[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 180510
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU OCT 18 2012

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
0445 UTC.

...TROPICAL WAVES...

WEAK TROPICAL WAVE IS ANALYZED ALONG 39W/40W BETWEEN 10N-21N.
THIS WAVE HAS BEEN DIFFICULT TO TRACK OVER THE PAST TWO DAYS.
NO ASSOCIATED DEEP CONVECTION.

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

THE MONSOON TROUGH IS ANALYZED ACROSS W AFRICA INTO THE E
TROPICAL ATLC NEAR 11N16W ALONG 7N24W TO 9N35W. THE ITCZ IS
ANALYZED STARTING NEAR 12N43W ALONG 10N51W TO 11N58W. A WEAK
SURFACE TROUGH IS OVER THE W TROPICAL ATLC EXTENDING ALONG 60W
FROM 10N-15N. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION
ARE WITHIN 150/180 NM N OF THE MONSOON TROUGH BETWEEN 18W-24W.
CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE
FROM 7N-13N BETWEEN 15W-18W...FROM 10N-19N BETWEEN 34W-38W...AND
FROM 7N-15N BETWEEN 43W-54W.

...DISCUSSION...

GULF OF MEXICO...
A STRONG SHORTWAVE UPPER TROUGH EXTENDS FROM THE NORTH CAROLINA
COAST TO ACROSS FLORIDA NEAR LAKE OKEECHOBEE THEN KEY WEST TO
THE COAST OF CUBA NEAR 23N83W COVERING THE NE GULF. A SECOND
UPPER TROUGH IS DIGGING S OVER THE MISSISSIPPI VALLEY TO
LOUISIANA RE-ENFORCING THE SHORTWAVE AND SUPPORTING THE NEXT
COLD FRONT EXPECTED TO ENTER THE GULF. A BROAD UPPER RIDGE
DOMINATES THE REMAINDER OF THE GULF WATERS WITH THE AXIS
EXTENDING FROM AN UPPER HIGH NEAR MEXICO CITY ACROSS THE BAY OF
CAMPECHE AND THE YUCATAN PENINSULA INTO THE FAR NW CARIBBEAN. A
SURFACE TROUGH EXTENDS FROM THE NW CARIBBEAN THROUGH THE YUCATAN
CHANNEL NEAR THE W TIP OF CUBA ALONG 22N85W TO 26N84W WITH
SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS S OF 26N E OF THE
TROUGH THROUGH THE STRAITS OF FLORIDA. A COLD FRONT WILL MOVE
OFF THE TEXAS COAST OVERNIGHT MOVING QUICKLY ACROSS THE GULF AND
REACHING FROM NEAR TAMPA FLORIDA TO BROWNSVILLE TEXAS BY FRI
MORNING. THE FRONT WILL DISSIPATE FROM NEAR FORT MYERS FLORIDA
TO SE TEXAS ON SAT. WEAK HIGH PRESSURE WILL BUILD ACROSS THE
AREA SAT AND SUN WITH INCREASING RETURN FLOW MON.

CARIBBEAN SEA...
A BROAD UPPER RIDGE EXTENDS AN AXIS FROM ACROSS THE YUCATAN
PENINSULA NEAR 18N89W TO OVER THE NW CARIBBEAN TO NEAR 17N82W. A
NARROW UPPER TROUGH EXTENDS FROM THE W ATLC INTO THE N/CENTRAL
CARIBBEAN THROUGH THE WINDWARD PASSAGE TO 15N80W. A SURFACE
TROUGH EXTENDS FROM 20N84W THROUGH THE YUCATAN CHANNEL NEAR THE
W TIP OF CUBA INTO THE GULF OF MEXICO. A SECOND SURFACE TROUGH
EXTENDS FROM 19N83W TO 15N83W. A SECOND BROAD UPPER RIDGE COVERS
THE REMAINDER OF THE CARIBBEAN ANCHORED NEAR 16N67W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 12N E OF 70W TO ACROSS
THE LESSER ANTILLES/PUERTO RICO AND S OF 13N BETWEEN 70W-75W. A
WEAK 1008 MB LOW IS ANALYZED IN THE SW CARIBBEAN NEAR 11N81W
WITH ISOLATED SHOWERS S OF 14N BETWEEN 77W-83W. LINGERING SWELLS
THROUGH THE NE CARIBBEAN PASSAGES WILL DIMINISH TONIGHT. A
SURFACE TROUGH E OF THE LESSER ANTILLES WILL MOVE W-NW ACROSS
THE WINDWARD ISLANDS LATER TONIGHT AND INTO THE SE AND E
CARIBBEAN THU. THE 1008 MB LOW IN SW CARIBBEAN WILL DRIFT N
THROUGH MON.

ATLANTIC OCEAN...
A NARROW UPPER TROUGH EXTENDS FROM OFF THE CANADIAN MARITIMES
INTO THE W ATLC OVER BERMUDA CONTINUING INTO THE N/CENTRAL
CARIBBEAN THROUGH THE WINDWARD PASSAGE SUPPORTING A DISSIPATING
STATIONARY FRONT THAT ENTERS THE REGION THROUGH 32N63W ALONG
29N71W TO 28N77W. A STRONG SHORTWAVE UPPER TROUGH EXTENDS FROM
THE NORTH CAROLINA COAST TO ACROSS FLORIDA NEAR LAKE OKEECHOBEE
INTO THE GULF OF MEXICO GENERATING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 23N-30N BETWEEN 72W-80W AND OVER S FLORIDA S
OF LAKE OKEECHOBEE. AN UPPER RIDGE EXTENDS FROM THE E CARIBBEAN
OVER THE LEEWARD/VIRGIN ISLANDS NEAR 17N62W ALONG 26N56W TO
BEYOND 32N50W PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS FROM 16N-21N BETWEEN 60W-66W AND
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN
90/120 NM OF LINE FROM 22N59W TO BEYOND 32N53W. AN UPPER TROUGH
EXTENDS ACROSS THE E ATLC FROM AFRICA JUST S OF THE CANARY
ISLANDS ALONG 27N25W 28N38W TO AN UPPER LOW NEAR 18N49W INTO THE
TROPICS TO THE BASE NEAR 12N50W. THIS UPPER TROUGH IS MASKING
THE TROPICAL WAVE MAKING IT DIFFICULT TO LOCATE. THE CENTRAL AND
E ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED WELL N OF THE
DISCUSSION AREA. LINGERING SWELLS FROM POST-TROPICAL CYCLONE
RAFAEL WILL CONTINUE TO SUBSIDE OVER THE CENTRAL ATLC TONIGHT. A
COLD FRONT WILL MOVE INTO THE NW WATERS LATE FRI AND EXTEND FROM
32N72W TO WEST PALM BEACH BY LATE SAT THEN FROM 32N70W TO WEST
PALM BEACH BY SUN AND FROM 32N58W TO SE FLORIDA BY LATE MON.

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

$$
PAW




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