000 AXNT20 KNHC 292355 RRA TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUN 29 2014 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 2345 UTC. ...SPECIAL FEATURES... BOTH SURFACE OBSERVATIONS AND SATELLITE DATA INDICATE THE LOW PRESSURE SYSTEM LOCATED ABOUT 150 NM E OF DAYTONA BEACH FLORIDA IS GRADUALLY BECOMING BETTER ORGANIZED WHILE MOVING SLOWLY SSW. EVEN THOUGH UPPER-LEVEL WINDS ARE ONLY MARGINALLY FAVORABLE...A TROPICAL DEPRESSION COULD FORM OVER THE NEXT DAY OR TWO. THIS LOW PRESSURE AREA IS CURRENTLY GENERATING SCATTERED MODERATE CONVECTION WITHIN 180 NM IN THE S QUADRANT. CONVECTION IS LIMITED ELSEWHERE AROUND THE SYSTEM. FOR ADDITIONAL INFORMATION REFER TO THE ATLC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20 KNHC. ...TROPICAL WAVES... TROPICAL WAVE IS SLIGHTLY N OF THE ITCZ WITH AXIS EXTENDING FROM 16N48W TO 6N50W MOVING WNW AT 20 KT DURING THE LAST 24 HOURS. VERY DRY AIR FROM A SAHARAN AIR LAYER OUTBREAK SPREADS OVER MOST OF THE WAVE ENVIRONMENT HINDERING ANY CONVECTIVE ACTIVITY. TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM 17N66W TO THE N COAST OF VENEZUELA AT 67W. THE WAVE WAS MOVING W AT 20 KT DURING THE LAST 24 HOURS. ALTHOUGH THE SSMI TPW AND WATER VAPOR IMAGERY INDICATED MID-UPPER LEVEL MOISTURE ASSOCIATED WITH THIS WAVE...STRONG DEEP LAYER ENVIRONMENTAL WIND SHEAR IS HINDERING THE DEVELOPMENT OF DEEP CONVECTION. A SECOND TROPICAL WAVE IS OVER THE CARIBBEAN WITH AXIS EXTENDING FROM 19N83W TO THE COAST OF HONDURAS AT 84W INTO CENTRAL AMERICA 9N82W MOVING W AT 15-20 KT DURING THE LAST 24 HOURS. SSMI TPW AND WATER VAPOR IMAGERY SHOW MID-UPPER LEVEL MOISTURE ASSOCIATED WITH THIS WAVE. SCATTERED SHOWERS AND TSTMS ARE WITHIN 100 NM EITHER SIDE OF THE AXIS OVER HONDURAS AND NICARAGUA. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA NEAR 14N17W TO 11N20W TO 5N36W. THE ITCZ BEGINS NEAR 5N36W AND CONTINUES ALONG 4N40W TO 3N51W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WAS NOTED WITHIN 180 NM S OF THE AXIS BETWEEN 22W AND 32W...AND WITHIN 60-90 NM EITHER SIDE OF THE AXIS BETWEEN 32W AND 40W. ...DISCUSSION... ...THE GULF OF MEXICO... A MID-LEVEL CYCLONIC CIRCULATION CENTERED OVER THE SABINE RIVER BETWEEN TEXAS/LOUISIANA IS DRIFTING WESTWARD BENEATH A BUILDING MID TO UPPER LEVEL RIDGE OVER THE MID-SOUTH WHICH EXTENDS SE ACROSS GEORGIA TO A SMALL ANTICYCLONE OVER NORTH-CENTRAL FLORIDA. ANOTHER SMALL MID-LEVEL CYCLONE WAS CENTERED NEAR 23N86W. ALL THE FEATURES COMBINED TO PRODUCE RATHER COMPLEX UPPER LEVEL FLOW OVER THE GULF. AT THE SURFACE...A RIDGE DOMINATED THE GULF AND WAS ANCHORED BY A 1022 MB HIGH JUST S OF PANAMA CITY FLORIDA. VARIABLE WINDS WERE IN THE 5 TO 10 KNOT RANGE NEAR THE HIGH AND OVER MOST OF THE GULF E OF 93W. WINDS WERE MORE SOUTHEASTERLY OVER THE WESTERN GULF...INCREASING TO 15 TO 20 KT ALONG THE TEXAS COAST AND ELSEWHERE W OF 93W. FAIR SKIES PREVAILED OVER MOST OF THE GULF WITH THE EXCEPTION OF OVERCAST MID AND HIGH CLOUDS SWEEPING WESTWARD FROM NUMEROUS THUNDERSTORMS OVER SW FLORIDA. SEVERAL REPORTS OF HAZE WERE NOTED OVER THE GULF AS SAHARAN AIR WAS BEING ADVECTED