000 AXNT20 KNHC 042335 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUL 04 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 20N28W TO 11N26W MOVING W NEAR 10-15 KT. THE WAVE LIES ON THE WRN SIDE OF A SURGE OF DEEP LAYER MOISTURE. THE WAVE ALSO LIES WITHIN A CLEARING IN THE SAHARAN AIR LAYER THAT IS PRESENT ACROSS THE TROPICAL ATLC. A SMALL AREA OF ISOLATED MODERATE CONVECTION IS FROM 9N-11N BETWEEN 23W-27W. ACTIVE TROPICAL WAVE IS MOVING ACROSS THE ERN CARIBBEAN ALONG 22N61W TO 11N64W MOVING W AT 15-20 KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES THAT THE WAVE LIES WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE COVERING THE ERN CARIBBEAN. SATELLITE IMAGERY ALSO SHOWS LOW-LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-22N BETWEEN 63W-69W...AND FROM 18N-22N BETWEEN 59W-53W. THIS AREA INCLUDES PUERTO RICO AND THE VIRGIN ISLANDS. TROPICAL WAVE IS OVER CENTRAL AMERICA ALONG 17N87W TO 11N84W MOVING W NEAR 15 KT. THE WAVE WAS MOVING W IN ACCORDANCE WITH A SURFACE OF DEEP LAYER MOISTURE THAT NOW APPEARS TO HAVE MOVED ACROSS CENTRAL AMERICA. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 11N-16N BETWEEN 82W-87W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALSO FROM 10N-13N BETWEEN 77W-82W...AS WELL AS ACROSS COSTA RICA AND PANAMA. SOME OF THIS ACTIVITY MAY BE LINKED TO THE E PACIFIC MONSOON TROUGH WHICH EXTENDS S OF PANAMA TO NRN COLOMBIA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF MAURITANIA AT 20N16W CONTINUING ACROSS ATLC WATERS ALONG 14N19W 10N29W 9N37W. THE ITCZ BEGINS AT 9N37W CONTINUING TO 6N54W. A CLUSTER OF STRONG CONVECTION IS FROM 7N-9N BETWEEN 49W-52W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING REMAINS ACROSS THE GULF OF MEXICO TODAY CENTERED AROUND A 1019 MB HIGH OFF THE W COAST OF FLORIDA NEAR 27N84W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED OVER GEORGIA NEAR 32N81W. UPPER RIDGING IS ALSO ACROSS THE SW GULF AND YUCATAN PENINSULA WITH UPPER TROUGHING TO EITHER SIDE. MOSTLY DRY AIR IS ACROSS THE BASIN WHICH IS HELPING MAINTAIN FAIR CONDITIONS OVER THE GULF WATERS. HOWEVER...SHOWERS/THUNDERSTORMS DOT MUCH OF FLORIDA...COASTAL ALABAMA....MISSISSIPPI...LOUISIANA...AND THE YUCATAN PENINSULA. THESE ARE LIKELY THE RESULT OF TYPICAL AFTERNOON CONVECTION THAT FORMS FROM DAYTIME HEATING AND INSTABILITY. LIGHT ANTI-CYCLONIC WINDS ARE AROUND THE SURFACE HIGH INCREASING IN SPEED TO 10-15 KTS IN THE WRN GULF AND ALONG THE MEXICAN COAST. EXPECT SURFACE RIDGING TO REMAIN ACROSS THE BASIN THROUGH THE END OF THE WEEK. AFTERNOON CONVECTION WILL LIKELY POP UP ACROSS FLORIDA AND THE NRN GULF COAST. CARIBBEAN SEA... A TROPICAL WAVE OVER CENTRAL AMERICA TO HELPING SUPPORT WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS MOST OF CENTRAL AMERICA. SOME OF THE ACTIVITY FARTHER S AND IN THE SW CARIBBEAN CAN ALSO BE ATTRIBUTED TO THE E PACIFIC MONSOON TROUGH THAT EXTENDS S OF PANAMA TO NRN COLOMBIA. CUBA IS ALSO IMPACTED BY HEAVY SHOWERS/THUNDERSTORMS LIKELY DUE TO DAYTIME HEATING AND INSTABILITY. DESPITE THE WIDESPREAD ACTIVITY OVER LAND...THE NW AND CENTRAL CARIBBEAN WATERS REMAIN MOSTLY CLEAR DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL TROUGH COVERING MUCH OF THE BASIN WITH AXIS FROM THE WINDWARD PASSAGE TO THE SW CARIBBEAN. A SECOND TROPICAL WAVE IS BRINGING MOIST CONDITIONS TO THE ERN CARIBBEAN WITH ACTIVITY ACROSS PUERTO RICO...THE VIRGIN ISLANDS...AND THE NRN LESSER ANTILLES. SEE TROPICAL WAVE SECTION FOR MORE DETAILS. ACTIVITY NEAR THE WAVE MAY ALSO BE INFLUENCED BY DIFFLUENCE ALOFT BETWEEN THE UPPER TROUGH OVER THE MAJORITY OF THE BASIN...AND AN UPPER LEVEL RIDGE OVER THE ERN CARIBBEAN ALONG 64W. EXPECT THE WAVE TO CONTINUE TO MOVE WWD DRAWING MOISTURE INTO THE CENTRAL CARIBBEAN. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE COVERS THE FAR WRN ATLC EXTENDING FROM THE SE CONUS SUPPORTING WEAK SURFACE RIDING AND MOSTLY FAIR CONDITIONS. A NARROW UPPER LEVEL TROUGH E OF THE RIDGE 36N60W ALONG 26N72W TO SRN FLORIDA. THE UPPER TROUGH IS HELPING SUPPORT SCATTERED SHOWERS/THUNDERSTORMS OVER THE WRN BAHAMAS...S FLORIDA...AND MUCH OF CUBA. AN UPPER LEVEL RIDGE IS E OF THE UPPER TROUGH EXTENDING FROM THE ERN CARIBBEAN. A TROPICAL WAVE IN THE ERN CARIBBEAN IS SUPPORTING SHOWERS/THUNDERSTORMS N OF LESSER ANTILLES BELOW THE UPPER RIDGE. SEE TROPICAL WAVE SECTION ABOVE. A BROAD UPPER LEVEL RIDGE OVER THE NRN CENTRAL ATLC SUPPORTS A BROAD SURFACE RIDGE ANCHORED BY A 1030 MB AZORES HIGH NEAR 42N33W...WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE CENTRAL AND ERN ATLC. AN UPPER LEVEL LOW CENTERED NEAR 37N42W CONTINUES TO SUPPORT A NOW VERY WEAK SURFACE TROUGH ALONG 32N44W TO 28N46W. NO SHOWER ACTIVITY IS NEAR THE TROUGH AXIS. UPPER LEVEL RIDGING ALSO COVERS THE TROPICAL ATLC CENTERED NEAR 22N34W. THE SURFACE RIDGE ACROSS THE ERN TRPCL ATLC IS ALSO ACCOMPANIED BY A STABLE SAHARAN AIR LAYER EXTENDING ALL THE WAY FROM AFRICA TO NEAR 60W AROUND THE TROPICAL WAVES. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON