000 AXNT20 KNHC 082336 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUL 08 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 20N22W TO 12N24W MOVING W AT 10-15 KT. THE WAVE LIES WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. THERE IS ALSO A CLEARING IN THE LARGE AREA OF SAHARAN DUST AROUND THE WAVE INDICATING ITS PRESENCE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-13N BETWEEN 20W-25W. TROPICAL WAVE IS ALONG 27N54W TO 17N60W MOVING W NEAR 15 KT. THE WAVE IS ON THE WRN SIDE OF AN AREA OF ENHANCED MOISTURE. THE WAVE ALSO LIES ON THE LEADING EDGE OF A LARGE AREA OF SAHARAN DUST THAT EXTENDS ACROSS MUCH OF THE TROPICAL ATLC. THE DUST IS SUPPRESSING MOST CONVECTION NEAR THE WAVE EXCEPT FOR SOME WIDELY ISOLATED MODERATE CONVECTION FROM 22N-26N BETWEEN 52W-56W. TROPICAL WAVE IS EMERGING OFF THE YUCATAN PENINSULA ALONG 23N90W TO 14N91W MOVING W NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT THE WAVE LIES WITHIN A SURGE OF DEEP LAYER MOISTURE COVERING THE YUCATAN PENINSULA AND SW GULF OF MEXICO. SATELLITE IMAGERY ALSO SHOWS BROAD LOW-MID LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS E OF THE WAVE AXIS ACROSS THE YUCATAN PENINSULA FROM 18N-22N BETWEEN 86W-90W. SIMILAR ACTIVITY IS W OF THE WAVE FROM 17N-20N BETWEEN 93W-96W. SCATTERED STRONG CONVECTION IS NEAR THE SRN EXTENT OF THE WAVE FROM 14N-16N BETWEEN 90W-94W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SENEGAL AT 14N17W TO 10N27W. THE ITCZ BEGINS AT 10N27W TO A 1010 MB SURFACE LOW NEAR 7N43W CONTINUING TO 4N52W. A CLUSTER OF STRONG CONVECTION IS MOVING OFF THE COAST OF AFRICA FROM 8N-12N BETWEEN 13W-15W. ISOLATED MODERATE CONVECTION IS FROM 6N-9N BETWEEN 28W-39W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NEAR THE LOW CENTER FROM 5N-8N BETWEEN 39W-47W. SCATTERED MODERATE CONVECTION IS FROM 5N-9N BETWEEN 47W-52W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING IS ACROSS THE GULF OF MEXICO AROUND A 1020 MB HIGH NEAR THE BIG BEND OF FLORIDA AT 29N85W. LIGHT ANTI-CYCLONIC FLOW IS AROUND THE SURFACE RIDGE. DRY AIR ALOFT IS KEEPING A GOOD PORTION OF THE BASIN UNDER MOSTLY FAIR CONDITIONS WITH ONLY A FEW ISOLATED SHOWERS/THUNDERSTORMS IN THE CENTRAL GULF. HOWEVER...SHOWERS/THUNDERSTORMS HAVE POPPED UP INLAND ACROSS AREAS OF THE GULF COAST. SHOWERS/THUNDERSTORMS ARE ACROSS S FLORIDA AND THE FLORIDA STRAITS DUE TO DIFFLUENCE ALOFT AROUND AN UPPER LEVEL TROUGH OVER THE ERN GULF. SIMILAR ACTIVITY ALSO COVERS PORTIONS OF LOUISIANA....TEXAS...MISSISSIPPI...AND ALABAMA...DUE TO A SECOND UPPER LEVEL TROUGH THAT IS SANDWICHED BETWEEN TWO LARGE UPPER RIDGES OVER THE ERN CONUS AND SW CONUS. THE UPPER RIDGE OVER THE SW CONUS EXTENDS OVER THE NW GULF. A SECOND UPPER LEVEL RIDGE OVER THE WRN CARIBBEAN COVERS THE SRN GULF OF MEXICO. A TROPICAL WAVE IS MOVING OFF THE YUCATAN PENINSULA SUPPORTING SHOWERS/THUNDERSTORMS ACROSS THE PENINSULA AND SW GULF. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS. SURFACE RIDGING WILL REMAIN ACROSS THE BASIN WHILE THE TROPICAL WAVE NEAR THE YUCATAN PENINSULA CONTINUES WWD OVER THE SW GULF. MOIST CONDITIONS ARE EXPECTED ACROSS THE SW GULF AS WELL AS ACROSS INLAND PORTIONS OF THE GULF COAST. CARIBBEAN SEA... MOST OF THE MOISTURE ASSOCIATED WITH THE TROPICAL WAVE OVER THE YUCATAN PENINSULA HAS MOVED W OF THE AREA. A FEW SHOWERS/THUNDERSTORMS REMAIN NEAR THE ERN SIDE OF THE YUCATAN. SHOWERS/THUNDERSTORMS ARE ALSO ACROSS WRN CUBA ASSOCIATED WITH DIFFLUENCE ALOFT AROUND THE E SIDE OF AN UPPER LEVEL TROUGH OVER THE ERN GULF OF MEXICO. UPPER LEVEL RIDGING COVERS MOST OF THE WRN HALF OF THE CARIBBEAN. STRONG SHOWERS/THUNDERSTORMS COVER SRN NICARAGUA...COSTA RICA...AND WRN PANAMA LIKELY DUE TO THE E PACIFIC MONSOON TROUGH THAT EXTENDS ACROSS SRN COSTA RICA AND PANAMA TO NRN COLOMBIA. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO OVER HISPANIOLA AND PUERTO RICO MOSTLY ASSOCIATED WITH DAYTIME HEATING AND INSTABILITY. THE ERN CARIBBEAN AND CENTRAL CARIBBEAN WATERS ARE MOSTLY CLEAR DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE OVER THE NE CARIBBEAN. A WEAK INVERTED UPPER TROUGH IS ACROSS THE CENTRAL CARIBBEAN BETWEEN THE TWO UPPER RIDGES ACROSS THE ERN AND WRN SIDES. TRADEWIND FLOW OF 15-20 KT IS ACROSS MUCH OF THE BASIN WITH WINDS REACHING 25 AND POSSIBLY 30 KT IN THE S CENTRAL CARIBBEAN. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. A TROPICAL WAVE NE OF THE BASIN MAY IMPACT THE NRN LESSER ANTILLES...BUT WILL LIKELY REMAIN MOSTLY N OF THE BASIN. ATLANTIC OCEAN... A SMALL UPPER LEVEL TROUGH OVER THE ERN GULF OF MEXICO IS PROVIDING DIFFLUENCE ALOFT ACROSS THE WRN BAHAMAS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS W OF 78W. THE REMAINDER OF THE WRN ATLC IS EXPERIENCING MOSTLY FAIR CONDITIONS DUE TO DRY AIR ALOFT AROUND A BROAD UPPER RIDGE COVERING THE ERN CONUS AND W ATLC. TO THE E...AN UPPER TROUGH EXTENDS FROM NEAR 29N57W TO 24N71W...BUT IS NOT CAUSING ANY SIGNIFICANT WEATHER. A SECOND UPPER TROUGH EXTENDS ALONG 51W SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS 20N-28N BETWEEN 51W-58W. THIS ACTIVITY MAY ALSO BE RELATED TO A TROPICAL WAVE. THE HAVE HAS BEEN MOSTLY DRY FOR THE PAST FEW DAYS DUE TO A LARGE AREA OF DUST TRAILING IT. THE UPPER TROUGH IS PROVIDING JUST ENOUGH LIFT TO PRODUCE SOME OF THIS WEAK ACTIVITY. BROAD SURFACE RIDGING COVERS THE REMAINDER OF THE CENTRAL AND ERN ATLC ANCHORED BY A 1030 MB AZORES HIGH NEAR 41N33W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE OVER THE N CENTRAL ATLC. UPPER RIDGING ALSO COVERS THE TROPICAL ATLC. AS MENTIONED PREVIOUSLY...A LARGE AREA OF AFRICAN DUST EXTENDS BETWEEN THE WAVE IN THE CENTRAL ATLC AND AROUND THE TROPICAL WAVE NEAR THE COAST OF AFRICA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON