000 AXNT20 KNHC 161739 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST MON NOV 16 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 1700 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 8N10W 6N26W 7N41W 6N46W 3N52W. ISOLATED MODERATE/STRONG CONVECTION IS WITHIN 150 NM N OF THE AXIS BETWEEN 14W-18W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 200 NM N OF THE AXIS BETWEEN 30W-40W. A SURFACE TROUGH IS ANALYZED FROM 10N45W TO 5N43W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS E OF THE AXIS FROM 2N-7N BETWEEN 40W-42W...AND SHEARED E ALONG A LINE FROM 10N44W TO 15N37W. ...DISCUSSION... GULF OF MEXICO... AS OF 1500 UTC...A COLD FRONT HAS EMERGED OFF THE COAST OF TEXAS OVER THE NW GULF OF MEXICO EXTENDING FROM A 1012 MB LOW CENTERED OVER NRN ARKANSAS NEAR 36N91W TO THE TEXAS/LOUISIANA COAST NEAR 30N93W CONTINUING ALONG 28N95W TO THE TIP OF SRN TEXAS NEAR 26N97W AND INTO MEXICO. RADAR IMAGERY INDICATES A NARROW LINE OF SHOWERS/THUNDERSTORMS ALONG THE FRONT AXIS. A CLUSTER OF SHOWERS/THUNDERSTORMS ARE ALSO AHEAD OF THE FRONT NEAR 28N93W...AND A FEW CLUSTERS FROM 24N-26N BETWEEN 95W-98W. THE FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH OVER THE CENTRAL CONUS EXTENDING OVER NRN MEXICO AND THE FAR NW GULF OF MEXICO. A SURFACE RIDGE DOMINATES THE ERN GULF OF MEXICO ANCHORED BY A 1019 MB HIGH NEAR 28N87W. THE RIDGE IS PROVIDING GENERALLY FAIR WEATHER ACROSS THE REMAINDER OF THE BASIN. AN AREA OF STRATOCUMULUS CLOUDS LIE OVER ERN PORTIONS OF THE SURFACE RIDGE OFF THE W FLORIDA COASTLINE. LIGHT SFC WINDS FLOW ANTI-CYCLONICALLY AROUND THE SURFACE RIDGE WITH STRONGER WINDS ACROSS THE WRN GULF AHEAD OF THE COLD FRONT. AN UPPER LEVEL RIDGE EXTENDS OVER THE MAJORITY OF THE BASIN WITH AXIS EXTENDING FROM S OF MEXICO ACROSS THE CENTRAL GULF AND FLORIDA TO THE W ATLC. STRONG SUBSIDENCE AND DRY AIR REMAINS OVER THE ERN BASIN NOTED IN WATER VAPOR IMAGERY. EXPECT THE SURFACE RIDGE TO WEAKEN AS THE COLD FRONT CONTINUES PUSHING SE ACROSS THE BASIN. AS THE FRONT REACHES THE BAY OF CAMPECHE TUE...GALE FORCE WINDS ARE EXPECTED S OF 21N W OF 95W. CARIBBEAN SEA... MUCH OF THE CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF DRY AIR AND SUBSIDENCE ASSOCIATED WITH AN UPPER LEVEL RIDGE COVERING THE WRN CARIBBEAN EXTENDING FROM THE E PACIFIC NEAR 12N95W UP ACROSS THE GULF OF MEXICO AND NW CARIBBEAN INTO THE WRN ATLC. SCATTERED SHOWERS/THUNDERSTORMS ARE IN THE SW CARIBBEAN AFFECTING PORTIONS OF PANAMA S OF 10N BETWEEN 76W-82W DUE TO SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ. AN AREA OF STRONG SHOWERS/THUNDERSTORMS ARE ACROSS PUERTO RICO AND THE NW LEEWARD ISLANDS N OF 16N BETWEEN 61W-67W ASSOCIATED WITH SURFACE CONVERGENCE NEAR A SURFACE TROUGH EXTENDING FROM THE ATLC ACROSS CENTRAL PUERTO RICO TO NEAR 17N68W. AN UPPER LEVEL TROUGH EXTENDING FROM THE ATLC ACROSS PUERTO RICO AND INTO THE ERN CARIBBEAN TO NEAR 9N70W SUPPORTS THE SURFACE TROUGH. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER TROUGH AND AN UPPER LEVEL RIDGE TO ITS E IS ENHANCING THE LARGE AREA OF STRONG SHOWER ACTIVITY. MODERATE TRADE WINDS ARE ACROSS MUCH OF THE BASIN. