000 AXNT20 KNHC 141731 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT NOV 14 2009 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N12W 7N26W 5N36W 8N44W 8N60W. ISOLATED MODERATE CONVECTION IS FROM 4N-8N BETWEEN 13W-24W. A SURFACE TROUGH IS ANALYZED FROM 11N28W TO 5N27W. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE TROUGH AXIS FROM 5N-8N. A SECOND SURFACE TROUGH IS ANALYZED FROM 12N38W TO 6N42W. ISOLATED SHOWERS ARE POSSIBLE W OF THE TROUGH AXIS. ...DISCUSSION... GULF OF MEXICO... A SURFACE RIDGE DOMINATES THE GULF OF MEXICO ANCHORED BY A 1016 MB HIGH IN THE N CENTRAL GULF NEAR 27N89W. THE RIDGE IS PROVIDING GENERALLY FAIR WEATHER ACROSS THE BASIN WITH EXTREMELY CLEAR SKIES OVER FLORIDA AND THE NE GULF STATES. A LARGE AREA OF STRATOCUMULUS CLOUDS LIE OVER THE CENTRAL GULF WITH AN INTRUSION OF STABLE AIR AND CLEAR SKIES N OF THE YUCATAN PENINSULA. LIGHT SFC WINDS FLOW ANTI-CYCLONICALLY AROUND THE SURFACE RIDGE WITH STRONGER SLY RETURN FLOW ACROSS THE WRN GULF. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE EXTENDS FROM CENTRAL MEXICO ACROSS THE NRN GULF AND UP MUCH OF THE ERN CONUS AROUND AN UPPER LEVEL LOW OVER THE SW GULF AND SE COAST OF MEXICO NEAR 21N97W. STRONG SUBSIDENCE AND DRY AIR REMAINS ACROSS THE BASIN NOTED IN WATER VAPOR IMAGERY. EXPECT THE SURFACE RIDGE TO DRIFT E AS SLY RETURN FLOW GRADUALLY INCREASES ACROSS THE WRN GULF AHEAD OF THE NEXT COLD FRONT FORECAST TO MOVE OFF THE TEXAS COAST MON AFTERNOON. CARIBBEAN SEA... A STATIONARY FRONT EXTENDS FROM THE W ATLC TO WRN HAITI NEAR 20N73W INTO THE NRN CARIBBEAN TO 18N79W. A PRE-FRONTAL SURFACE TROUGH IS SE OF THE FRONT FROM S OF HAITI NEAR 18N74W TO 14N82W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE FRONT/TROUGH. THE FRONTAL SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH OVER THE W ATLC EXTENDING TO NEAR 18N73W JUST S OF HAITI. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE SW CARIBBEAN S OF 11N BETWEEN 78W-84W DUE TO SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ. THE REMAINDER OF THE BASIN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF RELATIVELY DRY AIR AND SUBSIDENCE TO EITHER SIDE OF THE UPPER TROUGH SUPPORTING THE FRONTAL SYSTEM. AN UPPER LEVEL RIDGE COVERS THE WRN CARIBBEAN CENTERED OVER NICARAGUA NEAR 14N84W. ZONAL WLY FLOW ALOFT EXTENDS ACROSS THE CENTRAL AND ERN CARIBBEAN TO A SECOND UPPER LEVEL RIDGE WITH AXIS ACROSS THE LEEWARD ISLANDS INTO THE CENTRAL ATLC. EXPECT THE FRONT TO GRADUALLY SLIDE E AND DISSIPATE BY TUE. ATLANTIC OCEAN... LOW PRESSURE IS ACROSS THE WRN ATLC CENTERED AT A 1002 MB LOW N OF THE DISCUSSION AREA NEAR 34N72W. A PRIMARY STATIONARY FRONT EXTENDS E OF THE LOW SYSTEM ENTERING THE AREA NEAR 32N65W ALONG 26N67W TO NE HAITI NEAR 18N74W. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED E OF THE FRONT ALONG A LINE OF STRONG CONVECTION FROM 28N62W TO 24N66W. NUMEROUS STRONG CONVECTION IS WITHIN 50 NM EITHER SIDE OF THE TROUGH AXIS. SCATTERED SHOWERS/THUNDERSTORMS COVER THE SURROUNDING AREA FROM 20N-24N BETWEEN 63W-70W...AND N OF 24N BETWEEN 52-65W. A SECONDARY SURFACE TROUGH IS W OF THE PRIMARY FRONT ALONG 33N70W 28N71W TO THE CENTRAL BAHAMAS NEAR 25N76W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE TROUGH AXIS. THE ENTIRE SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH WITH AXIS ALONG 71W CENTERED NEAR 33N71W. UPPER DIFFLUENCE AROUND THE E SIDE OF THE UPPER TROUGH BETWEEN THE TROUGH AND AN UPPER LEVEL RIDGE EXTENDING NE FROM THE LEEWARD ISLANDS IS ENHANCING THE LARGE AREA OF SHOWER ACTIVITY AHEAD OF THE FRONT. TO THE E...A WEAK 1019 MB SURFACE HIGH IS CENTERED NEAR 26N48W. A 1015 MB LOW IS CENTERED AT THE EDGE OF THE DISCUSSION AREA NEAR 31N39W. A STATIONARY FRONT EXTENDS W FROM THE LOW CENTER ALONG 30N45W 32N53W. A WARM FRONT EXTENDS E FROM THE LOW CENTER TO NEAR 30N34W. ISOLATED SHOWERS/THUNDERSTORMS ARE N OF 27N BETWEEN 36W-52W. A COLD FRONT ENTERS THE AREA NEAR 32N27W TO NEAR 28N35W. ISOLATED SHOWERS ARE ALONG THE FRONT AXIS. THIS SECOND SERIES OF FRONTS IS SUPPORTED BY A BROAD UPPER LEVEL TROUGH OVER THE NRN ATLC N OF 27N. A SHORTWAVE UPPER TROUGH EXTENDS FROM 27N40W TO 6N54W. UPPER DIFFLUENCE AROUND THE E SIDE OF THIS UPPER TROUGH IS SUPPORTING AN AREA OF HIGH CLOUDS AND POSSIBLE SHOWERS FROM 12N-20N BETWEEN 34W-46W. THE REMAINDER OF THE ERN ATLC IS COVERED BY A BROAD SURFACE RIDGE EXTENDING SW FROM NRN AFRICA. $$ WALTON