000 AXNT20 KNHC 240003 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 23 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... WEAKENING TROPICAL STORM DEBBY IS CENTERED NEAR 17.9N 33.0W 0R ABOUT 530 NM WEST-NORTHWEST OF THE CAPE VERDE ISLANDS AT 23/2100 UTC MOVING NW AT 17 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. CONVECTION ASSOCIATED WITH DEBBIE HAS GENERALLY BEEN DECAYING AND DISPLACED FROM THE CENTER OVER THE LAST SEVERAL HOURS. A NEW SMALL CLUSTER OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION HAS DEVELOPED AFTER 21Z NEAR 18N34W...BUT OVERALL THE ORGANIZATION OF DEBBY IS NOT AS IMPRESSIVE AS THIS MORNING. SCATTERED MODERATE CONVECTION IS ALSO NOTED ABOUT 100 NM SOUTH OF DEBBIE...FROM 13N-16N BETWEEN 31W-35W. ONLY SLOW DEVELOPMENT IS EXPECTED FOR THE NEXT DAY OR TWO AS DEBBY MOVES WNW TO NW. A STRONG TROPICAL WAVE LOCATED ALONG 55W OR ABOUT 280 NM EAST-SOUTHEAST OF THE WINDWARD ISLANDS IS MOVING WEST-NORTHWESTWARD AT ABOUT 17 KT. THIS SYSTEM HAS BECOME MUCH BETTER ORGANIZED TODAY...AND ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR A TROPICAL DEPRESSION OR A TROPICAL STORM TO DEVELOP DURING THE NEXT DAY OR SO. INTERESTS IN THE WINDWARD ISLANDS SHOULD MONITOR THE PROGRESS OF THIS SYSTEM AS IT COULD PRODUCE WIND GUSTS TO TROPICAL STORM FORCE ALONG WITH LOCALLY HEAVY RAINFALL TOMORROW. AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THE SYSTEM THURSDAY AFTERNOON...IF NECESSARY. A 1012MB SURFACE LOW ACCOMPANIES THIS WAVE NEAR 11N55W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE AREA FROM 9N-15N BETWEEN 54W-62W. ...TROPICAL WAVES... TROPICAL WAVE MOVING INTO THE CENTRAL CARIBBEAN IS ALONG 68W S OF 20N MOVING W 15 TO 20 KT. CYCLONIC CURVATURE ALONG WITH INVERTED-V PATTERN REMAINS VAGUE ON SATELLITE IMAGERY AS THE WAVE IS BENEATH THE WRN PORTION OF A BROAD UPPER RIDGE. A CLUSTER OF SCATTERED MODERATE CONVECTION IS NOTED FROM 13N-16N BETWEEN 68W-72W. SCATTERED SHOWERS AND TSTMS ARE ALSO NOTED FROM 15N-21N BETWEEN 68W-74W...WHICH INCLUDES HISPANIOLA. TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 84W/85W S OF 19N MOVING W NEAR 15 KT. THIS WAVE HAS BEEN DIFFICULT TO LOCATE BUT THE MID LEVEL ROTATION IN THE EPAC S OF PANAMA MAY SUGGEST THE WAVE HAS SLOWED DOWN. ISOLATED SHOWERS AND TSTMS DOT THE NW CARIBBEAN...WITH A MORE IMPRESSIVE AREA OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION AFFECTING THE YUCATAN PENINSULA AND NRN GUATEMALA...AND BEGINNING TO AFFECT THE ERN MOST PORTION OF THE BAY OF CAMPECHE. A SMALL PATCH OF SCATTERED MODERATE CONVECTION LIES JUST W OF THE CENTRAL NICARAGUA COAST NEAR 14N83W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE ALSO FOUND OVER PANAMA AND THE SW CARIBBEAN...N OF THE CYCLONIC SWIRL SEEN IN THE EPAC NEAR 7N82W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N15W 8N33W 10N51W 10N58W...AND INTO THE SE CARIBBEAN TO NEAR 12N67W. A SMALL CLUSTER OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS SEEN JUST OFF THE AFRICAN COAST NEAR 9N14W...WITH ANOTHER JUST TO ITS W NEAR 8N15W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE NOTED FROM 5N-10N BETWEEN 20W-33W. ONLY