000 AXNT20 KNHC 302351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON JUL 30 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 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 17N36W TO A 1009 MB LOW AT 9N36W. THE WAVE/LOW IS MOVING W AT ABOUT 10-15 KT. THE WAVE IS FAIRLY LOW AMPLITUDE WITH A WEAK SIGNAL IN TOTAL PRECIPITABLE WATER. HOWEVER...AN ANALYSIS OF THE SAHARAN AIR LAYER SHOWS A CLEARING IN THE WIDESPREAD DUST NEAR THE WAVE AXIS INDICATING ITS PRESENCE. THE SURFACE LOW IS EMBEDDED WITHIN THE MONSOON TROUGH AND HAS BEEN FOR THE PAST SEVERAL DAYS. MODEL GUIDANCE INDICATES THAT THE LOW WILL PERSIST FOR THE NEXT FEW DAYS AND THE SYSTEM WILL BE MONITORED FOR POSSIBLE DEVELOPMENT. CURRENTLY...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS LIMITED TO THE MONSOON TROUGH REGION FROM 6N-10N BETWEEN 35W-41W. ACTIVE TROPICAL WAVE IS ACROSS THE EASTERN CARIBBEAN FROM 21N62W TO 11N64W MOVING W AT 15-20 KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT THE WAVE LIES WITHIN A SURGE OF DEEP LAYER MOISTURE WITH MAXIMUM VALUES NEAR THE AXIS. SURFACE OBSERVATIONS ALSO INDICATE LOW LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS. CURRENTLY SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 16N-20N BETWEEN 59W-67W COVERING MUCH OF THE NE CARIBBEAN ISLANDS. TROPICAL WAVE IS MOVING INTO CENTRAL AMERICAN AND THE NW CARIBBEAN ALONG 19N82W TO 10N84W TRAVELING W AT 20-25 KT. THE WAVE ALIGNS WITH A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE ALSO IS MOVING UNDERNEATH AN AREA OF DIFFLUENCE ALOFT WHICH IS ENHANCING CONVECTION. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-17N BETWEEN 84W-88W ACROSS MUCH OF HONDURAS. SIMILAR ACTIVITY IS TO THE S ACROSS PORTIONS OF COSTA RICA AND PANAMA...BUT THIS ACTIVITY IS MORE TIED TO THE DIFFLUENCE ALOFT AND THE MONSOON TROUGH. IT WILL BE DISCUSSED IN THE CARIBBEAN SECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SENEGAL AT 15N17W OVER ATLC WATERS ALONG 10N28W 11N32W TO A 1009 MB LOW ASSOCIATED WITH A WAVE AT 9N36W TO 8N48W. THE ITCZ BEGINS AT 8N48W CONTINUING TO 12N60W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-11N BETWEEN 18W-22W. ISOLATED MODERATE CONVECTION IS FROM 7N-10N BETWEEN 28W-32W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 6N-9N BETWEEN 41W-49W. ...DISCUSSION... GULF OF MEXICO... SCATTERED SHOWERS/THUNDERSTORMS COVER MUCH OF THE NE GULF AND THE FLORIDA PENINSULA ASSOCIATED WITH AN UPPER LEVEL TROUGH EXTENDING DOWN THE EASTERN SEABOARD. THE UPPER TROUGH SUPPORTS A PAIR OF SURFACE TROUGHS...AS OF 2100 UTC. ONE EXTENDS FROM THE W ATLC ACROSS CENTRAL FLORIDA ALONG 29N81W TO 27N84W. THE SECOND EXTENDS FROM GEORGIA TO 31N84W TO 30N89W. SOME ISOLATED SHOWERS/THUNDERSTORMS EXTEND INTO THE CENTRAL PORTIONS OF THE GULF. ACROSS