000 AXNT20 KNHC 150549 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU MAY 15 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 19W S OF 12N MOVING W AT 10-15 KT. A LARGE AREA OF SHOWERS AND EMBEDDED TSTMS ARE ASSOCIATED WITH THE WAVE...BUT MOST OF THIS ACTIVITY IS W OF THE WAVE AXIS. IN ADDITION...THE MIMIC-TPW PRODUCT FROM CIMSS SHOWS THE PRESENCE OF THIS SYSTEM WITH AN AREA OF MOISTURE EXTENDING NWD TO NEAR 12N. A WEAK TROPICAL WAVE IS ALONG 63W/64W S OF 12N MOVING W AT 10 KT. THE WAVE IS VERY ILL-DEFINED AND MOSTLY INLAND OVER E VENEZUELA WHERE IT IS GENERATING SCATTERED MODERATE CONVECTION. THE GFS MODEL GUIDANCE INDICATES LOW-LEVEL MOISTURE WILL REMAIN ACROSS N VENEZUELA AND ADJACENT COASTAL WATERS IN THE CARIBBEAN SEA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 5N2W 4N9W 5N16W 3N22W 1N32W 7N51W 8N59W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM EQ-4N BETWEEN THE PRIME MERIDIAN TO 3W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 1N-4N BETWEEN 8W-15W. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE WITHIN 120-150 NM FROM A LINE 7N22W TO 4S28W. ...DISCUSSION... GULF OF MEXICO... THE GULF OF MEXICO LIES BETWEEN A 1021 MB SURFACE HIGH OFFSHORE OF THE CAROLINAS IN THE W ATLC AND LOW PRESSURE TROUGHING OVER E TEXAS AND E MEXICO. THIS WEATHER PATTERN IS PRODUCING FAIRLY UNIFORM 15-20 KT SOUTHERLY WINDS ACROSS THE GULF. SCATTERED SHOWERS AND THUNDERSTORMS REMAIN ALONG THE EASTERN COASTS OF N MEXICO AND EXTREME S TEXAS THIS EVENING. THIS ACTIVITY WILL CONTINUE TO DISSIPATE ACROSS THE FAR W GULF OVERNIGHT. ALOFT...A LARGE UPPER HIGH CENTERED OVER THE YUCATAN PENINSULA EXTENDS A RIDGE ACROSS THE ENTIRE GULF WITH ITS ASSOCIATED FLOW TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE FROM THE EPAC THROUGH MEXICO INTO SE TEXAS AND MUCH OF THE GULF. GIVEN DIFFLUENT UPPER LEVEL PATTERN ACROSS THE NW GULF INCREASED PRECIPITATION CHANCES ARE EXPECTED AHEAD OF THE NEXT COLD FRONT WHICH IS FORECAST TO ENTER THE GULF ON THURSDAY AFTERNOON. CARIBBEAN SEA... THE TAIL END OF A COLD FRONT EXTENDING FROM THE CENTRAL ATLC IS PRODUCING SOME SCATTERED SHOWER ACTIVITY N OF JAMAICA...ACROSS HISPANIOLA AND THE WINDWARD PASSAGE. OTHERWISE...VERY TRANQUIL WEATHER RESIDES ACROSS THE CARIBBEAN BASIN IN LARGE PART DUE TO A LARGE MID-UPPER RIDGE CENTERED OVER THE YUCATAN PENINSULA AND UPPER TROUGHING OVER THE E CARIBBEAN. THESE UPPER FEATURES ARE PRODUCING MODERATE TO STRONG SUBSIDENCE ACROSS THE CARIBBEAN SEA SUPPRESSING THE DEVELOPMENT OF ANY SIGNIFICANT CONVECTION. THE GFS MODEL GUIDANCE KEEPS MOISTURE FROM THE TAIL END OF THE FRONT AFFECTING HISPANIOLA THROUGH FRI. ATLANTIC OCEAN... A LARGE 999 MB LOW PRESSURE SYSTEM IS WELL N OF THE AREA OVER THE W ATLC. THE ASSOCIATED COLD FRONT ENTERS THE FORECAST AREA NEAR 32N54W THEN CONTINUES SW CROSSING JUST N OF HISPANIOLA INTO THE WINDWARD PASSAGE AND S OF CUBA. LOW-LEVEL CONVERGENCE ALONG THE FRONTAL BOUNDARY COUPLED WITH UPPER DIFFLUENT FLOW IS PRODUCING A 120-150 NM WIDE BAND OF SCATTERED SHOWERS AND THUNDERSTORMS IMMEDIATELY E OF THE FRONT. COLD AIR STRATOCUMULUS CLOUDS ARE BEHIND THE FRONT ACROSS THE W ATLC AND IMPLY THAT A COOL AND DRIER AIR MASS HAS TAKEN HOLD ACROSS THE BAHAMAS. THE REST OF THE CENTRAL AND E ATLC IS DOMINATED BY A 1026 MB SURFACE HIGH LOCATED NEAR 30N39W. IN THE UPPER LEVELS...RIDGING SUPPORTS CENTRAL ATLC SURFACE HIGH WITH AXIS EXTENDING ALONG 40W. BROAD TROUGHING WITH BASE S OF THE CANARY ISLANDS WILL CONTINUE TO MOVE EASTWARD AND PROVIDE ONLY MID-UPPER LEVEL CLOUDINESS ALONG AND NW OF COASTAL MOROCCO. OF NOTE...TODAY MARKS THE BEGINNING OF THE EASTERN PACIFIC HURRICANE SEASON. BASED ON LATEST AVERAGES...EVERY YEAR 15 NAMED STORMS FORM...9 OF WHICH BECOME HURRICANES AND 4 OF THOSE HURRICANES WOULD BE OF CATEGORY 3 OR GREATER IN STRENGTH ON THE SAFFIR-SIMPSON SCALE. THE ATLANTIC HURRICANE SEASON BEGINS JUNE 1ST WITH BOTH ATLANTIC AND EASTERN PACIFIC TROPICAL SEASONS ENDING NOVEMBER 30TH. $$ HUFFMAN