ISOLATED SHOWERS/TSTMS LIE WITHIN 200NM OF EITHER SIDE OF THE AXIS BETWEEN 35W AND 52W...W OF THIS AREA LIES THE SCATTERED MODERATE/ISOLATED STRONG CONVECTION ASSOCIATED WITH THE SPECIAL FEATURE E OF THE WINDWARD ISLANDS. ...DISCUSSION... GULF OF MEXICO... AN UPPER LOW IS SEEN IN THE NORTH/CENTRAL GULF ON THIS EVENINGS WATER VAPOR IMAGERY CENTERED NEAR 27N88W. AN UPPER RIDGE IS SEEN OVER SRN MEXICO...WITH ITS AXIS EXTENDING E INTO THE SW GULF AND THROUGH THE YUCATAN ALONG 21N. UPPER DIFFLUENCE BETWEEN THESE FEATURES IS HELPING THE SCATTERED MODERATE CONVECTION SEEN IN THE W/SW GULF FROM 21N-26N BETWEEN 90W-96W. STRONG SHOWERS AND TSTMS ARE ALSO BEGINNING TO MOVE INTO THE ERN BAY OF CAMPECHE FROM THE YUCATAN. SCATTERED SHOWERS AND TSTMS IN THE NW GULF OFF THE TEXAS AND LOUISIANA COASTS ARE MOVING ANTICYCLONICALLY AROUND AN UPPER HIGH NEAR LUBBOCK TEXAS. ISOLATED SHOWERS AND TSTMS ARE ALSO NOTED IN THE VICINITY OF THE UPPER LOW FROM 24N-30N BETWEEN THE W COAST OF FLORIDA AND 91W. THE CLUSTER OF MODERATE CONVECTION OVER WRN CUBA IS BEGINNING TO AFFECT THE EXTREME SE GULF. A VERY WEAK GRADIENT IS DOMINATING THE SURFACE PRESSURE PATTERN OVER THE GULF WITH WINDS/SEAS GENERALLY LIGHT/LOW EXCEPT POTENTIALLY UNDER CONVECTION. THE WRN EXTENSION OF A WEAK ATLC HIGH WILL GENERALLY EXTEND INTO THE GULF OVER THE NEXT COUPLE OF DAYS...THOUGH PRECIPITABLE WATER AMOUNTS TO REMAIN RELATIVELY HIGH WITH SCATTERED SHOWER/TSTMS EXPECTED OVER MUCH OF THE GULF...WITH THE STATIONARY FRONT OVER THE SE STATES...AND THE UPPER LOW MOVING SLOWLY W THROUGH THE GULF. CARIBBEAN SEA... THE MAIN WEATHER MAKERS IN THE CARIBBEAN ARE THE TWO TROPICAL WAVES. BROAD UPPER RIDGE EXTENDS ACROSS THE YUCATAN INTO THE W CARIBBEAN W OF 80W WITH A SECOND UPPER RIDGE EXTENDING FROM THE W TROPICAL ATLC ACROSS THE LESSER ANTILLES OVER THE E CARIBBEAN E OF 75W. UPPER CONFLUENCE BETWEEN THESE RIDGES IS INDUCING A WEAK UPPER TROUGH EXTENDING SSE THROUGH ERN CUBA WHERE DRY UPPER AIR IS ONLY ABLE TO SUPPORT ISOLATED SHOWERS FROM 12N-21N BETWEEN 75W AND 80W. 15-25KT TRADE FLOW DOMINATES MUCH OF THE CARIBBEAN AS THE S/SW PORTION OF THE ATLC HIGH INTERACTS WITH THE COLOMBIAN LOW. THIS WILL PERSIST OVER THE NEXT COUPLE OF DAYS...WITH SHOWERS AND TSTMS MOVING W WITH THE TROPICAL WAVES. ATLANTIC OCEAN... AN UPPER HIGH IS IN THE W ATLC OFF THE COAST OF FLORIDA/GEORGIA WITH ANOTHER UPPER RIDGE JUST WSW OF BERMUDA. SCATTERED SHOWERS AND TSTMS BETWEEN THESE FEATURES ARE MOVING SLOWLY IN THE ASSOCIATED UPPER COL REGION...FROM 26N-30N BETWEEN 73W-79W. AN ELONGATED UPPER TROUGH IS SEEN RUNNING NE/ENE CENTERED ALONG 20N75W 24N68W 30N50W. THE MOST DISTINCT UPPER LOW CENTER IN THIS REGION IS SEEN NEAR 26N61W. INSTABILITY E OF THIS UPPER LOW IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 24N-28N BETWEEN 55W-61W. AN UPPER HIGH IS LOCATED JUST E OF THE WINDWARD ISLANDS NEAR 14N57W...WITH ANOTHER UPPER ANTICYCLONE EXTENDING W FROM THE COAST OF AFRICA OUT TO 40W. AT THE SURFACE...ASIDE FROM DEBBIE AND THE WAVE NEARING THE WINDWARD ISLANDS...HIGH PRESSURE EXTENDING SW FROM THE NEAR AZORES 1026MB CENTER IS DOMINATING MUCH OF THE ATLC. $$ WILLIS