INTO THE REGION FROM THE NORTHERN CARIBBEAN. HIGH PRESSURE WILL PREVAIL ACROSS THE BASIN FOR THE NEXT COUPLE OF DAYS. ...THE CARIBBEAN SEA... TWO TROPICAL WAVES ARE MOVING ACROSS THE CARIBBEAN OVER THE EAST- CENTRAL PORTION S OF PUERTO RICO AND OVER THE GULF OF HONDURAS INTO CENTRAL AMERICA. SSMI TPW IMAGERY SHOW MODERATE MOIST CONDITIONS SOUTH OF 16N WHILE A TONGUE OF VERY DRY SAHARAN AIR MOVES WESTWARD OVER THE NORTHERN CARIBBEAN AND THE GREATER ANTILLES. THIS DRY AIR IS SUPPORTING MOSTLY FAIR BUT HAZY CONDITIONS IN THIS REGION OF THE CARIBBEAN. OVER THE MOIST REGION...STRONG DEEP LAYER ENVIRONMENTAL WIND SHEAR HINDERS THE DEVELOPMENT OF CONVECTION. AT THE UPPER LEVELS...A CYCLONIC CIRCULATION IS OFF THE FAR NW TIP OF CUBA WHILE A BROAD EAST TO WEST ELONGATED RIDGE COVERS THE REMAINDER OF THE BASIN S OF 17N. AN UPPER-LEVEL LOW N OF PUERTO RICO IS GENERATING DIFFLUENCE OVER THE FAR NE CARIBBEAN WHICH IS SUPPORTING SCATTERED SHOWERS OVER THE NORTHERN LEEWARD ISLANDS. THE PRESSURE GRADIENT BETWEEN THE ATLANTIC RIDGE AND THE MONSOON TROUGH IS MAINTAINING 20-25 KT TRADES IN THE CENTRAL CARIBBEAN AND 10-20 KT WINDS IN BOTH THE WESTERN AND EASTERN CARIBBEAN. THE WAVE OVER THE WESTERN CARIBBEAN WILL MOVE INLAND OVER CENTRAL AMERICA TONIGHT AND MON AND IS EXPECTED TO MERGE WITH AN AREA OF LOW PRESSURE IN THE EPAC WATERS TOMORROW MORNING. THE WAVE OVER THE E CARIBBEAN WILL CONTINUE TO MOVE W TOWARD THE WESTERN BASIN WHILE A NEW TROPICAL WAVE ENTERS THE E CARIBBEAN ON MON. ...HISPANIOLA... DRY SAHARAN AIRMASS CONTINUES TO MOVE ACROSS THE GREATER ANTILLES AND ADJACENT WATERS...THUS SUPPORTING FAIR BUT HAZY WEATHER CONDITIONS. THE 1200 UTC SANTO DOMINGO RAOB INDICATED PRECIPITABLE WATER VALUES OF ONLY 1.26 INCHES AND A STRONG CAPPING INVERSION AT 850 MB. DESPITE THE OVERALL SUPPRESSED ENVIRONMENT...ISOLATED THUNDERSTORMS ERUPTED OVER THE HIGHER TERRAIN OF EASTERN HAITI AND CENTRAL DOMINICAN REPUBLIC. THE CONTINUED PRESENCE OF THE SAHARAN AIR LAYER IN THE AREA OVER THE NEXT COUPLE OF DAYS SHOULD RESULT IN DELAYED DEVELOPMENT OF AFTERNOON CONVECTION WITH GENERALLY LESS COVERAGE THAN IS TYPICALLY EXPECTED. ...THE ATLANTIC OCEAN... AN UPPER LEVEL ANTICYCLONE OVER NORTH-CENTRAL FLORIDA DOMINATED THE FLOW OVER THE ATLANTIC W OF 72W. THE AREA OF LOW PRESSURE BEING MONITORED OFF THE FLORIDA EAST COAST WAS SITUATED IN NORTHERLY FLOW ALOFT AT THE PERIPHERY OF THE ANTICYCLONE. AN SHARP MID TO UPPER LEVEL TROUGH WAS DIGGING SOUTHWARD OVER THE ATLC N OF 26N BETWEEN 65W AND 72W. THIS TROUGH SUPPORTED A SURFACE TROUGH EXTENDING FROM 31N61W TO 26N66W. SCATTERED SHOWERS AND ISOLATED TSTMS WERE NOTED E OF THE SURFACE TROUGH N OF 27N BETWEEN 55W AND 61W. ANOTHER UPPER TROUGH EXTENDED FROM A CYCLONIC CIRCULATION NEAR 30N45W THROUGH 22N65W TO THE NW CARIBBEAN. IN BETWEEN THE TWO LOW PRESSURE AREAS...A 1021 MB HIGH SLOWLY DRIFTING S IS NEAR 27N70W. ELSEWHERE OVER THE ATLANTIC...A BROAD SURFACE RIDGE ANCHORED BY A 1029 MB HIGH NEAR 33N41W EXTENDED A RIDGE TO 16N AND SUPPORTS GENERALLY FAIR WEATHER CONDITIONS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ COBB