000 AXNT20 KNHC 170541 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU JUL 17 2014 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N19W TO 16N18W MOVING W AT 10-15 KT. A FAIRLY IMPRESSIVE AMOUNT OF CONVECTION IS ASSOCIATED WITH THE WAVE ACROSS WEST AFRICA AT THIS TIME IN AN AREA OF MAXIMUM LOW-LEVEL MOISTURE CONVERGENCE TO THE EAST OF THE WAVE AXIS. SCATTERED MODERATE AND STRONG CONVECTION IS FROM 06N-17N BETWEEN 09W-17W. TROPICAL WAVE EXTENDS FROM 05N36W TO 12N34W MOVING W AT 15 KT. THE WAVE COINCIDES WITH WEAK 700 MB TROUGHING BETWEEN 33W- 39W...AND A BROAD AREA OF 850 MB RELATIVE VORTICITY FROM 07-11N BETWEEN 29W-41W. ISOLATED MODERATE CONVECTION IS FROM 05N-10N BETWEEN 34W-41W. TROPICAL WAVE EXTENDS FROM 07N49W TO 14N48W MOVING W AT 15 KT. THE WAVE APPEARS AS PART OF A GREATER 700 MB TROUGH BETWEEN 46W- 59W...OF WHICH THE WEAKER 700 MB TROUGH IS ALONG 49W. CONVECTION REMAINS VERY LIMITED WITH ONLY ISOLATED MODERATE CONVECTION FROM 09N-10N BETWEEN 46W-48W. TROPICAL WAVE EXTENDS FROM 10N56W TO 19N54W MOVING W AT 15 KT. SIMILAR TO THE PRIOR WAVE...THE WAVE IS A PART OF A LARGER 700 MB TROUGH ALOFT BETWEEN 46W-59W. IT IS LIKELY ENERGY FROM BOTH THESE WAVE WILL MERGE OVER THE NEXT SEVERAL DAYS. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME. TROPICAL WAVE EXTENDS FROM 15N86W TO 22N84W MOVING W AT 15 KT. THE WAVE CONTINUES TO MOVE ON THE SOUTHERN PERIPHERY OF A MID- LEVEL RIDGE CENTERED OVER THE YUCATAN CHANNEL REGION WITH MOST OF THE LOW-LEVEL ENERGY FOCUSED OVER CENTRAL AMERICA AND AREAS OF THE EAST PACIFIC SOUTH OF NICARAGUA. NO SIGNIFICANT DEEP CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 11N20W TO 10N27W TO 09N32W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N37W TO 07N41W TO 06N49W TO 08N55W. ASIDE FROM CONVECTION ASSOCIATED WITH THE PREVIOUSLY MENTIONED TROPICAL WAVES...ISOLATED MODERATE CONVECTION IS FROM 07N-12N BETWEEN 20W- 33W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 05N-08N BETWEEN 38W-42W...AND FROM 06N-09N BETWEEN 50W-56W. ...DISCUSSION... GULF OF MEXICO... A LONGWAVE MIDDLE TO UPPER LEVEL TROUGH COVERS MUCH OF THE EASTERN CONUS WITH A TROUGH AXIS DIPPING SOUTHWARD OVER PORTIONS OF THE NE GULF. AS OF 17/0300 UTC...THE TROUGHING SUPPORTS A COLD FRONT EXTENDING FROM THE FLORIDA PANHANDLE NEAR 31N84W W-SW TO THE MISSISSIPPI RIVER DELTA REGION NEAR 29N90W. FROM THERE THE FRONT BECOMES STATIONARY ACROSS COASTAL LOUISIANA TO THE TEXAS AND LOUISIANA BORDER. IN ADDITION...A PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM NEAR JACKSONVILLE FLORIDA SW TO 28N87W IN THE NE GULF WATERS. WHILE THERE IS RELATIVELY DRY CONDITIONS ALONG THE FRONT...A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING ALONG THE FLORIDA COAST AND INLAND PORTIONS OF THE PENINSULA FROM 28N-29N BETWEEN 81W-84W. OTHER ISOLATED SHOWERS ARE OCCURRING FROM 25N-27N EAST OF 85W. OTHERWISE...A