000 AXNT20 KNHC 132351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU OCT 13 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS IN THE ERN TRPCL ATLC ALONG 11N27W TO 5N32W MOVING W 10-15 KT. THE WAVE REMAINS LOW AMPLITUDE...BUT DOES COINCIDE WITH A SLIGHT SURGE OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER. SCATTERED MODERATE/STRONG CONVECTION IS FROM 6N-11N BETWEEN 25W-32W. TROPICAL WAVE IS IN THE CENTRAL TRPCL ATLC ALONG 13N43W TO 6N48W MOVING W NEAR 15 KT. THE WAVE IS EMBEDDED WITHIN A RIDGE OF ENHANCED DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE ALSO IS WELL-DEFINED IN MODEL STREAMLINE ANALYSIS. CURRENTLY THE WAVE IS UNDER THE INFLUENCE OF AN UPPER LEVEL TROUGH WHICH IS SHEARING CONVECTION TO THE NE. CURRENTLY SCATTERED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE AXIS AS WELL AS NE OF THE AXIS FROM 14N-19N BETWEEN 38W-44W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS JUST SLIGHTLY OFF THE AFRICAN COAST ALONG 16N16W TO 14N19W. THE ITCZ PICKS UP ON THE W SIDE OF THE ERN-MOST TROPICAL WAVE ALONG 7N34W 8N45W CONTINUING ON THE OTHER SIDE OF THE WRN-MOST TROPICAL WAVE ALONG 8N49W 7N60W. ALL DEEP CONVECTION IS DESCRIBED IN ASSOCIATION WITH THE TROPICAL WAVES. ALTHOUGH...SCATTERED MODERATE/STRONG CONVECTION IS NEAR THE END OF THE ITCZ INLAND OVER VENEZUELA. ...DISCUSSION... THE GULF OF MEXICO... MAINLY WLY-NWLY FLOW ALOFT COVERS THE GULF OF MEXICO BETWEEN AN UPPER LEVEL RIDGE TO THE S OVER THE NW CARIBBEAN AND AN UPPER LEVEL TROUGH TO THE N OVER THE ERN CONUS. THIS UPPER TROUGH SUPPORTS A COLD FRONT EXTENDING FROM NEAR MOBILE ALABAMA TO BROWNSVILLE TEXAS ALONG 30N88W TO 26N98W. MOSTLY DRY AIR ALOFT COVERS THE BASIN WHICH IS LIMITING MOST OF THE SHOWER/THUNDERSTORM ACTIVITY ALONG THE FRONTAL BOUNDARY. ISOLATED SHOWERS ARE NOTED ALONG THE AXIS WITH MORE SCATTERED ACTIVITY S OF BROWNSVILLE AND AHEAD OF THE FRONT OVER THE FLORIDA PANHANDLE AND GEORGIA. A SURFACE TROUGH IS AHEAD OF THE FRONT EXTENDING FROM NE FLORIDA NEAR 31N81W TO 25N86W. A FEW ISOLATED SHOWERS ARE ALONG THE TROUGH AXIS. THE SE GULF IS LADEN WITH DEEP LAYER MOISTURE ASSOCIATED WITH THE MONSOON TROUGH WHICH HAS BEEN SITUATED N OF ITS TYPICAL POSITION. IT CURRENTLY EXTENDS ACROSS SRN MEXICO AND NRN CENTRAL AMERICA INTO THE WRN CARIBBEAN. WIDESPREAD SHOWERS/THUNDERSTORMS ARE ACROSS THIS AREA INCLUDING THE YUCATAN PENINSULA...CUBA AND REACHING THE FLORIDA STRAITS. THIS LARGE AREA OF MOISTURE IS EXPECTED TO REMAIN MOSTLY STATIONARY AND GRADUALLY LIFT N AND COVER THE SRN GULF. THE COLD FRONT IS EXPECTED TO CONTINUE TO PUSH SE AS HIGH PRESSURE WILL BUILD OVER THE NW GULF. THIS WILL INCREASE THE PRESSURE GRADIENT AND WINDS OVER THE BASIN. THE CARIBBEAN SEA... DEEP LAYER MOISTURE COVERS THE NW CARIBBEAN ASSOCIATED WITH THE MONSOON TROUGH THAT CONTINUES TO SIT N OF ITS USUAL LOCATION. IT CURRENTLY RUNS THROUGH SRN MEXICO ACROSS NRN GUATEMALA AND BELIZE TO A 1007 MB LOW NEAR 17N87W CONTINUING ESE TO NEAR 14N73W. WIDESPREAD SHOWERS/THUNDERSTORMS ARE ACROSS THIS AREA FROM 16N-22N BETWEEN 81W-87W...AS WELL AS OVER LAND INCLUDING NRN NICARAGUA...HONDURAS...GUATEMALA...BELIZE...THE YUCATAN PENINSULA...CUBA...AND JAMAICA. MANY OF THESE AREAS HAVE ALREADY RECEIVED SIGNIFICANT RAINFALL OVER THE PAST COUPLE OF DAYS AND FLOODING IS POSSIBLE. A LARGE CLUSTER OF STRONG SHOWERS/THUNDERSTORMS IS ALSO OVER THE SW CARIBBEAN FROM 9N-13N BETWEEN 78W-82W...AS WELL AS ACROSS COSTA RICA AND PANAMA. ALOFT...AN UPPER LEVEL RIDGE EXTENDS FROM HONDURAS ACROSS WRN CUBA. TO THE E...A NARROW UPPER LEVEL TROUGH IS ALONG 75W. UPPER LEVEL DIFFLUENCE AROUND THE ERN SIDE OF THE TROUGH IS SUPPORTING A FEW CLUSTERS OF SHOWERS/THUNDERSTORMS OVER HISPANIOLA WITH SCATTERED SHOWERS BETWEEN 64W-75W. FAIR CONDITIONS ARE ACROSS THE FAR ERN CARIBBEAN INCLUDING THE LESSER ANTILLES DUE TO DRY AIR ALOFT SINKING INTO THE BASIN AROUND AN UPPER LEVEL RIDGE ALONG 66W. EXPECT MOIST CONDITIONS TO REMAIN ACROSS THE WRN CARIBBEAN BRINGING CONTINUED STRONG SHOWERS AND THUNDERSTORMS TO THAT AREA. THE ATLANTIC OCEAN... A BROAD UPPER LEVEL TROUGH OVER THE ERN CONUS EXTENDS OVER THE FAR WRN ATLC. AN UPPER LEVEL RIDGE IS TO THE E ALONG 66W. AT THE SURFACE...A 1007 MB LOW LIES UNDERNEATH THE AREA OF DIFFLUENCE ALOFT CENTERED NE OF THE BAHAMAS NEAR 27N73W. THE SWLY FLOW ALOFT IS SHEARING THE SHOWERS/THUNDERSTORMS AWAY FROM THE LOW CENTER FROM 24N-30N BETWEEN 66W-72W. A FEW SHOWERS/THUNDERSTORMS ARE ALSO N OF HISPANIOLA AND PUERTO RICO. THE LOW IS EXPECTED TO MOVE NNE AT AROUND 15 KTS OVER THE NEXT COUPLE OF DAYS. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE AROUND A 1029 MB HIGH WELL N OF THE DISCUSSION AREA. A NARROW UPPER LEVEL TROUGH IS ALONG 33N40W TO E OF THE WINDWARD ISLANDS NEAR 11N58W. THIS UPPER TROUGH SUPPORTS A STATIONARY FRONT THAT ENTERS THE AREA ALONG 31N38W TO 29N46W. ISOLATED SHOWERS ARE ALONG THE BOUNDARY. A SURFACE TROUGH IS TO THE S ALONG 28N41W TO 21N47W. SCATTERED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE AXIS. THE UPPER TROUGH IS ALSO SHEARING MOISTURE FROM THE ITCZ AND A TROPICAL WAVE TOWARDS THE NE WHICH IS SUPPORTING UPPER LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS WITHIN A LARGE SWATH FROM NEAR 14N43W TO 32N30W. AN UPPER LEVEL RIDGE COVERS THE FAR ERN ATLC CENTERED NEAR 10N29W SUPPORTING A SURFACE RIDGE AROUND A 1021 MB HIGH NEAR 35N20W PROVIDING FAIR WEATHER ACROSS THIS PORTION OF THE BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON