000 AXNT20 KNHC 121032 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN AUG 12 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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. ...SPECIAL FEATURE... A VIGOROUS TROPICAL WAVE IS LOCATED OVER THE FAR EASTERN ATLANTIC OCEAN ALONG 22W S OF 19N. A 1006 MB LOW PRES IS NEAR 12N22W OR ABOUT 300 MILES SOUTHEAST OF THE SOUTHERNMOST CAPE VERDE ISLANDS. SHOWERS AND THUNDERSTORMS HAVE CHANGED LITTLE IN ORGANIZATION OVERNIGHT. HOWEVER...CONDITIONS APPEAR FAVORABLE FOR GRADUAL DEVELOPMENT OF THIS SYSTEM...AND A TROPICAL DEPRESSION COULD FORM DURING THE NEXT DAY OR TWO AS IT MOVES WESTWARD AT 15 TO 20 MPH. MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 60NM OF 12N24W. ...TROPICAL WAVES... WEAK TROPICAL WAVE IS ALONG 36W SOUTH OF 16N MOVING WEST 15 TO 20 KT. SOME TURNING IS SEEN ALONG THE WAVE AXIS NEAR 9N WHERE THERE ARE SCATTERED MODERATE CONVECTION. WEAK TROPICAL WAVE IS ALONG 49W SOUTH OF 15N MOVING WEST 10-15 KT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN THE ITCZ. THE TROPICAL WAVE THAT WAS PREVIOUSLY ALONG 71W IS RELOCATED FARTHER WEST ALONG 76W BASED ON SFC DATA...SATELLITE IMAGERY AND THE HOVMOLLER DIAGRAM. PRESSURE IS RISING OVER HISPANIOLA AND DRY AIR IS GRIPPING THE ISLAND INDICATING THAT THE WAVE IS MOVING AWAY FROM THE AREA. CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION ARE FROM 13N-20N BETWEEN 73W-80W. THIS CONVECTIVE ACTIVITY IS AFFECTING JAMAICA...WESTERN HAITI...CUBA AND THE CAYMAN ISLANDS. SCATTERED MODERATE CONVECTION IS ALSO NOTED ON THE SOUTHERN END OF THE WAVE AXIS OVER WESTERN VENEZUELA AND NORTHERN COLOMBIA. THE TROPICAL WAVE THAT WAS ANALYZED ALONG 81W ON THE 00Z SFC MAP IS ADJUSTED AHEAD ALONG 85W/86W ON THE 06Z SFC MAP...BASED ON LATEST SFC OBSERVATIONS...SATELLITE IMAGERY AND THE HOVMOLLER DIAGRAM. THIS WAVE IS INTERACTING WITH AN UPPER LOW LOCATED OVER THE STRAITS OF FLORIDA NEAR 24N81W. DIFFLUENT BETWEEN THIS UPPER LEVEL LOW AND AN UPPER HIGH OVER THE YUCATAN PENINSULA AND THIS TROPICAL WAVE ARE PRODUCING SHOWERS AND THUNDERSTORMS OVER CENTRAL AMERICA MAINLY BETWEEN NICARAGUA AND BELIZE. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 15N18W 9N30W 10N42W 9N60W. BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION... SCATTERED MODERATE CONVECTION IS FROM 7N-11N BETWEEN 35W-49W. DISCUSSION... THE GULF OF MEXICO... THE COMBINATION OF A STRONG UPPER HIGH OVER TEXAS-LOUISIANA AND AND AN UPPER LOW CURRENTLY OVER NORTH-CENTRAL MEXICO CONTINUES TO PRODUCE STRONG UPPER E TO NE WIND FLOW ACROSS THE NORTHERN GULF