[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230535
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...

A BROAD AREA OF LOW PRESSURE COVERS THE SW CARIBBEAN WITH A 1008
MB LOW ANALYZED NEAR 14N81W AT 23/0300 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 12N-19N BETWEEN 81W-85W 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 14N17W CONTINUING ALONG 10N25W 6N32W TO 6N38W.
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 120 NM OF LINE
FROM 15N18W TO 9N30W AND WITHIN 120/150 NM OF LINE FROM 7N29W TO
2N39W. A SURFACE TROUGH IS ANALYZED FROM 16N37W TO 14N48W WITH
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN
120 NM S OF THE TROUGH BETWEEN 37W-42W AND WITHIN 60 NM OF N OF
THE TROUGH BETWEEN 40W-42W. A 1006 MB LOW IS OFF THE COAST OF
SOUTH AMERICA NEAR 11N56W WITH CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION FROM 9N-13N BETWEEN 51W-56W.

...DISCUSSION...

GULF OF MEXICO...
NEAR ZONAL WESTERLY FLOW ALOFT CONTINUES TO DOMINATE THE GULF
WITH STRONG SUBSIDENCE AND DRY STABLE AIR. SOME LINGERING COLD
AIR STRATOCUMULUS CLOUDS ARE OVER THE SE GULF LEAVING THE
REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES AGAIN TONIGHT. A
SURFACE RIDGE COVERS THE GULF AND THE E CONUS. SURFACE RIDGE
WILL REMAIN ACROSS THE W GULF THROUGH WED NIGHT. AN INVERTED
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. AN
UPPER RIDGE IS ANCHORED OVER THE W CARIBBEAN NEAR 18N80W
COVERING THE AREA FROM 14N-22N BETWEEN 74W-86W 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 14N74W PROVIDING
DIFFLUENCE TO ENHANCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
FROM 12N-16N BETWEEN 73W-78W LEAVING THE REMAINDER OF THE
CARIBBEAN UNDER MOSTLY CLEAR SKIES TONIGHT. THE FRONTAL BOUNDARY
WILL GRADUALLY WASH OUT OVER THE NW CARIBBEAN THROUGH SUN. AN
INVERTED TROUGH S OF 14N ALONG 68W WILL MOVE INTO THE E
CARIBBEAN SUN NIGHT REACHING THE S CENTRAL CARIBBEAN WED AND
THU.

ATLANTIC OCEAN...
A NEAR STATIONARY FRONTAL BOUNDARY REMAINS OVER THE W ATLC
EXTENDING THROUGH 32N69W ALONG 27N76W ACROSS THE BAHAMA ISLANDS
TO OVER CUBA NEAR 21N78W AND A SURFACE TROUGH TO THE E EXTENDING
FROM 29N68W ALONG 25N69W TO 22N67W. ISOLATED SHOWERS ARE
POSSIBLE WITHIN 60 NM EITHER SIDE OF THE FRONT. BROKEN COLD AIR
STRATOCUMULUS CLOUDS ARE WITHIN 120/150 NM W OF THE FRONT. A
UPPER TROUGH COVERS THE W/CENTRAL ATLC EXTENDING THROUGH 32N63W
TO 21N63W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
WITHIN 120/150 NM OF LINE FROM 22N62W TO BEYOND 32N60W. A STRONG
UPPER TROUGH EXTENDS S OVER THE E ATLC INTO THE TROPICS TO 16N E
OF 45W 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 12N36W ALONG 18N23W TO
TO INLAND OVER W AFRICA NEAR 21N17W. A BROAD SURFACE RIDGE
DOMINATES THE ATLC N OF 23N E OF 65W ANCHORED BY A 1025 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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