000 AXNT20 KNHC 052346 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 05 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... THE PRESSURE GRADIENT ACROSS THE SW CARIBBEAN SEA IS CURRENTLY SUPPORTING FRESH TO STRONG BREEZE CONDITIONS THAT ARE FORECAST TO INCREASE INTO THE NEAR GALE TO GALE FORCE RANGE THIS EVENING AND CONTINUE THROUGH THE OVERNIGHT HOURS INTO EARLY THURSDAY. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 10N30W TO 18N32W MOVING W AT 15-20 KT. THE WAVE COINCIDES WITH A BROAD 700 MB TROUGH BETWEEN 28W- 40W THAT LIES ON THE WESTERN PERIPHERY OF A LOW-LEVEL MONSOONAL GYRE FOCUSED ON A 1010 MB LOW CENTERED ALONG THE MONSOON TROUGH AXIS NEAR 12N20W. THE WAVE IS EXPECTED TO CONTINUE WESTWARD AND GRADUALLY LOSE AMPLITUDE THROUGH LATE FRIDAY AS IT ENTERS THE CENTRAL TROPICAL ATLC. NO SIGNIFICANT CONVECTION IS OCCURRING WITH THE WAVE AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 18N16W INTO A 1010 MB LOW NEAR 12N20W TO 09N24W TO 10N30W TO 10N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 10N40W TO 10N46W INTO A 1013 MB LOW NEAR 12N50W TO 10N53W TO 10N61W. ISOLATED MODERATE CONVECTION IS FROM 12N-15N BETWEEN 18W- 22W...FROM 06N-10N BETWEEN 23W-35W...AND FROM 09N-12N BETWEEN 51W-57W. ...DISCUSSION... GULF OF MEXICO... NORTHEASTERLY FLOW ALOFT INFLUENCES MUCH OF THE GULF BASIN THIS EVENING WITH WATER VAPOR IMAGERY INDICATING MOST OF THE MOISTURE LYING N OF 28N. SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF 28N BETWEEN 81W-93W ON MAXIMUM LOW-LEVEL MOISTURE CONVERGENCE ALONG THE GULF COASTLINE. OTHERWISE...A SURFACE RIDGE AXIS EXTENDS ALONG 26N FROM THE SOUTHERN FLORIDA PENINSULA TO NEAR BROWNSVILLE TEXAS SUPPORTING GENTLE TO OCCASIONAL MODERATE BREEZE CONDITIONS. A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE SOUTHERN FLORIDA PENINSULA DUE TO SEABREEZE AND PEAK DAYTIME HEATING DYNAMICS...AND ALSO ACROSS THE YUCATAN PENINSULA AND ADJACENT COASTAL WATERS S OF 23N BETWEEN 86W-91W. THE SURFACE RIDGE IS EXPECTED TO REMAIN QUASI-STATIONARY THROUGH SUNDAY MAINTAINING THE GENTLE TO OCCASIONALLY MODERATE ANTICYCLONIC BREEZE CONDITIONS. CARIBBEAN SEA... MUCH OF THE CARIBBEAN IS UNDER THE INFLUENCE OF AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 17N70W. WATER VAPOR IMAGERY INDICATES DRY AIR ALOFT AND STRONG SUBSIDENCE GENERALLY E OF 78W PROVIDING FOR CLEAR SKIES AND FAIR CONDITIONS THIS EVENING ACROSS MUCH OF THE CENTRAL AND EASTERN CARIBBEAN. MOISTURE INCREASES W OF 78W WITHIN SOUTHERLY FLOW ALOFT BETWEEN THE RIDGING AND A LARGE AND BROAD ELONGATED UPPER LEVEL LOW CENTERED OVER WESTERN EL SALVADOR NEAR 14N90W. GIVEN THE FAVORABLE MIDDLE TO UPPER LEVEL LIFTING DYNAMICS IN PLACE AND AMPLE LOW-LEVEL MOISTURE CONVERGENCE ACROSS THE WESTERN CARIBBEAN AND CENTRAL AMERICA...SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS ARE OCCURRING ACROSS INLAND PORTIONS OF CENTRAL AMERICA AND THE YUCATAN PENINSULA THIS EVENING. THE PRIMARY MARINE IMPACT REMAINS FRESH TO STRONG TRADES BETWEEN 68W-80W WITH THE NEAR GALE TO GALE FORCE CONDITIONS EXPECTED TO MATERIALIZE IN CLOSE PROXIMITY OF THE COLOMBIA COAST LATER THIS EVENING. THE TRADES ARE THEN EXPECTED TO DIMINISH BY FRIDAY EVENING AS THE PRESSURE GRADIENT TO THE NORTH RELAXES. ...HISPANIOLA... A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE ISLAND THIS EVENING...BUT THIS ACTIVITY IS LIKELY TO DIMINISH THROUGH THE EVENING HOURS DUE TO A LACK OF DAYTIME HEATING. SKY CONDITIONS SHOULD REMAIN MOSTLY CLEAR DURING THE OVERNIGHT HOURS INTO THURSDAY AS AN UPPER LEVEL ANTICYCLONE IS CENTERED NEARLY OVER THE ISLAND NEAR 17N70W PROVIDING DRY AIR ALOFT AND STRONG SUBSIDENCE. ATLANTIC OCEAN... THE SW NORTH ATLC IS GENERALLY INFLUENCED BY A SURFACE RIDGE WITH AXIS EXTENDING FROM SOUTH OF BERMUDA NEAR 30N66W W-SW TO THE BAHAMAS AND FLORIDA STRAITS NEAR 24N80W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING ON THE NORTHERN FRINGE OF THE RIDGING AS WEAK SURFACE TROUGHING EXTENDS FROM 37N69W TO 32N75W. THE CONVECTIVE ACTIVITY IS N OF 30N BETWEEN 66W-73W. FARTHER EAST... A CUT-OFF UPPER LEVEL LOW IS CENTERED NEAR 27N58W THAT SUPPORTS A SURFACE TROUGH EXTENDING FROM 20N55W TO 27N53W. ISOLATED SHOWERS AND POSSIBLE ISOLATED TSTMS ARE OCCURRING FROM 20N-31N BETWEEN 48W-59W. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH NORTH OF THE DISCUSSION AREA CENTERED NEAR 36N48W. A REMNANT FRONTAL BOUNDARY IS NOTED ON THE SOUTHEASTERN PERIPHERY OF THIS RIDGE AS A SURFACE TROUGH ANALYZED FROM 32N27W TO 30N35W. POSSIBLE ISOLATED SHOWERS ARE OCCURRING N OF 27N BETWEEN 27W-35W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN