000 AXNT20 KNHC 042343 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE AUG 04 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 2330 UTC. ...SPECIAL FEATURES... A STRONG PRESSURE GRADIENT WILL DEVELOP ONCE AGAIN THIS EVENING BETWEEN THE SURFACE RIDGING ANCHORED ACROSS THE SW ATLANTIC AND LOWER PRESSURES ANALYZED ACROSS NORTHERN COLOMBIA AND EASTERN PANAMA. WITH THESE...GALE FORCE WINDS ARE EXPECTED TO DEVELOP BY 05/00 UTC FROM 11N-14N BETWEEN 72W-76W. SEE THE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE E ATLANTIC WITH AXIS EXTENDING FROM 17N24W TO 10N20W...MOVING W AT 15-20 KT. THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 13W-26W... FOCUSED ON A MID-LEVEL MONSOONAL GYRE CENTERED ON A 1010 MB LOW CENTERED NEAR 10N17W. THE WAVE IS EXPECTED TO CONTINUE PROPAGATING WESTWARD AND COME INTO PHASE WITH A MID-LATITUDE 700 MB TROUGH CURRENTLY NEAR 28W- 32W. SCATTERED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 15W- 29W. A LOW AMPLITUDE TROPICAL WAVE IS OVER THE CENTRAL ATLANTIC WITH AXIS EXTENDING FROM 18N39W TO 12N39W...MOVING W AT 10-15 KT. THE WAVE COINCIDES WITH A 700 MB TROUGHING BETWEEN 36W-42W. GLOBAL MODEL GUIDANCE ALSO INDICATED AN AREA OF MAXIMUM 850 MB RELATIVE VORTICITY ALONG THE WAVE AXIS NEAR 15N. NO SIGNIFICANT CONVECTION IS OCCURRING WITH THE WAVE AT THIS TIME AS AN AREA OF SAHARAN DUST SURROUNDS THIS WAVE INHIBITING ANY SIGNIFICANT ACTIVITY. A TROPICAL WAVE IS APPROACHING THE LESSER ANTILLES WITH AXIS EXTENDING FROM 17N51W TO 10N54W...MOVING W AT 15 KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 50W-60W. NO SIGNIFICANT CONVECTION IS OBSERVED AT THIS TIME AS SAHARAN DUST IS ALSO IN THE ENVIRONMENT OF THE WAVE. A TROPICAL WAVE IS OVER THE W CARIBBEAN AND ENTERING CENTRAL AMERICA WITH AXIS EXTENDING FROM 20N84W TO 10N84W...MOVING W AT 15 KT. THIS WAVE COINCIDES WITH WEAK AND SUBTLE 700 MB TROUGHING BETWEEN 80W-88W. THE SCATTERED MODERATE CONVECTION CURRENTLY SURROUNDING THIS WAVE IS MOSTLY RELATED TO AN UPPER-LEVEL LOW ANCHORED OVER NICARAGUA AND EXTENDING ACROSS THE W CARIBBEAN. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM A 1010 MB LOW NEAR 10N16W TO 13N35W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THAT POINT TO A 1012 MB LOW NEAR 11N45W TO 09N60W. ASIDE FROM CONVECTION OCCURRING ACROSS THE LOW ALONG 17W...ISOLATED MODERATE CONVECTION IS OBSERVED FROM 06N-13N BETWEEN 42W-52W. ...DISCUSSION... GULF OF MEXICO... AN UPPER-LEVEL HIGH ANCHORED OVER E TEXAS EXTENDS ACROSS WHOLE THE BASIN. AT THE SURFACE...THE ATLANTIC RIDGE EXTENDS W REACHING THE GULF WATERS AND ANCHORED BY A 1018 MB HIGH CENTERED NEAR 27N84W. A SURFACE TROUGH EXTENDS ACROSS THE COAST OF LOUISIANA SUPPORTING ISOLATED MODERATE CONVECTION N OF 29N BETWEEN 89W-91W.ANOTHER CLUSTER OF CONVECTION PREVAILS ACROSS PORTIONS OF NORTHERN FLORIDA AFFECTING THE NE GULF E OF 87W. AN UPPER LEVEL LOW IS CURRENTLY CENTERED OVER NICARAGUA AND EXTENDING ACROSS THE W CARIBBEAN AND FAR SOUTH GULF SUPPORTING ISOLATED CONVECTION S OF 24N AND E OF 91W. SCATTEROMETER DATA DEPICTS A LIGHT TO GENTLE ANTICYCLONIC FLOW PREVAILING ACROSS THE BASIN. EXPECT SIMILAR WEATHER CONDITION TO PREVAIL OVER THE NEXT 24 HOURS. CARIBBEAN SEA... AN ELONGATED UPPER-LEVEL LOW IS CENTERED OVER NICARAGUA AND EXTENDING ACROSS THE W CARIBBEAN IS SUPPORTING ISOLATED MODERATE CONVECTION ACROSS CUBA AND THE CARIBBEAN WATERS MAINLY W OF 77W. TO THE E...AN UPPER-LEVEL ANTICYCLONE CENTERED NEAR GUADELOUPE EXTENDS ACROSS THE E CARIBBEAN SUPPORTING SUBSIDENCE. WITH THIS...FAIR WEATHER PREVAILS ACROSS THIS AREA. SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE TRADES ACROSS THE BASIN EXCEPT MODERATE TO FRESH WINDS BETWEEN 68W-78W. DURING THE NEXT 24 HOURS ...THE PRIMARILY MARINE IMPACT WILL CONTINUE TO BE AN AREA OF FRESH TO STRONG TRADES WITH THE EMBEDDED AREA OF GALE FORCE WINDS N OF COLOMBIA. PLEASE REFER TOT HE SPECIAL FEATURES SECTION FOR MORE DETAILS. ...HISPANIOLA... DRY AIR AND STABLE CONDITIONS ALOFT CONTINUE TO SPREAD OVER THE ISLAND FROM THE EAST DUE TO AN UPPER-LEVEL ANTICYCLONIC CIRCULATION OVER GUADELOUPE AND EXTENDING ACROSS THE E CARIBBEAN. SIMILAR WEATHER PATTERN IS EXPECTED OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... A 1013 MB SURFACE LOW IS CENTERED NEAR 34N79W WITH A SURFACE TROUGH EXTENDING FROM THE LOW CENTER ACROSS THE W ATLANTIC AND INTO NE FLORIDA NEAR 30N81W. AN AREA OF UPPER-LEVEL DIFFLUENCE PREVAILS ACROSS THE W ATLANTIC BETWEEN 71W-80W SUPPORTING ISOLATED MODERATE CONVECTION MAINLY W OF 73W. A SURFACE TROUGH WAS ANALYZED ACROSS THE NORTHERN BAHAMAS FROM 25N79W TO 28N76W. ISOLATED CONVECTION IS OBSERVED ALONG THIS BOUNDARY BETWEEN 76W- 78W. TO THE E...A BROAD AREA OF HIGH PRESSURE EXTENDS ACROSS THE REMAINDER OF THE BASIN CENTERED NEAR 36N50W. FAIR WEATHER PREVAILS ACROSS THIS AREA. A PORTION OF THE ENERGY OF THE TROPICAL WAVE CURRENTLY ALONG 53W FRACTURED N AND WAS ANALYZED AS A SURFACE TROUGH WHICH EXTENDS FROM 19N49W TO 23N44W. NO CONVECTION IS CURRENTLY RELATED TO THIS FEATURE. EXPECT SIMILAR WEATHER CONDITIONS TO PREVAIL OVER THE NEXT 24 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA