000 AXNT20 KNHC 131756 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN AUG 13 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE... A TROPICAL WAVE IS GENERATING SHOWERS AND A FEW THUNDERSTORMS OVER THE WINDWARD ISLANDS. THIS WAVE IS ACCOMPANIED BY A 1012MB SURFACE LOW NEAR 13N58W. THIS SYSTEM HAS BECOME A LITTLE BETTER ORGANIZED TODAY AND SOME ADDITIONAL DEVELOPMENT IS POSSIBLE DURING THE NEXT COUPLE OF DAYS AS IT MOVES WEST-NORTHWESTWARD AT 10 TO 15 KT. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM THIS AFTERNOON. SCATTERED MODERATE/ISOLATED STRONG CONVECTION LIES FROM 11N TO 18N BETWEEN 55W AND 64W. ...TROPICAL WAVES... TROPICAL WAVE OFF THE W COAST OF AFRICA IS ALONG 23W S OF 18N MOVING W 10-15 KT. THE CLASSIC INVERTED V PATTERN ASSOCIATED WITH THIS WAVE IS MUCH MORE EVIDENT IN TODAYS LOW CLOUD MOTIONS THAN 24 HOURS AGO. CONVECTION ASSOCIATED WITH THIS WAVE REMAINS LIMITED ASIDE FROM THE SCATTERED SHOWERS AND TSTMS IN THE VICINITY OF THE ITCZ. ONLY ISOLATED SHOWERS/TSTMS LIE ELSEWHERE WITHIN 200NM OF EITHER SIDE OF THE AXIS. TROPICAL WAVE IN THE WRN CARIBBEAN IS ALONG 83W/84W S OF 20N MOVING W NEAR 15-20 KT. PATCHES OF SCATTERED MODERATE CONVECTION LIE FROM THE SW CARIBBEAN THROUGH ERN CENTRAL AMERICA AND INTO THE GULF OF HONDURAS. THIS MAY ALSO BE ASSOCIATED WITH INSTABILITY AROUND THE BASE OF THE UPPER TROUGH IN THE REGION...ALONG WITH UPSLOPE FLOW OVER THE CENTRAL AMERICAN TERRAIN. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 13N17W 11N22W 10N26W 11N55W 11N55W TO NEAR THE NE VENEZUELAN COAST NEAR 10N65W. SCATTERED MODERATE CONVECTION LIES FROM 6N TO 11N BETWEEN 24W AND 34W. ANOTHER AREA OF SCATTERED MODERATE CONVECTION IS OFF THE NE SOUTH AMERICAN COAST...MAINLY SOUTH OF THE AXIS...FROM 4N TO 10N BETWEEN 44W AND 55W. ONLY ISOLATED SHOWERS AND TSTMS ARE NOTED ELSEWHERE IN THE VICINITY OF THE AXIS. ...DISCUSSION... GULF OF MEXICO... WEATHER ACROSS THE GULF FOR THE MOST PART CONTINUES TO BE FAIRLY QUIET WITH ONLY A COUPLE OF EXCEPTIONS IN THE EXTREME SW AND NE PORTIONS. A CLUSTER OF MODERATE CONVECTION LIES IN THE FAR SW BAY OF CAMPECHE AND INTO COASTAL MEXICO. THIS SEEMS TO BE ASSOCIATED WITH LOW LEVEL UPSLOPE FLOW ALONG WITH UPPER DIFFLUENT AIR BETWEEN AN UPPER HIGH OVER SE MEXICO AND THE UPPER LOW SEEN SPINNING ABOUT 180NM W OF BROWNSVILLE TEXAS...WHICH EXTENDS INTO THE WRN GULF. THE OTHER INTERESTING FEATURE IN THE GULF IS A WEAK STATIONARY FRONT EXTENDING THROUGH THE NE GULF...BUT ONLY ISOLATED SHOWERS ARE NOTED NEAR THIS BOUNDARY...AT LEAST NEAR THE GULF PORTION WITH THE ATLC PORTION A DIFFERENT STORY AS DISCUSSED BELOW. AN UPPER