000 AXNT20 KNHC 080520 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU OCT 08 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0430 UTC. ...SPECIAL FEATURES... HENRI HAD BEEN DOWNGRADED TO A TROPICAL DEPRESSION AT 08/0300 UTC CENTERED NEAR 19.5N 59.6W...OR ABOUT 310 MILES ENE OF THE NRN LEEWARD ISLANDS MOVING WNW AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED WINDS HAVE DECREASED TO 30 KT WITH GUSTS TO 40 KT. FURTHER WEAKENING IS EXPECTED AND HENRI COULD BECOME A REMNANT LOW LATER TODAY. HENRI HAS AN EXPOSED CENTER WITH CONVECTION WELL E OF THE CENTER. NUMEROUS STRONG CONVECTION IS FROM 17N-20N BETWEEN 55W-59W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 52W S OF 14N MOVING W NEAR 20 KT. SATELLITE IMAGERY INDICATES LOW-LEVEL CYCLONIC FLOW AROUND THE WAVE AXIS. THE WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-12N BETWEEN 50W-56W. TROPICAL WAVE IS ALONG 72W S OF 17N MOVING W NEAR 20 KT. THE WAVE LIES IN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. DRY AIR AND SUBSIDENCE ALOFT ARE CONFINING DEEP CONVECTION TO COLOMBIA AND VENEZUELA NEAR A SURFACE LOW ANALYZED ALONG THE WAVE AXIS NEAR 9N. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-11N BETWEEN 72W-74W OVER COLOMBIA AND VENEZUELA. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 14N17W 8N26W 6N38W 8N51W 9N62W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-9N BETWEEN 22W-25W. SIMILAR ACTIVITY IS FROM 4N-8N BETWEEN 30W-34W...AND FROM 8N-10N BETWEEN 42W-48W. ...DISCUSSION... GULF OF MEXICO... THE GULF OF MEXICO REMAINS CALM AND CLEAR UNDER THE INFLUENCE OF A 1019 MB SURFACE HIGH CENTERED NEAR 27N85W. AN UPPER LEVEL RIDGE COVERS THE BASIN CENTERED NEAR 28N91W PROVIDING DRY AIR AND SUBSIDENCE ALOFT SUPPORTING THE FAIR WEATHER. A STATIONARY FRONT CLIPS THE BASIN ACROSS THE FLORIDA PANHANDLE FROM 31N86W TO 31N92W CONTINUING AS A WARM FRONT ACROSS TEXAS. NO SHOWER ACTIVITY IS CURRENTLY ASSOCIATED WITH THE FRONT. ANTI-CYCLONIC SURFACE WINDS ARE AROUND THE SURFACE RIDGE REACHING 10 KT IN THE ERN AND MIDDLE GULF...AND 20 KT IN THE WRN GULF. THE RIDGE SUPPORTED RECORD HIGHS OVER PORTIONS OF SOUTH FLORIDA YESTERDAY AND ARE EXPECTED TODAY AS WELL. THE RIDGE IS FORECAST TO PERSIST OVER THE NEXT 24 HRS...AND A COLD FRONT IS EXPECTED TO MOVE OFF THE TEXAS COAST FRI. CARIBBEAN SEA... MOST OF THE CARIBBEAN IS UNDER DRY SUBSIDENT AIR SUPPORTING GENERALLY FAIR WEATHER THROUGHOUT EXCEPT FOR A CLUSTER OF SHOWERS/THUNDERSTORMS OFF THE COAST OF CUBA FROM 19N-20N BETWEEN 78W-80W. THIS SHOWER ACTIVITY IS ATTRIBUTED TO UPPER DIFFLUENT FLOW BETWEEN AN UPPER RIDGE OVER THE GULF OF MEXICO EXTENDING OVER MUCH OF THE NRN CARIBBEAN AND AN UPPER LEVEL LOW OVER CENTRAL AMERICA NEAR 13N85W. THE UPPER LOW IS ALSO SUPPORTING A FEW ISOLATED SHOWERS/THUNDERSTORMS N OF HONDURAS. A TROPICAL WAVE IS ALONG 72W SUPPORTING A CLUSTER OF SHOWERS/THUNDERSTORMS OVER HAITI FROM 18N-19N BETWEEN 72W-74W. HOWEVER...DUE TO THE DRY AIR AND SUBSIDENCE ALOFT NO OTHER SHOWERS/THUNDERSTORMS ARE ASSOCIATED WITH THE WAVE EXCEPT INLAND OVER VENEZUELA AND COLOMBIA. SEE ABOVE. AN UPPER LEVEL TROUGH IS OVER THE ERN CARIBBEAN EXTENDING INTO THE ATLC. MODERATE TO FRESH TRADE WINDS ARE ACROSS MUCH OF THE BASIN WITH STRONGER WINDS IN THE SW AND ERN CARIBBEAN. EXPECT THE WAVE ALONG 72W TO CONTINUE WWD. ATLANTIC OCEAN... TROPICAL DEPRESSION HENRI REMAINS THE BIGGEST WEATHER MAKER OVER THE ATLANTIC. SEE SPECIAL FEATURES ABOVE. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1024 MB HIGH NEAR 26N46W...AND A 1023 MB HIGH NEAR 31N32W. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE ALONG WITH DRY AIR AND SUBSIDENCE ALOFT COVER THE WRN ATLC W OF 60W. A NARROW UPPER LEVEL TROUGH EXTENDS FROM THE ERN CARIBBEAN ACROSS PUERTO RICO TO NEAR 30N46W. STRONG SWLY WINDS ALOFT BETWEEN THIS UPPER TROUGH AND AN UPPER LEVEL RIDGE OVER THE TROPICAL ATLC CENTERED NEAR 16N49W ARE SHEARING HENRI AND SUPPORTING LINES OF HIGH CLOUDS AND ISOLATED SHOWERS FROM 20N-26N BETWEEN 44W-55W...AND N OF 27N BETWEEN 36W-41W. AN UPPER LEVEL TROUGH DIGS INTO THE ERN ATLC WITH AXIS ALONG 30W. $$ WALTON