000 AXNT20 KNHC 070001 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 06 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 HIGH AMPLITUDE TROPICAL WAVE IS LOCATED ALONG 38W SOUTH OF 21N MOVING W AT 15 KT. SATELLITE IMAGERY REVEALS AN INVERTED-V PATTERN...AND THE SSMI-DERIVED TPW PRODUCT FROM CIMSS SHOWS A NORTH-SOUTH MOISTURE MAXIMUM ALONG THE WAVE AXIS. NO DEEP CONVECTION IS ASSOCIATED WITH THIS FEATURE. MAINLY LOW/MID CLOUDS AND ISOLATED SHOWERS ARE EITHER SIDE OF THE WAVE AXIS. A TROPICAL WAVE IS ALONG 54W S OF 18N MOVING W NEAR 15 KT. THIS IS A LOW AMPLITUDE WAVE WITH SCATTERED SHOWERS WHERE THE WAVE MEETS THE ITCZ. A HIGH AMPLITUDE TROPICAL WAVE EXTENDS FROM THE SE BAHAMAS THROUGH HISPANIOLA TO THE COLOMBIA/VENEZUELA BORDER ALONG 73W MOVING WEST AROUND 15 KT. THE WAVE SHOWS UP VERY WELL ON THE MIMIC-TPW PRODUCT WHERE A GOOD SURGE OF MOISTURE IS NOTED. THIS SYSTEM IS ENHANCING SOME CONVECTIVE ACTIVITY OVER DOMINICAN REPUBLIC AND N COLOMBIA. THE TROPICAL WAVE THAT WAS PREVIOUSLY ALONG 96W IS NOW MAINLY OVER THE EASTERN PACIFIC. SEE TROPICAL WEATHER DISCUSSION FOR THE EPAC...TWDEP. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N16W 11N25W 13N34W 9N45W 9N62W. A LOW/MID CYCLONIC CIRCULATION IS SEEN EMBEDDED IN THE ITCZ NEAR 11N22W WITH A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION WITHIN 100 NM SW QUADRANT. WILL WAIT FOR ADDITIONAL DATA BEFORE PLACING A LOW ON THE SURFACE MAP. CLUSTERS OF MODERATE CONVECTION ARE NEAR 9N29W...9N32W AND 9N41W. ...DISCUSSION... GULF OF MEXICO... THE BOOK OF EDOUARD IS NOT CLOSED YET. AS A TROPICAL DEPRESSION CONTINUES TO WEAKEN ACROSS NORTH-CENTRAL TEXAS. STORM TOTAL RAINFALL AMOUNTS ARE BETWEEN 4 AND 6.5 INCHES IN HARRIS COUNTY TEXAS THROUGH 06/1800 UTC. ADDITIONAL RAINFALL ACCUMULATIONS OF 1 TO 2 INCHES WITH ISOLATED AMOUNTS TO 4 INCHES ARE EXPECTED ACROSS NORTH-CENTRAL TEXAS. MEANWHILE...HIGH PRES IS BUILDING OVER THE GULF REGION WITH A WEAK 1020 MB CENTER OVER SE LOUISIANA. SCATTERED SHOWERS AND ISOLATED TSTMS AREA OVER THE SE PORTION OF THE GULF AND THE YUCATAN PENINSULA. UPPER DIFFLUENT BETWEEN AN UPPER-LEVEL HIGH OVER THE SE CONUS/W ATLANTIC AND AN INVERTED TROUGH OVER THE CARIBBEAN SEA IS SUPPORTING THIS CONVECTIVE ACTIVITY. AN UPPER-LEVEL LOW HAS ALSO DEVELOPED OVER THE N GULF WATERS NEAR 29N88W AND IS HELPING TO INDUCE SCATTERED SHOWERS AND TSTMS OVER THE SE U.S.. SOME SHOWER ACTIVITY IS OBSERVER OVER THE SW GULF THANKS TO AN