QBO variability

The easterly and westerly modes of stratospheric QBO zonal winds that circle the globe over the equatorial regions have a substantial influence on Atlantic tropical cyclone activity (Gray 1984a; Shapiro 1989). About twice as much intense-hurricane activity (Vmax > 50 m s-1) occurs during seasons when the stratospheric QBO winds at 50 mb (20-km level) are in the westerly anomaly mode. As illustrated in Figs. 1 and 2, the absolute values of the zonal vertical wind shear between 50 mb (20 km) and 30 mb, (23 km) is relatively small in west-phase seasons. Table 2 shows the associations of forward-extrapolated (from November to September) stratospheric QBO zonal winds and Atlantic hurricane activity, particularly intense-hurricane activity. Note the large differences in the numbers of intense hurricane activity that occur between these two QBO stratified 15-yr groupings. Figure 3 shows the large differences in intense-hurricane tracks that are associated with these contrasting extrapolated QBO zonalwind variations.

The physical cause of these QBO-linked differences may be due to the contrasting stratospheric horizontal wind ventilation processes across the top of the hurricane, as illustrated in Fig. 2 and discussed by Gray (1988). During the east phase of the QBO, the absolute value of the stratospheric QBO winds at latitudes of 10�-15�N are strongly from the east. This condition causes net advection of hurricane structural elements that extend into the lower stratosphere away from the hurricane center. This relative advection is likely to act to restrain the stratospheric contribution to hurricane development and intensification. By contrast, during the west phase of the QBO, the absolute value of the zonal wind in the stratosphere (over hurricanes) at 10�- 15� N is weak. In this case, comparatively small horizontal wind ventilation may occur in the lower stratosphere (Fig. 2). This west-phase condition is a positive influence on the inner-core intensity of developing hurricanes. In this way the QBO west phase is a positive cyclone influence, and the east phase a negative influence. Additionally, it is possible that the QBO exerts other dynamical influences upon the largescale environment within which the hurricanes form. These involve hydrostatic height and temperature field differences associated with east and west phases of the QBO. Recent work (e.g., Gray et al. 1992a,b) shows support for these ideas; however, continued research into the QBO-tropical cyclone association is needed.


I actually have wondered if perhaps the easterly QBO would help keep waves weak and therfore following the trades until they gained enough latitude to get away from the negative effects ...Right about when they get into the carribean sounds right .. oh and where might they go? Yeah it might be a stretch but I think it's plausible that while it suppresses storms initially, if coupled with favorable conditions on the reciving end, it might lead to more landfalls despite a modestly lesser total ACE or storm number.
Member Since: 27 août 2008 Posts: 0 Comments: 1497
1486. SouthALWX
16:07 GMT le 11 juin 2010
this is interesting ... found it while I was verifying some of the acronyms (they are trickly little suckers sometimes .. especially spelling!)


The discovery of the QBO

The eruption of the Krakatau volcano (6 ° S 105 ° E) on August 27th 1883 led people to believe that the stratospheric wind above the equator blew in a westward direction. Dust from the eruption took 13 days to circle the equator and this upper air wind became known as the Krakatau easterlies.

In 1908 Berson launched observational balloons above Lake Victoria in Africa and found westerly winds at about 15km (120mb). These westerly winds are called Berson's westerlies.
These conflicting results were resolved through the work of Reed (1961) and Veryard and Edbon (1961), who showed that the wind above the equator oscillates in direction. It was shown that the wind in the stratosphere changed direction on average every 26 months and that the alternating easterly and westerly wind regimes descend with time.
Member Since: 27 août 2008 Posts: 0 Comments: 1497
1485. Levi32
16:05 GMT le 11 juin 2010
Quoting NCHurricane2009:
Surface analysis in post 1475 has NW Atlantic low at 1005 mb with occlusion, again just first step in low-level warm core. We'll have to wait and see if convection starts (comment in post 1465 explains how I believe it can start depending on stability of atm.)


24 hours....heavily baroclinic. From there it gets kicked out to the northeast. No chance of acquiring tropical characteristics of any kind. Not every wrapped up occluded system will get them.

