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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You beat me too.
Where are you finding these numbers on your computer?
Curious...how much did it cost?
GOES-12 Atlantic Basin with Frame Wobble
Tropical Cyclone Formation Probability Guidance Product
Developed by the
Regional and Mesoscale Meteorology Branch at CIRA
Tropical Atlantic - Visible to Night IR Loop
Especially the new laptops HP's coming out with. Pretty crazy how much more advanced this stuff has gotten from about nine years ago.
Last Result:
Download Speed: 9696 kbps (1212 KB/sec transfer rate)
Upload Speed: 2851 kbps (356.4 KB/sec transfer rate)
Is that good or bad? LOL My laptop is SUPER fast so I take it that is good?
Yeah thats very good. Curious, what OS?
What's up with that "wobble?" Strange. It's not a misalignment. It stretches, but not everywhere.
Never seen such a thing before. Seen jumps, but due to a missing frame.
Nice to see you, been a long time.
It's shrinking! It's shrinking! [/quote - 2010 The Movie]
The shear over the blob is shrinking!
Upload: 21022 kbps
Yea
Upload Speed: 4448 kbps (556 KB/sec transfer rate)
No way. Im pretty sure that if you were that fast the FBI would be knocking on your door.
Ah finally someone with Fios.
I can't handle you anymore..Since you can't just admit it..your going to make number one on my list.
That's what I'm saying, something must be wrong. Does it matter that I have my laptop hooked up to my desktop?
850 hPa Vorticity
North Atlantic
Get a second opinion
"Shame-based" behavior can be corrected in most U.S. citizens...but in the case of middle-east / south asia cultures...fugetaboutit!
GOM 84 Hour Wind Forecast
& StormW, your download speed is ridiculously fast, cool
Doing well - how about you? Glad to see another female has appeared - the guys seem to be ruling tonight, lol
In this loop, things are moving N in the N portion and S in the S portion.
Link
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