SURFACE RIDGE AXIS EXTENDS FROM ACROSS CUBA ALONG 22N INTO THE CENTRAL GULF THEN SW TO A 1016 MB HIGH ANCHORED ALONG THE MEXICO COAST NEAR 20N97W. MOSTLY CLEAR SKIES PREVAIL IN ASSOCIATION WITH THE SURFACE RIDGE WHICH IS FORECAST TO SHIFT EASTWARD THROUGH EARLY FRIDAY. BY FRIDAY...SOUTHERLY RETURN FLOW WILL HAVE ESTABLISHED ITSELF ACROSS THE WESTERN GULF AS AN AREA OF LOW PRESSURE DEVELOPS ACROSS THE INTERMOUNTAIN WEST. CARIBBEAN SEA... NORTHWESTERLY FLOW ALOFT PREVAILS OVER THE WESTERN CARIBBEAN W OF 76W THIS EVENING PROVIDING MOSTLY STABLE CONDITIONS AT THE SURFACE. HOWEVER...A PORTION OF UPPER LEVEL TROUGHING EXTENDS FROM THE SW NORTH ATLC OVER CUBA AND THE WINDWARD PASSAGE REGION GENERATING AN AREA OF SCATTERED SHOWERS AND TSTMS N OF 18N BETWEEN 74W-80W. OTHER ISOLATED SHOWERS AND TSTMS ARE NOTED ON SATELLITE IMAGERY ACROSS WESTERN CUBA AND THE ADJACENT COASTAL WATERS N OF 21N. FARTHER EAST...A BROAD UPPER LEVEL TROUGH IS OVER THE CENTRAL CARIBBEAN BETWEEN 70W-76W THAT REMAINS FAIRLY STABLE WITH WATER VAPOR IMAGERY INDICATING DRY AIR ALOFT. WEST- SOUTHWESTERLY FLOW ALOFT RESUMES E OF 70W ON THE SOUTHERN PERIPHERY OF THE UPPER LEVEL TROUGH WITH MOSTLY CLEAR SKIES PREVAILING THIS EVENING ACROSS PUERTO RICO...THE US/UK VIRGIN ISLANDS...AND THE REMAINDER OF THE LESSER ANTILLES. MODERATE TO FRESH TRADES ARE EXPECTED TO PERSIST THROUGH SATURDAY. ...HISPANIOLA... CURRENTLY CONDITIONS REMAIN FAIRLY TRANQUIL AND THIS IS EXPECTED THROUGH THE OVERNIGHT PERIOD. UPPER LEVEL TROUGHING LIES TO THE WEST OF THE ISLAND GENERATING SCATTERED SHOWERS AND TSTMS ACROSS EASTERN CUBA...HOWEVER MUCH OF THIS ACTIVITY SHOULD REMAIN W OF THE ISLAND. GIVEN LITTLE MOVEMENT OF THE UPPER LEVEL LOW AND ASSOCIATED TROUGH TO THE NORTH OVER THE SW NORTH ATLC...AN UPPER LEVEL DIFFLUENT ENVIRONMENT REMAINS ACROSS HISPANIOLA AND SCATTERED SHOWERS AND TSTMS ARE EXPECTED THURSDAY AFTERNOON AND EVENING WITH PEAK DAYTIME HEATING AND INSTABILITY. ATLANTIC OCEAN... A LONGWAVE MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE EASTERN CONUS THAT SUPPORTS A 1010 MB LOW CENTERED ACROSS SOUTH CAROLINA NEAR 34N80W. THE FRONTAL BOUNDARY ASSOCIATED WITH THE LOW REMAINS INLAND ALONG THE COAST...WITH MOSTLY SOUTHWESTERLY WINDS ALOFT AND AT THE SURFACE ADVECTING MOISTURE AND CLOUDINESS NORTHWARD THIS EVENING. ISOLATED SHOWERS AND TSTMS ARE OCCURRING EAST OF THE FRONT N OF 29N BETWEEN 73W- 80W. FARTHER SOUTH...MOISTURE ON THE WESTERN PERIPHERY OF AN ELONGATED UPPER LEVEL LOW CENTERED NEAR 26N72W IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 18N-27N BETWEEN 73W-79W. ON THE EASTERN PERIPHERY OF THE UPPER LEVEL LOW...SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 24N-30N BETWEEN 64W-71W. FARTHER EAST...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1031 MB HIGH CENTERED NEAR 36N53W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN