An early start to hurricane season? And, tornado kills 3 in Missouri
The 2009 Atlantic hurricane season may get off to an early start. For the past two days, most of our reliable hurricane forecast models have been predicting the possibility of a subtropical depression forming near Florida or Western Cuba Monday - Thursday next week. An area of disturbed weather associated with a mid- to upper-level trough of low pressure near eastern Cuba and the southeastern Bahama Islands is predicted to slide west-northwest over the next few days. Wind shear over this low, current a prohibitively high 40 knots, is expected to relax to just 10 knots by Monday in the region surrounding Florida. This may allow a disturbance with a surface warm core to develop, according to phase space analyses from Florida State. However, since the upper atmosphere will still be cold, any development of this system will likely be subtropical in nature. If a subtropical storm does form, it may be fairly dry, like Subtropical Storm Andrea of May 2007. This storm ended up fanning fires in Florida, instead of putting them out. Water vapor loops show plenty of dry, continental air in the region, and it will take many days for the atmosphere to moisten enough to support formation of a subtropical depression.
Figure 1. Water vapor image showing moisture from a weak mid- to upper-level low of low pressure over the southeastern Bahama Islands, surrounded by a large area of dry air, and sandwiched between the polar and subtropical jet stream. Image credit: NOAA/SSD.
The GFS and NOGAPS models predict a subtropical depression could form by Tuesday, while the ECMWF shows development later in the week. The latest UKMET model forecast puts development Wednesday or Thursday near Haiti. The area of predicted development is sandwiched in a relatively narrow band of low wind shear between two branches of the jet stream. This is not a typical set-up for formation of a May tropical cyclone. With so much shear and dry air around, I put the probability of a subtropical depression forming next week at about 10%. Any developing system will also have to contend with the arrival Tuesday of a strong upper-level low pressure system that is expected to drop down over the northern Gulf of Mexico. The eventual track of any depression that forms is highly uncertain, and the models support tracks up the U.S. East Coast towards South Carolina, or up the west coast of Florida in the Gulf of Mexico.
Season's first tropical wave arrives
The season's first tropical wave rolled off the coast of Africa yesterday, and is now located near 10N 20W, a few hundred miles off the coast of Africa, according to total precipitable water loops. Mid-May is a fairly typical time for these waves to begin moving across the Atlantic, though they usually don't start developing into tropical depressions until August. Last year was an exception, when Hurricane Bertha formed from a July tropical wave. Wunderground blogger Weather456 has been tracking the date of the first African wave each year since 2004, and these dates have ranged from May 2 to May 21. With Sea Surface Temperatures near average this year in the tropical Atlantic, an early season major hurricane in the eastern Atlantic like Bertha is unlikely.
Figure 2. The line of severe thunderstorms that spawned the Kirksville, MO tornado.
A wild night in Tornado Alley
Northern Missouri took a hard hit by a powerful tornado last night, when a twister passed through Kirksville, killing three people. The tornado flipped cars and damaged 30 - 40 buildings as it tore through the north end of town. The Storm Prediction Center recorded 23 tornado reports across Missouri, Illinois, Oklahoma, and Kansas yesterday.
The Vortex2 field study, the world's largest-ever tornado research project, caught last night's tornado outbreak with its armada of 40 research vehicles and radars. You can read about yesterday's chase on our new featured Vortex2 blog. Our team of University of Michigan students caught some severe thunderstorms, but were forced by darkness to quit before the storms spawned tornadoes.
Portlight/wunderground shirts for sale
The portlight.org disaster relief charity is selling spiffy new shirts sporting the portlight and wunderground logos, to help raise funds for relief operations during the coming hurricane season. I expect that their services will be needed this year, and I encourage you to shell out the $20 to get this fine piece or wunderwear.
I'll have an update on the tropics Friday.
Jeff Masters
Most of the V2 convoy waited in Canton, OK for initiation.
Reader Comments
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Not a chance. TX is too far west right now, and the system is too far north. The high would have to build all the way through the carolinas and ohio valley to force that. The chances of a system this time of year being able to run from the Bahamas, across FL, and all the way to TX is slim-to-none. (also, too many troughs cutting through the east to pick it up and pull the system north.
Reading comments this morning I would suggest everyone be careful opening emails looks like JVF may have figured away to take over some computers.
??
I think thats a better solution on the ECM with sub-tropical development of the coast of florida i can see that happening.
With the consistent model support over the past couple days, seems almost imminent.
More aggressive on this run.
Would not be the first time, had this other pesky storm "pop up" when I was their before, that started with an M, talk about a way to ruin your lobster dinner on the beach drinknig a cold Belikin under a thatched roof
Once the middle schoolers and the workers come home, it will get interesting here. I expect the wishcasting hysteria to commence tomorrow if the models become more pugnacious
Why?? Whats the reason for this ridiculous statement? Stuff like this is what keeps me from posting to much on this blog.
Love it! :)
what..you guys aren't in junior high?????..LOL
Even better lol
Junior =]
There is no such place as "Carolina", "the Carolinas", or "the Carolina coast"...
ya got North Carolina ...and ya got South Carolina...and it's gotta be one or the other....
Thank you for your attention to this critical detail....
Yep, good word use. Now KEEPER, you know tons but surprised has an "S" not a "Z" :o) JK. You know I love you!
They should have a storm named Carolina. I wonder which 'Carolina' it would hit
Global model guidance indicates an overall weakness in the surface pressure gradient across the gulf this weekend in response to the approach of a southern plains cold front and possible low/trough emerging from near nw cuba nwd towards the vicinity of florida as suggested by the global models. As a result...wind speeds and sea heights will decrease this weekend. Winds will also shift to n-ne and increase over just about the entire gulf. Present model indications are that this low will likely form near a southwestward trailing mid-level trough associated with the aforementioned front early monday...and generally track in a n or ne direction. It is still too early pinpoint just how close to the gulf this feature will be near the gulf. This feature may be a hybrid subtropical/extratropical low over the western atlc as opposed to the gulf of mexico. Forecast confidence is currently rather low in the particulars of this scenario...and will continue to be monitored.
It is always interesting to see this board explode as soon as any model begins to pick up on something imagined or not. So many people hanging on the edge of the seat waiting for the next model run, as if it were the results for a 2 billion dollar powerball lottery.
Especially at the beginning of the season, you kinda feel like yelling Norm every time some blog buddy returns who you have not heard from since last year
lol. A better vocabulary word could be used in place of that. The connotation really doesn't fit.
The models are indeed showing an increase in moisture with the mid/upper trough near/over southeast forida next week. Looks like at least POPs near climatology, if not higher.
Tropical Update
It would be interesting to see the playball field this weekend.
There's most likely to be a surface reflection as indicated by the majority of the computer models.
yeah. ...and kansas city is in MISSOURI, not kansas. kansas city kansas is about 10 square blocks of meth houses and that's about it. :)
thanks to the vortex2 people for, hopefully, improving twister knowledge and forecasting in the midwest
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