000 AXNT20 KNHC 150003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN AUG 14 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 2345 UTC. ...SPECIAL FEATURES... T.S. GERT IS CENTERED NEAR 29.5N 63.2W...OR ABOUT 187 NM SSE OF BERMUDA AT 15/0000 UTC...MOVING NNW AT 7 KT. ESTIMATED CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. PLEASE SEE THE LATEST NHC INTERMEDIATE PUBLIC ADVISORY MIATCPAT1/WTNT32 KNHC AND THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 27N-31N BETWEEN 61W-65W. A 1012 MB LOW IS CENTERED NEAR 24N60W GENERATING SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 70-120 NM AROUND THE CENTER. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN ONLY MARGINALLY CONDUCIVE FOR DEVELOPMENT OVER THE NEXT COUPLE OF DAYS DUE TO THE ITS PROXIMITY TO TROPICAL STORM GERT. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES TOWARD THE W-NW AT 13-17 KT. ...TROPICAL WAVES... TROPICAL WAVE MOVES ACROSS THE WEST TROPICAL ATLC ANALYZED FORM 16N50W TO 10N51W MOVING W NEAR 15-20 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYER MOISTURE AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 10N-17N BETWEEN 50W-57W. TROPICAL WAVE MOVES ACROSS THE BAY OF CAMPECHE ANALYZED FROM 22N91W TO 15N95W MOVING W AT 5-10 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 40 NM OVER THE WESTERN COASTAL WATERS OF THE YUCATAN PENINSULA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF MAURITANIA NEAR 19N16W ALONG 13N25W TO 11N37W. THE ITCZ IS ANALYZED FROM 7N42W ALONG 8N50W TO 10N60W. SCATTERED SHOWERS AND THUNDERSTORMS ARE WITHIN 80-120 NM ON EITHER SIDE OF THE ITCZ. SIMILAR ACTIVITY IS OVER THE COASTAL WATERS OF GUINEA...SIERRA LEONE...GUINEA BISSAU...THE GAMBIA...AND SENEGAL FROM 7N-18N E OF 20W. ...DISCUSSION... GULF OF MEXICO... A VIGOROUS UPPER LEVEL TROUGH MOVES ACROSS THE EASTERN AND SE CONUS...NOTICED ON WATER VAPOR IMAGERY. THE SOUTHERN EXTENSION OF THE UPPER TROUGH ENTERS THE N CENTRAL AND NE GULF SUPPORTING SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS IMPACTING THE COASTAL WATERS ACROSS EASTERN TEXAS...LOUISIANA...AND MISSISSIPPI E OF 96W WITHIN 50 NM OFFSHORE. SURFACE RIDGING WITH ISOLATED MODERATE SHOWERS ARE ACROSS THE REMAINDER OF THE DISCUSSION AREA N OF 23N...CENTERED AROUND A 1014 MB HIGH NEAR 27N92W. A TROPICAL WAVE IS MOVING ACROSS THE BAY OF CAMPECHE GENERATING SHOWERS AND THUNDERSTORMS WITHIN 40 NM OVER THE WESTERN COASTAL WATERS OF THE YUCATAN PENINSULA. THE SURFACE RIDGE WILL REMAIN THROUGH TUE. A WEAK COLD FRONT WILL MOVE INTO THE FAR NE GULF ON MON THEN STALL AND WEAKEN THROUGH WED. A SURFACE HIGH WILL THEN BECOME CENTERED OVER THE NW GULF WED AND THU. CARIBBEAN SEA... A LARGE CLUSTER OF HEAVY SHOWERS AND THUNDERSTORMS IS IN THE SW CARIBBEAN S OF 14N W OF 74W ASSOCIATED WITH THE MONSOON TROUGH THAT EXTENDS ACROSS COSTA RICA TO NORTHERN COLOMBIA. SIMILAR CONVECTION IS OVER THE WINDWARD PASSAGE N OF 18N...ASSOCIATED TO THE SURFACE TROUGH IN THE ATLC N OF HISPANIOLA. THE REMAINDER OF THE BASIN IS INFLUENCED BY DRY AIR ALOFT ADVECTING FROM THE W TROPICAL ATLC AND SUPPORTING MOSTLY FAIR WEATHER ACROSS THE NW...CENTRAL...AND ERN CARIBBEAN WITH 5-15 KT ELY TRADE WINDS. EXPECT CONVECTION TO DEVELOP ACROSS THE WATERS NEAR EASTERN CUBA AND N OF JAMAICA ASSOCIATED WITH THE SURFACE TROUGH N OF HISPANIOLA. A TROPICAL WAVE IN THE WEST TROPICAL ATLC IS EXPECTED TO MOVE INTO THE E CARIBBEAN ON TUE NIGHT WITH CONVECTION. ATLANTIC OCEAN... THE PRIMARY CONCERN THIS EVENING IS T.S. GERT DISCUSSED IN THE SPECIAL FEATURES...PRIMARILY FOR BERMUDA...SEE ABOVE. THE UPPER TROUGH INLAND OVER THE E AND SE CONUS IS GENERATING SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE COASTAL WATERS OF FLORIDA N OF 26N WITHIN 40-90 NM OFFSHORE...INCLUDING THE EASTERN COASTAL STATES N OF THE DISCUSSION AREA. TO THE EAST OF THIS AREA OF CONVECTION...A WEAK 1016 MB HIGH IS CENTERED AROUND 26N71W...PROVIDING FAIR WEATHER ACROSS MUCH OF THE BAHAMAS. HOWEVER A SURFACE TROUGH ANALYZED N OF HISPANIOLA FROM 19N71W TO 24N65W IS GENERATING SIMILAR CONVECTION S OF 22N BETWEEN 69W-74W. THIS AREA OF CONVECTION WILL MOVE ACROSS THE BAHAMAS OVER THE NEXT 24 HOURS. TO THE NE OF THE SURFACE TROUGH...A SPECIAL FEATURE 1012 MB LOW IS CENTERED NEAR 24N60W GENERATING SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 70-120 NM AROUND THE CENTER. A BROAD SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC...ANCHORED BY A 1022 MB HIGH NEAR 32N47W. LAST VISIBLE SATELLITE PICTURES OF THE DAY INDICATED A BROAD AREA OF AFRICAN DUST EXTENDING E OF 50W TO THE COAST OF AFRICA. THE SURFACE HIGH OVER THE W ATLC WILL DISSIPATE THROUGH TONIGHT AS T.S. GERT MOVES WNW. T.S. GERT IS FORECAST TO MOVE N OF THE DISCUSSION AREA MON MORNING BEFORE LIFTING FURTHER N. THE SURFACE TROUGH N OF HISPANIOLA WILL TRACK W ACROSS THE BAHAMAS TONIGHT THROUGH TUE BEFORE REACHING THE NW BAHAMAS AND FLORIDA WED. A WEAK COLD FRONT WILL ENTER THE NW ATLC MON NIGHT AND DISSIPATE WED. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA