ATL: TROPICAL DEPRESSION ALEX - DISCUSSION

[KWT]

I just think it spun up because the convection held there for quite some time as well Sanibel...

Interesting that they've put up possible tropical cyclone on that Cycloneye, seems to also confirm the idea that its going to pass very close to Yucatan, as that gives a pretty good indication as to what the thinking is at the moment with this system.

[Air Force Met]

That MLC could be a vortex from island interaction.


Obvious energy in the convection but poor organization. The longer it keeps that energy the more likely it will form.

Doubtful. That MLC has been there all day. I first saw it early this morning well south of the islands. It formed because of the deep convection in the area.

[Florida1118]

It looks better organized to day than yesterday, but starting to look a little less in the last 1hr or so...

[Ivanhater]

Much more spin

[I-wall]

Can someone explain in layman's terms why there is no rotation? Thank you.

There needs to be a low pressure area before any rotation develops. Rotation is a result of the air funneling towards the low pressure.

[vbhoutex]

Yes, thanks for the explanation/lesson AFM. What I am seeing now makes more sense to me. I can definitely see the spin of the low pressure area now and the MLC is becoming a little more apparent to me since it appears there is some convection beginning to blossom in that area. Next 24-36 hrs. could be interesting.

[cycloneye]

ABNT20 KNHC 222333
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT TUE JUN 22 2010

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A TROPICAL WAVE OVER THE CENTRAL CARIBBEAN SEA IS MOVING WESTWARD
ABOUT 10 MPH AND IS SPREADING CLOUDINESS AND THUNDERSTORMS OVER
PORTIONS OF THE DOMINICAN REPUBLIC...HAITI... JAMAICA...AND EASTERN
CUBA. THIS SYSTEM HAS CHANGED LITTLE IN ORGANIZATION TODAY BUT
ENVIRONMENTAL CONDITIONS ARE FORECAST TO BECOME MORE FAVORABLE FOR
SLOW DEVELOPMENT AS THE WAVE REACHES THE WESTERN CARIBBEAN SEA IN A
DAY OR TWO. THERE IS A LOW CHANCE...20 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER AVILA/ROBERTS

[Florida1118]

Still 20%?

[cycloneye]

Still 20%?

But this is the important sentence.

ENVIRONMENTAL CONDITIONS ARE FORECAST TO BECOME MORE FAVORABLE FOR
SLOW DEVELOPMENT AS THE WAVE REACHES THE WESTERN CARIBBEAN SEA IN A
DAY OR TWO

[KWT]

Yeah because the system, esp that MLC is currently in the fairly divergent but slightly sheared region on the very eastern side of an upper hight. Once the wave axis makes it under the upper high itself and develops some convergence for itself things should start to get going. Sometimes it takes land itself to help kick start that process it should be noted.

[brunota2003]

When was the last time that three major models formed a strong TS/Hurricane in the same general area and something did not form?

[ROCK]

AFM...I was saying that more in jest than anything so no disrespect to the HPC. Clearing there is a difference between the to orgs. I for one put more faith in the NHC than I would the HPC when it comes to TCs though. There is a reason they are not one organization....JMO...


BTW- glad to see you back and representing Pearland once more...

[cycloneye]

ROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE JUN 22 2010

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND
RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2230 UTC...

...SPECIAL FEATURES...

A STRONG TROPICAL WAVE IS MOVING THROUGH THE CENTRAL CARIBBEAN
EXTENDING FROM TURKS AND CAICOS NEAR 21N73W ACROSS THE WINDWARD
PASSAGE TO THE COAST OF COLOMBIA NEAR 11N74W MOVING W NEAR 12
KT. THE WAVE IS ACCOMPANIED BY A LARGE AREA OF DEEP LAYER
MOISTURE THAT COVERS THE ENTIRE CENTRAL AND ERN HALF OF THE
CARIBBEAN EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. BROAD LOW
TO MID-LEVEL CYCLONIC FLOW IS ABOUT THE WAVE. SCATTERED
MODERATE/STRONG CONVECTION IS FROM 14N-19N BETWEEN 66W-72W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-21N
BETWEEN 72W-78W. THIS LARGE AREA OF ACTIVITY IS EXPECTED TO
BRING 4-7 INCHES OF RAIN TO HISPANIOLA. HEAVY RAINFALL IS ALSO
POSSIBLE ACROSS PUERTO RICO.

http://www.storm2k.org/weather/hw3.php? ... hwvmetric=

[jlauderdal]

Still 20%?

For the newbies, its very important to know that the percentage means tropical cyclone development in the next 48 hours. It doesn't mean that there is a 20% percent chance of development beyond that. They could think cat 5 in 5 days but only 20% chance of development in the next 48.

In summary, the percentage is only for the next 48 hours and not one second beyond that. However, they are saying conditions look favorable beyond 48 hours so you would expect that percentage to start going up as long as those favorable conditions continue to be seen.

[Aquawind]

Ok Now I see a naked swirl near the surface ~77W 16N .. Closest to a LLC I have seen of yet.. Near the area AFM mentioned I see. That's all I needed to do was leave for a bit like jason mentioned..lol

http://www.ssd.noaa.gov/goes/flt/t1/flash-vis.html

[cycloneye]

00 UTC Best Track

AL, 93, 2010062300, , BEST, 0, 156N, 752W, 25, 1010, WV

Whole 93L Best Track positions

[KWT]

Ok Now I see a naked swirl near the surface ~77W 16N .. Closest to a LLC I have seen of yet.. Near the area AFM mentioned I see. That's all I needed to do was leave for a bit like jason mentioned..lol

http://www.ssd.noaa.gov/goes/flt/t1/flash-vis.html

Ah I think you've found the western edge of that broad low, if you look you can see the whole broad low circulating with the convection developing on the western side of the circulation, any tighter low I'd imagine would form near the convection if it can hold and develop a MLC.

[Comanche]

Can anyone tell me what looks good about this loop? All I see is 95% of the convection, moving rapidly off to the NE.

http://www.ssd.noaa.gov/goes/east/tatl/flash-wv.html

[HouTXmetro]

Looks like convection is trying to re-fire around the MLC....I also see some convection trying to generate where the sharp wave axis is.

[Nimbus]

If there is vorticity at the surface its probably back near 72w. There is some displacement of the convection by the shear at the mid levels. There should be a clearer dominant center evident in the first morning visible shots.