000 AXNT20 KNHC 301055 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 35W/36W S OF 12N MOVING W 10-15 KT. POSITION BASED ON EXTRAPOLATION AND CONTINUITY AND ANY CONVECTION REMAINS LIKELY EMBEDDED WITHIN THE ITCZ. A TROPICAL WAVE IS ALONG 45W/46W S OF 14N MOVING W 10-15 KT. A LOW-AMPLITUDE INVERTED-V SATELLITE SIGNATURE IS NOTED ON SATELLITE IMAGERY. LOW-LEVEL CURVATURE IS ALSO NOTED FROM 6N-11N ALONG THE WAVE AXIS. ISOLATED MODERATE CONVECTION IS FROM 6N-9N BETWEEN 44W-46W. A TROPICAL WAVE IS ALONG 62W 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 S OF 20N FROM WRN JAMAICA TO ERN PANAMA MOVING W NEAR 15 KT. THE MIMIC-TPW PRODUCT FROM CIMSS SUGGESTS WAVE HAS A SUSTAINED NORTHWARD SURGE OF MOISTURE ACROSS THE CENTRAL CARIBBEAN WHILE SATELLITE IMAGERY EXHIBITS AN INVERTED-V CLOUD SIGNATURE FROM 12N-16N. VERY DRY STABLE AIR IS ALOFT INHIBITING ANY DEEP CONVECTION. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N11W 8N25W 5N34W 8N37W 10N44W 10N47W AND INTO SOUTH AMERICA NEAR 9N60W. IN ADDITION TO ACTIVITY ASSOCIATED WITH TROPICAL WAVES...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 4N-10N BETWEEN 10W-16W. SIMILAR CONVECTION IS FROM 5N-9N BETWEEN 22W-34W. SCATTERED MODERATE CONVECTION IS FROM 2N-4N BETWEEN 40W-44W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 90 NM N OF THE AXIS BETWEEN 55W-59W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL TROUGHING SITUATED S OF THE FLORIDA PANHANDLE COAST EXTENDS ACROSS THE NRN 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. AN AREA OF SCATTERED SHOWERS AND TSTMS IS ALSO ALONG COASTAL MEXICO IN THE WRN BAY OF CAMPECHE DUE TO THE UPPER LEVEL DIFFLUENT PATTERN. A BAND OF HIGH-MID LEVEL CLOUDINESS 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 LATE MON BEFORE DISSIPATING TUE BRINGING WITH IT THE INCREASED POTENTIAL FOR LATE AFTERNOON SHOWERS AND TSTMS. 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 8N-12N BETWEEN 76W-84W AND ALONG COASTAL NICARAGUA/HONDURAS. STRONG SUBSIDENCE ALONG THE BASE OF A UPPER TROUGH EXTENDING ACROSS THE WINDWARD PASSAGE IS INHIBITING DEEP CONVECTION IN THE CENTRAL CARIBBEAN BETWEEN 72W-81W. 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 PRODUCING A LINE OF SHOWERS AND THUNDERSTORMS IN THE W ATLC W OF 76W N OF 30N. THIS ACTIVITY IS AIDED BY INSTABILITY ALONG AN UPPER SHORTWAVE TROUGH LOCATED ACROSS NRN FLORIDA AND THE N CENTRAL GULF OF MEXICO. ELSEWHERE...SWLY UPPER FLOW AROUND AN UPPER HIGH CENTERED EAST OF THE WINDWARD ISLANDS NEAR 14N49W 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 IN THE E ATLC BY A 1026 MB HIGH CENTERED NEAR 35N36W SW OF THE AZORES AND A SECOND 1026 MB HIGH IN THE CENTRAL ATLC E OF BERMUDA CENTERED NEAR 33N59W. BOTH OF THESE SURFACE RIDGES ARE MAINTAINING MODERATE EASTERLY FLOW THROUGHOUT THE ERN AND CENTRAL ATLC. $$ HUFFMAN