HIGH IS LOCATED OVER SOUTH CENTRAL FLORIDA...WITH DRY AIR SEEN HOVERING OVER MUCH OF THE REMAINDER OF THE ERN AND CENTRAL GULF. A 1017MB SURFACE HIGH IS ANALYZED ABOUT 200NM SOUTH OF PENSACOLA WHICH IS PRODUCING FAIRLY LIGHT WINDS ACROSS THE GULF. SLIGHTLY STRONGER 15KT SE FLOW OBSERVED IN THE WRN GULF AS THIS HIGH INTERACTS WITH LOWER PRESSURE OVER MEXICO. CARIBBEAN SEA... TWO TROPICAL WAVES ARE AFFECTING THE CARIBBEAN...ONE ALONG 84W AND THE OTHER MOVING INTO THE WINDWARD ISLANDS. CONVECTION ASSOCIATED WITH THE LATTER IS PRODUCING SHOWERS AND TSTMS OVER PORTIONS OF THE WINDWARD ISLANDS AND ADJACENT ERN CARIBBEAN WATERS AS NOTED IN THE SPECIAL FEATURE. AN UPPER TROUGH DOMINATES THE WRN GULF...WITH AN UPPER HIGH NEAR THE LEEWARD ISLANDS EXTENDING WEST OVER THE CENTRAL AND ERN GULF. ASIDE FROM THE FAR WRN AND FAR ERN CARIBBEAN NEAR THE TROPICAL WAVES...FAIR WEATHER DOMINATES MUCH OF THE REMAINDER OF THE CARIBBEAN. 15 TO 25 KT TRADE FLOW DOMINATES WITH THE STRONGEST WINDS LIKELY JUST NORTH OF THE COLOMBIAN COAST...AS THE S PORTION OF THE ATLC HIGH INTERACTS WITH LOWER PRESSURE OVER COLOMBIA. SHOWERS AND TSTMS ASSOCIATED WITH THE TROPICAL WAVE WILL MOVE THROUGH THE ERN CARIBBEAN THROUGH MONDAY. ATLANTIC OCEAN... STRONG MID TO UPPER LEVEL TROUGH HAS PUSHED OFF THE EAST COAST WITH ITS SOUTHERN MOST PORTION EXTENDING SOUTH TO NEAR 30N OFF THE GEORGIA/NE FLORIDA COAST. SURFACE HIGH PRESSURE HAS BUILT INTO THE MID ATLANTIC STATES BRINGING VERY PLEASANT WEATHER. IN THE REGION OF CONFLUENCE BETWEEN THIS HIGH AND THE ATLC HIGH TO ITS SOUTH LIES A FRONTAL BOUNDARY THAT HAS NOW SAGGED TO NEAR CAPE CANAVERAL AND EXTENDS ENE INTO THE ADJACENT ATLC WATERS. A 1012MB SURFACE LOW IS ALONG THIS FRONT NEAR 29N77W. THIS NON-TROPICAL LOW PRESSURE SYSTEM IS PRODUCING A SMALL AREA OF SHOWERS AND THUNDERSTORMS. SOME SLOW DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS AS IT MOVES SLOWLY TO THE SOUTHEAST OR SOUTH. AN UPPER RIDGE AXIS EXTENDS EAST FROM CENTRAL FLORIDA TO NEAR 72W. AN UPPER TROUGH IS EXTENDING NE THROUGH CUBA AND THE BAHAMAS INTO THE ADJACENT WATERS...BUT IS NOT GENERATING MUCH SHOWER ACTIVITY. UPPER RIDGING DOMINATES THE AREA FROM 10N TO 32N BETWEEN 52W AND 68W. A FEW SMALL/BENIGN UPPER LOWS LIE E OF THIS AREA...NEAR 26N46W...25N36W AND THE LAST NEAR 15N33W. AN UPPER HIGH OVER THE COAST OF W AFRICA EXTENDS OUT TO NEAR 35W WITH THE AXIS ALONG 19N. OVERALL FAIR WEATHER DOMINATES MUCH OF THE AREA OUTSIDE OF THE TROPICAL WAVES AND FRONTAL BOUNDARY...WITH A 1021MB SURFACE HIGH ANALYZED NEAR 25N33W...AND THE RIDGE AXIS EXTENDING W THROUGH THE SRN BAHAMAS AND INTO CUBA. $$ WILLIS