[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 151744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT OCT 15 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1735 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ANALYZED FROM 14N30W TO A 1009 MB LOW
PRESSURE CENTER NEAR 9N33W. CYCLONIC FLOW IN THE LOW LEVEL CLOUD
FIELD ON SATELLITE VISIBLE IMAGES SINCE THIS MORNING INDICATE
SOME SIGNS OF ORGANIZATION. HOWEVER...UPPER-LEVEL WINDS WILL
BECOME MUCH LESS FAVORABLE FOR TROPICAL CYCLONE FORMATION OVER
THE NEXT DAY OR SO. SCATTERED MODERATE CONVECTION SURROUNDS THIS
SYSTEM FROM 5N-11N BETWEEN 30W-37W.

A TROPICAL WAVE IS ANALYZED FROM 15N53W TO 8N55W. THIS WAVE IN
EMBEDDED IN A REGION ON ELEVATED VALUES OF MOISTURE NOTICED ON
TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...NO SIGNIFICANT
CONVECTION IS OCCURRING AT THE MOMENT.

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

THE MONSOON TROUGH EXTENDS FROM THE NORTHERN AFRICAN COAST OF
GUINEA NEAR 11N15W TO 8N23W. WIDELY SCATTERED AREAS OF MODERATE
TO STRONG CONVECTION ARE FROM 4N TO 10N BETWEEN THE COAST OF
AFRICA AND 27W.

...DISCUSSION...

THE GULF OF MEXICO...
A NEARLY STATIONARY FRONT EXTENDS ACROSS THE SOUTHERN FLORIDA
PENINSULA INTO THE GULF ALONG MARCO ISLAND TO 24N90W. SCATTERED
HEAVY SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 150 NM S OF
THE BOUNDARY...WITH THE STRONGEST AREA OF CONVECTION MOVING
NORTHWARD ACROSS THE FLORIDA STRAITS NOTICED ON DOPPLER RADAR
IMAGERY. SIMILAR ACTIVITY IS MOVING NORTHWARD ACROSS THE FAR NW
CARIBBEAN INTO THE SE GULF ACROSS THE YUCATAN CHANNEL. THIS
AREA OF CONVECTION IS ASSOCIATED TO A BROAD LOW PRESSURE SYSTEM
E OF BELIZE...AND THE BROAD CYCLONIC CIRCULATION COMBINED WITH
LOW LEVEL CONVERGING E TO NE WINDS IS GENERATING SCATTERED
SHOWERS MOVING SSW INTO THE BAY OF CAMPECHE. SURFACE OBSERVATION
ACROSS THE AREA INDICATE A GUSTY ENE FLOW OF UP TO 30 KT S OF
27N. A SURFACE RIDGE OF HIGH PRESSURE ANCHORED OVER CENTRAL
ALABAMA IS KEEPING FAIR WEATHER CONDITIONS ELSEWHERE ACROSS THE
GULF BASIN ON SATELLITE IMAGERY.

THE CARIBBEAN SEA...
A BROAD 1006 MB LOW PRESSURE SYSTEM IS CENTERED 100 NM E OF
BELIZE CITY IN THE NW CARIBBEAN. THIS SYSTEM IS EMBEDDED IN THE
MONSOON TROUGH ANALYZED ACROSS CENTRAL AMERICA TO THE LOW CENTER
...THEN EASTWARD TO NEAR 18N81W. AN EARLIER WINDSAT PASS SHOWED
BROAD CYCLONIC FLOW W OF 80W RANGING FROM 15-30 KT. THE
COMBINATION OF LOW LEVEL CONVERGENCE AND PLENTY OF AVAILABLE
MOISTURE IS GENERATING SCATTERED HEAVY SHOWERS AND
THUNDERSTORMS OVER THE WESTERN CARIBBEAN W OF 79W. THIS SYSTEM
WILL CONTINUE TO MOVE WNW INLAND INTO THE YUCATAN PENINSULA OVER
THE NEXT 24 HOURS WITH CONTINUOUS CONVECTION AFFECTING PORTIONS
OF THE NW BASIN AND CENTRAL AMERICA DURING THE FORECAST
PERIOD...RESULTING IN LIFE-THREATENING FLASH FLOODS AND MUD
SLIDES. A SURFACE TROUGH IS TO THE E OF THIS AREA OF
CONVECTION...ANALYZED FROM THE SOUTHERN BAHAMAS ACROSS EASTERN
CUBA TO S-WRN JAMAICA NEAR 17N78W. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE WITHIN 140 NM ON EITHER SIDE OF THE
TROUGH AXIS.  THIS TROUGH WILL GRADUALLY BECOME ABSORBED INTO
THE LARGER CIRCULATION ASSOCIATED WITH THE LOW PRESSURE SYSTEM
MENTIONED ABOVE DURING THE NEXT SEVERAL DAYS. IT IS POSSIBLE
THAT THE PERIOD OF HEAVY RAINFALL MAY CONTINUE INTO EARLY NEXT
WEEK.

THE ATLANTIC OCEAN...
WATER VAPOR IMAGERY SHOWS A BROAD UPPER LEVEL TROUGH MOVING OFF
THE ERN CONUS SEABOARD SUPPORTING A COLD FRONT EXTENDING INTO
THE AREA ALONG 32N67W TO THE NRN BAHAMAS NEAR FREEPORT...THEN
BECOMING NEAR STATIONARY ACROSS THE SRN FLORIDA PENINSULA. A
THIN CLOUD LINE CAN BE TRACKED ALONG THE COLD FRONT WITH VERY
LIMITED CONVECTION. HOWEVER...THE ACTIVITY INCREASES WITHIN 100
TO 140 NM S OF THE BOUNDARY W OF 77W. SHORT RANGE COMPUTER
MODELS SUGGEST THE COLD FRONT WILL BECOME NEAR STATIONARY WITHIN
THE NEXT 12 HRS. A PRE FRONTAL TROUGH HAS DEVELOP E OF THE COLD
FRONT OVER THE PAST 6 HOURS...WITH AXIS EXTENDING ALONG 32N64W
TO 25N70W SCATTERED SHOWERS ARE WITHIN 50-100 NM E OF THE AXIS.
THE REMAINDER OF THE ATLC OCEAN IS DOMINATED BY A RATHER LARGE
SURFACE RIDGE OF HIGH PRESSURE ANCHORED N OF THE DISCUSSION
AREA.

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

$$

GARCIA




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