[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121137
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE OCT 12 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
1015 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS OFF THE COAST OF W AFRICA ALONG 18W S OF 15N
DRIFTING W. WAVE IS WELL DEFINED AS A BROAD MID LEVEL CYCLONIC
CIRCULATION S OF 10N WHICH CORRESPONDS TO A SURGE IN DEEP
MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY.
CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 4N-10N
BETWEEN 10W-24W.

TROPICAL WAVE IS IN THE E CARIBBEAN ALONG 65W/66W S OF 18N
MOVING W NEAR 10 KT. WAVE IS ILL-DEFINED ON SATELLITE IMAGERY
AND IS EMBEDDED WITHIN AN BROAD AREA OF MOISTURE THAT COVERS THE
ENTIRE CARIBBEAN AS DEPICTED ON THE TOTAL PRECIPITABLE WATER
IMAGERY. WAVE IS INDUCING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 12N-20N BETWEEN 56W-62W INCLUDING THE LESSER
ANTILLES.

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

THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST NEAR
14N16W. THE ITCZ EXTENDS FROM 7N30W ALONG 8N36W TO SOUTH AMERICA
NEAR 6N57W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION ARE FROM THE ITCZ AXIS TO 12N BETWEEN 30W-40W AND
FROM THE ITCZ AXIS TO 10N BETWEEN 42W-50W. CLUSTERS OF SCATTERED
MODERATE CONVECTION ARE 5N-9N BETWEEN 24W-30W.

...DISCUSSION...

GULF OF MEXICO...
BROAD UPPER RIDGE DOMINATES THE GULF WATERS ANCHORED OVER S
MEXICO E OF CIUDAD DEL CARMEN. A SHORTWAVE UPPER TROUGH
CONTINUES TO MOVE NE FROM NE TENNESSEE TO THE COAST OF SOUTH
CAROLINA SUPPORTING A 1009 MB SURFACE LOW AT 12/0900 UTC IS
CENTERED JUST NE OF TALLAHASSEE FLORIDA AND A SURFACE TROUGH
EXTENDING INTO THE GULF ALONG 26N86W 24N90W TO A WEAKENING 1009
MB LOW IN THE SW GULF NEAR 23N92W. SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 60 NM EITHER SIDE OF
THE SURFACE TROUGH AND SURROUNDING THE SW GULF LOW. BROKEN/
OVERCAST LOW CLOUDS WITH PATCHES OF FOG AND DRIZZLE COVER THE NE
GULF N OF 27N BETWEEN 84W-89W. UPPER LEVEL MOISTURE WITH
POSSIBLE ISOLATED SHOWERS ARE BEING DRAWN ACROSS MEXICO TO OVER
THE NW GULF FROM HURRICANE JOVA IN THE E PACIFIC REGION.
OTHERWISE...THE REMAINDER OF THE GULF IS EXPERIENCING FAIR
CONDITIONS THIS MORNING. THE 1008 MB LOW OVER THE FLORIDA
PANHANDLE WILL MOVE NE OF THE AREA THIS MORNING WHILE THE 1009
MB LOW IN THE SW GULF WILL DISSIPATE LATER TODAY. A WEAK COLD
FRONT WILL MOVE INTO THE NW GULF THU AND EXTEND FROM TAMPA BAY
TO BAY OF CAMPECHE FRI AND INTO THE W ATLC SAT. STRONG HIGH
PRESSURE WILL BUILD BEHIND THE FRONT INCREASING E SURFACE WINDS
OVER THE WEEKEND.

