000 AXNT20 KNHC 221149 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT AUG 22 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... HURRICANE DANNY IS CENTERED NEAR 15.2N 50.8W AT 22/0900 UTC OR ABOUT 640 NM E OF THE LEEWARD ISLANDS MOVING WNW AT 9 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 982 MB. MAXIMUM SUSTAINED WIND SPEED IS 85 KT WITH GUSTS TO 105 KT. SCATTERED MODERATE CONVECTION IS OCCURRING FROM 14N-18N BETWEEN 48W-51W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N24W TO 18N26W MOVING W AT 10-15 KT. THE WAVE COINCIDES WITH A RELATIVELY BROAD LOW-LEVEL MONSOONAL GYRE FOCUSED ON A 1009 MB LOW CENTERED ALONG THE MONSOON TROUGH AND WAVE AXIS NEAR 12N25W. THE GYRE AND ASSOCIATED WAVE ENERGY IS EXPECTED TO DRIFT WESTWARD THROUGH SUNDAY. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 13N-17N BETWEEN 22W-27W...WITH WIDELY SCATTERED MODERATE CONVECTION ELSEWHERE FROM 05N-13N BETWEEN 18W-30W. TROPICAL WAVE EXTENDS FROM 10N33W TO 20N40W MOVING W AT 10-15 KT. THIS WAVE IS EMBEDDED WITHIN SAHARAN DUST AND DRY AIR RESULTING IN MOSTLY STABLE CONDITIONS. THE OVERALL STABILITY SURROUNDING THE WAVE AXIS IS INHIBITING ANY SIGNIFICANT DEEP CONVECTION AT THIS TIME. TROPICAL WAVE EXTENDS FROM 09N80W TO 18N81W MOVING W AT 15-20 KT. THE WAVE IS ENCOUNTERING DRY AND STABLE AIR ALOFT OVER THE NORTHERN PORTION OF THE AXIS WITH SCATTERED MODERATE CONVECTION OCCURRING S OF 12N BETWEEN 79W-86W ACROSS THE SOUTHERN EXTENT OF THE WAVE AXIS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 17N16W INTO A 1009 MB LOW CENTERED NEAR 12N25W TO 08N30W TO 06N41W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 25W...ISOLATED MODERATE CONVECTION IS FROM 05N-11N BETWEEN 07W-16W...AND FROM 05N-08N BETWEEN 39W-42W. ...DISCUSSION... GULF OF MEXICO... GENERALLY EAST-SOUTHEASTERLY FLOW ALOFT INFLUENCES MUCH OF THE GULF BASIN BETWEEN AN UPPER LEVEL RIDGE ANCHORED OVER NORTHERN FLORIDA AND THE SW NORTH ATLC NEAR 29N79W AND AN UPPER LEVEL LOW CENTERED OVER THE SW GULF NEAR 20N92W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING AROUND THE PERIPHERY OF BOTH UPPER LEVEL FEATURES WITH NO SIGNIFICANTLY ORGANIZED CONVECTION. LIGHT AND VARIABLE ANTICYCLONIC WINDS AND 1-3 FT SEAS WILL PERSIST ACROSS THE NE HALF OF THE GULF...WITH MODERATE TO LOCALLY FRESH SE RETURN FLOW AND 3-6 FT SEAS ACROSS THE SW HALF OF THE GULF. THE STRONGEST WINDS ARE EXPECTED NW OF THE YUCATAN PENINSULA DURING THE EVENING AND OVERNIGHT HOURS AS DIURNAL TROUGHING DEVELOPS ACROSS THE PENINSULA EACH AFTERNOON. THE TROUGHING WILL THEN MOVE TO THE WESTERN OFFSHORE WATERS AND INTO THE SW GULF WHERE IT WILL DISSIPATE BY SUNRISE EACH DAY. THESE CONDITIONS ARE FORECAST TO PERSIST THROUGH THE NEXT 48 HOURS. CARIBBEAN SEA... AN UPPER LEVEL CYCLONE IS CENTERED OVER THE SW GULF OF MEXICO NEAR 20N92W WHILE AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE SW CARIBBEAN NEAR 13N81W. W OF 74W...ONLY ISOLATED SHOWERS AND TSTMS ARE OCCURRING AROUND THE PERIPHERY OF BOTH OF THESE FEATURES WITH THE MOST ACTIVE AREA...SCATTERED SHOWERS AND TSTMS...NOTED S OF 13N W OF 78W IN ASSOCIATION WITH A TROPICAL WAVE ALONG 81W. THE CONVECTION INCLUDES INLAND PORTIONS OF COSTA RICA AND SOUTHERN NICARAGUA. E OF 74W...AN UPPER LEVEL TROUGH AXIS EXTENDS FROM 19N59W TO 16N71W AND REMAINS EMBEDDED WITHIN VERY DRY AND STABLE AIR ALOFT. MAINLY MODERATE TO LOCALLY FRESH TRADES AND 3-6 FT SEAS WILL PREVAIL ACROSS THE BASIN THROUGH THE WEEKEND...EXCEPT IN THE S CENTRAL CARIBBEAN WHERE THE PRESSURE GRADIENT WILL BE STRONG ENOUGH TO SUPPORT OCCASIONAL WINDS TO 20- 25 KT WHICH WILL BUILD SEAS TO 7-9 FT. ...HISPANIOLA... CURRENTLY...SKIES HAVE CLEARED SOMEWHAT FROM LINGERING EARLIER EVENING AND OVERNIGHT ISOLATED SHOWERS AND TSTMS. MOSTLY CLEAR SKIES LIE TO THE EAST...HOWEVER SIMILAR DEVELOPMENT OF LATE AFTERNOON AND EARLY EVENING ISOLATED SHOWERS AND TSTMS IS POSSIBLE THROUGH THE WEEKEND WITH LITTLE CHANGE IN OVERALL SYNOPTIC CONDITIONS ANTICIPATED. ATLANTIC OCEAN... AN UPPER LEVEL ANTICYCLONE IS CENTERED EAST OF NORTHERN FLORIDA NEAR 29N79W. AN UPPER LEVEL CYCLONE IS JUST N OF THE DISCUSSION AREA NEAR 32N66W WITH A TRAILING UPPER LEVEL TROUGH EXTENDING S TO 25N66W. THE UPPER LEVEL CYCLONE AND TROUGH ARE SUPPORTING A 1011 MB LOW NEAR 27N66W WITH A SURFACE TROUGH EXTENDING FROM 32N64W INTO THE LOW THEN TO 25N70W TO 27N74W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF 28N BETWEEN 56W-63W TO THE EAST OF THE BOUNDARY AND FROM 23N-27N BETWEEN 61W-69W SE OF THE BOUNDARY. LIGHT AND VARIABLE WINDS WILL PERSIST ACROSS THE ENTIRE SW NORTH ATLC OFFSHORE WATERS BASIN THROUGH THE NEXT 48 HOURS. SEAS OF 3 FT OR LESS ARE EXPECTED W OF 70W...WITH 3-5 FT SEAS E OF 70W. ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 32N49W THAT SUPPORTS A SURFACE TROUGH FROM 32N46W TO 30N46W TO 27N49W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 29N-34N BETWEEN 43W-47W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN