000 AXNT20 KNHC 291752 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE APR 29 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 6N10W 4N16W...CROSSING THE EQUATOR NEAR 26W...1S40W AND INTO NE BRAZIL NEAR 2S44W. A CLUSTER OF MODERATE TO STRONG CONVECTION IS FROM THE EQUATOR TO 3N BETWEEN 6W AND 10W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE WITHIN 150 NM S OF AXIS BETWEEN 18W AND 26W. SIMILAR CONVECTION IS FOUND WITHIN 120 NM EITHER SIDE OF AXIS BETWEEN 36W AND 44W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL TROUGH AXIS EXTENDS FROM THE SE CONUS TO THE CENTRAL GULF TO NEAR TAMPICO MEXICO. A SURFACE COLD FRONT EXTENDS FROM THE WESTERN ATLANTIC OCEAN ACROSS THE FLORIDA KEYS THROUGH WESTERN CUBA TO THE YUCATAN PENINSULA. AS FRONT EXITS THE SOUTHEASTERN GULF OF MEXICO A 1022 MB SURFACE HIGH PRESSURE NEAR 27N97W CONTINUES TO BUILD IN ACROSS THE NORTHWESTERN GULF. UPPER LEVEL SUBSIDENCE/DRY AIR IS IN PLACE OVER MUCH OF THE GULF OF MEXICO WEST OF 90W. WITHIN 90 TO 120 NM OF FRONTAL BOUNDARY LINGERING MIDDLE AND UPPER LEVEL CLOUDINESS PERSISTS AND WILL CONTINUE TO THIN OUT DURING THE NEXT 24 HOURS. SCATTERED SHOWERS AND ISOLATED TSTMS ARE EXPECTED INLAND THIS AFTERNOON ACROSS THE EASTERN COASTAL YUCATAN PENINSULA...BELIZE...AND NORTHERN GUATEMALA IN ASSOCIATION WITH COLD FRONT. CARIBBEAN SEA... UPPER LEVEL RIDGE AXIS EXTENDS FROM NORTHERN COLOMBIA THROUGH THE CENTRAL CARIBBEAN SEA TO BERMUDA. MODERATE TO FRESH TRADEWINDS CONTINUE TO DOMINATE AT THE SURFACE ACROSS MUCH OF THE CARIBBEAN SEA. BROAD SCALE WEAK CYCLONIC SURFACE FLOW EXISTS IN THE SOUTHWESTERN CARIBBEAN SEA AND WILL CONTINUE TO PROVIDE SCATTERED MIDDLE AND UPPER LEVEL CLOUDS. COLD FRONT EXTENDS FROM THE FLORIDA KEYS THROUGH WESTERN CUBA SOUTHWESTWARD TO THE YUCATAN PENINSULA. EASTWARD MOVEMENT IS EXPECTED TO BRING INCREASED CLOUDINESS TO THE NORTHWESTERN CARIBBEAN SEA WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED DURING THE NEXT 24 HOURS ACROSS COASTAL YUCATAN AND WESTERN CUBA. ATLANTIC OCEAN... UPPER LEVEL RIDGE EXTENDS FROM HISPANIOLA NORTHWARD TO BERMUDA. THIS IS AHEAD OF AN UPPER LEVEL TROUGH THAT IS LOCATED ACROSS THE EASTERN US SEABOARD. SURFACE COLD FRONT EXTENDS FROM NEAR 32N74W TO GRAND BAHAMA ISLAND THROUGH THE FLORIDA KEYS AND WESTERN CUBA. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS THE WESTERN ATLANTIC DURING THE NEXT 24 HOURS AS THE FRONT PROPAGATES EASTWARD. A 1019 MB HIGH PRESSURE IS LOCATED NEAR 28N64W. CLEAR SKIES AND FAIR WEATHER EXIST IN THE CENTRAL ATLANTIC OCEAN FROM 13N TO 31N BETWEEN 52W AND 71W. AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG 48W BETWEEN 14N TO 29N. A SURFACE TROUGH EXTENDS FROM NEAR 31N41W 25N44W TO 22N52W AND WILL CONTINUE TO PROVIDE SCATTERED SHOWERS AHEAD OF SURFACE TROUGH FROM 20N TO 25N BETWEEN 37W AND 45W. ANOTHER SURFACE TROUGH IS POSITIONED NEAR 31N31W TO 25N24W. AN EARLIER ASCAT PASS SHOWS THE WIND SHIFT ASSOCIATED WITH THIS TROUGH. SCATTERED MIDDLE AND UPPER LEVEL CLOUDS ARE PRESENT WITH THIS FEATURE. INLAND SURFACE LOW PRESSURE CENTERED NEAR 25N11W OVER THE WESTERN SAHARA IS CREATING TIGHT PRESSURE GRADIENT WITH 20 TO 25 KT WINDS ALONG COASTAL WESTERN AFRICA AND ARE EXPECTED TO GRADUALLY DECREASE OVER THE NEXT 24 HOURS. $$ HUFFMAN/GR