[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250602
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED SEP 25 2013

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE W OF THE CAPE VERDE ISLANDS IS NO LONGER
DISCERNIBLE AND WAS DROPPED FROM THE 25/0000 UTC ANALYSIS.

TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS FROM 17N45W
TO 9N39W MOVING W-SW NEAR 15 KT. WAVE IS EMBEDDED WITHIN A SURGE
OF DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY. WAVE IS WELL DEFINED IN THE SATELLITE DERIVED WINDS.
CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION
WITHIN 180 NM BOTH SIDES THE WAVE AXIS.

TROPICAL WAVE E OF THE LEEWARD ISLANDS EXTENDS FROM 21N56W TO
13N56W MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN DRY AIR AS
DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS WELL
DEFINED IN THE SATELLITE DERIVED WINDS. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 75 NM W OF THE WAVE BETWEEN 18N-
20N.

...THE ITCZ/THE MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF SENEGAL
THEN RESUMES NEAR 8N29W THROUGH A 1012 MB LOW NEAR 7N36W TO
8N40W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 7N45W TO 9N49W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 7N-10N E OF 16W TO INLAND OVER SW AFRICA...FROM 5N-8N
BETWEEN 19N-23W...WITHIN 120 NM N OF THE MONSOON TROUGH BETWEEN
30W-39W...AND WITHIN 60 NM S OF THE MONSOON TROUGH BETWEEN 36W-
39W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH EXTENDS FROM THE UPPER MISSISSIPPI VALLEY OVER
THE W GULF N OF 25N W OF 87W. A LOW LEVEL SURFACE TROUGH IS
BENEATH THIS UPPER TROUGH EXTENDING AT 25/0300 UTC FROM 29N92W
THROUGH A 1008 MB LOW NEAR 27N93W TO 25N95W. ISOLATED SHOWERS
ARE POSSIBLE WITHIN 75 NM EITHER SIDE OF THE TROUGH. AN UPPER
TROUGH IN THE W ATLC IS SUPPORTING A STATIONARY FRONT THAT
CROSSES FLORIDA NEAR FLAGLER BEACH TO CEDAR KEY ACROSS THE NW
GULF ALONG 29N84W TO A 1008 MB LOW ALONG THE COAST NEAR THE
MISSISSIPPI/LOUISIANA. AN UPPER RIDGE COVERS THE REMAINDER OF
THE GULF ANCHORED ALONG THE NW COAST OF CUBA NEAR 23N84W AND
EXTENDING A RIDGE AXIS OVER THE W ATLC. THIS UPPER RIDGE IS
PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED TO NUMEROUS
SHOWERS WITH EMBEDDED THUNDERSTORMS N OF 27N W OF 87W TO INLAND
OVER FLORIDA...WITHIN 30/45 NM OF LINE FROM 25N90W TO 27N87W...
AND IN THE SW GULF AND THE BAY OF CAMPECHE S OF 20N. A WEAK
SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS S FLORIDA TO OVER
THE SE GULF. THE REMAINDER OF THE GULF IS UNDER MOSTLY CLEAR
SKIES. THE LOW IN THE W GULF IS EXPECTED TO MOVE E-NE REACHING
NEAR MOBILE ALABAMA BY THU. THE SURFACE RIDGE WILL PERSIST
THROUGH THU THEN BUILD NW TO THE TEXAS COAST ON FRI WITH THE
RIDGE BECOMING ORIENTATED FROM SW LOUISIANA TO THE YUCATAN
PENINSULA ON SAT.

CARIBBEAN SEA...
THE UPPER RIDGE ANCHORED ALONG THE NW COAST OF CUBA COVERS THE
NW CARIBBEAN N OF LINE FROM HAITI TO S NICARAGUA. AN UPPER LOW
IS IN THE SW CARIBBEAN NEAR 11N79W COVERING THE AREA S OF 14N
BETWEEN 75W-82W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S
OF 12N BETWEEN 76W-79W. THE MONSOON TROUGH IS INLAND OVER
PANAMA...COSTA RICA...AND NICARAGUA GENERATING SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS INLAND AND WITHIN 60 NM ALONG THE
COAST OF PANAMA BETWEEN 80W-83W. THE E CARIBBEAN IS DOMINATED BY
W FLOW ALOFT S OF 15N AND E FLOW ALOFT N OF 15N. ISOLATED
SHOWERS ARE POSSIBLE OVER THE E CARIBBEAN USHERED IN ON THE
STRONG EASTERLY TRADE WINDS. TRADE WINDS WILL CONTINUE ACROSS
THE S/CENTRAL CARIBBEAN THROUGH LATE WED NIGHT THEN DIMINISH TO
FRESH TRADES THU AND FRI. ELSEWHERE...MODERATE TO FRESH E TRADE
WINDS ARE EXPECTED THROUGH SUN.

HISPANIOLA...
SKIES ARE MOSTLY CLEAR ACROSS THE ISLAND TONIGHT WITH SOME
POSSIBLE ISOLATED SHOWERS/THUNDERSTORMS OVER SW HAITI AND IN THE
GULF OF GONAVE. EASTERLY FLOW ALOFT AND AT THE SURFACE WILL
CONTINUE THROUGH FRI. THE UPPER RIDGE RESPONSIBLE FOR THE E FLOW
ALOFT WILL THEN RETREAT E AS AN UPPER RIDGE ANCHORED TO THE S
CHANGES THE UPPER FLOW TO WESTERLY. A WEAK TROPICAL WAVE WILL
MOVE ACROSS THE ISLAND FRI BEFORE DISSIPATE SAT. THIS WILL
POSSIBLY INCREASE OR INTENSIFY AFTERNOON SHOWERS/THUNDERSTORMS.

ATLANTIC OCEAN...
THE UPPER RIDGE ANCHORED ALONG THE NW COAST OF CUBA EXTENDS AN
AXIS THROUGH THE STRAITS OF FLORIDA NEAR 25N80W TO 31N73W COVERS
THE FAR W ATLC AND PROVIDING DIFFLUNCE ALOFT TO GENERATE
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 26N W OF 76W. AN
UPPER TROUGH EXTENDS FROM THE CANADIAN MARITIMES ACROSS BERMUDA
TO 27N66W SUPPORTING A COLD FRONT THAT ENTERS THE REGION AT
25/0300 UTC NEAR 32N62W ALONG 27N67W TO 27N73W WHERE IT BECOMES
STATIONARY ALONG 28N77W TO A WEAK 1009 MB LOW NEAR 30N80W THEN
CONTINUES ACROSS FLORIDA NEAR FLAGLER BEACH. SCATTERED TO
NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 225 NM E OF
THE FRONT N OF 28N WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS WITHIN 60/75 NM OF LINE FROM 28N61W TO 23N71W. THE
REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED
BY A 1020 MB HIGH NEAR 26N40W AND EXTENDING INTO THE GULF OF
MEXICO S OF THE ABOVE FRONTAL SYSTEM. THE LOW ALONG THE FRONT
WILL MOVE MAINLY E THROUGH WED NIGHT AND PASS S OF BERMUDA THU
NIGHT REACHING THE CENTRAL ATLC FRI NIGHT. A SECOND LOW WILL
DEVELOP ALONG THE SAME FRONTAL BOUNDARY OVER THE NW ATLC BY THU
AND WILL DRIFT MAINLY E THROUGH SUN.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
PAW


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