000 AXNT20 KNHC 300554 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON JUN 30 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 34W/35W S OF 12N MOVING W 10-15 KT. THE WAVE REMAINS EMBEDDED WITHIN THE ITCZ WITH SCATTERED MODERATE CONVECTION FROM 5N-8N BETWEEN 32W-35W. A TROPICAL WAVE IS ALONG 44W S OF 14N MOVING W 10-15 KT. A LOW-AMPLITUDE INVERTED-V CURVATURE IS NOTED ON SATELLITE IMAGERY FROM 8N-11N. SCATTERED MODERATE CONVECTION IS FROM 5N-9N BETWEEN 43W-46W. A TROPICAL WAVE IS ALONG 61W S OF 14N MOVING W NEAR 15 KT. NO SIGNIFICANT CONVECTION IS ASSOCIATED WITH THIS WAVE. THE POSITION OF THE AXIS IS BASED ON CONTINUITY. A TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 77W FROM ERN CUBA THROUGH JAMAICA TO NWRN COLOMBIA MOVING W NEAR 15 KT. THE WAVE IS POSITIONED BASED ON SURFACE OBSERVATIONS ACROSS JAMAICA AND SATELLITE IMAGERY EXHIBITING INVERTED-V CURVATURE FROM 11N-15N. VERY DRY STABLE AIR IS ALOFT WITH ONLY A FEW ISOLATED MODERATE CONVECTIVE CELLS BETWEEN HAITI/JAMAICA AND CUBA. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 6N10W 7N20W 6N33W 5N36W 6N43W 7N46W AND INTO GUYANA NEAR 8N59W. IN ADDITION TO ACTIVITY ASSOCIATED WITH TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 3N-8N BETWEEN 10W-18W. SIMILAR CONVECTION IS WITHIN 90 NM OF A LINE FROM 11N21W TO 7N32W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 2N-4N BETWEEN 40W-43W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL TROUGHING SITUATED OFF THE MISSISSIPPI AND ALABAMA COASTS EXTENDS ACROSS THE NW GULF TO THE TEXAS/MEXICO BORDER. AN UPPER RIDGE COVERS THE REMAINDER OF THE GULF WHICH IS ANCHORED ACROSS SRN MEXICO NEAR THE GULF OF TEHUANTEPEC. DIFFLUENT W-SW FLOW BETWEEN THESE FEATURES IS ADVECTING A DEEP LAYER OF TROPICAL MOISTURE INTO THE REGION AND IS SUPPORTING WIDELY SCATTERED SHOWERS WITHIN 120 NM OF A LINE FROM NEAR TAMPICO MEXICO ENE TO NEAR ST. PETERSBURG FLORIDA ACROSS CENTRAL PORTIONS OF THE GULF. A BAND OF SCATTERED SHOWERS IS MOVING AHEAD OF A FRONTAL BOUNDARY OVER THE SERN CONUS AND IS ACROSS THE FAR NRN GULF WATERS BETWEEN GALVESTON TEXAS AND THE ERN FLORIDA PANHANDLE. EXPECT THIS FRONTAL TROUGH TO ENTER THE NE GULF MON BEFORE DISSIPATING TUE. A SURFACE RIDGE EXTENDS FROM THE CENTRAL ATLC ACROSS CENTRAL FLORIDA AND INTO MEXICO PRODUCING LIGHT SOUTHERLY RETURN FLOW THROUGHOUT THE REGION. CARIBBEAN... AN UPPER-LEVEL RIDGE/TROUGH/RIDGE PATTERN REMAINS IN PLACE OVER THE CARIBBEAN. DIVERGENCE ALONG THE SRN EXTENT OF A WRN UPPER RIDGE ANCHORED OVER SRN MEXICO COUPLED WITH LOW-LEVEL WIND SPEED CONVERGENCE ACROSS THE WRN CARIBBEAN IS GENERATING SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE SW CARIBBEAN FROM 9N-13N BETWEEN 81W-84W AND ACROSS INLAND NICARAGUA/COSTA RICA. STRONG SUBSIDENCE ALONG THE BASE OF A UPPER TROUGH EXTENDING ACROSS THE WINDWARD PASSAGE IS INHIBITING DEEP CONVECTION IN THE CENTRAL CARIBBEAN BETWEEN 73W-81W WITH THE ONLY EXCEPTION BEING A FEW ISOLATED TSTMS BETWEEN HAITI/JAMAICA AND CUBA MOST LIKELY DUE TO THE TROPICAL WAVE ALONG 77W. DIVERGENCE ALONG THE LEADING EDGE OF THE TROUGH ACROSS THE ERN CARIBBEAN IS GENERATING SCATTERED SHOWERS N OF 15N AS WELL AS OVER HISPANIOLA...PUERTO RICO...AND THE US/UK VIRGIN ISLANDS. A STRONG SURFACE RIDGE OVER THE CENTRAL ATLC CONTINUES TO PROVIDE A TIGHT PRESSURE GRADIENT ACROSS THE BASIN WITH STRONG EASTERLY TRADES THROUGHOUT. ATLANTIC... A PRE-FRONTAL TROUGH OVER THE ERN CONUS IS PUSHING A BAND OF SHOWERS AND THUNDERSTORMS INTO THE W ATLC W OF 79W N OF 29N. A SECOND AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS REMAIN ACROSS THE NW BAHAMAS AND ADJACENT COASTAL WATERS. THIS ACTIVITY IS INDUCED BY INSTABILITY ALONG AN UPPER SHORTWAVE TROUGH LOCATED ACROSS THE N CENTRAL GULF OF MEXICO. ELSEWHERE... SWLY UPPER FLOW AROUND A HIGH EAST OF THE WINDWARD ISLANDS IS ADVECTING MOISTURE INTO THE ATLC S OF 23N AND W OF 55W. THE REMAINDER OF THE DISCUSSION AREA IS DOMINATED BY A VERY STABLE SURFACE RIDGE ANCHORED BY A 1030 MB HIGH PRESSURE CENTERED NEAR 34N33W SW OF THE AZORES AND A SECOND 1027 MB HIGH E OF BERMUDA CENTERED NEAR 32N60W. BOTH OF THESE SURFACE RIDGES ARE MAINTAINING MODERATE EASTERLY FLOW THROUGHOUT THE ERN AND CENTRAL ATLC. $$ HUFFMAN