000 AXNT20 KNHC 010556 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT OCT 31 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 0515 UTC. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 47W TO THE SOUTH OF 16N MOVING WEST-NORTHWESTWARD 10 TO 15 KT. THIS WAVE IS MOVING THROUGH THE SOUTH AND SOUTHEAST OF THE ATLANTIC OCEAN DEEP LAYER TROUGH AND FRONTAL BOUNDARIES. ISOLATED MODERATE SHOWERS FROM 10N TO 16N BETWEEN 37W AND 40W. A SURFACE TROUGH IS ALONG 36W/38W FROM 18N TO 26N DRIFTING WESTWARD. THIS TROUGH REPRESENTS WHAT USED TO BE THE NORTHERN EXTENSION OF THE 38W TROPICAL WAVE. THE TROUGH HAS BROKEN AWAY FROM THE TROPICAL WAVE. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE FROM 16N TO 28N BETWEEN 35W AND 38W. AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 65W/66W TO THE SOUTH OF 16N MOVING WESTWARD 10 TO 15 KT. NO ORGANIZED DEEP CONVECTIVE PRECIPITATION ACCOMPANIES THIS WAVE. A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 86W/87W TO THE SOUTH OF 17N MOVING WESTWARD 10 KT. THIS WAVE IS MOVING THROUGH THE AREA OF THE BELIZE CYCLONIC CENTER. ...THE ITCZ... 12N13W 7N24W 10N43W...INTO NORTHEASTERN VENEZUELA NEAR 10N62W. STRONG SHOWERS AND THUNDERSTORMS FROM 5N TO 7N BETWEEN 14W AND 22W. ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 4N TO 10N BETWEEN AFRICA AND 60W. ...DISCUSSION... THE NORTHWESTERN CARIBBEAN SEA INCLUDING SOUTHERN MEXICO AND THE SOUTHWESTERN GULF OF MEXICO... THE ONE-TIME HEALTHY LARGE-SCALE UPPER LEVEL CYCLONIC CIRCULATION CENTER DURING THE LAST FOUR DAYS HAS DIMINISHED IN SIZE AND INFLUENCE. THE CENTER NOW IS IN SOUTHERN BELIZE. THE CYCLONIC FLOW AROUND THIS CENTER IS NOW ONLY REMOTELY APPARENT FROM THE COASTS OF GUATEMALA AND EL SALVADOR TO THE WATERS JUST TO THE NORTH OF THE YUCATAN PENINSULA BETWEEN 86W AND THE ISTHMUS OF TEHUANTEPEC. STRONG SHOWERS AND THUNDERSTORMS COVER THE AREAS FROM THE GULF OF HONDURAS TO THE YUCATAN PENINSULA COAST NEAR 20N...AND IN THE NORTHERN ISTHMUS OF TEHUANTEPEC OF MEXICO. THE MEXICO EASTERN PACIFIC OCEAN COAST BETWEEN THE GULF OF TEHUANTEPEC AND 100W...WHERE STRONG SHOWERS AND THUNDERSTORMS HAVE BEEN OCCURRING DURING THE LAST SIX HOURS...FINDS ITSELF AT THE FRINGES OF THE UPPER LEVEL CYCLONIC FLOW FROM THE BELIZE CYCLONIC CENTER. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS COVER PARTS OF CENTRAL AMERICA FROM COSTA RICA TO HONDURAS...IN AN AREA OF UPPER LEVEL DIFFLUENT WIND FLOW. THE REST OF THE GULF OF MEXICO... A COLD FRONT PASSES THROUGH NORTH CENTRAL FLORIDA INTO THE EAST- CENTRAL GULF OF MEXICO...TO THE SOUTH CENTRAL PART...BECOMING STATIONARY AND CONTINUING TO THE EASTERN ISTHMUS OF TEHUANTEPEC OF MEXICO. DRY AIR IN SUBSIDENCE IS TO THE WEST AND NORTHWEST OF THE LINE FROM THE WESTERN TIP OF THE FLORIDA PANHANDLE TO THE MEXICO GULF COAST NEAR 21N/22N...AND TO THE EAST OF THE LINE FROM THE FLORIDA BIG BEND TO THE CENTRAL YUCATAN CHANNEL. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE IN THE GULF OF MEXICO FROM THE SOUTH CENTRAL GULF TO THE NORTHERN ISTHMUS OF TEHUANTEPEC. GALE FORCE WINDS ARE OBSERVED TO THE SOUTH OF 21N TO THE WEST OF THE FRONT. THE REST OF THE CARIBBEAN SEA... THE GFS MODEL FOR 500 MB SHOWS A NORTHWEST-TO-SOUTHEAST ORIENTED INVERTED TROUGH FROM NORTHEASTERN NICARAGUA TO THE NORTHERN COLOMBIA COAST ALONG 74W/75W. SHOWERS AND POSSIBLE THUNDERSTORMS HAVE BEEN IN THE AREA OF THE 500 MB INVERTED TROUGH SINCE 31/2245 UTC. 500 MB ANTICYCLONIC FLOW AND BROAD 200 MB CYCLONIC FLOW ON TOP OF THAT...MIXED IN WITH THE DRY AIR IN SUBSIDENCE FROM 24 HOURS AGO...COVER THE REST OF THE AREA. THE ATLANTIC OCEAN... DEEP LAYER CYCLONIC FLOW AROUND A 31N52W CYCLONIC CIRCULATION CENTER COVERS THE AREA FROM 19N TO 34N BETWEEN 47W AND 64W. THE TROUGH EVENTUALLY EXTENDS TO THE EASTERN CARIBBEAN SEA NEAR 15N60W. THIS DEEP LAYER TROUGH SUPPORTS THE 1001 MB GALE LOW PRESSURE CENTER THAT IS NEAR 30N49W. A COLD FRONT EXTENDS FROM THE GALE CENTER TO 30N46W 25N47W 21N52W. A STATIONARY FRONT CONTINUES FROM 21N52W TO 19N60W. THE COMPARATIVELY STRONGEST SHOWERS AND THUNDERSTORMS NOW ARE FROM 15N TO 16N BETWEEN 48W AND 49W...AND WITHIN A 30 NM RADIUS OF 16N51W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE ELSEWHERE FROM 10N TO 20N BETWEEN 42W AND 56W...AND TO THE NORTH OF 20N BETWEEN 39W AND 56W. $$ MT