000 AXNT20 KNHC 290000 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI AUG 28 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 2345 UTC. ...SPECIAL FEATURES... TROPICAL STORM ERIKA IS CENTERED NEAR 17.9N 71.2W AT 28/2100 UTC OR ABOUT 84 NM WSW OF SANTO DOMINGO DOMINICAN REPUBLIC AND ABOUT 224 NM SSE OF GREAT INAGUA ISLAND MOVING W AT 18 KT. ESTIMATED CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. TWO CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION ARE ASSOCIATED WITH ERIKA...ONE FROM 17N TO 20N BETWEEN 69W AND 72W...THE SECOND FROM 15N TO 18N BETWEEN 68W AND 71W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 14N TO 20N BETWEEN 66W AND 72W. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC ASSOCIATED WITH A 1012 MB LOW EMBEDDED IN THE MONSOON TROUGH NEAR 12N38W. THE WAVE AXIS AT 700 MB FORMERLY E OF THE LOW MERGED WITH IT LAST NIGHT...RESULTING IN A WESTWARD TRANSLATION MOVEMENT OF 20-25 KT WITHIN THE LAST 24 HOURS. MODERATE MOISTURE IS ASSOCIATED WITH THIS WAVE FROM THE SURFACE TO 700 MB AS INDICATED BY CIRA LAYER PRECIPITABLE WATER IMAGERY. UPPER LEVEL DIFFLUENCE W OF THE LOW SUPPORT SCATTERED MODERATE CONVECTION FROM 08N TO 14N BETWEEN 43W AND 47W. ISOLATED SHOWERS ARE ELSEWHERE FROM 07N TO 17N BETWEEN 32W AND 48W. A TROPICAL WAVE IS WITHIN 440 NM E OF THE LESSER ANTILLES WITH AXIS NEAR 53W...MOVING W AT 15 KT DURING THE PAST 24 HOURS. MODERATE MOISTURE FROM THE SURFACE TO NEARLY 700 MB IS ASSOCIATED WITH THIS WAVE AS INDICATED BY CIRA LAYER PRECIPITABLE WATER IMAGERY. A SLIGHT MIDDLE LEVEL DIFFLUENT ENVIRONMENT AHEAD OF THE WAVE AXIS SUPPORT ISOLATED SHOWERS AND TSTMS FROM 11N TO 15N BETWEEN 54W AND 58W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO 12N30W TO 11N41W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 11N41W TO 10N51W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 05N-11N E OF 30W. ...DISCUSSION... GULF OF MEXICO... A BROAD AND ELONGATED MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE NORTH-CENTRAL GULF NEAR 29N89W THAT STRETCHES TROUGHING ALOFT FROM OVER THE SE CONUS SW TO A BROAD BASE OVER THE S-SW GULF. WHILE NORTHERLY FLOW EMBEDDED IN DRY AIR ALOFT... AND STABLE CONDITIONS ARE NOTED OVER THE W GULF WATERS N OF 21N W OF 88W...THE TROUGHING SUPPORTS A DISSIPATING STATIONARY FRONT MEANDERING FROM THE FLORIDA PANHANDLE NEAR 30N84W SW TO 25N86W TO 23N95W. LOW-LEVEL MOISTURE CONVERGENCE ALONG AND SOUTH OF THE WEAK FRONT...ALONG WITH MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF THE TROUGH AXIS IS GENERATING SCATTERED SHOWERS AND TSTMS E OF A LINE FROM 30N87W SW TO 25N90W TO 18N95W. THE FRONT IS EXPECTED TO DISSIPATE FULLY BY SATURDAY WITH GENERALLY GENTLE TO MODERATE E-SE BREEZE CONDITIONS PREVAILING. CERTAINLY WITH THE APPROACH OF TROPICAL STORM ERIKA BY SUNDAY... INTERESTS LOCATED IN THE EASTERN GULF WATERS AND FLORIDA STRAITS...KEYS...AND PENINSULA SHOULD MONITOR THE PROGRESS OF ERIKA. CARIBBEAN SEA... TROPICAL STORM ERIKA IS THE MAIN FEATURE OF INTEREST IN THE CARIBBEAN AS ITS CURRENT TRACK TAKES THE CYCLONE ACROSS HISPANIOLA TONIGHT AND OVER CUBA SATURDAY TO SUNDAY. THE MAIN IMPACT OUTSIDE OF TROPICAL STORM FORCE WINDS WILL BE HEAVY RAINFALL ACROSS HISPANIOLA AND THE ADJACENT COASTAL WATERS RESULTING IN FLASH FLOODING AND DANGEROUS MUD SLIDES. OTHERWISE...THE REMAINDER OF THE BASIN REMAIN RELATIVELY QUIET WITH MOSTLY DRY AIR NOTED ON WATER VAPOR IMAGERY ALOFT DUE TO AN UPPER LEVEL RIDGE ANCHORED NEAR 12N83W COVERING THE CENTRAL AND WESTERN BASIN. OTHERWISE...SCATTERED SHOWERS AND TSTMS ARE ALONG THE SOUTHERN COAST OF CUBA AND ADJACENT WATERS. ISOLATED SHOWERS ARE ACROSS PUERTO RICO AND COASTAL WATERS. ACROSS PORTIONS OF THE CENTRAL CARIBBEAN AND THE WESTERN CARIBBEAN...MODERATE TO OCCASIONAL FRESH E-NE TRADES PREVAIL AND WITH THE PASSAGE OF ERIKA TO THE NORTH THROUGH THE WEEKEND...AS SURFACE RIDGING FOLLOWS IN ERIKA'S WAKE...TRADES ARE FORECAST TO INCREASE ACROSS THE CENTRAL CARIBBEAN INTO THE FRESH TO STRONG BREEZE RANGE AND PERSIST THROUGH SUNDAY...THEN DECREASE SLIGHTLY INTO MONDAY. ...HISPANIOLA... THE CENTER OF TROPICAL STORM ERIKA IS EXPECTED TO MOVE OVER HISPANIOLA TONIGHT. THE MAIN IMPACT FROM ERIKA ASIDE FROM TROPICAL STORM FORCE WINDS IS HEAVY RAINFALL WITH THE POTENTIAL OF LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. THE CENTER OF THE STORM IS FORECAST TO MOVE TO THE WINDWARD PASSAGE SATURDAY MORNING BUT SHOWERS ARE EXPECTED TO CONTINUE THROUGH SUNDAY MORNING. ATLANTIC OCEAN... MIDDLE TO UPPER-LEVEL DIFFLUENCE ACROSS THE SW NORTH ATLC IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 24N W OF 76W...INCLUDING THE NW BAHAMAS. TO THE E...ISOLATED SHOWERS AND TSTMS ARE FROM 25N TO 27N BETWEEN 70W AND 75W. SCATTERED HEAVY SHOWERS ARE OVER HISPANIOLA NORTHERN WATERS ASSOCIATED WITH TROPICAL STORM ERIKA THAT IS EXPECTED TO MOVE ACROSS THE ISLAND TONIGHT. THE REMAINDER OF THE BASIN IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A PAIR OF 1021 MB HIGHS CENTERED NEAR 28N64W AND NEAR 26N32W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR