000 AXNT20 KNHC 192340 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON MAY 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 43W S OF 12N MOVING W 10 KT. SATELLITE IMAGERY SHOWS VERY LOW-AMPLITUDE TO THE WAVE WITH SOME CYCLONIC TURNING ALONG THE WAVE AXIS NEAR 7N. SMALL BULGE OF MOISTURE IS EVIDENT ON THE MIMIC-TPW PRODUCT FROM CIMSS WITH ONLY SCATTERED SHOWERS FROM 2N-8N BETWEEN 40W-45W. MOST LIKELY ANY PRECIPITATION IS EMBEDDED WITHIN THE ITCZ. A TROPICAL WAVE IS IN THE CARIBBEAN SEA ALONG 67W S OF 13N MOVING W 10 KT. MUCH OF THE WAVE IS INLAND OVER CENTRAL VENEZUELA...WHICH WILL MAKE IT DIFFICULT TO TRACK FOR THE NEXT COUPLE OF DAYS. THIS WAVE MAY BE ENHANCING CONVECTION W OF THE AXIS OVER W VENEZUELA. ..THE ITCZ... ITCZ AXIS IS CENTERED ALONG 5N9W 5N20W 3N30W 4N40W 4N45W AND INTO NE BRAZIL NEAR 3N52W. CLUSTERS OF MODERATE TO STRONG CONVECTION ARE WITHIN 150-180 NM ON EITHER SIDE OF THE AXIS BETWEEN 13W-21W. SIMILAR CONVECTION IS FROM EQ-6N BETWEEN THE PRIME MERIDIAN AND 5W. ALSO SCATTERED MODERATE CONVECTION IS FROM 4N-6N BETWEEN 47W-49W. ...DISCUSSION... THE GULF OF MEXICO... A SURFACE TROUGH...REMNANTS OF AN OLD FRONTAL BOUNDARY...EXTENDS FROM N FLORIDA TO NEAR 26N87W IN THE CENTRAL GULF. SCATTERED SHOWERS ARE E OF THE TROUGH ACROSS S FLORIDA AND THE E GULF. SECONDARY SURFACE TROUGH EXTENDS FROM NEAR 23N88W INLAND ACROSS THE YUCATAN PENINSULA. SCATTERED SHOWERS AND THUNDERSTORMS REMAIN INLAND ACROSS THE YUCATAN PENINSULA AND WILL CONTINUE TO DIMINISH. A WEAK 1012 MB HIGH IS BEHIND THE TROUGH AXIS CENTERED NEAR 26N92W KEEPING SURFACE WINDS LIGHT ACROSS THE GULF W OF 88W. ALOFT...STRONG SW FLOW DOMINATES MUCH OF THE GULF OF MEXICO MOISTENING THE MID AND UPPER LEVELS SE OF A LINE FROM THE TEXAS/MEXICO BORDER TO N FLORIDA. MODERATE TO STRONG SUBSIDENCE IS OVER THE N GULF WATERS. THE SURFACE TROUGH IS FORECAST TO GRADUALLY WEAKEN TONIGHT THROUGH TUE. THE GFS MODEL KEEPS MOISTURE FROM THIS TROUGH OVER THE BAY OF CAMPECHE AND PARTS OF THE YUCATAN PENINSULA DURING THE NEXT 12-24 HOURS. THE CARIBBEAN SEA... CLUSTERS OF MODERATE TO STRONG CONVECTION HAVE CONTINUED OVER THE SW CARIBBEAN POSSIBLY ASSOCIATED WITH THE COLOMBIAN LOW AND A DIFFLUENT PATTERN ALOFT. A 1011 MB LOW IS ANALYZED NEAR 9N76W. THIS ACTIVITY IS FORECAST BY THE COMPUTER MODELS TO SPREAD OVER PARTS OF CENTRAL AMERICA DURING THE NEXT FEW DAYS. THE PRESSURE GRADIENT BETWEEN A SURFACE RIDGE ALONG THE GREATER ANTILLES AND THE COLOMBIAN LOW IS PRODUCING MODERATE TO FRESH TRADE WINDS ACROSS THE CARIBBEAN SEA. THESE WINDS VEER SE OVER THE NW WATERS IN RESPONSE TO THE TROUGH IN THE GULF OF MEXICO. A BROAD MID/UPPER LEVEL RIDGE CONTINUES TO COVER MOST OF THE BASIN. THIS UPPER FEATURE IS PRODUCING MODERATE TO STRONG SUBSIDENCE AND AN OVERALL DRY AND STABLE AIR MASS OVER THE CARIBBEAN SEA. THE ATLANTIC OCEAN... THE SURFACE TROUGH THAT LIES OVER THE GULF OF MEXICO AND N FLORIDA EXTENDS NEWD OVER THE FAR NW PORTION OF THE W ATLC. THIS FEATURE IS GENERATING SOME SHOWER ACTIVITY WITH EMBEDDED ISOLATED THUNDERSTORMS MAINLY N OF 27N AND WEST OF 70W. SURFACE HIGH PRESSURE CENTERED S OF THE AZORES NEAR 34N31W DOMINATES THE WEATHER PATTERN ACROSS THE REMAINDER OF THE REGION WITH THE EXCEPTION OF A WEAK TROUGH THAT RUNS FROM 31N42W TO 24N50W. THERE IS SOME SHOWER ACTIVITY WITHIN 150 NM E OF THE TROUGH AXIS NEAR THE NORTHERN END. A SURFACE RIDGE EXTENDS SW ENVELOPING THE S BAHAMAS...THE GREATER ANTILLES AND THE NE CARIBBEAN. PRESSURE GRADIENT BETWEEN THE AZORES HIGH AND LOWER PRESSURE OVER W AFRICA IS PRODUCING A SWATH OF MODERATE TO STRONG NELY WINDS NEAR THE AFRICAN COAST BETWEEN THE CANARY AND THE CAPE VERDE ISLANDS. THESE CONDITIONS WILL PERSIST OVER THE NEXT FEW DAYS. IN THE MID AND UPPER LEVELS...A LARGE SCALE RIDGE LIES OVER MUCH OF THE CENTRAL AND W ATLC ANCHORED ON A HIGH NEAR 20N63W. THIS BROAD SYSTEM IS PROVIDING DRY STABLE AIR ALOFT ACROSS MUCH OF THE AREA W OF 50W. UPPER-LEVEL TROUGHING WITH AXIS ALONG 32N31W 20N40W 9N50W EXTENDS ACROSS THE REMAINDER OF THE CENTRAL AND E ATLC E OF 50W. $$ HUFFMAN