000 AXNT20 KNHC 272350 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI APR 27 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 5N9W 3N20W 1N40W TO THE EQUATOR NEAR 50W INLAND OVER SOUTH AMERICA TO 1S52W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS N OF 4N INLAND OVER LIBERIA AND COTE D'IVOIRE AND EXTENDING WESTWARD TO 17W. CLUSTERS OF SIMILAR CONVECTION ARE S OF 5N W OF 48W TO INLAND OVER SOUTH AMERICA OVER FRENCH GUIANA. ...DISCUSSION... GULF OF MEXICO... SLOW MOVING AND WEAKENING COLD FRONT EXTENDS ACROSS SOUTHEAST GEORGIA AND THE FLORIDA BIG BEND AND INTO THE GULF NEAR CEDAR KEY THEN SOUTHWEST TO 26N86W WHERE IT BECAME STATIONARY TO 25.5N91W. THE FRONT WILL WEAKEN FURTHER...POSSIBLY DISSIPATE ALTOGETHER AS IT MOVES ACROSS THE FLORIDA PENINSULA AND E OF THE GULF SAT. WIDELY SCATTERED SHOWERS ARE ALONG THE FRONT NEAR ORLANDO. LIGHTNING DATA INDICATED STRONGER THUNDERSTORM ACTIVITY SE OF THE FRONT WITHIN 30-45 NM OF 24.5N86.5W. SUPPORT FOR THIS FRONT IS WANING AS THE ASSOCIATED SHORTWAVE UPPER LEVEL TROUGH MOVING ACROSS THE FAR SE/OFF THE FLORIDA NE COAST IS SHEARING OUT TO THE NORTHEAST AND IS GRADUALLY BEING OVERRUN BY ANTICYCLONIC FLOW ASSOCIATED WITH A BUILDING UPPER LEVEL RIDGE THAT EXTENDS FROM AN ANTICYCLONE OVER THE GULF OF TEHUANTEPEC ACROSS MEXICO THROUGH THE BAY OF CAMPECHE TO THE LOWER MISSISSIPPI VALLEY. AXIS OF SUBTROPICAL JET STREAM AROUND THE PERIPHERY OF THE RIDGE AND JUST TO THE E OF ANOTHER SHORTWAVE TROUGH OVER NORTHERN MEXICO IS ADVECTING MAINLY MID AND UPPER LEVEL TROPICAL MOISTURE ACROSS MEXICO...TEXAS AND THE NORTHWEST THIRD OF THE GULF OF MEXICO. CARIBBEAN SEA... THE SOUTHERN END OF THE SHORTWAVE UPPER TROUGH ALONG THE E COAST OF FLORIDA DIPS INTO THE FAR NW CARIBBEAN N OF 18N ALONG 80W WITH MODERATE TO STRONG SUBSIDENCE/DRY AIR ALOFT OVER THE AREA. THE REMAINDER OF THE CARIBBEAN IS UNDER THE INFLUENCE OF A FLAT BROAD UPPER RIDGE ANCHORED OVER SOUTH AMERICA WITH THE AXIS EXTENDING ACROSS THE ABC ISLANDS NORTHWARD OVER HISPANIOLA. AN UPPER LEVEL WIND MAX IS ADVECTING TROPICAL MOISTURE ACROSS PANAMA...COSTA RICA AND THE SW CARIBBEAN. DAYTIME HEATING COUPLED WITH SEABREEZE CONVERGENCE IS RESULTING IN SCATTERED SHOWERS/THUNDERSTORMS ACROSS NORTHWEST COLOMBIA...PANAMA AND COSTA RICA WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INDICATED ELSEWHERE OVER THE SW CARIBBEAN S OF 13N BETWEEN 79W AND 84W. THE LEADING EDGE OF A MODERATE/STRONG EASTERLY TRADE WIND SURGE ARE RESULTING IN AN AREA OF BROKEN TO OVERCAST LOW AND MID CLOUDS WITH WIDELY SCATTERED SHOWERS ACROSS THE E CARIBBEAN E OF 67W BETWEEN THE ABC ISLANDS AND PUERTO RICO. THE BULK OF THE ACTIVITY HAS MOVED WEST OF THE CENTRAL LESSER ANTILLES. THE REMAINDER OF THE AREA IS UNDER FAIR SKIES. ATLANTIC... BROAD HIGH PRESSURE IS IN CONTROL OVER VIRTUALLY THE ENTIRE ATLANTIC OCEAN WITH A 1026 MB HIGH LOCATED NEAR 31N63W. AT THE UPPER LEVELS THE SHEARING SHORTWAVE TROUGH ALONG THE E COAST OF FLORIDA EXTENDS NORTHEASTWARD OVER THE ATLC TO JUST OFF THE NORTH CAROLINA COAST AND WAS SHEARING WITH TIME. ASSOCIATED SHOWER ACTIVITY CURRENTLY NEAR ORLANDO TO TITUSVILLE WILL MOVE OFF THE FLORIDA COAST INTO THE COASTAL WATERS OVER THE NEXT FEW HOURS. NARROW EXTENSION OF CARIBBEAN UPPER RIDGE CUTS ACROSS HISPANIOLA INTO THE W ATLC TO BEYOND 32N66W. SLIGHTLY DIFFLUENT FLOW OVER THE SE BAHAMAS AND ADJACENT ATLANTIC WATERS IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE REGION. OVER THE CENTRAL ATLC...A SHEARED MID TO UPPER TROUGH EXTENDS THROUGH 31N38W SOUTHWESTWARD TO SMALL CYCLONIC CIRCULATIONS NEAR 23N57W AND 24N61W. THESE FEATURES ARE PRODUCING ONLY ISOLATED SHOWERS WITHIN 60-90 NM OF THEIR RESPECTIVE LOCATIONS. THIS TROUGH HAS FRACTURED OFF OF A DEEP LAYERED TROUGH OVER THE NE ATLC THAT HAS MOVED EASTWARD NOW COVERING THE AREA N OF 23N E OF 25W. OVER THE DEEP TROPICS A RATHER LARGE CYCLONIC CIRCULATION NEAR 13N42W WAS MOVING WESTWARD AT 10-15 KT WITH AN ASSOCIATED AREA OF MODERATE TO STRONG SUBSIDENCE/DRY AIR ALOFT FROM 6N TO 20N WEST OF 35W. A BUILDING RIDGE WAS IN PLACE TO THE EAST OF THE CYCLONIC CIRCULATION AND EXTENDED ACROSS THE CAPE VERDE ISLANDS TO THE WEST COAST OF AFRICA. THE SURFACE RIDGE OVER THE ATLC WILL REMAIN ACROSS THE AREA WITH SOME WEAKNESS IN THE RIDGE EXPECTED WITH THE APPROACHING FRONT OFF THE FLORIDA EAST COAST. $$ COBB