[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211154
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...SPECIAL FEATURE...

REMNANT MOISTURE OVER THE W CARIBBEAN COUPLED WITH A SURFACE
TROUGH THAT EXTENDS ALONG 79W/80W WITH A 1010 MB LOW ALONG THE
TROUGH NEAR 14N ARE GENERATING CLUSTERS OF SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS S OF 20N BETWEEN THE SURFACE TROUGH AND
85W. SURFACE PRESSURES ARE FALLING AND UPPER-LEVEL WINDS ARE
EXPECTED TO BECOME MORE FAVORABLE FOR DEVELOPMENT. THIS SYSTEM
HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 14N16W CONTINUING ALONG 10N21W TO 6N25W. A SURFACE
TROUGH IS ANALYZED WITHIN THE TROPICS EXTENDING FROM 20N36W
THROUGH A 1006 MB LOW NEAR 12N45W TO 10N47W. CLUSTERS OF
SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N-10N BETWEEN
10W-20W AND S OF 11N W OF 49W TO INLAND OVER SOUTH AMERICA.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE S
OF 10N BETWEEN 42W-50W TO INLAND OVER SOUTH AMERICA. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE FROM 5N-8N BETWEEN 23W-32W.
THE ITCZ IS DISRUPTED BY THE ABOVE SURFACE TROUGH.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER TROUGH DOMINATES THE GULF TO OVER S MEXICO AND THE
YUCATAN CHANNEL 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 26N91W
AT 21/0900 UTC. SOME LINGERING COLD AIR STRATOCUMULUS CLOUDS ARE
OVER THE SE GULF LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY
CLEAR SKIES TONIGHT. SURFACE RIDGE WILL CONTINUE TO BUILD ACROSS
THE W 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 INTO THE FAR NW CARIBBEAN N OF 19N W OF 85W. THE
REMAINDER OF THE CARIBBEAN IS UNDER EASTERLY FLOW ALOFT. DRY
STABLE AIR ALOFT COVERS THE E CARIBBEAN E OF 75W WITH SOME
ISOLATED SHOWERS USHERED IN ON THE NE SURFACE FLOW. SURFACE LOW
OVER THE SW CARIBBEAN WILL SLOWLY DRIFT W THROUGH THE WEEKEND. A
SURFACE TROUGH WILL ENTER THE E CARIBBEAN MON AND THE CENTRAL
CARIBBEAN TUE NIGHT.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS OVER THE W ATLC
W OF 72W SUPPORTING A STATIONARY FRONT THAT AT 21/0900 UTC
EXTENDS THROUGH 32N69W TO THE BAHAMA ISLANDS NEAR 23N75W AND A
SURFACE TROUGH CONTINUING TO THE COAST OF CUBA NEAR 22N77W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 45 NM EITHER
SIDE OF THE FRONT/TROUGH. COLD AIR STRATOCUMULUS CLOUDS ARE
WITHIN 200 NM W OF THE FRONT/TROUGH. A SURFACE RIDGE IS BUILDING
FROM THE N GULF OF MEXICO W TO THE FRONT. AN UPPER LOW COVERS
THE REMAINDER OF THE W ATLC AND CENTRAL ATLC CENTERED NEAR
21N55W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM
18N-25N BETWEEN 50W-61W. A BROAD E/W UPPER RIDGE COVERS THE E
ATLC AND THE TROPICAL S OF 30N E OF 50W WITH THE AXIS ALONG
13N/14N. A BROAD SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC
N OF 25N E OF THE FRONT TO AFRICA. THE STATIONARY FRONT WILL
DISSIPATE LATER TODAY. REMNANTS OF THE FRONT WILL DRIFT W
TONIGHT THROUGH SUN. A SECOND COLD FRONT WILL MOVE SE ACROSS THE
NW ATLC SUN NIGHT MERGING WITH THE FRONTAL TROUGH MON WITH THE
MERGED FRONT EXTENDING FROM BERMUDA TO THE SE BAHAMAS MON NIGHT
THEN MOVING INTO THE CENTRAL ATLC LATE TUE.

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

$$
PAW




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