000 AXNT20 KNHC 140606 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI AUG 14 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS IN THE CENTRAL ATLC WITH AXIS NEAR 35W ...MOVING W AT 15 KT OVER THE PAST 24 HOURS. CIRA LAYER PRECIPITABLE WATER IMAGERY FROM THE SURFACE TO 850 MB SHOW THE WAVE IS WITHIN A VERY DRY ENVIRONMENT...COINCIDING WITH THE PRESENCE OF SAHARAN DRY AIR AND DUST AS INDICATED BY ENHANCED METEOSAT IMAGERY. THERE IS NO CONVECTION ASSOCIATED WITH THIS WAVE. A TROPICAL WAVE IS E-SE OF THE LESSER ANTILLES WITH AXIS NEAR 56W...MOVING W AT 10-15 KT OVER THE PAST 24 HOURS. THE WAVE IS ASSOCIATED WITH A MODERATE MOIST ENVIRONMENT FROM THE SURFACE TO 850 MB ACCORDING TO CIRA LAYER PRECIPITABLE WATER IMAGERY. SAHARAN DRY AIR AND DUST ENGULF THE WAVE...WHICH IS LIMITING THE CONVECTION TO ISOLATED MODERATE FROM 10N TO 15N BETWEEN 53W AND 59W. A TROPICAL WAVE IS MOVING ACROSS CENTRAL AMERICA WITH AXIS NEAR 83W EXTENDING NORTHWARD OVER THE NW CARIBBEAN NEAR 18N. THE WAVE IS ASSOCIATED WITH A MODERATE MOIST ENVIRONMENT FROM THE SURFACE TO 850 MB ACCORDING TO CIRA LAYER PRECIPITABLE WATER IMAGERY. AN UPPER-LEVEL LOW CENTERED W OF JAMAICA NEAR 18N81W ALONG WITH THE AFOREMENTIONED MOISTURE SUPPORT ISOLATED SHOWERS AND TSTMS WITHIN 120 NM E OF THE WAVE AXIS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL AFRICA NEAR 13N16W AND CONTINUES TO 09N23W TO 08N33W. THE ITCZ BEGINS W OF A TROPICAL WAVE NEAR 08N36W AND CONTINUES ALONG 08N45W TO 09N54W. OTHER THAN CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 56W...ISOLATED MODERATE CONVECTION IS FROM 10N-14N E OF 23W AND FROM 04N TO 10N BETWEEN 28W AND 52W. ...DISCUSSION... ...GULF OF MEXICO... THE SE PERIPHERY OF A BROAD MIDDLE TO UPPER LEVEL RIDGE CENTERED BETWEEN SOUTHERN UTAH AND NORTHERN NEW MEXICO COVERS THE CENTRAL AND WESTERN GULF OF MEXICO WHILE A TROUGH EXTENDS ALONG THE EASTERN CONUS SW TO A BASE OVER THE NE BASIN. THIS TROUGH ALOFT SUPPORTS A STATIONARY FRONT ACROSS NORTHERN FLORIDA AND A 1015 MB LOW NEAR 27N85W FROM WHICH A SURFACE TROUGH EXTENDS W-SW TO 24N89W TO 23N94W. SCATTERED SHOWERS AND TSTMS ARE FROM 24N TO 28N E OF 84W. OVER THE SW GULF...A 1016 MB HIGH IS NEAR 23N95W. VARIABLE WINDS OF LESS THAN 15 KT ARE BASIN-WIDE. THE STATIONARY FRONT WILL DISSIPATE FRIDAY MORNING LEAVING A TROUGH OF LOW PRESSURE FROM THE NE TO THE CENTRAL GULF DURING THE NEXT TWO DAYS...POSSIBLE ISOLATED TO SCATTERED SHOWERS WILL ACCOMPANY THIS AREA OF LOW PRESSURE. CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS CENTRAL AMERICA WITH AXIS EXTENDING N INTO THE NW CARIBBEAN. CONVECTION ASSOCIATED WITH THIS WAVE IS OCCURRING MAINLY ALONG THE COASTLINES FROM NICARAGUA TO NORTHERN PANAMA. SEE TROPICAL WAVES SECTION. A BROAD UPPER-LEVEL LOW CENTERED W OF JAMAICA IS GENERATING A DIFFLUENT WIND ENVIRONMENT BETWEEN EASTERN CUBA AND WESTERN HISPANIOLA WHERE SCATTERED SHOWERS AND TSTMS ARE OBSERVED N OF 17N...INCLUDING THE WINDWARD PASSAGE. LOW PRESSURE OVER NW COLOMBIA ENHANCES CONVECTION OVER THE SW BASIN S OF 11N E OF 80W. SHALLOW MOISTURE IS ACROSS THE REMAINDER BASIN WITH DRIER CONDITIONS OBSERVED OVER THE E-NE CARIBBEAN. STRONG DEEP LAYER WIND SHEAR OVER THE CENTRAL AND E CARIBBEAN HINDER THE DEVELOPMENT CONVECTION AT THIS TIME. NE TO E WINDS OF 20 TO 25 KT ARE FROM 11N TO 13N BETWEEN 70W AND 77W WITH SEAS TO 9 FT. WINDS OF 20 KT OR LESS ARE FROM 13N TO 15N BETWEEN 71W AND 75W WITH SEAS TO 8 FT IN E SWELL. THE NEXT TROPICAL WAVE WILL APPROACH THE LESSER ANTILLES FRIDAY EVENING WITH ASSOCIATED SHOWERS AND TSTMS MAINLY AFFECTING THE WINDWARD ISLANDS. ...HISPANIOLA... A BROAD UPPER-LEVEL LOW CENTERED W OF JAMAICA IS GENERATING A DIFFLUENT WIND ENVIRONMENT BETWEEN EASTERN CUBA AND WESTERN HISPANIOLA WHERE SCATTERED SHOWERS AND TSTMS ARE OBSERVED N OF 17N...INCLUDING THE WINDWARD PASSAGE. SHOWER ACTIVITY IS EXPECTED THROUGH LATER THIS MORNING. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH EXTENDS ALONG THE EASTERN CONUS SW TO A BASE OVER THE NE GULF OF MEXICO SUPPORTING A STATIONARY FRONT EXTENDING FROM 30N78W SW TO JACKSONVILLE...THEN W ACROSS NORTHERN FLORIDA. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM 29N78W SW TO 24N82W SUPPORTING SCATTERED SHOWERS AND TSTMS FROM 25N TO 30N BETWEEN 77W AND 80W. A BROAD SURFACE RIDGE COVERS THE REMAINDER BASIN AND SUPPORTS FAIR WEATHER. A WEAKNESS IN THE RIDGE IS ANALYZED AS A 1012 MB LOW NEAR 23N19W WITH ASSOCIATED TROUGH...HOWEVER LACKING CONVECTION. FOR TROPICAL WAVES SEE SECTION ABOVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR