000 AXNT20 KNHC 180521 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI MAY 18 2007 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...THE ITCZ... THE ITCZ AXIS IS ALONG 6N9W 5N15W 6N34W 4N52W. SCATTERED MODERATE/STRONG CONVECTION IS FROM THE EQUATOR TO 3N BETWEEN 1W-7W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 120/150 NM OF THE ITCZ AXIS ACROSS THE ENTIRE ATLC. ...DISCUSSION... GULF OF MEXICO... UPPER RIDGE EXTENDS E/W ACROSS CENTRAL AMERICA AND MEXICO COVERING THE SW GULF. BROAD UPPER TROUGH DOMINATES THE E US AND THE REMAINDER OF THE GULF MOVING INTO THE W ATLC. THE ASSOCIATED FRONTAL BOUNDARY EXTENDS FROM THE W ATLC ACROSS NE FLORIDA TO A 1012 MB LOW OVER FLORIDA NEAR 30N84W WITH A COLD FRONT EXTENDING INTO THE GULF TO NEAR 26N90W WHERE IT DISSIPATES TO JUST OFF THE TEXAS COAST NEAR 26N96W. THIS IS A WEAK FRONT AND WITH THE DRY AIR IN PLACE ONLY WIDELY ISOLATED SHOWERS ARE BEING GENERATED ALONG THE FRONTAL BOUNDARY. HIGH PRESSURE IS AGAIN BUILDING BEHIND THE FRONT WITH NORTHERLY WINDS BRIDGING THE FRONT ACROSS THE ENTIRE GULF. THE FRONT WILL CONTINUE TO DRIFT SLOWLY S ACROSS THE GULF WITH THE MAIN ENERGY MOVING E INTO THE W ATLC. CARIBBEAN SEA... AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO DIPS INTO THE NW CARIBBEAN N OF 18N W OF 77W. THIS UPPER TROUGH IS GENERATING SOME SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE NW CARIBBEAN WITHIN 120 NM OF LINE FROM 19N79W TO 16N84W. BROAD UPPER LEVEL E/W RIDGE EXTENDS FROM SOUTH AMERICA ACROSS CENTRAL AMERICA COVERING THE REMAINDER OF THE CARIBBEAN. THE UPPER RIDGE IS ENHANCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 120/150 NM OF LINE FROM 19N78W ACROSS CUBA INTO THE W ATLC NEAR 21N76W. THE 1010 MB LOW ANALYZED NEAR 17N82W HAS DETERIORATED TO A SURFACE TROUGH AT 18/0300 UTC EXTENDING FROM THE CAYMAN ISLANDS TO OFF THE COAST OF NICARAGUA NEAR 13N82W. THE ITCZ IN THE E PACIFIC EXTENDS ACROSS COLOMBIA/PANAMA AND JUST S OF COSTA RICA COUPLED WITH THE 1007 MB LOW ALONG THE COAST OF COLOMBIA NEAR 11N76W ARE GENERATING SCATTERED MODERATE/ISOLATED STRONG CONVECTION S OF 13N FROM 74W-80W AND S OF 11N W OF 80W TO INLAND OVER CENTRAL AMERICA. ALTHOUGH SOME HIGH CLOUDS ARE OBSERVED OVER THE E CARIBBEAN...DRY CONDITIONS DOMINATE THAT AREA TONIGHT. MODERATE/STRONG EASTERLY TRADE WINDS DOMINATE THE CARIBBEAN. ATLANTIC OCEAN... UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS INTO THE W ATLC W OF 75W WITH THE ASSOCIATED FRONTAL BOUNDARY EXTENDING FROM A 1013 MB LOW ALONG THE SOUTH CAROLINA COAST TO THE 1012 MB LOW OVER NE FLORIDA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90 NM E OF THE FRONT TO JUST INLAND OVER NE FLORIDA. EMBEDDED WITHIN THE UPPER TROUGH IS A 1010 MB LOW OVER THE N BAHAMAS NEAR 27N76W WITH A SURFACE TROUGH EXTENDING TO OVER CENTRAL CUBA NEAR 22N78W. AN UPPER RIDGE TO THE E IS ENHANCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION TO THE E OF THE SURFACE FEATURES WITHIN 150/200 NM OF LINE FROM OVER CUBA NEAR 21N76W ALONG 26N70W TO BEYOND 32N69W. DEEP LAYERED LOW COVERS THE CENTRAL ATLC N OF 17N BETWEEN 40W-55W WITH THE UPPER LOW CO-LOCATED WITH THE 1018 MB SURFACE LOW NEAR 29N50W AND A SURFACE TROUGH EXTENDING S TO 21N52W. THESE FEATURES ARE EMBEDDED WITHIN DRY AIR AND ARE ONLY ABLE TO GENERATE A NARROW BAND OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45 NM OF A LINE FROM 24N47W-27N46W-29N47W. AN UPPER TROUGH IS OVER THE NE ATLC EXTENDING FROM OVER MOROCCO TO AN UPPER LOW NEAR 30N20W TO BEYOND 32N28W COVERING THE AREA N OF 26N. BROAD UPPER RIDGE EXTENDS E/W ACROSS THE TROPICAL ATLC ALONG 5N/6N TO AN UPPER HIGH NEAR 6N48W. THIS UPPER RIDGE IS ADVECTING TROPICAL MOISTURE ACROSS THE E TROPICAL ATLC...HOWEVER DUE TO THE DRY AIR AND AFRICAN DUST PRESENT NO SHOWERS AND CLOUDS ARE FORMING. AT THE SURFACE...A RIDGE DOMINATES THE ATLC W OF 65W WITH A WEAKNESS IN THE CENTRAL ATLC IN THE REGION OF THE DEEP LAYERED LOW. $$ WALLACE