000 AXNT20 KNHC 081756 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION HENRI IS CENTERED NEAR 19.8N 62.0W AT 08/1500 UTC...OR ABOUT 110 NM N-NE OF THE NRN LEEWARD ISLANDS MOVING W AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SCATTERED STRONG CONVECTION IS FROM 17N-23N BETWEEN 56W-61W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/ WTNT25 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 22W S OF 15N MOVING W NEAR 15 KT. LOW-LEVEL SATELLITE DERIVED WINDS SHOW CYCLONIC CURVATURE S OF 13N IN THE VICINITY OF THE WAVE AXIS. ISOLATED SHOWERS COVER A VERY LIMITED AREA SURROUNDING THE WAVE FROM 8N-13N BETWEEN 19W-23W AS SAHARAN DUST IS LOCATED N OF 10N E OF 30W TO THE W AFRICA COAST. TROPICAL WAVE IS ALONG 56W S OF 15N MOVING W NEAR 22 KT. VISIBLE SATELLITE IMAGERY INDICATES AN INVERTED-V CLOUD SIGNATURE NEAR THE WAVE AXIS. A MAXIMUM IN DEEP LAYER MOISTURE IS ALSO OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY BETWEEN 50W-60W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-14N BETWEEN 54W-60W. TROPICAL WAVE IS ALONG 75W S OF 16N MOVING W NEAR 18 KT. THE WAVE LIES IN A VERY BROAD AREA OF DEEP LAYER MOISTURE ACROSS THE SRN HALF OF THE CARIBBEAN BASIN S OF 15N AS OBSERVED IN THE TOTAL PRECIPITABLE WATER IMAGERY. LOCATED BENEATH AN UPPER LEVEL RIDGE...DRY AIR AND SUBSIDENCE ALOFT ARE CONFINING ANY DEEP CONVECTION NEAR THE WAVE. ISOLATED SHOWERS ARE OCCURRING FROM 12N-16N BETWEEN 75W-79W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 12N16W 12N20W 10N23W 6N38W 7N54W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM EITHER SIDE OF THE AXIS BETWEEN 26W-40W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 30N85W COVERS THE ENTIRE GULF AND STATE OF FLORIDA. STRONG SUBSIDENCE AND PLENTY OF DRY AIR IS NOTED ON WATER VAPOR IMAGERY ASSOCIATED WITH THE UPPER LEVEL HIGH. AT THE SURFACE...A 1021 MB HIGH IS CENTERED IN THE NE GULF NEAR 28N86W. WIND FLOW CIRCULATING AROUND THE SURFACE HIGH CONTINUES TO PROVIDE MOST OF THE GULF WITH SELY WINDS OF 10-15 KT OVER THE CENTRAL GULF WATERS AND UP TO 25 KT ACROSS THE WRN GULF. A WEAKNESS IN THE SURFACE RIDGE ACROSS NRN FLORIDA SUPPORTS A STATIONARY FRONT FROM FLAGLER BEACH TO THE BIG BEND REGION AND OVER THE FLORIDA PANHANDLE. BECAUSE OF THE STRONG SUBSIDENCE ALOFT...THE FRONT REMAINS DRY AND IS FORECAST TO BECOME MORE DIFFUSE THROUGH THE REST OF THE AFTERNOON AND EVENING. THE WINDS ARE FORECAST TO REMAIN STRONG THROUGH FRIDAY ACROSS THE WRN GULF EAST OF A DEVELOPING AREA OF LOW PRESSURE ACROSS THE SRN U.S. PLAINS WITH A COLD FRONT POISED TO ENTER THE NW GULF FRIDAY EVENING. CARIBBEAN SEA... THE WRN CARIBBEAN W OF 72W IS UNDER E-NE UPPER LEVEL FLOW ON THE SRN PERIPHERY OF A BROAD UPPER LEVEL RIDGE CENTERED IN THE NE GULF OF MEXICO. DRY SUBSIDENT AIR IS SUPPORTING GENERALLY FAIR WEATHER N OF A LINE FROM THE MONA PASSAGE WWD TO THE CENTRAL NICARAGUA COAST NEAR 13N84W. LOW-LEVEL MOISTURE IS LOCATED GENERALLY S OF 15N AS NOTED BY TOTAL PRECIPITABLE WATER IMAGERY AND COUPLED WITH ATMOSPHERIC INSTABILITY IS GENERATING WIDELY SCATTERED SHOWERS AND TSTMS OVER THE SW CARIBBEAN BETWEEN 77W-84W. AN UPPER LEVEL TROUGH IS ACROSS THE CENTRAL CARIBBEAN WITH THE AXIS STRETCHING FROM NRN COLOMBIA THROUGH THE MONA PASSAGE TO 21N66W. E OF THE TROUGH AXIS...MOIST SLY UPPER LEVEL FLOW DOMINATES OVER THE ERN CARIBBEAN AND IS GENERATING ISOLATED SHOWERS S OF 16N BETWEEN 67W-72W. FRESH TO STRONG TRADE WINDS ARE ACROSS MUCH OF THE BASIN WITH THE STRONG WINDS LOCATED ALONG THE COAST OF COLOMBIA. ATLANTIC OCEAN... TROPICAL DEPRESSION HENRI CONTINUES TO IMPACT THE TROPICAL NORTH ATLC WATERS NE OF THE NRN LEEWARD ISLANDS...SEE SPECIAL FEATURES ABOVE. FARTHER TO THE NW OVER THE W ATLC...AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE NE GULF AND EXTENDS UPPER LEVEL RIDGING TO 60W. MOSTLY DRY AIR AND STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY...HOWEVER THE TAIL END OF A WRN ATLC COLD FRONT ENTERS THE DISCUSSION AREA NEAR BERMUDA AND EXTENDS WSW TO 30N77W...THEN CONTINUES WWD TO FLAGLER BEACH FLORIDA AS A WEAKENING STATIONARY BOUNDARY. WITH DRY CONDITIONS ALOFT AND A VERY STABLE ATMOSPHERE IN PLACE OVER THE W ATLC...SIGNIFICANT SHOWERS AND CONVECTION REMAIN N OF 32N IN ASSOCIATION WITH THE FRONTAL BOUNDARY. THE REMAINDER OF THE CENTRAL AND ERN ATLC IS UNDER THE INFLUENCE OF A RATHER LARGE SURFACE RIDGE OF HIGH PRESSURE. CENTERED ON A 1024 MB HIGH NEAR 26N45W...THE RIDGE EXTENDS NE TO A 1023 MB HIGH CENTERED NEAR 31N30W AND BEYOND 32N27W. A WEAKNESS WITHIN THE RIDGE IS ANALYZED AS A SURFACE TROUGH FROM 29N37W TO 32N37W. THIS TROUGH IS SUPPORTED ALOFT BY A SHARP UPPER LEVEL SHORTWAVE TROUGH WITH AXIS FROM 24N46W TO BEYOND 32N36W. ISOLATED SHOWERS ARE FROM 25N-32N BETWEEN 35W-40W. $$ HUFFMAN