Masters student in tropical meteorology at FSU. Raised in Alaskan blizzards, but drawn toward tropical cyclones by their superior PGF.
By: Levi32 , 4:29 PM GMT on July 31, 2007
Afternoon Update on 99L:
99L is at the very best holding steady, but the circulation now looks very ragged and more like part of the ITCZ than an invest. After looking up the MJO today I saw that there is a huge downward motion pulse in the western Atlantic/Caribbean that is a graveyard for any tropical system right now. Until we move back into an upward motion pulse in 1-2 weeks we shouldn't expect a lot of developments. Unless 99L can pull a miracle during the diurnal max tonight...it's probably dead. Next wave in line probably dead as well as its too far south, and the next one after that just came off Africa and should be watched, although the outcome will probably be the same as the other 20 waves that have come off this season.
Well TD 3 beat all odds and was upgraded to TS Chantal today with 50mph winds. In reality this is a sub-tropical storm not tropical because on satellite you can clearly see a warm front and a cold front, showing that there is obviously a lot of extratropical influence. Chantal is no threat to anyone except shipping lanes, and should move across the north Atlantic as a strong extratropical low for the next few days.
99L isn't feeling that good, and after attempting a comeback last night during the diurnal max, convection has once again all but completely died this morning due to dry air. The latest QuikScat pass is 7 hours old, but it shows a poorly defined elongated circulation which is still partially embedded in the ITCZ. I don't think we will see anything come from 99L today, as the dry air will continue to choke off any convection that tries to form. However with enough time, if it survives, the system could be a threat to develop once it's in the Caribbean, where the dry air will slack off a little bit. Wind shear remains favorable, although it is forecasted to increase slightly in the central Caribbean.
None of the models are really developing this system, but it is really hard to pick up because of how weak and small it is. Right now I think the only thing 99L really needs is a well-developed surface circulation. If it can get that, then it would probably be able to survive while these intermittent bursts of convection slowly moisten the atmosphere around it. The next QuikScat pass will be interesting to see if 99L was able to do any reorganization overnight. Bottom line, this thing still needs to be watched, and will be around for a long while before it develops.
In the rest of the Atlantic we still may have a few surprises popping out of the hat. Actually they're called rabbits in the Meteorology world, but I won't get into that now. An old but vigorous cold front coming off the SE coast is spawning deep thunderstorms in the NE Gulf of Mexico and off the Carolinas. Both these areas have potential to slowly develop over the next couple days. The area off the Carolinas has the most potential, but will be no threat to land even if something comes out of it. Something else worthy of attention is yet another new wave emerging off the coast of Africa as we speak. Convection is impressive at the moment, but as usually happens will probably die off as it moves over water. What I find interesting though is that this wave is very large, and is the farthest north we have seen a wave come off this year. It is actually at the latitude of the Cape Verde Islands, making it a true Cape Verde wave. The higher latitude position of this wave gives it a huge edge over the waves before it in being able to develop. Only time will tell, but the African wave train will start heating up really soon.
We shall see what happens!
ABNT20 KNHC 311543
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT TUE JUL 31 2007
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON RECENTLY
UPGRADED TROPICAL STORM CHANTAL...LOCATED ABOUT 305 MILES SOUTH OF
HALIFAX NOVA SCOTIA.
A WEAK AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
CENTERED ABOUT 600 MILES EAST OF THE SOUTHERN WINDWARD ISLANDS AND
IS MOVING WESTWARD AROUND 10 TO 15 MPH. ALTHOUGH THIS SYSTEM HAS
BECOME LESS ORGANIZED OVER THE PAST FEW HOURS...IT STILL HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
PUBLIC ADVISORIES ON TROPICAL STORM CHANTAL ARE ISSUED UNDER WMO
HEADER WTNT33 AND UNDER AWIPS HEADER MIATCPAT3. FORECAST/ADVISORIES
ON TROPICAL STORM CHANTAL ARE ISSUED UNDER WMO HEADER WTNT23 AND
UNDER AWIPS HEADER MIATCMAT3.
^Click for Loop^
^Click for Loop^
NASA zoomed-in visible loop of 99L
Model tracks for 99L
Model intensity forecasts for 99L
SSD Dvorak Intensity Estimates
CIMSS Dvorak Intensity Estimates
SSD tropical formation probability and other maps
CIMSS satellite derived winds and analysis
Navy Tropical Cyclone Page
National Hurricane Center
NASA High-resolution GOES Satellite Imagery
CIMSS Saharan Air Layer Analysis
METEOSAT Satellite Imagery (Updated every hour)
North Atlantic WV Loop (The Big Picture)
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