000 AXNT20 KNHC 302354 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT JUN 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 2245 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 19N22W TO 11N23W MOVING W NEAR 10-15 KT. UPPER AIR TIME SECTION DATA FROM DAKAR SENEGAL INDICATES THAT THE WAVE MOVED OFF THE COAST OF AFRICA BETWEEN 28/1200 UTC AND 29/0000 UTC. TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT THE WAVE LIES WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE. THERE IS ALSO A BROAD CLEARING WITHIN THE SAHARAN AIR LAYER. SCATTERED MODERATE CONVECTION IS S OF THE WAVE FROM 6N-9N BETWEEN 19W-26W. LOW-AMPLITUDE TROPICAL WAVE IS ALONG 12N36W TO 8N37W MOVING W NEAR 10-15 KT. THE WAVE WAS ADDED DUE TO A TRACKABLE AREA OF CONVECTION THAT COULD BE TRACED BACK TO THE COAST OF AFRICA. HOWEVER...THE EXACT LOCATION OF THE WAVE IS DIFFICULT TO DISCERN DUE TO ITS LOW-AMPLITUDE. SCATTERED MODERATE CONVECTION IS FROM 8N-10N BETWEEN 35W-39W. TROPICAL WAVE IS ALONG 19N58W TO 11N57W MOVING W NEAR 15-20 KT. THE WAVE COINCIDES WITH A SURGE IN DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. VISIBLE SATELLITE IMAGERY SHOWS BROAD LOW-LEVEL CYCLONIC FLOW NEAR THE WAVE AXIS WHICH IS CONFIRMED BY AN OSCAT SCATTEROMETER PASS. SCATTERED MODERATE CONVECTION IS E OF THE WAVE AXIS FROM 10N-15N BETWEEN 54W-58W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF MAURITANIA NEAR 17N16W CONTINUING ACROSS ATLC WATERS ALONG 11N24W 9N34W 6N41W. THE ITCZ CONTINUES FROM 6N41W TO 3N52W. BESIDES CONVECTION NEAR TROPICAL WAVES...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-10N BETWEEN 26W-33W. ...DISCUSSION... GULF OF MEXICO... DESPITE SURFACE RIDGING AROUND A 1018 MB HIGH OFF THE W COAST OF FLORIDA NEAR 26N83W...ACTIVE WEATHER CONTINUES ACROSS THE NW GULF OF MEXICO AND NE MEXICO DUE TO THE UPPER LEVEL PATTERN. A STRONG UPPER LEVEL LOW IS SITUATED OVER NE MEXICO NEAR 27N101W PROVIDING DIFFLUENCE ALOFT ACROSS THE NW GULF. CURRENTLY A LARGE CLUSTER OF STRONG SHOWERS/THUNDERSTORMS IS FROM 24N-28N BETWEEN 92W-96W. STRONG SHOWERS/THUNDERSTORMS ALSO COVER MUCH OF MEXICO AND SRN TEXAS. A SURFACE TROUGH HAS FORMED ALONG THE TEXAS COASTLINE ALONG 29N95W TO 27N97W. UPPER LEVEL RIDGING COVERS THE CENTRAL GULF FROM MISSISSIPPI TO THE BAY OF CAMPECHE WHILE AN INVERTED UPPER TROUGH COVERS THE ERN GULF. THIS SECOND UPPER TROUGH AND THE UPPER RIDGE ARE ACCOMPANIED BY DRY AIR ALOFT WHICH IS HELPING PROVIDE FAIR CONDITIONS E OF 90W EXCEPT FOR A FEW SHOWERS/THUNDERSTORMS THAT HAVE POPPED UP OVER S FLORIDA...WRN CUBA...AND THE FLORIDA STRAITS. WINDS ARE LIGHT AND ANTI-CYCLONIC AROUND THE SURFACE HIGH IN THE ERN GULF...BUT REACH UP TO 20 KTS ACROSS THE WRN GULF...AND POSSIBLY HIGHER IN THUNDERSTORMS. SURFACE RIDGING IS EXPECTED TO REMAIN ACROSS THE AREA WITH THE AREA OF ACTIVE WEATHER INB THE NW GULF EXPECTED TO MOVE INLAND. CARIBBEAN SEA... CLEAR SKIES AND FAIR WEATHER ARE ACROSS MUCH OF THE CARIBBEAN DUE TO DRY AIR ALOFT AROUND BROAD UPPER LEVEL CYCLONIC FLOW CENTERED OVER THE BASIN NEAR 14N72W. AFTERNOON CONVECTION ACROSS THE NRN ISLANDS IS STILL PRESENT ESPECIALLY ACROSS PORTIONS OF CUBA AND HISPANIOLA. SHOWERS/THUNDERSTORMS ALSO DOT PORTIONS OF CENTRAL AMERICA...ESPECIALLY COSTA RICA AND PANAMA...DUE TO THE MONSOON TROUGH THAT EXTENDS THROUGH PANAMA TO NRN COLOMBIA. A FEW SHOWERS/THUNDERSTORMS ARE IMPACTING THE LESSER ANTILLES E OF 64W FROM 13N-17N DUE TO MOISTURE AHEAD OF A TROPICAL WAVE JUST E OF THE ISLANDS. TRADEWIND FLOW OF 15-20 KTS IS PRESENT ACROSS MUCH OF THE BASIN. EXPECT LITTLE CHANGE EXCEPT FOR AN INCREASE IN SHOWERS/THUNDERSTORMS ACROSS THE ERN CARIBBEAN DUE TO THE TROPICAL WAVE E OF THE ISLANDS WHICH CONTINUES TO MOVE WWD. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE OVER THE BAHAMAS SUPPORTS A WEAK SURFACE RIDGE AROUND A 1018 MB HIGH W OF FLORIDA PROVIDING FAIR CONDITIONS ACROSS THE FAR WRN ATLC. AN UPPER LEVEL TROUGH TO THE E NEAR 29N58W SUPPORTS A STATIONARY FRONT ENTERING THE DISCUSSION AREA ALONG 32N61W 29N64W 27N70W. ISOLATED SHOWERS ARE WITHIN 100 NM S AND E OF THE AXIS. A SURFACE TROUGH IS TO THE S OF THE FRONT ALONG 25N63W TO 20N69W WITH POSSIBLE ISOLATED SHOWERS WITHIN 100 NM EITHER SIDE THE AXIS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FARTHER E OF THE FRONT FROM 25N-30N BETWEEN 56W-60W IN THE AREA OF DIFFLUENCE ALOFT AROUND THE UPPER LOW. A WEAK UPPER RIDGE SEPARATES THE UPPER LOW FROM A SECOND UPPER LOW FARTHER E NEAR 29N36W. THIS UPPER LOW SUPPORTS A SURFACE TROUGH ALONG 31N33W TO 27N39W. SCATTERED SHOWERS ARE WITHIN 45 NM EITHER SIDE THE TROUGH AXIS. THE SURFACE TROUGH IS WITHIN A BROAD SURFACE RIDGE ANCHORED BY A 1031 MB HIGH NEAR THE AZORES ISLANDS. THE RIDGE IS SUPPORTED BY UPPER LEVEL RIDGING BOTH N AND S OF THE UPPER LOW. THE RIDGE IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE CENTRAL AND ERN ATLC BESIDES NEAR THE SURFACE TROUGH. VISIBLE SATELLITE IMAGERY ALONG WITH GOES-R DUST ENHANCEMENT IMAGERY INDICATE THAT A LARGE AREA OF SAHARAN DUST EXTENDS FROM THE COAST OF AFRICA AROUND THE TROPICAL WAVES TO NEAR 50W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON