[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210550
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI OCT 21 2011

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.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 13N16W CONTINUING ALONG 10N18W 7N23W TO 9N28W. A
SURFACE TROUGH IS ANALYZED WITHIN THE TROPICAL ATLC EXTENDING
FROM 16N39W THROUGH A 1010 MB LOW NEAR 16N38W AND A 1008 MB LOW
NEAR 12N44W TO 9N47W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE WITHIN 120 NM E OF THE TROUGH S OF 13N. A
SECOND SURFACE TROUGH IS ANALYZED OFF THE COAST OF SOUTH AMERICA
FROM 12N56W TO 6N55W. CLUSTERS OF SCATTERED MODERATE/ISOLATED
STRONG CONVECTION ARE S OF 10N W OF 51W TO INLAND OVER SOUTH
AMERICA. THE ITCZ IS DISRUPTED BY THE ABOVE SURFACE TROUGHS.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N-11N
BETWEEN 11W-16W INCLUDING THE COAST OF W AFRICA...FROM 6N-12N
BETWEEN 20W-26W...AND S OF 5N ACROSS THE EQUATOR W OF 42W TO
INLAND OVER SOUTH AMERICA.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER TROUGH DOMINATES THE GULF TO OVER S MEXICO ADVECTING
A COOL/DRY AIRMASS OVER THE GULF WATERS IN WAKE OF THE RECENT
FRONTAL PASSAGE. A SURFACE RIDGE COVERS THE GULF AND THE SE
CONUS WITH A 1021 MB HIGH NEAR 27N91W AT 21/0300 UTC. SOME
LINGERING COLD AIR STRATOCUMULUS CLOUDS ARE OVER THE SE GULF
LEAVING THE REMAINDER OF THE GULF UNDER CLEAR SKIES TONIGHT.
SURFACE RIDGE WILL CONTINUE TO BUILD ACROSS THE GULF THROUGH TUE.

CARIBBEAN SEA...
THE UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS TO OVER THE
YUCATAN CHANNEL WITH THE DRY AIR OVER THE GULF OF MEXICO
EXTENDING TO OVER THE FAR NW CARIBBEAN W OF 85W. THE REMAINDER
OF THE CARIBBEAN IS UNDER EASTERLY FLOW ALOFT. REMNANT MOISTURE
OVER THE W CARIBBEAN COUPLED WITH A SURFACE TROUGH THAT EXTENDS
ALONG 79W WITH A 1009 MB LOW ALONG THE TROUGH NEAR 14N ARE
GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
BETWEEN 75W-85W. DRY STABLE AIR ALOFT COVERS THE E CARIBBEAN E
OF 75W WITH SOME ISOLATED SHOWERS USHERED IN ON THE NE SURFACE
FLOW. LOW AND SURFACE TROUGH WILL REMAIN NEARLY STATIONARY
THROUGH TUE.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS OVER THE W ATLC
W OF 70W SUPPORTING A COLD FRONT THAT EXTENDS THROUGH 32N69W TO
TO 30N71W WHERE IT CONTINUES AS A STATIONARY FRONT TO 24N74W
WHERE TI DISSIPATES ACROSS THE BAHAMA ISLANDS TO THE N COAST OF
CUBA NEAR 21N77W. SCATTERED SHOWERS AND POSSIBLE ISOLATED
THUNDERSTORMS ARE WITHIN 45 NM E OF THE COLD FRONT. COLD AIR
STRATOCUMULUS CLOUDS ARE WITHIN 180 NM W OF THE ENTIRE FRONT. A
SURFACE RIDGE IS BUILDING FROM THE GULF OF MEXICO TO W OF THE
FRONT. AN UPPER LOW COVERS THE REMAINDER OF THE W ATLC AND
CENTRAL ATLC CENTERED NEAR 20N54W GENERATING SCATTERED SHOWERS/
THUNDERSTORMS FROM 19N-23N BETWEEN 50W-59W WITH ISOLATED
SHOWERS/THUNDERSTORMS FROM 23N-26N BETWEEN 52W-58W. A BROAD E/W
UPPER RIDGE COVERS THE E ATLC AND THE TROPICAL S OF 30N E OF 50W
WITH THE AXIS ALONG 14N. A BROAD SURFACE RIDGE COVERS THE
REMAINDER OF THE ATLC N OF 23N E OF THE FRONT TO AFRICA. THE A
FRONT WILL REMAIN NEARLY STATIONARY INTO FRI. REMNANTS OF THE
FRONT WILL DRIFT W FRI NIGHT THROUGH SUN. A SECOND COLD FRONT
WILL MOVE SE ACROSS THE NW ATLC SUN NIGHT MERGING WITH THE
FRONTAL TROUGH MON THEN THE MERGED FRONT WILL EXTEND FROM
BERMUDA TO THE SE BAHAMAS MON NIGHT MOVING INTO THE CENTRAL ATLC
LATE TUE.

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

$$
PAW





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