THE REMAINDER OF THE BASIN...SURFACE RIDGING DOMINATES AROUND A 1019 MB HIGH CENTERED NEAR 27N93W. LIGHT ANTI-CYCLONIC WINDS ARE AROUND THE HIGH. AN UPPER LEVEL RIDGE COVERING THE CENTRAL CONUS SUPPORTS THE SURFACE HIGH. THE SRN GULF IS COVERED BY A PAIR OF UPPER LEVEL LOWS. ONE IS OVER WESTERN CUBA NEAR 23N82W...WHILE THE SECOND IS CENTERED OVER CENTRAL MEXICO NEAR 22N102W. NEITHER UPPER LOW IS CAUSING SIGNIFICANT WEATHER OVER THE BASIN. EXPECT A SIMILAR PATTERN OVER THE NEXT COUPLE OF DAYS. CARIBBEAN SEA... A PAIR OF TROPICAL WAVES ARE CAUSING ACTIVE WEATHER IN THE CARIBBEAN THIS EVENING. A WAVE IS ACROSS THE NW CARIBBEAN INTO CENTRAL AMERICA ACROSS HONDURAS AND NICARAGUA. SHOWERS/THUNDERSTORMS ARE MAINLY ACROSS WESTERN HONDURAS. SCATTERED SHOWERS/THUNDERSTORMS ALSO COVER THE SW CARIBBEAN INCLUDING COSTA RICA AND PANAMA ASSOCIATED WITH THE MONSOON TROUGH S OF BOTH COUNTRIES ALONG WITH DIFFLUENCE ALOFT BETWEEN BROAD INVERTED UPPER TROUGHING OVER THE E PACIFIC AND AN UPPER LEVEL RIDGE OVER THE CENTRAL CARIBBEAN. AN UPPER LEVEL LOW CENTERED OVER WESTERN CUBA IS ALSO ENHANCING THE ACTIVITY NEAR THE WAVE AS WELL AS SHOWERS/THUNDERSTORMS OVER MUCH OF CUBA HISPANIOLA. DRY AIR ALOFT IS KEEPING THE CENTRAL CARIBBEAN UNDER FAIR CONDITIONS. THE EASTERN CARIBBEAN IS IMPACTED BY THE SECOND TROPICAL WAVE WHICH EXTENDS ALONG 64W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE NRN LEEWARD ISLANDS WITH THE SE CARIBBEAN REMAINING MOSTLY DRY. STATIONS ACROSS THE BASIN CONTINUE TO REPORT DUST EXCEPT IN AREAS WHERE THERE ARE SHOWERS/THUNDERSTORMS. EXPECT THE WESTERN WAVE TO MOVE OUT OF THE BASIN...WHILE THE EASTERN WAVE CONTINUES INTO THE CENTRAL CARIBBEAN. ATLANTIC OCEAN... SHOWERS/THUNDERSTORMS ASSOCIATED WITH AN UPPER LEVEL TROUGH EXTENDING DOWN THE EASTERN SEABOARD ARE ACROSS THE FLORIDA PENINSULA AND OFFSHORE WATERS. SOME OF THESE ARE NEAR A SURFACE TROUGH ALONG 32N77W TO 29N81W. AN UPPER LEVEL LOW CENTERED NEAR 28N68W IS ALSO CAUSING SHOWERS/THUNDERSTORMS FROM 27N-29N BETWEEN 70W-73W. THE REMAINDER OF THE W ATLC IS COVERED BY SURFACE RIDGING AROUND A SERIES OF HIGH CENTERED N OF THE AREA. THEY ARE ALL SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED NEAR 34N55W. ANOTHER UPPER LEVEL LOW IS FARTHER E CENTERED NEAR 28N42W SUPPORTING A WEAK 1016 MB LOW NEAR 31N46W. ISOLATED SHOWERS ARE SW OF THE LOW. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY SURFACE RIDGING EXTENDING FROM THE N THAT IS PROVIDING FAIR CONDITIONS ACROSS MUCH OF THE AREA. IT IS SUPPORTED BY THE LARGE UPPER LEVEL RIDGE CENTERED NEAR 38N40W. SATELLITE IMAGERY CONTINUES TO SHOW A LARGE AREA OF SAHARAN DUST THAT EXTENDS FROM THE COAST OF AFRICA TO NEAR 55W...WHICH FURTHER SUPPORTS FAIR WEATHER. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON