000 AXNT20 KNHC 262359 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUN 26 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IN THE FAR EASTERN ATLANTIC LIES ALONG 19W S OF 14N. THE WAVE IS MOVING W AT 15-20 KT. METEOSAT-8 DATA THRU 1630Z SHOWED A BROAD LOW TO MID LEVEL CIRCULATION ASSOCIATED WITH THE WAVE. OBSERVATIONS ARE VERY LIMITED IN THE FAR EASTERN ATLC AFTER THE LAST AVAILABLE METEOSAT-8 IMAGERY FROM 1630Z....WITH NO CURRENT SCATTEROMETER DATA AVAILABLE. A WEAK TROPICAL WAVE CAN BE FOUND OVER EASTERN SURINAME ALONG 55W S OF 11N MOVING W AT 15-20 KT. THE POSITION OF THE TROPICAL WAVE IS CONFIRMED BY SFC OBS IN NORTH CENTRAL AND SOUTH CENTRAL SURINAME THAT CONTINUE TO SHOW WESTERLY FLOW AHEAD OF THE WAVE. SHOWERS AND THUNDERSTORMS CAN BE FOUND OVER SURINAME AND FRENCH GUIANA ASSOCIATED WITH THE WAVE WITH MORE SCATTERED CONVECTION FOUND NORTH OF THE WESTERN FRENCH GUIANA COAST S OF 8N. A TROPICAL WAVE CURRENTLY CENTERED NEAR 86W S OF 20N IS MOVING THROUGH CENTRAL AMERICA. A BROAD LOW TO MID LEVEL CIRCULATION IS EVIDENT ON VISIBLE SATELLITE IMAGERY. SFC OBS OVER CENTRAL HONDURAS SHOW A DISTINCT TURNING OF THE FLOW FROM NW TO E BETWEEN 1500Z AND 2100Z...VERIFYING THE POSITION. WIDESPREAD CONVECTION CAN BE FOUND PRIMARILY ON THE EASTERN SIDE OF THE WAVE OVER NICARAGUA AND EASTERN HONDURAS...WITH A REGION OF VIGOROUS CONVECTION CURRENTLY PUSHING WESTWARD TOWARD THE SOUTHERN HONDURAS AND NORTHERN COSTA RICA COASTLINE. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N14W 10N19W 6N23W 5N40W TO S AMERICA NEAR 5N53W. IN ADDITION TO CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED SHOWERS AND THUNDERSTORMS CAN BE FOUND IN THE CENTRAL NORTH ATLANTIC IN THE REGION BETWEEN 10N30W TO 4N23W AS WELL AS 26N65W AND 21N59W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL LOW IS PINCHING OFF IN THE WEST CENTRAL GULF NEAR 26N93W. S TO SWLY FLOW BETWEEN THIS LOW AND THE RIDGE TO ITS EAST CENTERED FROM THE CAYMAN ISLANDS NORTHEASTWARD TOWARD CAPE HATTERAS IS PUMPING DEEP LAYER TROPICAL MOISTURE NORTHWARD INTO THE EASTERN GULF AND ACROSS FLORIDA. INSTABILITY DUE TO AFTERNOON HEATING IN ADDITION TO LARGE SCALE LIFT ASSOCIATED WITH UPPER LEVEL DIFFLUENCE IS YIELDING WIDESPREAD CONVECTION OVER THE FLORIDA PENINSULA. FARTHER SOUTH IN THE GULF... INCREASED INSTABILITY AHEAD OF THE NORTHERN END OF A TROPICAL WAVE APPROACHING THE YUCATAN PENINSULA IS ALSO ACTING ON THE DEEP LAYER MOISTURE ...GENERATING WIDESPREAD THUNDERSTORMS IN THE VICINITY OF THE YUCATAN AND CURRENTLY PROGRESSING WESTWARD INTO THE BAY OF CAMPECHE. ELSEWHERE...SCATTERED SHOWERS AND THUNDERSTORMS CAN BE FOUND IN THE WATERS OFF THE CENTRAL GULF COAST BETWEEN GALVESTON...TEXAS AND FORT WALTON BEACH....FLORIDA. CARIBBEAN... A VIGOROUS TROPICAL WAVE MAKING ITS WAY THROUGH CENTRAL AMERICA IS YIELDING WIDESPREAD SHOWERS AND THUNDERSTORMS OVER THE WESTERN CARIBBEAN WITH THE REGION OF STRONGEST CONVECTION CURRENTLY APPROACHING THE HONDURAS AND NORTHERN COSTA RICA COAST. THIS CONVECTION IS SUPPORTED BY BROAD UPPER LEVEL DIFFLUENT FLOW WEDGED BETWEEN THE UPPER HIGH NEAR THE CAYMAN ISLANDS AND THE UPPER LOW IN THE WEST CENTRAL GULF OF MEXICO. TO THE EAST...AN UPPER TROF EXTENDS FROM THE DOMINICAN REPUBLIC SOUTHWESTWARD TOWARD ARUBA. MID TO UPPER LEVEL SOUTHERLY FLOW AND UPPER LEVEL DIFFLUENCE IS HELPING THE CAUSE FOR MAINLY SCATTERED SHOWERS AND THUNDERSTORMS TO THE EAST OF THE UPPER TROF AXIS FR0M PUERTO RICO THROUGH THE LESSER ANTILLES AND WESTWARD TOWARD ARUBA. LIFT AHEAD OF THE TROPICAL WAVE PASSING THROUGH SURINAME IS ALSO HELPING TO ENHANCE CONVECTION OVER THE FAR SOUTHEASTERN CARIBBEAN. IN ADDITION...A ZONAL RIDGE AXIS CENTERED ALONG 28N COUPLED WITH LOW PRESSURE OVER NORTHER SOUTH AMERICA IS PROVIDING A STRONG PRESSURE GRADIENT AND ACCOMPANYING STRONG EASTERLY FLOW ACROSS MUCH OF THE CARIBBEAN. ATLANTIC... VIGOROUS CONVECTION IS PASSING EASTWARD OFF THE FLORIDA COAST THIS EVENING. AS MENTIONED EARLIER...THIS CONVECTION IS SUPPORTED BY AFTERNOON HEATING OVER THE PENINSULA IN ADDITION TO BROAD UPPER LEVEL DIFFLUENCE. TO THE EAST...SHOWERS AND THUNDERSTORMS ARE WANING N OF 20N AND SOUTH OF THE ZONAL LOW LEVEL TROUGH NEAR 28N BETWEEN 52W AND 68W. IN THE FAR SOUTHWEST ATLC...A TROPICAL WAVE OVER SURINAME IS YIELDING SCATTERED SHOWERS AND THUNDERSTORMS E OF 53W AND S OF 13N. FARTHER EAST...ANOTHER TROPICAL WAVE IS MOVING OFF OF WESTERN AFRICA. LIMITED OBS ARE AVAILABLE TO ANALYZE THIS WAVE WITH THE MOST CURRENT SATELLITE INFORMATION COMING FROM THE 1630Z METEOSAT-8 IMAGERY. AN ENHANCED LOW LEVEL SUBTROPICAL RIDGE IS CENTERED NEAR 29N WITH FAIR WEATHER CUMULUS FOUND IN MUCH OF THE REMAINDER OF THE ATLC EAST OF 50N AND N OF 15N. THE TIGHT PRESSURE GRADIENT BETWEEN THIS RIDGE AND THE ITCZ IS GENERATING PERSISTENT EASTERLY FLOW ACROSS MUCH OF THE BASIN E OF 30W. $$ SCHAUER CLARK