000 AXNT20 KNHC 141759 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU AUG 14 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. ...SPECIAL FEATURES... TROPICAL WAVE IS IN THE W TROPICAL ATLC/E CARIBBEAN ALONG 61W/62W WITH A 1009 MB LOW ALONG THE WAVE NEAR 18N MOVING W 10-15 KT. WHILE THE ASSOCIATED THUNDERSTORM ACTIVITY HAS BECOME MORE CONCENTRATED...MOST OF THE ACTIVITY IS LOCATED WELL EAST OF THE LOW CENTER AT THIS TIME. SCATTERED MODERATE/STRONG CONVECTION IS E OF THE LOW CENTER FROM 16N-19N BETWEEN 60W-62W WITH SCATTERED MODERATE/ ISOLATED STRONG CONVECTION N OF THE LOW CENTER WITHIN 45 NM OF LINE FROM 20N59W 21N61W TO 20N63W. NOAA AND AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT ARE CURRENTLY INVESTIGATING THE SYSTEM TO SEE IF A TROPICAL DEPRESSION HAS FORMED. REGARDLESS OF DEVELOPMENT...THIS SYSTEM COULD BRING LOCALLY HEAVY RAINS AND GUSTY WINDS TO PORTIONS OF THE N LEEWARD/VIRGIN ISLANDS...PUERTO RICO...AND HISPANIOLA DURING THE NEXT DAY OR TWO. ...TROPICAL WAVES... TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC IS TILTED FROM 20N41W THROUGH A WEAK 1011 MB LOW NEAR 15N43W TO 10N42W MOVING W NEAR 20 KT. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE N AND W OF THE LOW WITHIN 60 NM OF LINE FROM 16N39W 17N42W TO 13N46W. TROPICAL WAVE IS INLAND OVER GUATEMALA AND INTO THE E PACIFIC REGION ALONG 90W/91W. SEE WEATHER DISCUSSION UNDER AWIPS/WFO HEADERS MIATWDEP/AXPZ20 KNHC FOR FURTHER INFORMATION. ...THE ITCZ... THE ITCZ IS CENTERED ALONG 14N16W 8N26W 12N41W 8N51W 9N62W. SCATTERED MODERATE/STRONG CONVECTION IS MOVING OFF THE COAST OF W AFRICA WITHIN 75 NM S OF THE ITCZ E OF 17W...INDICATING THE POSSIBLE EMERGING OFF THE COAST INTO THE E TROPICAL ATLC. LARGE CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM OF THE ITCZ FROM 25W-36W. ...DISCUSSION... GULF OF MEXICO... AN BROAD UPPER TROUGH IS OVER THE SE U.S. INTO THE W ATLC WITH ASSOCIATED FRONTAL BOUNDARY EXTENDING FROM THE W ATLC TO A WEAK 1010 MB LOW OVER S GEORGIA/NE FLORIDA N OF TALLAHASSEE FLORIDA INTO THE GULF NEAR PANAMA CITY ACROSS EXTREME SE LOUISIANA BACK INTO THE NW GULF TO OVER E TEXAS NEAR CORPUS CHRISTI. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE N GULF WATERS S OF THE FRONT TO 26N FROM ACROSS N FLORIDA TO THE TEXAS COAST. AN UPPER LEVEL RIDGE EXTENDS ACROSS THE REMAINDER OF THE GULF ANCHORED OVER N/CENTRAL MEXICO TO ACROSS S FLORIDA. MODERATE S TO SW RETURN FLOW FROM THE RIDGE IN THE W ATLC IS ACROSS THE GULF S OF THE FRONT WITH LIGHT WINDS MORE NORTHERLY WINDS TO THE N OF THE FRONT. CARIBBEAN SEA... THE BROAD UPPER RIDGE OVER THE GULF OF MEXICO COVERS THE NW CARIBBEAN WITH NE UPPER FLOW. AN UPPER LOW IS OVER E CUBA EXTENDING AN UPPER TROUGH SW TO THE N COAST OF HONDURAS. S TO SE UPPER FLOW COVERS THE REMAINDER OF THE CARIBBEAN BEING DRAWN BETWEEN THE UPPER LOW/TROUGH AND THE TROPICAL LOW/WAVE OVER THE W TROPICAL ATLC/E CARIBBEAN. UPPER LEVEL DIFFLUENCE IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE SW CARIBBEAN S OF 11N W OF 75W TO INLAND OVER CENTRAL AMERICA. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE OVER PORTIONS OF THE LEEWARD ISLANDS AND VIRGIN ISLANDS WITH CONDITIONS EXPECTED TO CONTINUE TO DETERIORATE AS THE LOW/WAVE CONTINUES TO POSSIBLY DEVELOP AND MOVE TO THE W. OTHERWISE THE REMAINDER OF THE CARIBBEAN REMAINS FAIRLY CLEAR THIS AFTERNOON WITH MODERATE EASTERLY TRADE WINDS ACROSS THE AREA AND MAY USHER IN SOME ISOLATED SHOWERS. ATLANTIC OCEAN... THE UPPER TROUGH THAT IS OVER THE SE US. AND W ATLC EXTENDING A FRONTAL BOUNDARY THROUGH 32N74W ALONG 31N78W TO THE 1010 MB LOW JUST N OF TALLAHASSEE FLORIDA THEN INTO THE GULF OF MEXICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM THE FRONT TO 27N W OF 74W ACROSS FLORIDA AND INTO THE GULF OF MEXICO. AN UPPER LOW IS OVER E CUBA EXTENDING AN UPPER TROUGH NE TO 26N71W. THIS UPPER LOW IS EMBEDDED WITHIN A FAIR AMOUNT OF DRY AIR AND IS KEEPING SKIES MOSTLY CLEAR ACROSS HISPANIOLA...CUBA...AND THE BAHAMA ISLANDS ALTHOUGH A FEW ISOLATED SHOWERS AND AFTERNOON THUNDERSTORMS COULD DEVELOP OVER THESE ISLANDS. A BROAD UPPER LOW IS IN THE CENTRAL ATLC NEAR 27N49W IS ADVECTING MID/UPPER MOISTURE N AND PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 27N-31N BETWEEN 43W-51W. AN UPPER HIGH IS TO THE SE OVER THE LOW/TROUGH IN THE SPECIAL FEATURES PROVIDING UNIFORM OUTFLOW FOR THE POSSIBLE DEVELOPING SYSTEM. A COUPLE OF BENIGN UPPER LOWS ARE IN THE E ATLC WITH THE FIRST JUST W OF THE CANARY ISLANDS NEAR 28N17W AND A SECOND NEAR 30N36W. THESE UPPER LOWS ARE EMBEDDED WITHIN MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR THAT COVERS MOST OF THE ATLC BASIN...THUS FAIR WEATHER CONDITIONS ARE ACROSS THE REMAINDER OF THE ATLC. A SURFACE RIDGE CONTINUES TO DOMINATE THE ATLC ANCHORED BY A 1027 MB HIGH N OF THE REGION W OF THE AZORES EXTENDING A RIDGE AXIS SW THROUGH 32N48W TO THE CENTRAL BAHAMA ISLANDS. $$ WALLACE