[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 152342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT OCT 15 2005

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION TWENTY-FOUR HAS DEVELOPED NEAR 17.6N
78.8W...OR 170 NM SE OF GRAND CAYMAN...AT 15/2100 UTC MOVING W 3
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1003 MB. MAXIMUM
SUSTAINED WIND SPEED IS 25 KT WITH GUSTS TO 35 KT. SEE LATEST
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24
KNHC FOR MORE DETAILS. THE CIRCULATION AROUND THE DEPRESSION IS
QUICKLY STRENGTHENING AND THE TSTM ACTIVITY HAS BEGUN TO
CONSOLIDATE INTO WELL-DEFINED CONVECTIVE BANDS WITHIN ABOUT
60-75 NM OF THE CENTER. UPPER LEVEL OUTFLOW IS EXCELLENT OVER
ALL QUADRANTS EXCEPT THE NW QUADRANT WHERE AN UPPER LEVEL SHEAR
AXIS IS HARBORING DRY AIR AND SWLY FLOW IS CUTTING ACROSS THE
SYSTEM. DEEP CONVECTION IS WIDESPREAD AND EXTENDS FROM CUBA AND
HISPANIOLA SW TO NICARAGUA...BUT SCATTERED MODERATE/ISOLATED
STRONG CONVECTION IS DIRECTLY ASSOCIATED WITH THE DEPRESSION
FROM 14N-20N BETWEEN 76W-81W. SOME OF THIS ACTIVITY CONTINUES TO
MOVE ONSHORE THE S COAST OF JAMAICA PRODUCING VERY HEAVY RAIN
AND THE POSSIBILITY OF FLASH FLOODING. HEAVY RAINS WILL BEGIN
SPREADING OVER THE CAYMAN ISLANDS WITHIN THE NEXT 24-48 HRS AS
T.D. 24 SLOWLY DRIFTS TO THE W AND STRENGTHENS.

...TROPICAL WAVES...

EAST ATLANTIC TROPICAL WAVE ALONG 39W/40W S OF 21N MOVING W 15
KT WITH A 1008 MB LOW ALONG THE AXIS NEAR 16N39W. THE WAVE
REMAINS UNDER THE INFLUENCE OF STRONG 30-40 KT WESTERLY
SHEAR...WHICH IS KEEPING THE LOW AND AXIS EXPOSED FROM THE DEEP
CONVECTION. WIDESPREAD CLOUDINESS WITH ISOLATED MODERATE
CONVECTION EXTENDS FROM 8N-20N BETWEEN 30W-38W.

EAST CARIBBEAN TROPICAL WAVE ALONG 64W S OF 18N MOVING W 15 KT.
THE WAVE HAS A POOR SIGNATURE AND IS EMBEDDED IN BROAD S/SE FLOW
THAT IS FEEDING INTO THE BROADER CIRCULATION OF T.D. 24. WIDELY
SCATTERED MODERATE CONVECTION EXTENDS FROM 13N-22N BETWEEN
63W-68W MOVING FROM N TO S ACROSS PUERTO RICO AND THE U.S. AND
BRITISH VIRGIN ISLANDS.

...ITCZ...

ITCZ IS CENTERED ALONG 8N10W 6N30W 20N36W...THEN ALONG 12N41W
10N47W 11N54W. SCATTERED MODERATE CONVECTION MOVING OFF THE
AFRICAN COAST FROM 5N-12N E OF 15W. WIDELY SCATTERED MODERATE
WITHIN 120 NM OF THE AXIS BETWEEN 23W-31W. WIDELY SCATTERED
MODERATE WITHIN 90 NM OF THE AXIS BETWEEN 35W-54W.

...DISCUSSION...

GULF OF MEXICO...
BROAD SURFACE HIGH PRES REMAIN CENTERED OVER TEXAS...NE
MEXICO...AND THE W GULF OF MEXICO WITH DRIER N/NELY FLOW
EXTENDING FROM THE N GULF COAST TO THE BAY OF CAMPECHE. WITH
HIGH PRES BANKED AGAINST THE MOUNTAINS OF NE MEXICO...AREAS OF
CLOUDS EXTEND ACROSS THE COASTAL PLAINS ESPECIALLY S OF TAMPICO.
A LARGE MID/UPPER LEVEL HIGH IS LOCATED JUST N OF THE YUCATAN
PENINSULA NEAR 23N88W WITH MODERATE SUBSIDENCE COVERING THE
ENTIRE AREA...AND THE DRIEST AIR FUNNELING SWD ACROSS FLORIDA
AND THE E GULF. THE LINGERING MOISTURE AND CLOUDS ACROSS NE
MEXICO AND SRN TEXAS IS EXPECTED TO DIMINISH WITHIN THE NEXT
48-72 HRS.