WATERS. ANOTHER UPPER LOW IS SPINNING OVER THE STRAITS OF FLORIDA NEAR 24N81W AND IS FORECAST TO MOVE WWD INTO THE CENTRAL GULF INCREASING THE CHANGE OF RAIN OVER SOUTH FLORIDA AND THE KEYS. A CONSIDERABLE AMOUNT OF MOISTURE IS ON THE EASTERN SIDE OF THE LOW AND IS BEING TRANSPORTED NORTHWARD FROM THE WESTERN AND CENTRAL CARIB. MOSAIC DOPPLER RADAR FROM THE SE U.S. SHOWS AND AREA OF SHOWERS WITH EMBEDDED TSTMS NEAR THE WEST COAST OF FLORIDA. A SFC TROUGH IS ANALYZED IS THIS AREA AND EXTENDS FROM NEAR TAMPA BAY SW TO 23N85W. THE SFC PATTERN REMAINS WEAK ACROSS THE REGION WITH A 1015 MB HIGH LOCATED S OF LOUISIANA NEAR 27N90W. THIS WEAK PRES GRAD IS ALLOWING WINDS TO REMAIN LIGHT ACROSS THE GULF. ANOTHER SFC TROUGH RUNS FROM SE LOUISIANA TO THE MIDDLE TEXAS COAST. A BAND OF MAINLY LOW CLOUDS WITH ISOLATED SHOWERS IS ASSOCIATED WITH THIS TROUGH. THE CARIBBEAN SEA... A VERY MOIST AND UNSTABLE AIRMASS REMAINS OVER THE WESTERN HALF OF THE CARIBBEAN SEA THANKS TO A PAIR OF TROPICAL WAVES...A BROAD AREA OF LOW PRES AND TWO UPPER LEVEL FEATURES. THEY ARE...AN UPPER LOW SPINNING OVER THE STRAITS OF FLORIDA NEAR 24N81W AND AN UPPER HIGH OVER THE YUCATAN PENINSULA. DIFFLUENCE BETWEEN THESE TWO SYSTEM IS ENHANCING THE CONVECTIVE ACTIVITY OVER JAMAICA...THE CAYMAN ISLANDS...CUBA AND NORTHERN CENTRAL AMERICA...MAINLY FROM NICARAGUA TO BELIZE. A TUTT LOW IS OVER THE NORTHERN LEEWARD ISLANDS BRINGING UPPER DRY AIR/SUBSIDENCE TO THE NE CARIBBEAN...INCLUDING PUERTO RICO AND THE UK/US VIRGIN ISLANDS. THIS LOW WILL MOVE WESTWARD OVER PUERTO RICO AND HISPANIOLA MONDAY THROUGH TUE. LIGHT TO MODERATE WINDS ARE FOUND IN THE WRN PORTION OF THE BASIN AND MODERATE TO FRESH WINDS IN THE E AND CENTRAL CARIB. THE FRESH TRADES WILL PERSIST OVER THE CENTRAL CARIBBEAN THROUGH MON. THE ATLANTIC OCEAN... THE AFOREMENTIONED UPPER LOW LOCATED OVER THE STRAITS OF FLORIDA IS ALSO SUPPORTING SOME SHOWER ACTIVITY ACROSS THE BAHAMAS AND COASTAL WATERS. AN UPPER LOW IS OVER THE NORTHERN LEEWARD ISLANDS WITH A TROUGH EXTENDING NE ACROSS THE CENTRAL ATLC. THE REMAINDER OF THE FORECAST AREA IS DOMINATING BY AN UPPER HIGH LOCATED NEAR 22N25W. WV IMAGERY SHOWS ABUNDANT DRY AIR ALOFT RESULTING IN MODERATE TO STRONG SUBSIDENCE N OF 20N AND E OF 50W...ALLOWING FAIR WEATHER TO PREVAIL. AT THE SFC...THE MAIN WEATHER FEATURE IS THE AZORES HIGH WITH A 1025 MB CENTER NEAR 36N32W. AS IS USUAL FOR THIS TIME OF THE YEAR...THIS HIGH EXTENDS A RIDGE SW REACHING THE NE CARIBBEAN AND THE BAHAMAS. PATCHES OF LOW/MID CLOUDS AND MODERATE TRADE WINDS ARE FOUND UNDER THE INFLUENCE OF THIS SYSTEM. $$ GR