000 AXNT20 KNHC 241755 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI JUL 24 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 07N39W TO 14N38W MOVING W AT 20 KT. THE WAVE COINCIDES WITH WEAK 700 MB TROUGHING BETWEEN 34W-43W WITH A WEAK MAXIMUM OF 850 MB RELATIVE VORTICITY ALONG THE WAVE AXIS NEAR 11N. NO SIGNIFICANT CONVECTION IS OCCURRING IN ASSOCIATION WITH THE WAVE AT THIS TIME DUE TO A STRONG SAHARAN AIR LAYER PROVIDING OVERALL STABLE CONDITIONS OVER THE TROPICAL EASTERN ATLC. TROPICAL WAVE EXTENDS FROM 05N56W TO 14N51W MOVING W AT 15-20 KT. THE WAVE HAS CONTINUED TO GRADUALLY AMPLIFY AND EXAMINING PAST GLOBAL MODEL ANALYSES...GAINED STRETCHED OUT FASTER MOVING LOW-LEVEL ENERGY THAT APPEARS TO HAVE FRACTURED AWAY FROM THE WAVE TO THE EAST. THE WAVE IS FORECAST TO BRING INCREASED PRECIPITATION PROBABILITY TO THE WINDWARD ISLANDS AND NE VENEZUELA THIS WEEKEND. ISOLATED MODERATE CONVECTION IS FROM 07N- 11N BETWEEN 53W-60W. TROPICAL WAVE EXTENDS FROM 09N80W TO 17N81W MOVING W AT 15-20 KT. THE WAVE REMAINS EMBEDDED WITHIN A MAXIMUM OF TOTAL PRECIPITABLE WATER ACROSS THE WESTERN CARIBBEAN SEAS BETWEEN 76W- 84W. ISOLATED MODERATE CONVECTION IS FROM 09N-12N BETWEEN 81W- 85W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 10N20W TO 09N30W TO 07N39W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N39W TO 07N46W TO 10N53W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 07N- 12N BETWEEN 17W-28W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER LEVEL LOW CENTERED NEAR 23N95W INFLUENCES THE WESTERN GULF WHILE AN UPPER LEVEL RIDGE AXIS EXTENDING FROM OVER THE LOWER MISSISSIPPI RIVER VALLEY NEAR 31N92W TO OVER THE SW FLORIDA PENINSULA NEAR 26N82W INFLUENCES THE EASTERN GULF. WATER VAPOR IMAGERY INDICATES MOST OF THE MOISTURE OVER THE BASIN IS ASSOCIATED WITH THE RIDGE AS IT PROVIDES AN UPPER LEVEL DIFFLUENT ENVIRONMENT FOR ONGOING ACTIVE CONVECTION. AT THE SURFACE BENEATH THE UPPER LEVEL RIDGE...WEAK FRONTAL TROUGHING FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM NEAR JACKSONVILLE FLORIDA SW TO 28N85W CONTINUES TO PROVIDE FOCUS FOR SCATTERED SHOWERS AND TSTMS OCCURRING GENERALLY EAST OF A LINE FROM 30N89W TO 25N83W. OTHERWISE...A SURFACE RIDGE ANCHORED BY A 1019 MB HIGH CENTERED IN THE SE GULF NEAR 24N84W CONTINUES TO PROMOTE FAIR SKIES AND CONDITIONS ACROSS MUCH OF THE WESTERN GULF AND PORTIONS OF THE SE GULF IN THE VICINITY OF AND NORTH OF THE YUCATAN CHANNEL REGION. THE SURFACE RIDGING IS EXPECTED TO REMAIN ANCHORED ACROSS THE CENTRAL GULF THIS WEEKEND WITH GENTLE TO MODERATE ANTICYCLONIC BREEZE CONDITIONS THROUGH SUNDAY. CARIBBEAN SEA... A VERY BROAD CUTOFF UPPER LEVEL LOW IS CENTERED OVER THE APPROACHES TO THE WINDWARD PASSAGE NEAR 19N75W THAT INFLUENCES THE WESTERN CARIBBEAN W OF 77W WITH RELATIVELY DRY AIR ALOFT AND OVERALL STABLE CONDITIONS THIS AFTERNOON. MOST MOISTURE W OF 77W IS NOTED S OF 13N WITHIN AN AREA OF MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE ALONG WITH A TROPICAL WAVE ALONG 81W MOVING ACROSS THE SW CARIBBEAN. SCATTERED SHOWERS AND TSTMS ARE OCCURRING S OF 13N BETWEEN 81W-85W...INCLUDING PORTIONS OF WESTERN PANAMA...COSTA RICA...AND NICARAGUA. OTHERWISE...E OF 77W...MIDDLE TO UPPER LEVEL MOISTURE INCREASES DUE TO SOUTHWESTERLY FLOW ALOFT...HOWEVER LOW-LEVEL MOISTURE REMAINS SCARCE DUE TO THE SAHARAN AIR LAYER PROVIDING STABLE CONDITIONS IN THE LOWER LEVELS OF THE ATMOSPHERE OVER THE EASTERN CARIBBEAN WITH MOSTLY CLEAR SKIES PREVAILING. LASTLY...MODERATE TO FRESH TRADES PREVAIL OUTSIDE OF THE SOUTH-CENTRAL CARIBBEAN AND COLOMBIA COAST REGION WHERE SLIGHTLY STRONGER E-NE WINDS ARE OCCURRING IN THE FRESH TO STRONG BREEZE RANGE. ...HISPANIOLA... CURRENTLY...SKIES REMAIN MOSTLY CLEAR WITH A LACK OF ANY SIGNIFICANT CONVECTION AT THIS TIME OCCURRING IN THE REGION DUE THE SAHARAN AIR LAYER PROVIDING AN OVERALL STABLE ENVIRONMENT. DRY CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE EVENING AND OVERNIGHT HOURS INTO SATURDAY. ATLANTIC OCEAN... A LONGWAVE MIDDLE TO UPPER LEVEL TROUGH IS EVIDENT ON WATER VAPOR IMAGERY OVER THE WESTERN NORTH ATLC THAT SUPPORTS A STATIONARY FRONT EXTENDING FROM 34N60W INTO A 1011 MB LOW CENTERED NEAR 34N76W THEN TO THE SOUTH CAROLINA COAST NEAR 33N80W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING IN THE VICINITY OF THE FRONT WITHIN 120 NM EITHER SIDE. A PRE- FRONTAL SURFACE TROUGH EXTENDS FROM 31N77W TO 27N79W AND IS PROVIDING FOCUS OF MAXIMUM LOW-LEVEL MOISTURE CONVERGENCE IN WHICH SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF 27N W OF 72W. FARTHER EAST...A SURFACE RIDGE AXIS EXTENDING FROM 26N56W TO 24N76W INFLUENCES THE REMAINDER OF THE SW NORTH ATLC WITH ONLY A FEW ISOLATED SHOWERS OCCURRING FROM 26N-30N BETWEEN 55W- 62W. IN BETWEEN THIS RIDGE AND ANOTHER RIDGE TO THE EAST...A SURFACE TROUGH EXTENDS FROM 24N51W TO 31N48W. THE SURFACE TROUGH COINCIDES WITH AN UPPER LEVEL LOW CENTERED NEAR 26N51W THAT CONTINUES TO GENERATE ISOLATED SHOWERS WITHIN 120 NM EITHER SIDE OF THE BOUNDARY. LASTLY...THE EASTERN ATLC IS INFLUENCED BY A SURFACE RIDGE ANCHORED ON A 1028 MB HIGH CENTERED NEAR 33N32W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN