000
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