[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271047
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN SEP 27 2009

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 25W S OF 14N MOVING W 10-15 KT.
INVERTED-V CURVATURE IS OBSERVE ON VISIBLE SATELLITE IMAGERY
ALONG THE WAVE AXIS. WAVE COINCIDES WITH A MOISTURE MAXIMUM AS
INDICATED IN THE TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...DUE
TO THE SAHARAN DUST THAT COVERS THE AREA...ANY CONVECTION IS
EMBEDDED WITHIN THE ITCZ.

TROPICAL WAVE IS ALONG 72W S OF 18N MOVING W NEAR 15 KT. WAVE
REMAINS IN AN AREA OF RATHER DRY STABLE AIR...THUS SIGNATURE
OBSERVED ON SATELLITE IMAGERY AND NO ASSOCIATED SHOWERS OR
CONVECTION.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 11N15W 11N 24W 7N33W 9N52W
11N64W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE WITHIN 200 NM OF THE ITCZ FROM 26W-40W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH IS ALL THAT REMAINS OF THE SYSTEM THAT HAS
PLAGUED THE GULF OVER THE PAST FEW DAYS EXTENDING THROUGH
PENSACOLA FLORIDA TO 29N89W GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS N OF 28N E OF 87W TO INLAND OVER FLORIDA.
THE SURFACE TROUGH REMAINS IN THE SW GULF EXTENDING ALONG THE
COAST OF MEXICO FROM 22N97W INTO THE BAY OF CAMPECHE TO NEAR
18N95W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM THE
SURFACE TROUGH W INTO MEXICO WITH SCATTERED SHOWERS S OF 22N E
OF THE SURFACE TROUGH TO 92W. A THIRD SURFACE TROUGH IS INLAND
OVER THE FLORIDA PENINSULA AS WELL. BROAD UPPER RIDGE REMAINS
ANCHORED OVER THE CENTRAL GULF NEAR 26N85W EXTENDING AN AXIS NE
ACROSS THE CENTRAL FLORIDA PENINSULA AND SW TO NEAR TAMPICO
MEXICO ENHANCING SCATTERED FORCING SHOWERS/ISOLATED
THUNDERSTORMS WITHIN A 60/75 NM RADIUS OF 26N95.5W WITH SIMILAR
ACTIVITY THAT HAS DEVELOPED INLAND OVER THE FLORIDA PENINSULA IS
BEING PUSHED INTO THE SE GULF FROM THE FLORIDA KEYS TO FORT
MYERS E OF 83W.

CARIBBEAN SEA...
A SHARP UPPER TROUGH EXTENDS FROM THE CENTRAL ATLC OVER THE MONA
PASSAGE TO OVER CENTRAL AMERICA ALONG THE N COAST OF HONDURAS
SPLITTING THE CARIBBEAN WITH THE NW CARIBBEAN HAVING ELY UPPER
FLOW AND S AND E CARIBBEAN HAVING W UPPER FLOW. THE S CARIBBEAN
HAS AN ABUNDANCE OF TROPICAL MOISTURE PRODUCING CLUSTERS OF
SCATTERED SHOWERS/THUNDERSTORMS OVER THE SW CARIBBEAN SW OF A
LINE FROM COLOMBIA NEAR 10N75W TO NICARAGUA NEAR 14N84W AND
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE NE CARIBBEAN
FROM 14N-18N E OF 67W ACROSS THE LESSER ANTILLES. FRESH TO
STRONG EASTERLY TRADE WINDS CONTINUE ACROSS MUCH OF THE AREA
WITH THE REMAINDER OF THE CARIBBEAN REMAINING CLEAR AGAIN THIS
MORNING.

ATLANTIC OCEAN...
BROAD UPPER RIDGE ANCHORED IN THE GULF OF MEXICO COVERS THE W
ATLC AND COMBINED WITH A SHARP UPPER TROUGH IN THE CENTRAL ATLC
THAT EXTENDS ALONG 32N55W THROUGH AN UPPER LOW NEAR 28N62W ALONG
22N66W OVER THE MONA PASSAGE INTO THE CARIBBEAN ARE PRODUCING
STRONG NLY UPPER WINDS OVER THE W ATLC W OF THE UPPER TROUGH TO
NEAR 73W. THE UPPER TROUGH IS SUPPORTING A COLD FRONT THAT
ENTERS THE REGION NEAR 32N48W TO 29N61W AND A WEAKENING SURFACE
TROUGH THAT EXTENDS FROM 30N64W TO 24N70W. THIS IS ALL PRODUCING
A LARGE AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN
200 NM SE OF THE FRONT E OF 53W AND N OF 22N TO THE FRONT
BETWEEN 53W-64W. A 1010 MB LOW...REMNANTS OF TROPICAL DEPRESSION
EIGHT...IS IN THE E ATLC NEAR 19N38W WITH A SURFACE TROUGH
EXTENDING FROM 22N37W THROUGH THE LOW TO 17N38W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS TO THE E OF THE LOW FROM
17N-20N BETWEEN 33W-36W. OTHERWISE THE REMAINDER OF THE E ATLC
IS DOMINATED BY A SURFACE RIDGE N OF 23N E OF 45W. THE FIRST
VISIBLE SATELLITE IMAGES SHOW THE WEAKENING SURGE OF SAHARAN
DUST COVERING THE FAR E TROPICAL ATLC N OF THE CAPE VERDE
ISLANDS FROM 17N-25N TO 34W.

$$
WALLACE






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