000 AXNT20 KNHC 231730 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON JUN 23 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 1645 UTC. ...TROPICAL WAVES... A NEW TROPICAL WAVE HAS BEEN ADDED ALONG 34W S OF 10N. INITIAL ESTIMATES HAVE THE WAVE MOVING W NEAR 20 KT. DAKAR UPPER AIR DATA INDICATE THAT THE WAVE MOVED OFF THE AFRICAN COAST SATURDAY AFTERNOON. ASSOCIATED CONVECTION IS WEST OF THE AXIS DUE TO UPPER-LEVEL EASTERLY FLOW. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 33N-35N AND FROM 4N-6N BETWEEN 36W-39W. A TROPICAL WAVE IS ALONG 60W S OF 20N MOVING W AT 25-30 KT. CONVECTION AROUND THIS HIGH-AMPLITUDE WAVE IS BEGINNING TO AFFECT THE EASTERN CARIBBEAN ISLANDS. UPPER-AIR DATA FROM BARBADOS INDICATE THAT THE WAVE MOVED OVER THE ISLAND LATE SUN/EARLY MON MORNING. THE WAVE IS EXPECTED TO REACH THE WESTERN CARIBBEAN BY THU. BROAD LOW/MID LEVEL INVERTED-V CURVATURE IS NOTED ON SATELLITE IMAGERY WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OFF THE COAST OF GUYANA FROM 7N-11N BETWEEN THE AXIS AND 56W. A TROPICAL WAVE IS OVER THE YUCATAN PENINSULA ALONG 90W FROM 20N TO 6N IN THE E PACIFIC. BELIZE CITY UPPER AIR STATION SHOWS THE EXPECTED E TO ESE WIND SHIFT OCCURRED BETWEEN 12Z SUN AND 12Z TODAY. ASSOCIATED CONVECTION IS CONFINED TO THE E PACIFIC. EXPECT THE NORTHERN PORTION OF THE WAVE TO ENTER THE BAY OF CAMPECHE LATER TODAY. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N12W 9N23W 4N33W 5N46W AND INTO FRENCH GUIANA NEAR 5N52W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 100 NM EITHER SIDE OF THE AXIS FROM 15W-18W...AND FROM 20W-25W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 7N BETWEEN 27W-42W. ...DISCUSSION... GULF OF MEXICO... A STRONG RIDGE OF HIGH PRESSURE EXTENDS WESTWARD FROM FROM THE CENTRAL ATLANTIC INTO THE SOUTHEASTERN GULF. W TO SW UPPER FLOW AROUND THE RIDGE IS PUMPING TROPICAL MOISTURE INTO THE EASTERN GULF AND HELPING TO FUEL SCATTERED SHOWERS AND THUNDERSTORMS OVER THE NORTHEASTERN GULF NORTH OF 28N WHERE A SHORTWAVE SYSTEM IS DROPPING SOUTHEASTWARD INTO THE REGION. THIS CONVECTION IS ASSOCIATED WITH AN UPPER LEVEL TROUGH THAT EXTENDS SOUTHWARD THROUGH THE GULF INTO THE BAY OF CAMPECHE WHERE ANOTHER AREA OF MODERATE TO STRONG CONVECTION IS CURRENTLY ACTIVE MAINLY EAST OF VERACRUZ. AT THE SFC...A WEAK PRESSURE PATTERN IS SUPPORTING MAINLY LIGHT SOUTHEASTERLY FLOW ACROSS THE BASIN. CARIBBEAN... SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE DIFFLUENCE ALOFT IN THE VICINITY OF SOUTHEASTERN CUBA IS BEGINNING TO DISSIPATE AS THE UPPER LEVEL TROUGH CURRENTLY EXTENDING FROM HISPANIOLA SOUTHWESTWARD TO PANAMA BEGINS TO WEAKEN OVER THE AREA. THE EAST PACIFIC ITCZ CONTINUES TO MAINTAIN CONVECTION IN THE SOUTHWEST CARIBBEAN SOUTH OF 13N. MODERATE TO STRONG EASTERLY TRADE WINDS DUE TO THE TIGHT PRESSURE GRADIENT BETWEEN THE SUBTROPICAL HIGH IN THE CENTRAL ATLC AND THE LOWER PRESSURE OVER SOUTH AMERICA ARE EXPECTED TO CONTINUE OVER THE NEXT SEVERAL DAYS...WITH THE STRONGEST FLOW NEAR THE COAST OF SOUTH AMERICA. ISOLATED SHOWERS ARE BEGINNING TO MOVE INTO THE LEEWARD ISLANDS ASSOCIATED WITH THE APPROACHING TROPICAL WAVE. ATLANTIC... SHOWERS AND THUNDERSTORMS ON THE LEADING EDGE OF THE UPPER LEVEL TROF EXTENDING FROM THE EASTERN CONUS INTO THE NORTHEASTERN GULF OF MEXICO ARE MOVING INTO THE FAR WESTERN ATLC OFF THE NORTH FLORIDA/SOUTH GEORGIA COAST. FAIR WEATHER CUMULUS CAN BE FOUND OVER MUCH OF THE REGION SOUTH OF THE HIGH PRESSURE ANCHORED NEAR 32N49W. DOMINANT EASTERLY FLOW IS PREVAILING OVER THIS AREA. ELSEWHERE...DIVERGENCE AROUND AN UPPER RIDGE IN THE NORTH TROPICAL ATLC IS ENHANCING CONVECTION NEAR THE ITCZ. $$ WADDINGTON/SCHAUER CLARK