Member Since: 24 novembre 2005 Posts: 628 Comments: 26465
1483. Levi32
16:03 GMT le 11 juin 2010
Quoting Chicklit:
Good morning/afternoon.
Wondering if something can spin up around 33/75 near the Carolinas.
Loop


One good reason why it won't, among other things, is that surface pressures are over 1018mb in the area, and will be rising to over 1020mb during the next day or so. Nothing will develop under that kind of high pressure.
Member Since: 24 novembre 2005 Posts: 628 Comments: 26465
1482. SouthALWX
16:02 GMT le 11 juin 2010
Quoting StormW:


Actually...we are in an easterly QBO...as was 2005.

thanks for the correction, typo.
Member Since: 27 août 2008 Posts: 0 Comments: 1497
1481. NCHurricane2009
16:01 GMT le 11 juin 2010
Surface analysis in post 1475 has NW Atlantic low at 1005 mb with occlusion, again just first step in low-level warm core. We'll have to wait and see if convection starts (comment in post 1465 explains how I believe it can start depending on stability of atm.)
Member Since: 15 septembre 2009 Posts: 391 Comments: 3519
1478. SouthALWX
15:59 GMT le 11 juin 2010
Quoting MiamiHurricanes09:
Remember with the remnants of Agatha he insisted that the remnants were going to affect North Carolina and that he would "bet anything" on it. Now enough of this man. Back to the dead tropics.

anyway ... Once we get something that looks decent Ill start making posts again more often...
In the meantime a refresher course:
A) Above average SSTs in the tropical atlantic points to higher than average storms and intensity
B) El Nino transitioning rapidly to La Nina as evidenced by subsurface temperature anomalies and the positive Southern Oscillation Index (SOI)also indicates increased activity.
C) Strong Atlantic tripole focuses heat to the tropics and tends to shift tracks westward.
D) Predominant negative north atlantic oscillation points to westward tracks(-NAO)
E) Shift to Cold Pacific Decadal Oscillation (-PDO) climatological occurs near the peak of the Warm phase Atlantic Multidecadal OScillation (AMO).. this is also evidenced by recent readings indicating the highest values we use to determine AMO are occuring now and just recently
F) average to above average rainfall in the Sahel region of Africa should help keep dust near average.
G) very active wavetrain off of africa
H) while a easterly Quasi-Biennial zonal wind oscillation (QBO)prevails, this was present during 2005 as well and most professionals no longer use this to forecast activity as it shows little skill in the warm AMO phase ...



okay Im done ... time to go .. do stuff
edit: fixed typo
Member Since: 27 août 2008 Posts: 0 Comments: 1497
1476. Chicklit
15:59 GMT le 11 juin 2010
Good morning/afternoon.
Wondering if something can spin up around 33/75 near the Carolinas.
Loop
Member Since: 11 juillet 2006 Posts: 14 Comments: 11047
1475. BDAwx
15:59 GMT le 11 juin 2010
Member Since: 3 août 2009 Posts: 51 Comments: 525
1474. MiamiHurricanes09
15:58 GMT le 11 juin 2010
Quoting StormW:




Do you have one for La Nina years?
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032
1472. MiamiHurricanes09
15:57 GMT le 11 juin 2010
Quoting StormW:




Hmmm... Not liking that one.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032
1470. MiamiHurricanes09
15:54 GMT le 11 juin 2010
Quoting Levi32:
Good morning everyone.

Tropical Tidbit for Friday, June 11th
Good morning/afternoon!
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032
1469. errantlythought
15:53 GMT le 11 juin 2010
Quoting Orcasystems:
Responsible Companies Try Wriggling Out of Paying Oil Spill Costs
By: Scott Nance
June 7th, 2010 @ 9:35 pm

Its already starting... wait for it


Oh good lord, conspiracy moar elsewhere. Also try actual sources, not worthless blogs.

Especially when said worthless blogs report the story a month late to make it appear this is magically happening now.
Member Since: 27 août 2005 Posts: 0 Comments: 191
1468. Levi32
15:53 GMT le 11 juin 2010
Good morning everyone.

Tropical Tidbit for Friday, June 11th
Member Since: 24 novembre 2005 Posts: 628 Comments: 26465
1466. MiamiHurricanes09
15:52 GMT le 11 juin 2010
Quoting StormW:


Care to be more specific Lat/Long wise?
Just north of Panama. Ummm, here's a picture:



lol
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032
1465. NCHurricane2009
15:51 GMT le 11 juin 2010
Quoting MiamiHurricanes09:
SSTs don't support subtropical or for that matter tropical development.