UPPER-LEVEL LOW SPINNING INLAND OVER CENTRAL MEXICO. CONSIDERABLE UPPER LEVEL MOISTURE COVERS THE ENTIRE GULF OF MEXICO. LOOKING AHEAD...A COLD FRONT IS FORECAST TO APPROACH THE NRN GULF WATERS LATE SATURDAY. CARIBBEAN SEA... WATER VAPOR IMAGERY SHOWS AN INVERTED TROUGH EXTENDING OVER E CUBA AND JAMAICA TO THE SW CARIBBEAN. UPPER NLY WINDS ON THE WEST SIDE OF THE TROUGH ARE ENHANCING CONVECTION OVER PARTS OF CUBA AND THE CAYMAN ISLANDS. THESE WINDS ARE ALSO TRANSPORTING A FAIR AMOUNT OF UPPER-LEVEL MOISTURE ACROSS THE NW CARIBBEAN INTO N CENTRAL AMERICA. AN UPPER-LEVEL HIGH IS BUILDING OVER THE E CARIBBEAN PRODUCING MODERATE TO STRONG SUBSIDENCE/DRY AIR BETWEEN PUERTO RICO AND THE LEEWARD ISLANDS. HAZY CONDITIONS DUE TO AFRICAN DUST SHOULD CONTINUE OVER THOSE ISLANDS TONIGHT THROUGH MOST OF THURSDAY. THE SAHARAN AIR LAYER FROM CIMSS AND LATEST VIS IMAGERY FOR THE DAY CONFIRM THE PRESENCE OF AFRICAN DUST OVER THE NE CARIBBEAN AND THE TROPICAL N ATLC. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN. SEE ABOVE. MODERATE TO ISOLATED STRONG CONVECTION HAS DEVELOPED OVER N COLOMBIA LIKELY ASSOCIATED WITH THE COLOMBIAN LOW THAT IS CENTERED NEAR 9N75W WITH 1006 MB. TRADE WINDS OF 20 TO 25 KT ARE FOUND OVER THE SOUTH-CENTRAL CARIBBEAN. ATLANTIC OCEAN... A SMALL AREA OF SHOWERS AND THUNDERSTORMS PREVIOUSLY ASSOCIATED WITH A HIGH AMPLITUDE TROPICAL WAVE IS MOVING WWD ACROSS THE CENTRAL BAHAMAS. CONDITIONS ARE NOT FAVORABLE FOR SIGNIFICANT DEVELOPMENT OF THIS SYSTEM...BUT IT COULD PRODUCE PERIODS OF SHOWERS OVER PORTIONS OF THE BAHAMAS AND SOUTHERN FLORIDA DURING THE NEXT DAY OR TWO. A SFC TROUGH IS ANALYZED IN THAT AREA AND RUNS FROM 27N70W TO 23N76W. ELSEWHERE...THREE WEAK HIGH PRES CENTERS DOMINATES THE FORECAST REGION WITH THE MAIN ONE LOCATED NEAR 29N52W WITH 1022 MB. THE RIDGE AXIS EXTENDS WWD TO CENTRAL FLORIDA. ALOFT...A RIDGE IS OVER THE W ATLANTIC N OF 25N W OF 65W. AN UPPER-LEVEL LOW REMAINS OVER THE SE BAHAMAS WITH A TROUGH EXTENDING ACROSS E CUBA AND JAMAICA INTO THE SW CARIBBEAN. ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 18N54W. YET ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 23N41W. AN UPPER-LEVEL TROUGH ENTERS THE AREA THROUGH THE CANARY ISLANDS THEN CONTINUES MAINLY WWD TO THE UPPER LOW LOCATED NEAR 23N41W. SOUTH OT THIS UPPER TROUGH THERE IS AN UPPER-LEVEL HIGH NEAR 19N31W. THIS HIGH IS ASSISTING THE DEVELOPMENT OF SCATTERED DEEP CONVECTION ALONG THE ITCZ AXIS. $$ GR