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE OVER THE NE CARIBBEAN AS THE SURFACE TROUGH REMAINS MAINLY STATIONARY. ATLANTIC OCEAN... LOW PRESSURE IS ACROSS THE WRN ATLC CENTERED AT A 1008 MB LOW NEAR 30N67W. A PAIR OF SURFACE TROUGHS EXTEND E OF THE LOW CENTER. THE FIRST IS ALONG 28N65W 24N67W TO THE SE BAHAMAS NEAR 22N73W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE AXIS N OF 23N BETWEEN 61W-66W. THE SECOND SURFACE TROUGH EXTENDS ALONG 31N61W 24N62W 20N64W ACROSS PUERTO RICO TO NEAR 17N68W. AN AREA OF STRONG SHOWERS/THUNDERSTORMS ARE E OF THE SRN PORTION OF THE TROUGH FROM 16N-21N BETWEEN 59W-66W AFFECTING PUERTO RICO AND THE NW LEEWARD ISLANDS. ISOLATED SHOWERS/THUNDERSTORMS ARE N OF 21N WITHIN 250 NM E OF THE TROUGH AXIS. THIS SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH CENTERED NEAR 28N66W. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER TROUGH AND AN UPPER LEVEL RIDGE TO THE E WITH AXIS ALONG 48W IS SUPPORTING THE LARGE AREA OF SHOWER ACTIVITY. ACROSS THE ERN ATLC...A BROAD SURFACE RIDGE EXTENDS FROM A 1031 MB HIGH NEAR 35N41W. A COLD FRONT PROTRUDES INTO THE RIDGE ENTERING THE DISCUSSION AREA NEAR 32N16W CONTINUING SW ALONG 25N22W 21N34W 22N41W EXTENDING NW AS A STATIONARY FRONT ALONG 26N48W 32N53W OUT OF THE DISCUSSION AREA. ISOLATED SHOWERS ARE WITHIN 150 NM E AND SE AHEAD OF THE COLD FRONT BETWEEN 14W-34W. ISOLATED SHOWERS ARE WITHIN 100 NM SW AND W OF THE STATIONARY FRONT BETWEEN 45W-54W. A LONGWAVE UPPER LEVEL TROUGH EXTENDING FROM THE NE ATLC ALONG 20W N OF 30N CONTINUING TO NEAR 20N32W SUPPORTS THE FRONTAL SYSTEM. A SHORTWAVE TROUGH EXTENDS FROM THE BASE OF THE LONGWAVE TO NEAR 8N44W. UPPER LEVEL DIFFLUENCE AND STRONG SHEAR TO THE NE BETWEEN THIS SHORTWAVE TROUGH AND AN UPPER LEVEL RIDGE TO THE E OVER THE TROPICAL ATLC SUPPORTS SHOWER ACTIVITY NEAR THE ITCZ. 34N67W 30N64W 25N64W 21N69W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 200 NM E OF THE TROUGH AXIS...WITH ISOLATED SHOWERS WITHIN 400 NM E OF THE AXIS. THE SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH CENTERED NEAR 32N67W WITH AXIS EXTENDING S ACROSS THE LEEWARD ISLANDS INTO THE ERN CARIBBEAN. UPPER LEVEL DIFFLUENCE AROUND THE E SIDE OF UPPER TROUGH IS ENHANCING THE LARGE AREA OF SHOWER ACTIVITY E OF THE SURFACE TROUGH. THE UPPER DIFFLUENT ZONE IS ALSO SUPPORTING AN AREA OF SCATTERED SHOWERS/THUNDERSTORMS E OF THE LESSER ANTILLES FROM 12N-15N BETWEEN 53W-59W. A WEAK 1013 MB LOW IS OVER THE ERN ATLC NEAR 29N28W. A COLD FRONT EXTENDS FROM THE LOW CENTER TO THE SW ALONG 25N35W 26N46W BECOMING STATIONARY TO THE NW ALONG 29N51W 32N54W. A SECOND STATIONARY FRONT EXTENDS TO THE NE FROM THE LOW CENTER TO 32N21W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 120 NM SE OF THE LOW AND ADJACENT FRONTAL SYSTEMS BETWEEN 22W-33W. ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO N OF 23N BETWEEN 53W-60W NEAR THE STATIONARY FRONT THAT EXTENDS TO THE NW FROM THE COLD FRONT. THIS FRONTAL SYSTEM IS SUPPORTED BY A LONGWAVE UPPER LEVEL TROUGH EXTENDING FROM THE NE ATLC ACROSS THE AZORES TO NEAR 22N34W. IN THE TROPICS...A SHORTWAVE UPPER TROUGH IS SHEARING MOISTURE FROM THE ITCZ TO THE ENE SUPPORTING CLOUDS AND POSSIBLE ISOLATED SHOWERS FROM 13N-21N BETWEEN 34W-42W. $$ WALTON