I see it is crossing ESE along north wall of Gulf Stream, and we saw Vince 2005 and Grace 2009 develop over SSTs below 26 deg C. You're right, it could be that SSTs are too cool, but I think you also have to look at upper air temps too. If upper air is really cold in its parent upper trough/low (like with Grace), then you can induce instability with SSTs and low-level temps cooler than 26 deg C.

I think this process is impossible with surface temps in the teens deg C, but as this system crosses toward Gulf Stream (temps toward 20s deg C), depending on upper air temp), maybe convection could develop. Just curious, wonder what upper air (200 mb) temp is?
Member Since: 15 septembre 2009 Posts: 391 Comments: 3519
1463. 850Realtor
15:50 GMT le 11 juin 2010
What's the latest news on Alex? Is he feeling any better?
Member Since: 14 septembre 2009 Posts: 0 Comments: 283
1462. 850Realtor
15:49 GMT le 11 juin 2010
Sorry...image didn't post. It was the image from post 1212 by DestinJeff.
Member Since: 14 septembre 2009 Posts: 0 Comments: 283
1460. MiamiHurricanes09
15:48 GMT le 11 juin 2010
Quoting StormW:
Atlantic Hurricane Tracks El Nino vs La Nina

Atlantic Hurricane Tracks
The Caribbean, GOM coast, and eastern seaboard are all much more greatly affected during La Nina. Not a good sign for this upcoming year.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032
1459. MiamiHurricanes09
15:47 GMT le 11 juin 2010
Quoting SouthALWX:

anyone who says he'll "bet anything" when talking about a specific forecast being accurate ... especially weeks/months in advance ...is exceptionally arrogant. Right or wrong it doesnt matter. His attitude is horrible.
Remember with the remnants of Agatha he insisted that the remnants were going to affect North Carolina and that he would "bet anything" on it. Now enough of this man. Back to the dead tropics.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032
1458. 850Realtor
15:46 GMT le 11 juin 2010
Quoting DestinJeff:


you just know this is coming ...

"This wave looks very impressive for June. IMO it is the one to watch for possible development."


How long will this take to come across Africa?
Member Since: 14 septembre 2009 Posts: 0 Comments: 283
1456. MiamiHurricanes09
15:45 GMT le 11 juin 2010
Quoting NCHurricane2009:


Darn, can't see from NHC surface analysis in tropical weather discussion if it has an occluded front, first step toward low-level warm core. Then we need convection to advance that warm core.

Keeping only a faint eye on it at this time too until convection starts to develop.
SSTs don't support subtropical or for that matter tropical development.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032
1455. NCHurricane2009
15:44 GMT le 11 juin 2010
Quoting MiamiHurricanes09:
It looks nice, but should not be recognized as anything that could possibly develop.


Darn, can't see from NHC surface analysis in tropical weather discussion if it has an occluded front, first step toward low-level warm core. Then we need convection to advance that warm core.

Keeping only a faint eye on it at this time too until convection starts to develop.
Member Since: 15 septembre 2009 Posts: 391 Comments: 3519
1453. MiamiHurricanes09
15:44 GMT le 11 juin 2010
Quoting StormW:


Good article...good section on the NAO:

Forecasting U.S. Hurricanes 6 Months in Advance
Hello! What do you think about the SW Caribbean being completely closed off for development as Jeff9641 insisted on.

By the way thanks for the link.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032
1452. SouthALWX
15:42 GMT le 11 juin 2010
Quoting FLWeatherFreak91:
It may sound ridiculous to you, (I won't give an opinion on it) but why don't you wait to see if he's right before you put him on your ignore list? Because it seems to me that by putting someone that you said yourself sounds knowledgeable on your ignore list is arrogant.

anyone who says he'll "bet anything" when talking about a specific forecast being accurate ... especially weeks/months in advance ...is exceptionally arrogant. Right or wrong it doesnt matter. His attitude is horrible.
Member Since: 27 août 2008 Posts: 0 Comments: 1497
1451. MiamiHurricanes09
15:42 GMT le 11 juin 2010
Quoting SouthALWX:

With the predominant -NAO I expect further west. If it begins to stay neutral or positive I feel the east coast faces more threats. Also, the atlantic tripole should help steer most things west as well as it reinforces the high.
True.
Member Since: 2 septembre 2009 Posts: 130 Comments: 21032

Viewing: 1500 - 1450

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30Blog 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.

Local Weather

Clear
46 ° F
Ciel dégagé