[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 030004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE OCT 02 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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
2315 UTC.

...SPECIAL FEATURE...

AS OF THE 02/2100 UTC...A 1005 MB AREA OF LOW PRESSURE IS OVER
THE GULF OF MEXICO NEAR 26N84W OR ABOUT 125 MILES W-SW OF FORT
MYERS FLORIDA. THIS SYSTEM COUPLED WITH A BROAD UPPER-LEVEL LOW
OVER THE AREA IS PRODUCING SHOWERS AND TSTMS OVER THE EASTERN
GULF...WITH THE MOST CONCENTRATED CLUSTER OF MODERATE CONVECTION
FROM 24N-28N BETWEEN 84W-88W. THIS SYSTEM SHOWS SOME SIGNS OF
ORGANIZATION...AND HAS THE POTENTIAL TO EVOLVE INTO A SUBTROPICAL
OR TROPICAL CYCLONE DURING THE NEXT DAY OR SO AS IT MOVES TO THE
W OR W-NW NEAR 10 KT.  INTERESTS ALONG THE NORTHERN GULF COAST
SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. FRESH TO STRONG NE
WINDS HAVE CONTINUED TO BLOW OVER THE NE GULF DUE TO THE
INTERACTION BETWEEN THE SFC LOW AND STRONG HIGH PRES JUST SE OF
THE CANADIAN MARITIMES. SEAS AT THE MID GULF BUOY 42001 HAVE
BEEN IN THE 10 FT RANGE FOR THE LAST SEVERAL HOURS...WHICH IS
BEING HANDLED WELL BY THE NEW MULTIGRID WW3 MODEL.


...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 35W/36W S OF 15N MOVING W NEAR 15 KT.
THIS WAVE CONTINUES TO SHOW UP WELL IN BOTH CONVENTIONAL AND
DERIVED SATELLITE PRODUCTS...ALTHOUGH APPEARS TO BE CATCHING UP
TO THE REMNANTS OF MELISSA TO ITS NW NEAR 19N44W. SCATTERED
CLUSTERS OF MODERATE CONVECTION REMAIN DISORGANIZED BUT COVER
THE FAIRLY LARGE AREA WITHIN 350 NM EITHER SIDE OF THE AXIS.

TROPICAL WAVE IS ALONG 49W S OF 14N MOVING W 10-15 KT. THIS WAVE
REMAINS DIFFICULT TO LOCATE VIA SATELLITE...WITH VERY LITTLE
SHOWER ACTIVITY OR EVEN CLOUDINESS IN THE VICINITY. THUS...THE
POSITION REMAINS BASED MAINLY ON CONTINUITY.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N13W 7N23W 9N38W 8N60W. MOST OF THE
CONVECTION NEAR THE ITCZ IS CONFINED TO THE REGION NEAR THE
TROPICAL WAVE ALONG 36W. ISOLATED SHOWERS AND TSTMS ARE
ELSEWHERE WITHIN 300 NM S OF THE AXIS E OF 30W TO THE AFRICAN
COAST.

DISCUSSION...

GULF OF MEXICO...
THE MAIN ACTIVITY IN THE GULF IS ASSOCIATED WITH THE DEEP
LAYERED LOW OVER THE ERN GULF AS DESCRIBED ABOVE IN SPECIAL
FEATURE SECTION. THE WRN GULF W OF 91W IS MUCH MORE
TRANQUIL...WITH VERY DRY MID TO UPPER AIR IN PLACE AND SPREADING
SW THROUGH MEXICO WITH UPPER NE FLOW. THE SFC PRES GRADIENT IS
ALSO WEAKER IN THE WRN GULF WITH WINDS MOSTLY 15 KT OR LESS.

CARIBBEAN SEA...
SCATTERED SHOWER AND ISOLATED TSTMS PERSIST S OF CUBA AND
HISPANIOLA THIS EVENING...MOST CONCENTRATED N OF 14N BETWEEN
75W-83W...AND ALSO N OF 15N BETWEEN 69W-74W. LOW LEVEL
CONVERGENCE IS THE MAIN TRIGGER FOR THIS ACTIVITY...BETWEEN THE
FLOW AROUND THE SPECIAL FEATURE OVER THE ERN GULF COLLIDING WITH
THE MORE TYPICAL TRADE FLOW FROM THE ERN CARIBBEAN. THE FAR NW
PORTION OF THE BASIN/YUCATAN CHANNEL HAS VERY LITTLE CLOUD
COVER/SHOWER ACTIVITY DUE TO A SWATH OF DRY AIR ROTATING THROUGH
THE AREA AROUND THE UPPER LOW FROM THE GULF. A LARGE SCALE UPPER
RIDGE FROM THE WRN ATLC COVERS THE BASIN BETWEEN 63W-82W...WHILE
UPPER MOISTURE AND A FEW SHOWERS ARE OVER THE FAR SE CARIBBEAN
ASSOCIATED WITH AN UPPER LOW JUST E OF BARBADOS. SCATTERED
SHOWER ACTIVITY TO PERSIST ESPECIALLY BETWEEN 72W-84W THROUGH
WED...WITH LIFT AHEAD OF THE UPPER LOW OVER THE GULF AND LOW
LEVEL CONFLUENCE PERSISTING.

ATLANTIC OCEAN...
MESSY WEATHER PERSISTS OVER THE WRN ATLC THIS EVENING ASSOCIATED
WITH A VERY DIFFLUENT PATTERN ALOFT...BETWEEN THE UPPER LOW OVER
THE ERN GULF AND AN UPPER HIGH NEAR THE SE BAHAMAS. LIFT S OF
THE WARM FRONT EXTENDING ENE FROM NORTHERN FLORIDA IS ALSO
SUPPORTING THIS ACTIVITY. THE MOST CONCENTRATED AREAS OF
CONVECTION ARE CURRENTLY OVER THE STRAITS OF FLORIDA S OF 25N
BETWEEN 77W-81W...AND ALSO NE OF THE BAHAMAS FROM 23N-29N
BETWEEN 66W-75W. THE REMNANT FRONTAL BOUNDARY CLIPS THE AREA
ALONG 32N46W STRETCHING W TO THE COAST OF N FLORIDA NEAR 29N81W.
BESIDES FOR THE ACTIVITY ALREADY OUTLINED...SCATTERED SHOWERS
AND ISOLATED TSTMS ARE ALSO WITHIN 120NM S OF THE FRONT BETWEEN
44W-62W. AN UPPER LOW AND PERHAPS SOME WEAK ASSOCIATED SFC
TROUGHING IS PRODUCING A FEW SHOWERS AND TSTMS NEAR BARBADOS AND
THE TROPICAL ATLC FROM 10N-19N BETWEEN 54W-61W. THE NEXT WEATHER
PRODUCER IS THE REMNANTS OF MELISSA...ANALYZED AS A WEAK 1015 MB
LOW NEAR 18N44W. ASSOCIATED MODERATE CONVECTION IS WITHIN 120NM
N SEMICIRCLE...WITH SW SHEAR STILL AFFECTING THE SYSTEM. THE
REMAINDER OF THE E ATLC SFC PATTERN IS DOMINATED BY A 1022MB
HIGH NEAR 28N28W AND MOSTLY STABLE CONDITIONS.

$$
WILLIS




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