Still watching for a potential early-season Atlantic subtropical storm

By: Dr. Jeff Masters , 7:10 PM GMT on May 16, 2009

Share this Blog
1
+

The latest 00Z and 12Z runs of the GFS, UKMET, NOGAPS, and ECMWF global dynamical computer models continue to indicate the possibility of an early season subtropical storm forming in the Gulf of Mexico 3 - 7 days from now. A modest area of low shear air is expected to open up between the polar jet stream to the north and the subtropical jet stream to the south, between Cuba and the northern Gulf of Mexico. The models have not been consistent with the timing or the size of this low shear area, and I wouldn't be surprised to see them back off again from this forecast with Sunday's set of runs. Nevertheless, I'll call once again for a 10% chance of development of a subtropical depression in the eastern Gulf of Mexico, 4 - 7 days from now. There isn't much of a disturbance at present to look at--there are some scattered showers between Cuba and Jamaica, but they are under a hefty 30 knots of wind shear. These showers should gradually increase in intensity and areal coverage over the next two days, and phase space diagrams from Florida State University indicate that an extratropical low may form near the western tip of Cuba 2 - 3 days from now. The storm may then gradually transition to a subtropical or tropical system later in the week, if the shear is low enough. Even if the shear is high and the storm remains extratropical, it could be a substantial rain-maker where it comes ashore. The models target the northern Gulf Coast between Louisiana and the Florida Panhandle as the most likely landfall location, but it is too early to place any confidence in this track.

There is also about a 10% chance a subtropical storm may form in the mid-Atlantic a few hundred miles east of Bermuda. There, a large upper-level cold low has cut off from the jet stream, and it may spin in place long enough over the next week to develop a warm core and be classified as a subtropical storm. It is unlikely that a subtropical storm forming that far out in the Atlantic this early in the year would pose a threat to any land areas, with the possible exception of Bermuda.

Climatology of early-season Atlantic tropical cyclones
Tropical storms are uncommon in the Atlantic before June 1, with only 26 named storms on record between 1851 - 2008. Five of these have made it to hurricane strength, and only one--Hurricane Able of 1951--made it to major hurricane status. Last year's Tropical Storm Arthur may be the deadliest May tropical cyclone on record. Though only a 40 mph tropical storm at landfall, Arthur killed five people in Belize and caused $78 million in damage. Three early-season storms have brought hurricane-force winds to land. The March 1908 hurricane swept through the northern Lesser Antilles Islands as a Category 1 or 2 hurricane, destroying at least 24 boats and causing damage to buildings on St. Bartholomew. Hurricane Able of 1951 brought sustained winds of 90 - 95 mph to the northern Bahama Islands, but caused little damage. Hurricane 2 of May 1908 hit North Carolina's Outer Banks as a Category 1 hurricane, but also caused little damage.


Figure 1. Tracking map for the earliest hurricane to make landfall, the March 1908 hurricane in the northern Lesser Antilles Islands.

List of all early season (formed in January - May) Atlantic named storms
May 31, 2008: Tropical Storm Arthur
May 6, 2007: Subtropical Storm Andrea
April 18, 2003: Tropical Storm Ana
April 21, 1992: Subtropical Storm 1
May 6, 1981: Tropical Storm Arlene
January 18, 1978: Subtropical Storm 1
May 21, 1976: Subtropical Storm 1
May 23, 1972: Subtropical Storm Alpha
May 17, 1970: Hurricane Alma (Category 1)
May 28, 1959: Tropical Storm Arlene
February 2, 1953: Tropical Storm Alice
May 25, 1952: Tropical Storm 1
May 15, 1951: Hurricane Able (Category 3)
May 22, 1948: Tropical Storm 1
May 19, 1940: Tropical Storm 1
May 27, 1934: Tropical Storm 1
May 14, 1933: Tropical Storm 1
May 5, 1932: Tropical Storm 1
May 13, 1916: Tropical Storm 1
May 24, 1908: Hurricane 2 (Category 1)
March 6, 1908: Hurricane 1 (Category 2)
May 27, 1890: Tropical Storm 1
May 16, 1889: Hurricane 1 (Category 1)
May 17, 1887: Tropical Storm 2
May 15, 1887: Tropical Storm 1
May 30, 1865: Tropical Storm 1

I'll have an update Sunday.

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: 237 - 187

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 | 25Blog Index

Quoting WeatherStudent:
drak do you think folsk down here will be caugth entirely off guard by this thing when it begisn to affect us if the media doesn't begin to talk about this as earlya s tonight?


Can you stop with the dramatics.
Member Since: Posts: Comments:
235. IKE
Quoting stormhank:
Hey IKE....wonder if we'll get some rains up here in panhandle from what ever developes??


Yes we will....I think.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting Drakoen:


We're on the same brain wave lol. This looks more surface trough based. If it did manage to start in the Caribbean with out the upper level vortex it might become more tropical.


I was wondering that.
Im glad we are all on the same page...
Member Since: September 7, 2008 Posts: 17 Comments: 1604
Well,..thats enough of Drama Saturday for me..


Das "POOF"
Member Since: Posts: Comments:
Pressures in the Caribbean are a bit lower than their normal diurnal phase. See how long that keeps up.
Member Since: Posts: Comments:
Quoting IKE:


Okay WeatherStudentJFV....that sound better?

Now, back to the tropics.


LMAO!!!
Member Since: September 7, 2008 Posts: 17 Comments: 1604
Quoting WeatherStudent:
any south floridains on ehre if so, plz ya'll watch your local news affeliates this evening


Are you serious , you're treating this like it's a cat 5 . CHILL OUT.
Member Since: August 12, 2007 Posts: 2 Comments: 2838
Quoting WeatherStudent:
guys i've got an auncle which resides in the dry tortugas, what should he be doing now in anticipation to this storm?


WS that is a National Park, is he a ranger?
Member Since: June 12, 2005 Posts: 6 Comments: 8188
Quoting IKE:


Okay WeatherStudentJFV....that sound better?

Now, back to the tropics.


LOL
Member Since: Posts: Comments:
Hey IKE....wonder if we'll get some rains up here in panhandle from what ever developes??
Member Since: Posts: Comments:
Will be very interested in watching how the meteorologists at the local news stations here in South Florida handle the latest model solutions since this possible scenario is being portrayed much sooner and we are finally seeing rather impressive model consensus.
Member Since: Posts: Comments:
Quoting beell:
The distinction here is the "ULL" may be more of a mid-level feature. Any surface low could be looked at like any other surface reflection stacked under a closed mid-level low-they ususally tend to stay in the SE quadrant of the mid-low and deepen some. Over land or over the Gulf.

Earlier, I did think the surface low would arise mostly from a surface reflection of the cut-off low. Still on the chicken-or-the-egg fence however.

GFS has backed way off in the strength of the system at 500mb. Initial spin given from the windshift at the base of the surface trough. Amplified by good upper level conditions.


We're on the same brain wave lol. This looks more surface trough based. If it did manage to start in the Caribbean with out the upper level vortex it might become more tropical.
Member Since: Posts: Comments:
The new 18Z GFS develops the surface low now 18 hours out, or tomorrow morning south of Cuba. Seems like the GFS also develops this low much further east than the 12Z run. Seems like we may finally be getting model consensus.

Member Since: Posts: Comments:
218. beell
The distinction here is the "ULL" may be more of a mid-level feature. Any surface low could be looked at like any other surface reflection stacked under a closed mid-level low-they ususally tend to stay in the SE quadrant of the mid-low and deepen some. Over land or over the Gulf.

Earlier, I did think the surface low would arise mostly from a surface reflection of the cut-off low. Still on the chicken-or-the-egg fence however.

GFS has backed way off in the strength of the system at 500mb. Initial spin given from the windshift at the base of the surface trough. Amplified by good upper level conditions.
Member Since: Posts: Comments:
217. IKE
Quoting WeatherStudent:



I am not JFV.


Okay WeatherStudentJFV....that sound better?

Now, back to the tropics.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting IKE:
Looks like the 18Z GFS is further east on the low at 18 hours.


What I find really interesting is the fact it pops the low in the exact same spot as where the convection is now.
Member Since: September 7, 2008 Posts: 17 Comments: 1604
Buoy 42057-1009 mb and falling
Member Since: Posts: Comments:
Quoting WeatherStudent:


can i lie to you? seriously though i need to know cause i live in a high raiser in ft. lauderdale and i need to know


Relax. I live in Broward County also and I am not worried one bit. Remember it's May and the most we'll see from this system (if anything at all) is a lot of rain and some light wind (probably nothing over 50-60 mph in the most extreme case).
Member Since: Posts: Comments:
Quoting Stormchaser2007:
Whos Dral? ROFL


I'm wondering the same thing.
Member Since: Posts: Comments:
211. IKE
Looks like the 18Z GFS is further east on the low at 18 hours.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting weatherblog:


lol, same here :). I thought you would know because you stated they only affect tropical entities unless you made it up (which I doubt you did).


Well from what I understand Sub-Tropical Storms use Wind-Sheer to build convection in simple terms. :D
Member Since: September 7, 2008 Posts: 17 Comments: 1604
Whos Dral? ROFL
Member Since: Posts: Comments:
Quoting WeatherStudent:


can i lie to you? seriously though i need to know cause i live in a high raiser in ft. lauderdale and i need to know


It has not formed yet JFV.
Member Since: September 7, 2008 Posts: 17 Comments: 1604
Quoting SevereHurricane:


You tell me.
Im here to Learn.


lol, same here :). I thought you would know because you stated they only affect tropical entities unless you made it up (which I doubt you did).
Member Since: Posts: Comments:
Quoting hurricanealley:
Why was futuremet ban?



He was banned for an indefinite period of time for no reason. So I was told...
Member Since: Posts: Comments:
203. IKE
Quoting WeatherStudent:


can i lie to you? seriously though i need to know cause i live in a high raiser in ft. lauderdale and i need to know


You're JFV...the last several posts you've made would convince anyone.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Why was futuremet ban?

Member Since: Posts: Comments:
The other models especially the GFS and UKMET are showing more of an accompaniment of the upper level low for a more subtropical system.
Member Since: Posts: Comments:
Quoting weatherblog:


Ok, I see but why not subtropical?


You tell me.
Im here to Learn.
Member Since: September 7, 2008 Posts: 17 Comments: 1604
I noticed that Low Well off the SE coast. The enhanced sat. shows it good.
Member Since: Posts: Comments:
I hope this weather system, whatever it turns out to be does not mess up my bday plans, my bday is May 23rd
Member Since: August 23, 2006 Posts: 0 Comments: 121
Quoting SevereHurricane:


If its fully tropical and on a certain side of it.


Ok, I see but why not subtropical?
Member Since: Posts: Comments:
LOL...OMG,this is Like a BAD rerun on HULU.
Member Since: Posts: Comments:
Quoting WeatherStudent:
guys i've got an auncle which resides in the dry tortugas, what should he be doing now in anticipation to this storm?


It hasen't even formed yet...
Member Since: September 7, 2008 Posts: 17 Comments: 1604
Quoting WeatherStudent:


widn wise, dral???????????????


If you admit you are JFV I will tell you.
Member Since: Posts: Comments:
18z NAM
Member Since: Posts: Comments:
Quoting weatherblog:


In some cases, an ULL can destroy a storm.


If its fully tropical and on a certain side of it.
Member Since: September 7, 2008 Posts: 17 Comments: 1604

Viewing: 237 - 187

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 | 25Blog 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.

JeffMasters's Recent Photos

Lake Effort Snow Shower Over Windsor, Ontario
Sunset on Dunham Lake
Pictured Rocks Sunset
Sunset on Lake Huron