[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231136
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN OCT 23 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
1115 UTC.

...SPECIAL FEATURES...

A BROAD AREA OF LOW PRESSURE COVERS THE SW CARIBBEAN WITH A 1008
MB LOW ANALYZED NEAR 14N81W AT 23/0900 UTC. A REMNANT FRONTAL
BOUNDARY REMAINS N OF THIS LOW AND COUPLED WITH LINGERING
MOISTURE CONTINUES TO GENERATE SCATTERED/HEAVY SHOWERS WITH
ISOLATED THUNDERSTORMS FROM 13N-18N BETWEEN 81W-84W INCLUDING NE
NICARAGUA AND HONDURAS.

ENVIRONMENTAL CONDITIONS ARE GRADUALLY
BECOMING MORE CONDUCIVE FOR DEVELOPMENT OF THIS SYSTEM AND A
TROPICAL DEPRESSION COULD FORM LATER TODAY OR TONIGHT. THIS
SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING
THE NEXT 48 HOURS AS IT MOVES SLOWLY NORTHWARD AND THEN
NORTHWESTWARD. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINS
AND GUSTY WINDS SHOULD CONTINUE TO AFFECT PORTIONS OF HONDURAS
AND NICARAGUA THROUGH MONDAY. AN AIR FORCE RESERVE HURRICANE
HUNTER AIRCRAFT IS SCHEDULED TO INVESTIGATE THIS DISTURBANCE
THIS AFTERNOON...IF NECESSARY.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 13N16W CONTINUING ALONG 10N24W 7N32W TO 6N38W.
SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN 60 NM N OF THE
MONSOON TROUGH BETWEEN 32W-36W. SCATTERED MODERATE/STRONG
CONVECTION IS WITHIN 90/120 NM OF LINE FROM 15N20W TO 8N27W AND
WITHIN 120/150 NM OF LINE FROM 8N27W TO 5N36W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 1N-10N
BETWEEN 34W-45W. A SURFACE TROUGH IS ANALYZED FROM 16N39W TO
13N47W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION
FROM 12N-15N BETWEEN 39W-43W AND CLUSTERS OF SIMILAR CONVECTION
FROM 9N-12N BETWEEN 42-49W. A 1008 MB LOW IS OFF THE COAST OF
SOUTH AMERICA NEAR 11N55W WITH SCATTERED MODERATE/ISOLATED
STRONG CONVECTION FROM 9N-12N BETWEEN 52W-57W.

...DISCUSSION...

GULF OF MEXICO...
NEAR ZONAL WESTERLY FLOW ALOFT CONTINUES TO DOMINATE THE GULF
WITH STRONG SUBSIDENCE AND DRY STABLE AIR. A SURFACE TROUGH
ALONG 84W BETWEEN 28N AND THE COAST OF CUBA IS EMBEDDED WITHIN
SOME LINGERING BROKEN/OVERCAST COLD AIR STRATOCUMULUS CLOUDS
THAT COVER THE SE GULF LEAVING THE REMAINDER OF THE GULF UNDER
MOSTLY CLEAR SKIES AGAIN THIS MORNING. A SURFACE RIDGE COVERS
THE GULF AND THE E CONUS. SURFACE RIDGE WILL REMAIN ACROSS THE W
GULF THROUGH WED NIGHT. A TROUGH WILL DEVELOP OVER THE S CENTRAL
GULF WED AND MOVE W REACHING ALONG 91W THU NIGHT.

CARIBBEAN SEA...
THE PRIMARY CONCERN CONTINUES TO BE THE SURFACE LOW IN THE
SPECIAL FEATURES SECTION ABOVE. A REMNANT NEAR STATIONARY
FRONTAL BOUNDARY REMAINS OVER THE NW CARIBBEAN EXTENDING ACROSS
CENTRAL CUBA NEAR 22N79W W OF THE CAYMAN ISLANDS TO 18N84W WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM E OF THE
FRONT S OF 21N. AN UPPER RIDGE IS ANCHORED OVER THE W CARIBBEAN
NEAR 17N81W COVERING THE AREA FROM 13N-22N BETWEEN 76W-87W
FURTHER ENHANCING THE ACTIVITY ASSOCIATED WITH THE LOW IN THE
SPECIAL FEATURES. AN UPPER RIDGE COVERS THE REMAINDER OF THE
CARIBBEAN EXTENDING FROM THE TROPICAL ATLC ACROSS THE LESSER
ANTILLES TO 14N76W PROVIDING DIFFLUENCE TO ENHANCE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90/120 NM OF LINE FROM
14N74W TO 16N80W LEAVING THE REMAINDER OF THE CARIBBEAN UNDER
MOSTLY CLEAR SKIES THIS MORNING. THE FRONTAL BOUNDARY OVER THE
NW CARIBBEAN WILL GRADUALLY DISSIPATE THROUGH TODAY. THE 1008 MB
LOW IN THE W TROPICAL ATLC WILL BECOME A SURFACE TROUGH LATER
TODAY AND WILL MOVE INTO THE E CARIBBEAN LATE TONIGHT REACHING
THE S CENTRAL CARIBBEAN WED THEN MERGING INTO THE MONSOON TROUGH
IN THE SW CARIBBEAN THU.

ATLANTIC OCEAN...
A NEAR STATIONARY FRONTAL BOUNDARY REMAINS OVER THE W ATLC
EXTENDING THROUGH 32N70W ALONG 27N76W ACROSS THE BAHAMA ISLANDS
TO OVER CUBA NEAR 22N79W AND A SURFACE TROUGH TO THE E EXTENDING
FROM 29N69W TO 21N68W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
ARE WITHIN 45 NM EITHER SIDE OF THE FRONT BETWEEN 25N-27N WITH
ISOLATED SHOWERS POSSIBLE WITHIN 60 NM EITHER SIDE OF THE
REMAINDER OF THE FRONT. A UPPER TROUGH COVERS THE W/CENTRAL ATLC
EXTENDING THROUGH 32N65W TO 22N64W GENERATING SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM 22N64W TO
BEYOND 32N59W. A STRONG UPPER TROUGH EXTENDS S OVER THE E ATLC
INTO THE TROPICS TO 15N E OF 47W SUPPRESSING THE E/W UPPER RIDGE
OVER THE TROPICAL ATLC TO THE S AND GENERATING SCATTERED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM
12N31W ACROSS THE CANARY ISLANDS TO 18N18W. A BROAD SURFACE
RIDGE DOMINATES THE ATLC N OF 23N E OF 65W ANCHORED BY A 1024 MB
HIGH NEAR 35N44W. THE FRONTAL BOUNDARY WILL DRIFT W THROUGH MON.
A COLD FRONT WILL ENTER THE NW ATLC SUN NIGHT MERGING WITH THE
FRONTAL BOUNDARY MON AND THE MERGED BOUNDARY WILL EXTEND FROM
BERMUDA TO THE SE BAHAMAS EARLY TUE MOVING INTO THE CENTRAL ATLC
WED. A SURFACE RIDGE WILL EXTEND E TO W ALONG 32N ON THU.

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

$$
PAW





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