000 AXNT20 KNHC 171957 RRA TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED JUN 17 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 1600 UTC. ...SPECIAL FEATURES... A STRONG PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE WESTERN ATLC AND A 1006 MB LOW OVER COLOMBIA SUPPORTS GALE FORCE WINDS WITHIN CLOSE PROXIMITY TO THE COAST OF COLOMBIA. THIS WIND FIELD IS FORECAST TO DECREASE BELOW TO GALE FORCE THIS AFTERNOON...THEN PULSE BACK TO GALE FORCE TONIGHT. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 06N21W TO 15N21W MOVING W AT 15 KT. THIS WAVE EMERGED OFF THE AFRICAN COAST ON TUESDAY MORNING AND COINCIDES WITH A NORTHWARD EXTENSION OF DEEP TROPICAL MOISTURE NOTED IN SSMI TPW IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 06N TO 10N BETWEEN 16W AND 23W. TROPICAL WAVE EXTENDS FROM 06N50W TO 15N50W MOVING W AT 20-25 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE EMBEDDED WITHIN A RELATIVELY LOW AMPLITUDE AREA OF MOISTURE S OF 09N. ISOLATED MODERATE CONVECTION IS FROM 07N TO 11N BETWEEN 48W AND 51W. TROPICAL WAVE EXTENDS FROM 05N61W TO 15N61W MOVING W AT 15 TO 20 KT. THIS WAVE HAS BEEN TRACKED ON LONG TERM IR SATELLITE IMAGERY AS WELL AS NOTED IN 700 MB HEIGHTS. THIS WAVE IS AT THE TRAILING EDGE OF DEEP MOISTURE OVER THE CARIBBEAN. ISOLATED MODERATE CONVECTION IS WITHIN 100 NM OF THE WAVE AXIS...INCLUDING THE LEEWARD ISLANDS. TROPICAL WAVE EXTENDS FROM 08N77N TO 17N75W MOVING W AT 20 KT. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE EMBEDDED WITHIN A POLEWARD SURGE OF DEEP MOISTURE ACROSS THE CENTRAL AND EASTERN CARIBBEAN SEA. CONVECTION ACROSS COLOMBIA IS MAINLY ASSOCIATED WITH THE MONSOON TROUGH TO THE WEST OF THE WAVE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO 12N19W. THE ITCZ AXIS EXTENDS FROM 10N23W THROUGH 07N34W TO 04N48W. ISOLATED MODERATE CONVECTION IS WITHIN 150 NM OF EITHER SIDE OF THE ITCZ AXIS EAST OF 43W. ...DISCUSSION... GULF OF MEXICO... LOW LEVEL CONVERGENCE ASSOCIATED WITH THE REMNANTS OF BILL CONTINUE TO PRODUCE CLUSTERS OF MODERATE TO STRONG CONVECTION FROM 26N TO THE TX COAST BETWEEN 94W AND 98W. DEEP TROPICAL MOISTURE NOTED IN SSMI TPW ACROSS THE WESTERN HALF OF THE GULF COMBINED WITH UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER TROUGH OVER W TEXAS AND UPPER LEVEL HIGH PRESSURE OVER THE SW GULF SUPPORTS ISOLATED THUNDERSTORMS S OF 26N AND W OF 94W. A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH MOVING WESTWARD ACROSS FL SUPPORTS ISOLATED MODERATE CONVECTION FROM 22N TO 29N BETWEEN 83W AND 88W. SURFACE RIDGING ANCHORED BY A PAIR OF HIGH CENTERS OVER THE SOUTHEAST US AND NE OF THE BAHAMAS IS PRODUCING 10 TO 15 KT EAST TO SOUTHEAST SURFACE WINDS OVER MOST OF THE GULF...EXCEPT AN AREA OF 20 KT IN THE VICINITY OF THE CONVECTION ASSOCIATED WITH THE REMNANTS OF BILL OVER THE NW BASIN. OVER THE NEXT 24 HOURS CONVECTION WILL DECREASE OVER THE NW GULF AS THE REMNANTS OF BILL MOVE FARTHER INLAND. DEEP MOISTURE AND FAVORABLE UPPER LEVEL CONDITIONS WILL SUPPORT CONVECTION OVER THE SW GULF STARTING THURSDAY. CARIBBEAN SEA... TWO TROPICAL WAVES ARE OVER THE CARIBBEAN...ONE EXTENDING FROM THE SW CARIBBEAN TO SE OF JAMAICA...THE OTHER CROSSING THE LESSER ANTILLES. PLEASE SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. AN UPPER LEVEL LOW IS CENTERED OVER THE NW CARIBBEAN NEAR 21N85W WITH WESTERLY FLOW ALOFT OVER THE CENTRAL AND EASTERN CARIBBEAN. THE UPPER LOW IS OVER A FAIRLY DRY ENVIRONMENT AND THEREFORE SUPPORTS ONLY ISOLATED THUNDERSTORMS FROM 17N TO 20N BETWEEN 83W AND 88W. AN AREA OF UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED TO NUMEROUS SHALLOW THUNDERSTORMS FROM 09N TO 16N BETWEEN 79W AND 84W. FRESH TO MODERATE TRADE WINDS COVER MOST OF THE CARIBBEAN BASIN. HOWEVER...AN AREA OF STRONGER TRADE WINDS OF GALE FORCE IS LOCATED N OF COLOMBIA DUE TO A TIGHT PRESSURE GRADIENT BETWEEN WESTERN ATLC HIGH PRESSURE AND A 1006 MB LOW OVER N COLOMBIA. PLEASE SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS THE GALE FORCE WINDS WILL PULSE BELOW AND ABOVE GALE FORCE. CONVECTION WILL CONTINUE TO BE POSSIBLE OVER THE WESTERN CARIBBEAN. ...HISPANIOLA... AN INCREASE IN TROPICAL MOISTURE IS NOTED MOVING NORTHWARD ACROSS THE ISLAND TODAY. THIS WILL BRING AN INCREASE IN THUNDERSTORM COVERAGE THIS AFTERNOON. MOST OF THIS ACTIVITY WILL DIMINISH DURING THE EVENING. SCATTERED THUNDERSTORMS WILL BE POSSIBLE AGAIN ON THURSDAY. ATLANTIC OCEAN... A 1020 MB HIGH IS CENTERED NEAR 28N74W AND SUPPORTS WEAK ANTICYCLONIC FLOW OVER THE SW NORTHERN ATLC. A MID LEVEL TROUGH AXIS EXTENDS FROM NEAR 30N60W TO 26N68W...SUPPORTING WIDELY SCATTERED MODERATE CONVECTION WITHIN 100NM OF EITHER SIDE OF THE TROUGH AXIS. A PAIR OF COLD FRONTS ARE ALONG OUR AREA OF DISCUSSION BOUNDARY NEAR 31N ALONG 58W AND 43W. SCATTERED THUNDERSTORMS ARE POSSIBLE NEAR THE INTERSECTION OF THESE COLD FRONTS WITH OUR BOUNDARY. 1031 MB HIGH PRESSURE CENTERED NW OF THE AZORES SUPPORTS GENERALLY FAIR WEATHER ACROSS THE EASTERN SUBTROPICAL ATLC. CONVECITON ALONG THE MID LEVEL TROUGH IS FORECAST TO CONTINUE THROUGH THE NEXT 24 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO