000 AXNT20 KNHC 062353 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE OCT 06 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... TROPICAL STORM HENRI HAS DEVELOPED AT 06/2100 UTC...NEAR 17.8N 54.0W...OR ABOUT 600 MILES/965 KM TO THE EAST OF THE NORTHERN LEEWARD ISLANDS. HENRI IS MOVING TOWARD THE WEST- NORTHWEST 16 KT. THE CENTER OF HENRI AND THE ASSOCIATED STRONG WINDS ARE EXPECTED TO REMAIN WELL TO THE NORTH OF THE LESSER ANTILLES. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KT WITH GUSTS TO 45 KT. HENRI IS EXPECTED TO BE A SHORT-LIVED TROPICAL CYCLONE AND COULD WEAKEN TO A REMNANT LOW BY WEDNESDAY NIGHT. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 50 MILES/85 KM TO THE NORTHEAST OF THE CENTER. PLEASE READ THE NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/ WTNT25 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 13N TO 19N BETWEEN 50W AND 54W. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 40W/41W TO THE SOUTH OF 10N MOVING WEST 15 KT. WIDELY SCATTERED TO SCATTERED STRONG SHOWERS AND THUNDERSTORMS FROM 6N TO 10N BETWEEN 41W AND 48W. AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 62W/63W TO THE SOUTH OF 14N MOVING WESTWARD 15 KT. AN UPPER LEVEL TROUGH IS SHEARING THE CLOUD TOPS THAT HAVE BUILT UP AROUND THE WAVE. THE CYCLONIC FLOW OF THE TROUGH ALSO IS DISRUPTING THE CONTINUED DEVELOPMENT OF THE WIDELY SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 10N TO 14N BETWEEN 60W AND 67W. A TROPICAL WAVE IS ALONG 90W...MOVING THROUGH THE AREA FROM THE SOUTHERN YUCATAN PENINSULA...THROUGH GUATEMALA ENTIRELY AND TOUCHING A TINY BIT OF WESTERN EL SALVADOR AND BEYOND INTO THE EASTERN PACIFIC OCEAN. ISOLATED MODERATE SHOWERS THAT STRETCH FROM SOUTHERN GUATEMALA TO CAMPECHE MEXICO/THE BAY OF MEXICO PROBABLY ARE MORE CORRECTLY RELATED TO AN UPPER LEVEL CYCLONIC CIRCULATION CENTER THAT IS MOVING ONSHORE NEAR THE EASTERN HONDURAS/NORTHEASTERN NICARAGUA BORDER. ...THE ITCZ... 10N14W 8N28W 9N39W 6N43W INTO FRENCH GUIANA NEAR 5N52W. STRONG THUNDERSTORMS FROM 5N TO 7N BETWEEN 21W AND 22W. ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 4N TO 10N BETWEEN THE COAST OF AFRICA AND 40W. ...DISCUSSION... THE GULF OF MEXICO... BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA IN A GENERAL SENSE. THE GFS MODEL FOR 200 MB SHOWS A DEFINITE CENTER IN EAST CENTRAL MEXICO NEAR 23N99W. THE GFS MODEL FOR 500 MB SHOWS A DEFINITE ANTICYCLONIC CENTER IN THE NORTH CENTRAL GULF WATERS. THE 850 MB CENTER FOR THE GFS MODEL IS IN THE EAST CENTRAL GULF ABOUT 150 NM OFF THE SOUTHWESTERN FLORIDA COAST. UPPER LEVEL DRY AIR/SUBSIDENCE COVERS THE ENTIRE AREA. THE SURFACE PRESSURE GRADIENT IS WEAK ACROSS THE GULF WATERS. THE CARIBBEAN SEA... AN UPPER LEVEL TROUGH PASSES THROUGH THE MONA PASSAGE...THROUGH THE CENTER OF THE CARIBBEAN SEA...TO AN UPPER LEVEL CYCLONIC CIRCULATION CENTER NEAR 15N81W. CYCLONIC FLOW AROUND THIS CENTER GOES FROM THE PANAMA AND COSTA RICA TO 20N BETWEEN 76W AND 86W. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS COVER PARTS OF PANAMA...COSTA RICA...NICARAGUA...HONDURAS...EL SALVADOR AND POSSIBLY EVEN SOUTHEASTERN GUATEMALA. CONVECTIVE DEBRIS CLOUDS AND POSSIBLY LINGERING SHOWERS ARE TO THE SOUTH OF 15N BETWEEN 75W AND THE COASTS OF NICARAGUA AND COSTA RICA. A NORTH-TO-SOUTH ORIENTED UPPER LEVEL TROUGH IS IN THE EASTERN PART OF THE AREA... ON TOP OF THE 62W/63W TROPICAL WAVE. THE TROUGH IS DISRUPTING THE CONTINUED DEVELOPMENT OF DEEP LAYER PRECIPITATION NEAR THE WAVE. THE ATLANTIC OCEAN... UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA TO THE WEST OF 66W. AN UPPER LEVEL TROUGH PASSES THROUGH 32N59W TO 28N62W TO 25N65W. A SURFACE TROUGH AND COLD FRONT END ALONG 31N BETWEEN 53W AND 58W...AT THE NORTHERN EDGE OF THE AREA OF THIS BULLETIN. SHOWERS AND THUNDERSTORMS FROM 30N TO 32N BETWEEN 49W AND 53W. THE SOUTHERNMOST POINT OF A COLD FRONT IS 31N21W. A TROUGH CONTINUES FROM 31N21W TO 29N30W TO 27N40W. BROKEN TO OVERCAST MULTILAYERED CLOUDS ARE WITHIN 45 NM ON EITHER SIDE OF 30N21W BEYOND THE MADEIRA ARCHIPELAGO. SCATTERED LOW LEVEL TO MIDDLE LEVEL CLOUDS COVER THE AREA FROM 27N TO 30N BETWEEN 20W AND 40W. $$ MT