000 AXNT20 KNHC 192349 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 19 2015 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. ...SPECIAL FEATURES... TROPICAL STORM DANNY CENTERED NEAR 11.5N 42.0W AT 19/2100 UTC OR 1151 NM E OF THE LESSER ANTILLES MOVING W AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS MAINLY CONFINED TO THE NW HALF OF THE STORM WITHIN 120 NM IN THE NW SEMICIRCLE. THE OFFICIAL FORECAST IS FOR DANNY TO STRENGTHEN TO A HURRICANE BY 48 HOURS AS IT MOVES TO THE W-NW AT A SLIGHTLY SLOWER FORWARD SPEED. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING ACROSS THE CAPE VERDE ISLANDS WITH AXIS EXTENDING FROM 21N22W TO 10N24W MOVING W AT 5-10 KT. ONLY ISOLATED SHOWERS ARE EVIDENT NEAR THE WAVE AXIS WITH THE METEOSAT EXPERIMENTAL ENHANCED SATELLITE IMAGERY INDICATING SAHARAN DRY AIR AND DUST SURROUNDING THE FEATURE. EVEN SO...TOTAL PRECIPITABLE WATER SATELLITE IMAGERY INDICATES A LARGE PLUME OF MOISTURE ASSOCIATED WITH THIS WAVE. 700 MB STREAMLINE ANALYSIS CLEARLY SHOWS THE WAVE AXIS WHILE 850 MB RELATIVE VORTICITY INDICATES A MAXIMUM ALONG THE WAVE AXIS. A TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES EXTENDING FROM NEAR 18N58W TO ACROSS TRINIDAD INTO NE VENEZUELA NEAR 07N62W MOVING W AT 10-15 KT. ISOLATED SHOWERS ARE POSSIBLE ALONG THE NORTHERN HALF OF THE AXIS WHILE SCATTERED MODERATE CONVECTION IS ASSOCIATED WITH THE PORTION S OF 12N. TPW SATELLITE IMAGERY SHOWS A 180-240 NM WIDE POCKET OF MOISTURE ALONG THE WAVE AXIS. 700 MB STREAMLINE ANALYSIS INDICATES CURVATURE ALOFT ALONG THE WAVE AXIS WHILE 850 MB VORTICITY SHOWS A MAXIMUM ACROSS NE VENEZUELA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS WESTERN AFRICA INTO THE TROPICAL E ATLANTIC NEAR 13N17W TO 14N20W WHERE IT IS DISRUPTED BY A TROPICAL WAVE THEN RESUMES FROM 13N25W TO 12N34W. THE ITCZ AXIS EXTENDS FROM 10N46W TO 09N60W. SCATTERED MODERATE CONVECTION IS WITHIN 90-180 NM S OF THE AXIS BETWEEN 28W-33W... FROM 10N-13N BETWEEN 35W-39W...FROM 07N-10N BETWEEN 44W-50W... FROM 11N-13N BETWEEN 45W-48W...AND FROM 10N-12N BETWEEN 50W-54W. ...DISCUSSION... GULF OF MEXICO... AN ELONGATED UPPER-LEVEL RIDGE IS OVER THE GULF EXTENDING FROM THE FLORIDA PANHANDLE NEAR 31N85W TO THE SW THROUGH 26N90W TO SE MEXICO OVER THE CHIVELA PASS. CONVECTION HAS DEVELOPED ACROSS THE FLORIDA PENINSULA WITH LATE MORNING AND AFTERNOON SEABREEZE DEVELOPMENT AND RESULTANT BOUNDARY INTERACTIONS WHILE THIS AREA IS ALSO UNDER UPPER LEVEL DIFFLUENCE. ADDITIONAL CONVECTION HAS DEVELOPED ACROSS THE REMAINDER OF THE U.S. GULF COAST STATES AROUND THE UPPER RIDGE AND AHEAD OF A COLD FRONT WHICH IS MARCHING TOWARD THE MISSISSIPPI VALLEY REGION. LIGHT TO MODERATE ANTICYCLONIC FLOW WILL PREVAIL AT THE SURFACE ACROSS THE NE HALF OF THE GULF THROUGH THE NEXT 48 HOURS...WITH MODERATE TO STRONG RETURN SE FLOW ACROSS THE SW HALF OF THE GULF...INCREASING TO FRESH TO STRONG EACH EVENING AND DURING THE OVERNIGHT HOURS AS SURFACE TROUGHING FORMS OVER THE YUCATAN PENINSULA BEFORE PUSHING TO THE W INTO THE SW GULF OF MEXICO. SEAS WILL BE 1-3 FT ACROSS THE NE HALF...AND 4-6 FT ACROSS THE SW HALF. CARIBBEAN SEA... A LARGE UPPER LEVEL CYCLONE LOCATED NEAR 17N82W DOMINATES THE BASIN W OF 73W. ISOLATED SHOWERS AND TSTMS CONTINUE TO ROTATE AROUND THE PERIPHERY OF THE LOW. AN UPPER LEVEL ANTICYCLONE IS LOCATED OVER THE COAST OF NORTHERN VENEZUELA NEAR 10N66W WITH A RIDGE AXIS EXTENDING OFF TO THE NW-N TO ACROSS CENTRAL HISPANIOLA. VERY DRY AIR...STABLE CONDITIONS AND SUBSIDENCE ARE EVIDENT E OF 73W OUTSIDE OF THE INFLUENCE OF THE APPROACHING TROPICAL WAVE. MAINLY MODERATE TO LOCALLY FRESH TRADES WILL PREVAIL ACROSS THE BASIN THROUGH THE NEXT 48 HOURS...EXCEPT NEAR THE COAST OF COLOMBIA AND IN THE GULF OF VENEZUELA WHERE STRONG TO NEAR GALE FORCE WINDS WILL PERSIST...AND IN THE GULF OF HONDURAS WHERE WINDS WILL PULSE TO FRESH TO STRONG DURING THE OVERNIGHT HOURS. SEAS WILL BE MAINLY 3-6 FT...EXCEPT UP TO 13 FT NEAR THE COAST OF COLOMBIA AND UP TO 7 FT IN THE GULF OF HONDURAS. ...HISPANIOLA... MAINLY FAIR WEATHER PREVAILS ACROSS THE ISLAND...EXCEPT FOR A FEW WIDELY ISOLATED SHOWERS AND TSTMS WHICH HAVE DEVELOPED WITH THE ASSISTANCE OF DAYTIME HEATING AND OROGRAPHIC LIFTING. SIMILAR CONDITIONS ARE ANTICIPATED FOR THU HOWEVER PRECIPITATION CHANCES ARE FORECAST TO INCREASE THU NIGHT THROUGH FRI AS A TROPICAL WAVE APPROACHES FROM THE E. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE IS ACROSS THE SE PART OF THE SW N ATLC OFFSHORE WATERS EXTENDING FROM THE NORTHERN BAHAMAS TO THE SE-E NEAR 24N65W...WHILE BROAD MID TO UPPER LEVEL TROUGHING IS MOVING ACROSS THE NORTHERN PORTION. SCATTERED SHOWERS AND TSTMS ASSOCIATED WITH THE TROUGHING ARE PASSING THROUGH THE WATERS N OF 27N...WHILE THE AREA S OF 27N REMAINS MAINLY CLEAR. 1020 MB SURFACE HIGH PRES IS LOCATED NEAR 27N67W WITH A RIDGE AXIS EXTENDING WESTWARD ALONG 27N. LIGHT TO MODERATE ANTICYCLONIC WINDS PREVAIL AT THE SURFACE...EXCEPT AROUND THE SW PERIPHERY OF THE RIDGE WHERE SCATTEROMETER DATA INDICATED MODERATE TO LOCALLY FRESH WINDS. LITTLE CHANGE IN THESE CONDITIONS IS EXPECTED DURING THE NEXT 48 HOURS WITH MAINLY 2-4 FT SEAS...EXCEPT 4-6 FT S OF 22N. AN EXCEPTION WILL BE THE INTRODUCTION OF A SURFACE LOW WHICH WILL DROP IN FROM E OF THE CAROLINAS INTO THE NE PORTION OF THE SW N ATLC BY EARLY THU DRAGGING A TRAILING SURFACE TROUGH ACROSS THE AREA. WINDS MAY INCREASE TO 20-25 KT AHEAD OF THE TROUGH BY THU AFTERNOON TROUGH FRI. ANOTHER HIGH AT 1022 MB IS LOCATED NEAR 28N50W WITH MAINLY LIGHT TO MODERATE WINDS N OF 20N ACROSS THE REMAINDER OF THE BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LEWITSKY