CARIBBEAN SEA...
THE UPPER RIDGE THAT DOMINATES THE GULF OF MEXICO COVERS THE W
CARIBBEAN W OF 80W ENHANCING ISOLATED SHOWERS/THUNDERSTORMS
INLAND OVER CENTRAL AMERICA AND ALONG THE COAST OF HONDURAS S OF
18N BETWEEN 83W-87W. A SHARP NARROW UPPER TROUGH OVER THE FAR W
ATLC EXTENDS ACROSS CUBA INTO THE CENTRAL CARIBBEAN N OF 14N
BETWEEN 72W-80W SUPPORTING A LOW BETWEEN THE N COAST OF CUBA AND
THE BAHAMAS AND A SURFACE TROUGH THAT EXTENDS FROM THE LOW
ACROSS CUBA JUST E OF SANTIAGO DE CUBA TO THE E TIP OF JAMAICA.
MODERATE DRY AIR ALOFT IS BEING FUNNELED INTO THE W CARIBBEAN BY
THE UPPER RIDGE THEN INTO THE UPPER TROUGH AT THE BASE GIVING
THE REMAINDER OF THE W CARIBBEAN FAIR WEATHER THIS MORNING. THE
MONSOON TROUGH CONTINUES TO LIFT N AND NOW EXTENDS FROM 13N77W
ACROSS CENTRAL AMERICA AND INTO THE E PACIFIC REGION ACROSS NE
NICARAGUA NEAR 15N84W WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS S OF 14N W OF 76W. A SHARP NARROW UPPER RIDGE
EXTENDS FROM THE GULF OF VENEZUELA ACROSS THE DOMINICAN REPUBLIC
NEAR 18N70W INDUCED BY A LARGE UPPER TROUGH OVER THE CENTRAL
ATLC THAT EXTENDS S OVER THE FAR E CARIBBEAN AND THE W TROPICAL
ATLC. THE UPPER RIDGE IS ENHANCING SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS THAT DOT THE AREA BETWEEN
70W-76W FROM COLOMBIA TO ACROSS THE GREATER ANTILLES LEAVING THE
REMAINDER OF THE E CARIBBEAN UNDER FAIR CONDITIONS THIS MORNING.
A WEAK PRESSURE PATTERN WILL MAINTAIN LIGHT TO MODERATE WINDS
OVER MUCH OF THE CARIBBEAN THROUGH WED. WINDS WILL INCREASE OVER
THE E CARIBBEAN THROUGH FRI AS A SURFACE RIDGE BUILDS OVER THE W
ATLC. A BROAD LOW PRESSURE WILL MOVE FROM THE E PACIFIC ACROSS
CENTRAL AMERICA THU THEN INTO THE W CARIBBEAN SAT AND SUN.

ATLANTIC OCEAN...
A SHARP NARROW UPPER TROUGH EXTENDS ALONG 78W OVER THE BAHAMAS
AND INTO THE CENTRAL CARIBBEAN SUPPORTING A 1010 MB LOW CENTERED
BETWEEN THE BAHAMAS AND THE N COAST OF CUBA NEAR 22N75W WITH A
SURFACE TROUGH EXTENDING INTO THE CARIBBEAN ACROSS E CUBA JUST
E OF SANTIAGO DE CUBA AND GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 20N-24N BETWEEN 70W-75W WITH SCATTERED
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 24N BETWEEN
70W-76W. A NARROW UPPER RIDGE IS TO THE E ALONG 69W INDUCED
BY A LARGE UPPER TROUGH THAT COVERS THE CENTRAL ATLC EXTENDING
THROUGH 32N45W ALONG 22N52W ACROSS THE W TROPICAL ATLC/E
CARIBBEAN TO SOUTH AMERICA NEAR THE SURINAME/GUYANA BORDER.
A WEAK SURFACE TROUGH IS ALONG THE E SIDE OF THE UPPER TROUGH
EXTENDING FROM 29N397W ALONG 25N43W TO 21N47W. SCATTERED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 90/120 NM EITHER
SIDE OF THE SURFACE TROUGH. WEAK HIGH PRESSURE COVERS THE ATLC
BETWEEN 22N-32N WITH A 1019 MB HIGH SE OF BERMUDA NEAR 31N61W.
THE 1010 MB LOW IN THE W ATLC WILL LIFT N THROUGH THE CENTRAL
BAHAMAS TODAY THEN DISSIPATE. A WEAK COLD FRONT WILL ENTER NW
ATLC THU AND EXTEND FROM 31N76W TO S FLORIDA FRI AND FROM
31N70W TO STRAITS OF FLORIDA SAT THEN DISSIPATE SUN.

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

$$
PAW





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