CARIBBEAN...
TROPICAL DEPRESSION TWENTY-FOUR HAS DEVELOPED JUST W OF JAMAICA
AND WILL DRIFT TO THE W OVER THE NEXT SEVERAL DAYS. SEE SPECIAL
FEATURES FOR FURTHER DISCUSSION. AN UPPER LEVEL SHEAR AXIS LIES
OVER THE NW CARIBBEAN FROM BELIZE TO THE ISLE OF YOUTH WITH THE
NORTHERLY FLOW N OF THE BOUNDARY BRINGING IN DRY AIR AS FAR SE
AS THE CAYMAN ISLANDS. AN UPPER LEVEL ANTICYCLONE HAS FORMED
OVER THE DEPRESSION AND IS EXPANDING CIRRUS OUTFLOW EWD OVER
MUCH OF THE AREA. ASIDE FROM THE DEEP CONVECTION IMMEDIATE NEAR
THE DEPRESSION...NUMEROUS MODERATE/SCATTERED STRONG CONVECTION
ALSO EXTENDS FROM E CUBA TO THE WINDWARD PASSAGE AND HISPANIOLA
FROM 16N-22N BETWEEN 70W-79W. WIDELY SCATTERED MODERATE
CONVECTION IS OVER THE SW CARIBBEAN FROM 8N-15N BETWEEN 79W-86W.
FARTHER E...CONDITIONS ARE NOT AS CONVECTIVE YET AN UPPER LOW
CENTERED JUST NE OF THE LEEWARD ISLANDS NEAR 19N61W IS INDUCING
A NARROW BAND OF SCATTERED SHOWERS/TSTMS EXTENDING FROM PUERTO
RICO/VIRGIN ISLANDS SE TO THE WINDWARD ISLANDS.

WEST ATLANTIC...
A COMPLEX AREA OF LOW PRES OFF THE NEW ENGLAND COAST HAS A COLD
FRONT WHICH HAS MOVED SE OF BERMUDA ALONG 32N59W 28N63W
27N68W...THEN FAINTLY CONNECTING TO A 1007 MB LOW JUST SE OF
MIAMI FLORIDA NEAR 25N80W. THE FRONT HAS USHERED IN SLIGHTLY
COOLER AND DRIER AIR OVER THE W ATLC AND A SECOND REINFORCING
SHOT IS COMING IN ALONG 32N69W 29N75W. A PRE-FRONTAL TROUGH
EXTENDS FROM HISPANIOLA NEWD TO 24N66W 27N60W 32N56W WITH WIDELY
SCATTERED MODERATE CONVECTION FROM 29N-33N BETWEEN 52W-57W.
ISOLATED SHOWERS/TSTMS ARE ALSO ALONG THE SRN END OF THE TROUGH
FROM 20N-25N BETWEEN 62W-70W.

EAST/CENTRAL ATLANTIC...
A LARGE UPPER LEVEL LOW IS LOCATED JUST NE OF THE LEEWARD
ISLANDS NEAR 19N61W WITH AN AXIS STRETCHING SWD THROUGH BARBADOS
AND IS PRODUCING AN AREA OF SCATTERED SHOWERS/TSTMS FROM 11N-16N
BETWEEN 55W-62W. A SHARP MID-OCEANIC TROUGH IS OVER THE CENTRAL
ATLC ALONG 17N30W 10N40W AND IS PRODUCING STRONG W/NW SHEAR OVER
THE TROPICAL WAVE ALONG 39W...AND IS DISPLACING THE DEEP
CONVECTION E OF THE AXIS. A SECOND UPPER TROUGH IS DIGGING SWD
OVER THE E ATLC ALONG 32N27W 23N35W WITH A COLD FRONT STRETCHING
FROM MADEIRA ISLAND TO 28N20W 27N30W 26N40W. CLOUD COVER AND A
LACK OF SURFACE OBSERVATIONS MAKE IT HARD TO SEE...BUT IT IS
POSSIBLE THAT THERE IS A PRE-FRONTAL TROUGH WHICH IS TRIGGERING
SCATTERED MODERATE CONVECTION FROM 20N-26N BETWEEN 25W-35W.
MODERATE TO STRONG UPPER LEVEL WESTERLIES EXTEND ACROSS MOST OF
THE E ATLC N OF 12N...PRODUCING AN UNFAVORABLE ENVIRONMENT FOR
TROPICAL DEVELOPMENT.

$$
BERG


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