000 AXNT20 KNHC 181731 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED JUN 18 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 44W S OF 17N MOVING W 15-20 KT. A BROAD MID LEVEL CYCLONIC TURNING IS APPARENT JUST AHEAD OF THE WAVE AXIS NEAR 13N47W WITH SIGNATURE INVERTED-V CLOUD PATTERN EVIDENT ON VISIBLE SATELLITE IMAGERY. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE NOTED FROM 7N-12N BETWEEN 40W-44W. THE TPW PRODUCT FROM CIMSS SHOWS A VERY GOOD SURGE OF MOISTURE ASSOCIATED WITH THIS WAVE. A TROPICAL WAVE IS ALONG 59W/60W S OF 9N MOVING W 15-20 KT. WAVE HAS BECOME VERY ILL-DEFINED AND HAS MOVED INLAND ACROSS GUYANA AND FAR E VENEZUELA WITH ANY ASSOCIATED CONVECTION LIKELY EMBEDDED WITHIN THE ITCZ ACROSS CENTRAL GUYANA. A TROPICAL WAVE IS OVER THE YUCATAN PENINSULA AND GUATEMALA WITH AXIS ALONG 91W S OF 21N MOVING W NEAR 10 KT. NO ORGANIZED CONVECTION IS ASSOCIATED WITH THE WAVE WITH ONLY SCATTERED SHOWERS ACROSS SRN MEXICO. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 4N27W 5N35W 8N42W 9N47W 6N56W. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 3N-11N BETWEEN 12W-20W. ...DISCUSSION... GULF OF MEXICO... AN UPPER-LEVEL TROUGH EXTENDS ACROSS THE GULF REGION WITH ITS AXIS STRETCHING FROM THE SE CONUS TO THE YUCATAN PENINSULA. A DIFFLUENT PATTERN BETWEEN THE LEADING EDGE OF THE TROUGH AND AN UPPER-LEVEL HIGH LOCATED OVER THE CARIBBEAN...JUST SOUTH OF JAMAICA...IS HELPING TO INDUCE A WIDE AREA OF SHOWERS AND THUNDERSTORMS ACROSS THE NW CARIBBEAN...WESTERN CUBA...SOUTH FLORIDA AND THE NW BAHAMAS. ADDITIONAL SHOWERS AND TSTMS ARE ACROSS THE NRN GULF WATERS ALONG A FRONTAL BOUNDARY THAT CURRENTLY LIES MAINLY ALONG 28N...EXTENDING FROM THE W ATLC WATERS ACROSS NRN FLORIDA TO NEAR GALVESTON TEXAS. THE REMAINDER OF THE GULF IS RATHER TRANQUIL UNDER THE INFLUENCE OF A WEAK 1015 MB SURFACE HIGH ANCHORED IN THE CENTRAL WRN GULF NEAR 25N92W. THE WEAK PRESSURE GRADIENT AROUND THE HIGH IS PRODUCING MAINLY LIGHT WINDS ACROSS THE BASIN. EXPECT THE COLD FRONT TO STALL ACROSS THE NE GULF WATERS AND CENTRAL FL TONIGHT LIFTING NE OF THE AREA THU NIGHT. CARIBBEAN... A BROAD UPPER-LEVEL RIDGE AROUND A HIGH NEAR 15N76W DOMINATES THE WEATHER PATTERN IN THE CARIBBEAN WITH MODERATE TO STRONG SUBSIDENCE S OF 18N KEEPING THE CENTRAL AND EASTERN CARIBBEAN MOSTLY CLEAR. DIFFLUENCE ALOFT BETWEEN THIS RIDGE AND THE AFOREMENTIONED TROUGH OVER THE GULF OF MEXICO IS GENERATING AN AREA OF SHOWERS AND TSTMS ACROSS THE NW CARIBBEAN AND WRN CUBA WITHIN 60 NM OF A LINE FROM CIENFUEGOS CUBA TO 17N85W. REINFORCING HIGH PRESSURE IN THE CENTRAL ATLC IS KEEPING TRADE WIND FLOW THROUGH THE CARIBBEAN NEAR 20-25 KT. ATLANTIC... AS PREVIOUSLY MENTIONED...A BROAD AREA OF SHOWERS AND TSTMS IS ACROSS WRN CUBA TO THE NW BAHAMAS...INCLUDING PORTIONS OF SRN FLORIDA AND THE W ATLC W OF 67W. THIS CONVECTIVE ACTIVITY IS BEING DRIVEN BY UPPER-LEVEL DIFFLUENCE BETWEEN A SHARP TROUGH OVER THE ERN GULF OF MEXICO AND AN AMPLIFIED RIDGE OVER THE CARIBBEAN SEA. A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N75W AND EXTENDS ACROSS CENTRAL FLORIDA. IT WILL PROVIDE FOCUS FOR ADDITIONAL SHOWERS AND TSTMS AS IT CONTINUES TO DRIFT SLOWLY OFF TO THE NE BY THU NIGHT. MOSTLY ZONAL UPPER FLOW DOMINATES THE WEST AND CENTRAL ATLC WITH A SHORTWAVE MID-UPPER LEVEL TROUGH NEAR 55W N OF 15N. SCATTERED SHOWERS AND ISOLATED TSTMS ARE JUST AHEAD OF THE TROUGH AXIS FROM 24N-28N BETWEEN 49W-55W. A 1024 MB HIGH CENTERED NEAR 29N34W REMAINS IN CONTROL AT THE SURFACE ACROSS MUCH OF THE ERN AND CENTRAL ATLC. THE PRESSURE GRADIENT BETWEEN THIS HIGH AND LOWER PRESSURE OVER AFRICA WILL CONTINUE TO PRODUCE MODERATE NLY WINDS MAINLY N OF 16N AND E OF 25W. AN UPPER LEVEL LOW IS OVER THE E ATLC NEAR 28N23W WITH AN UPPER LEVEL TROUGH EXTENDING FROM THE LOW TO THE CAPE VERDE ISLANDS. $$ HUFFMAN