000 AXNT20 KNHC 281746 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT JUL 28 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 10N47W TO 19N45W MOVING W AT 10 TO 15 KT. THIS WAVE ON SATELLITE HAS THE CLASSIC TROPICAL WAVE APPEARANCE WITH A BROAD LOW TO MIDDLE LEVEL CYCLONIC TURNING ABOUT THE AXIS. WHAT THIS WAVE LACKS IS CONVECTION...AND FURTHERMORE SUSTAINED CONVECTION. ISOLATED SHOWERS ARE OCCURRING FROM 14N-17N BETWEEN 46W-49W AND THIS LIMITED ACTIVITY REMAINS EMBEDDED WITHIN VERY DRY AIR ALOFT AS WELL AS AREAS OF SAHARAN DUST TO THE NE AND W OF THE WAVE AXIS. TROPICAL WAVE EXTENDS FROM 12N64W TO 19N61W MOVING W AT 10 TO 15 KT. AN INTERESTING WAVE AS IT HAS APPROACHED THE LESSER ANTILLES DUE TO MID-LEVEL ENERGY WHICH APPEARED TO MERGE WITH THE WAVE AROUND 60 TO 72 HOURS AGO. SOME OF THIS ENERGY HAS CONTINUED TO DRIFT NORTH OF THE WAVE AND IS ANALYZED AS A SURFACE TROUGH FROM 20N61W TO 25N57W WITH ISOLATED SHOWERS OCCURRING WITHIN 150 NW OF THE SURFACE TROUGH AXIS. THE WAVE HOWEVER CONTINUES A WESTWARD MOTION AND EXAMINING SATELLITE IMAGERY IS SOMEWHAT DIFFICULT TO TRACK. TOTAL PRECIPITABLE WATER IMAGERY INDICATES A MAXIMUM IN DEEP LAYER MOISTURE ACROSS THE SE CARIBBEAN SEA AND PORTIONS OF VENEZUELA. ANOTHER NEGATIVE FOR THE WAVE IS SAHARAN DUST THAT CONTINUES TO SUPPRESS DEEP CONVECTION AND ANY SUBSTANTIAL PRECIPITATION AT THIS TIME. TROPICAL WAVE EXTENDS FROM 18N96W TO 21N97W ACROSS THE EAST-CENTRAL COAST OF MEXICO AND ENERGY ASSOCIATED WITH THIS WAVE IS EXPECTED TO DISSIPATE BEFORE 28/1800 UTC. EXAMINING PAST GLOBAL MODEL ANALYSES OVER THE PAST SEVERAL DAYS AND FORECASTS FOR THE NEXT FEW DAYS...IT IS POSSIBLE THAT SOME ENERGY ASSOCIATED WITH THIS WAVE REMAINS OVER THE EAST PACIFIC WATERS IN THE REGION SOUTH OF THE GULF OF TEHUANTEPEC AND THAT A TRACKABLE FEATURE MAY BE ADDED IN THE FUTURE. IN ANY CASE... LINGERING LOW TO MIDDLE LEVEL MOISTURE IN THE VICINITY OF THE WAVE ALONG THE MEXICO COAST IS GENERATING ISOLATED SHOWERS FROM 21N-24N BETWEEN 97W-99W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO A 1014 MB LOW PRES NEAR 10N23W TO 10N31W TO 11N47W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 11N47W TO 07N54W TO 07N59W. SCATTERED MODERATE CONVECTION IS FROM 07N-13N BETWEEN 15W-36W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL LOW IS CENTERED OVER THE SW GULF NEAR 23N93W AND THIS FEATURE IS CONTINUING TO ADVECT MIDDLE TO UPPER LEVEL MOISTURE ACROSS PORTIONS OF THE WESTERN GULF THIS AFTERNOON WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING IN CLOSE PROXIMITY TO THE UPPER LEVEL LOW CENTER...AND ALSO FROM 18N-24N BETWEEN 91W-96W. THIS ACTIVITY IS EXPECTED TO CONTINUE MOVING W-NW ON THE SOUTHERN PERIPHERY OF A SURFACE RIDGE EXTENDING ALONG 27N AND ANCHORED BY A 1021 HIGH CENTERED NEAR 27N89W. TO THE NORTH OF THIS SURFACE RIDGE...UPPER LEVEL TROUGHING IS ACROSS THE EASTERN CONUS AND IS SUPPORTIVE OF WEAK SURFACE TROUGHING ACROSS PORTIONS OF THE U.S. EAST COAST INTO CENTRAL GEORGIA AND SOUTHERN ALABAMA. THIS TROUGHING CONTINUES FROM PORTIONS OF THE FLORIDA PANHANDLE INTO THE NE GULF ALONG 30N85W TO 29N88W. MOSAIC DOPPLER RADAR IMAGERY AND LIGHTNING DATA INDICATE WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING N OF 29N E OF 90W. A FEW ISOLATED SHOWERS AND TSTMS LINGER FARTHER TO THE SOUTH FROM 25N-28N E OF 86W. THE SURFACE RIDGE IS FORECAST TO REMAIN IN PLACE ALONG 27N THROUGH WEDNESDAY OF NEXT WEEK. CARIBBEAN SEA... AN UPPER LEVEL LOW IS CENTERED NORTH OF EASTERN CUBA NEAR 22N77W AND AN UPPER LEVEL ANTICYCLONE IS CENTERED TO THE EAST OVER PUERTO RICO NEAR 19N67W. WITH SAHARAN DUST IN PLACE ACROSS MUCH OF THE CARIBBEAN AND SW NORTH ATLC OVER THE PAST FEW DAYS...THE MIDDLE TO UPPER LEVELS OF THE ATMOSPHERE REMAIN DRY AND LACK ANY SIGNIFICANT AREAS OF DEEP CONVECTION. A TROPICAL WAVE...AS MENTIONED ABOVE...IS MOVING WESTWARD ACROSS THE EASTERN CARIBBEAN HOWEVER VERY LITTLE MOISTURE IS ASSOCIATED WITH THIS FEATURE. BRISK EASTERLY TRADEWINDS IN THE RANGE OF 15 TO 25 KT PERSIST AND ARE EXPECTED THROUGH MONDAY. BY MONDAY...THE TROPICAL WAVE ALONG 46W WILL BEGIN TRACKING ACROSS THE LESSER ANTILLES PROVIDING THE POSSIBILITY OF INCREASED CLOUDINESS AND ISOLATED SHOWER ACTIVITY. ATLANTIC OCEAN... OVERALL AN MIDDLE TO UPPER LEVEL RIDGE IS ACROSS MUCH OF THE WESTERN AND CENTRAL ATLC ANCHORED IN THE VICINITY OF 32N59W. THIS SUPPORTS A BROAD SURFACE RIDGE EXTENDING FROM A 1028 MB HIGH CENTERED NORTH OF THE AZORES NEAR 43N30W TO A 1026 MB HIGH CENTERED NEAR 32N48W TO A 1021 MB HIGH CENTERED IN THE SW NORTH ATLC NEAR 28N72W. NEAREST TO THIS WESTERN-MOST HIGH IS A SURFACE TROUGH ANALYZED FROM 27N69W TO 31N67W WITH WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM 25N-28N BETWEEN 67W-74W. OTHERWISE THE REMAINDER OF THE ATLC BASIN IS FAIRLY QUIET AND TRANQUIL WITH THE EXCEPTION OF THE SURFACE TROUGH MENTIONED ABOVE IN ASSOCIATION WITH THE TROPICAL WAVE ACROSS THE EASTERN CARIBBEAN SEA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT