000 AXNT20 KNHC 130540 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS S OF THE CAPE VERDE ISLANDS FROM 15N23W TO 8N25W MOVING W NEAR 15 KT. WAVE IS WELL DEFINED IN THE GFS STREAMLINES AND IN THE UPPER LEVEL SATELLITE WINDS. WAVE IS ILL-DEFINED ON SATELLITE IMAGERY WITH A WEAK MOISTURE SURGE IN AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. NO ASSOCIATED CONVECTION IS NOTED. TROPICAL WAVE WAS INTRODUCED ON THE 13/0000 UTC MAP ALONG 39W/40W S OF 14N. WAVE IS THE WESTERN EDGE OF AN UPPER RIDGE AND AT THE LEADING EDGE OF A MOISTURE SURGE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY.THE UPPER RIDGE IS ENHANCING CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION FROM 8N-15N BETWEEN 33W-42W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST NEAR 17N16W. THE ITCZ EXTENDS FROM 8N31W S OF THE TROPICAL WAVE ALONG 9N41W 8N50W TO 8N57W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 200 NM ALONG THE COAST OF SW AFRICA BETWEEN 6N-11N. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 5N-9N BETWEEN 20W-34W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE 6N-11N BETWEEN 42W-49W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER TROUGH COVERS THE E HALF OF THE US CONUS INTO THE GULF OF MEXICO N OF 27N WITH A SURFACE TROUGH ENTERING THE GULF NEAR CEDAR KEY FLORIDA EXTENDING ALONG 26N87W TO 24N95W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS. THIS UPPER TROUGH IS ALSO SUPPORTING A COLD FRONT CURRENTLY OVER THE CENTRAL PLAIN STATES. THIS UPPER TROUGH IS BRINGING DRY CONTINENTAL AIR OVER THE NW GULF WITH ACCOMPANYING CLEAR SKIES N OF 26N W OF 87W AND A WEAK 1012 MB HIGH JUST OFF THE MISSISSIPPI DELTA. A BROAD UPPER RIDGE DOMINATES THE S GULF ANCHORED OVER S MEXICO NEAR CIUDAD DEL CARMEN. THE REMNANTS OF TROPICAL DEPRESSION TWELVE-E MADE LANDFALL EARLIER THIS EVENING FROM THE E PACIFIC REGION NEAR THE ISTHMUS OF TEHUANTEPEC GENERATING SCATTERED/HEAVY SHOWERS AND SCATTERED THUNDERSTORMS OVER S MEXICO AND INTO THE BAY OF CAMPECHE S OF 20N E OF 95W TO OVER THE YUCATAN PENINSULA. THE SURFACE TROUGH WILL MOVE SLOWLY SE AND EXIT THE GULF ON THU AHEAD OF A APPROACHING COLD FRONT. THIS COLD FRONT WILL MOVE INTO THE NW GULF THU EXTENDING FROM TAMPA BAY TO THE BAY OF CAMPECHE FRI THEN STALL ACROSS THE SE GULF THROUGH THE WEEKEND. STRONG HIGH PRESSURE NW OF THE FRONT WILL COMBINE WITH BROAD LOW PRESSURE THAT IS EXPECTED TO ENCOMPASS CENTRAL AMERICA FRI THROUGH MON. CARIBBEAN SEA... THE UPPER RIDGE THAT DOMINATES THE S GULF OF MEXICO COVERS THE W CARIBBEAN W OF 80W ENHANCING ISOLATED SHOWERS/THUNDERSTORMS IN THE GULF OF HONDURAS FROM 17N-20N W OF 83W. AN ELONGATED UPPER LOW EXTENDS FROM CUBA JUST E OF SANTIAGO DE CUBA JUST OFF THE E TIP OF JAMAICA TO THE COAST OF COLOMBIA NEAR 11N74W GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS BETWEEN 70W-78W WITH THE HIGHEST CONCENTRATION OF THUNDERSTORMS INLAND AND WITHIN 75 NM ALONG THE COAST OF COLOMBIA. THE MONSOON TROUGH REMAINS N EXTENDING FROM 12N74W 12N78W ACROSS CENTRAL AMERICA AND INTO THE E PACIFIC REGION OVER NE NICARAGUA NEAR 14N84W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF THE TROUGH W OF 81W TO INLAND OVER CENTRAL AMERICA. A LARGE UPPER TROUGH OVER THE CENTRAL ATLC EXTENDS OVER THE FAR E CARIBBEAN GIVING THE AREA MOSTLY FAIR WEATHER TONIGHT WITH SOME ISOLATED SHOWERS USHERED IN ON THE EASTERLY SURFACE WINDS. A DEVELOPING BROAD LOW PRESSURE IS EXPECTED ACROSS CENTRAL AMERICA AND THE W CARIBBEAN TO THE FAR SW GULF OF MEXICO FRI THROUGH MON. ATLANTIC OCEAN... THE BROAD UPPER TROUGH THAT COVERS THE N GULF OF MEXICO EXTENDS INTO THE W ATLC N OF 27N W OF 74W GENERATING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS WITHIN 75 NM ALONG THE COAST OF FLORIDA N OF 26N. A WEAK SURFACE TROUGH REMAINS IN THE W ATLC EXTENDING FROM 26N76W OVER THE TURKS AND CAICOS TO 21N72W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 23N-26N BETWEEN 70W-74W AND SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 26N BETWEEN 68W-73W. A NARROW UPPER RIDGE IS TO THE E ALONG 67W INDUCED BY A LARGE UPPER TROUGH THAT COVERS THE CENTRAL ATLC EXTENDING THROUGH 32N47W ALONG 22N50W ACROSS THE W TROPICAL ATLC/E CARIBBEAN TO 10N60W. A WEAK SURFACE TROUGH IS ANALYZED WITHIN THIS UPPER TROUGH EXTENDING FROM 28N36W TO 23N46W CONTINUING AS A SHEAR AXIS ALONG 22N51W TO 23N58W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 20N-22N BETWEEN 50W-52W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE SURFACE TROUGH. SURFACE TROUGH IN THE W ATLC WILL LIFT N AND DISSIPATE LATER TONIGHT. A COLD FRONT WILL ENTER NW PORTION OF THE AREA THU AND EXTEND FROM 31N70W TO STRAITS OF FLORIDA SAT THEN BECOME NEARLY STATIONARY AND WEAKEN SUN FROM BERMUDA TO STRAITS OF FLORIDA. HIGH PRES WILL BUILD ACROSS W ATLC SAT NIGHT THROUGH MON. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW