000 AXNT20 KNHC 192323 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUN 19 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE ALONG 29W EXTENDS FROM 5N-11N AND IS BASED ON THE SATELLITE HOVMOLLER DIAGRAM AS WELL AS THE SUNY-ALBANY WAVE DIAGNOSTICS FROM THE GFS. THE WAVE...HOWEVER...IS WEAK AND HAS A RATHER NEGLIGIBLE SURFACE SIGNATURE. NO DEEP CONVECTION IS NOTED IN ASSOCIATION WITH THE WAVE. THE WAVE WILL CONTINUE TO MOVE WESTWARD AT ABOUT 15 KT. A TROPICAL WAVE IS CURRENTLY AFFECTING THE LESSER ANTILLES WITH SOME SHOWER ACTIVITY. IT EXTENDS AT THE SURFACE FROM 19N62W TO 11N62W MOVING W AT 15-20 KT. THE WAVE HAS A TURNING OF THE SURFACE WINDS FROM SOUTHEAST TO EAST ACROSS THE AXIS AND IS ACCOMPANIED BY A SURGE OF MOISTURE AS SEEN IN THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE ISOLATED DEEP CONVECTION IS OCCURRING WITHIN 120 NM OF THE WAVE NORTH OF 17N. IT APPEARS THAT THE 700 MB TROUGH AXIS IS SIGNIFICANTLY FARTHER WEST...NEAR 71W. MOISTURE ASSOCIATED WITH THE SURFACE COMPONENT OF THE WAVE IS SPREADING ACROSS THE EASTERN CARIBBEAN IS REACHING THE UK/US VIRGIN ISLANDS THIS EVENING...PUERTO RICO EARLY ON FRIDAY...AND DOMINICAN REPUBLIC FRIDAY NIGHT INTO SATURDAY. THIS SHOULD PROMOTE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. A TROPICAL WAVE IS MOVING ACROSS CENTRAL AMERICA WITH AXIS ALONG 90W SOUTH OF 20N AND EXTENDS INTO THE EAST PACIFIC. THE WAVE IS INDISTINCT ONLY IS TRACKABLE WITH THE SUNY-ALBANY TROUGH DIAGNOSTICS. NO SIGNIFICANT DEEP CONVECTION IS IN ASSOCIATION WITH THE WAVE...AS IT IS LOCATED WEST OF AN UPPER TROUGH... PLACING IT WITHIN UPPER-LEVEL CONVERGENCE. THE WAVE AXIS WILL CONTINUE TO MOVE WESTWARD ACROSS NORTHERN CENTRAL AMERICA AND SE MEXICO DURING THE NEXT 24 HOURS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH ENTERS THE ATLANTIC ALONG THE THROUGH THE COAST OF GUINEA-BISSAU NEAR 12N16W THEN CONTINUES TO 06N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N20W TO 06N28W THEN RESUMES W OF THE TROPICAL WAVE ALONG 29W FROM 5N31W TO 2N50W AT THE COAST OF BRAZIL. SCATTERED MODERATE IS LOCATED WITHIN 180 NM OF THE ITCZ AND MONSOON TROUGH EAST OF 28W. ...DISCUSSION... GULF OF MEXICO... A WEAK SURFACE RIDGE IS LOCATED ALONG COAST AND THE RESULTING SMALL PRESSURE GRADIENT IS FORCING EAST TO SOUTHEAST SURFACE WINDS OF GENERALLY 15 KT OR LESS ACROSS THE GULF. A WEAK SURFACE TROUGH EXTENDS FROM 30N85W TO 26N87W. WHILE THIS WAS HELPING TO PROMOTE CONVECTION EARLIER TODAY...NO SIGNIFICANT DEEP CONVECTION IS SEEN ACROSS THE GULF AT THIS TIME. A POCKET OF DRY AIR...PERHAPS A SAHARAN AIR LAYER...IS SEEN IN THE SOUTHERN GULF OF MEXICO FROM BOTH THE TOTAL PRECIPITABLE WATER IMAGERY AS WELL AS MURKY VISIBLE IMAGERY. WEAK RIDGING SHOULD MEANDER TO NEAR THE CENTRAL GULF DURING THE NEXT TWO DAYS AND GENERALLY DRY CONDITIONS WILL PREVAIL. CARIBBEAN SEA... A MODERATE NORTH-SOUTH PRESSURE GRADIENT IS FORCING EASTERLY TRADEWINDS ACROSS THE CARIBBEAN TODAY. SEE DISCUSSION ABOVE ABOUT THE EFFECT OF THE TROPICAL WAVE IN THE EASTERN CARIBBEAN. ELSEWHERE...THE COMBINATION OF THE EASTERN PACIFIC MONSOON TROUGH IMPINGING UPON THE SOUTHWESTERN CARIBBEAN SEA ALONG WITH AN UPPER-LEVEL TROUGH ALONG 85W HAS PROMOTED SPORADIC CONVECTION OVER SOUTHERN CENTRAL AMERICA AND THE SW CARIBBEAN. CONTINUED SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE LIKELY IN THE SAME VICINITY DURING THE NEXT COUPLE OF DAYS. ...HISPANIOLA... RELATIVELY FEW SHOWERS AND THUNDERSTORMS OCCURRED TODAY OVER HISPANIOLA...AS DRY CONDITIONS PREVAIL AHEAD OF THE TROPICAL WAVE IN THE EASTERN CARIBBEAN. THIS WAVE AND ASSOCIATED DEEP MOISTURE IS FORECAST TO BRING AN INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY BY SATURDAY...ENHANCING THE DIURNAL LATE AFTERNOON-EARLY EVENING MAXIMUM IN CONVECTION. ATLANTIC OCEAN... A DISSIPATING STATIONARY FRONT IS ANALYZED FROM 31N57W TO 29N61W...AND THEN THE FEATURE BECOMES A TROUGH EXTENDING TO 26N71W. NO SIGNIFICANT DEEP CONVECTION IS OCCURRING ALONG THIS BOUNDARY. THE FRONT/TROUGH SHOULD DISSIPATE IN A DAY OR SO. A WEAK TROUGH AND EMBEDDED 1019 MB SURFACE LOW IS LOCATED JUST EAST OF THE FLORIDA PENINSULA NEAR 28N80W. ISOLATED DEEP CONVECTION IS LOCATED WITHIN 120 NM IN THE SOUTHERN SEMICIRCLE. HOWEVER...THE FEATURE APPEARS TO SHORT-LIVED AND WILL LIKELY DISSIPATE IN THE NEXT DAY OR SO. FINALLY...A WEAK 1016 MB LOW IS LOCATED NEAR 31N21W WITH A COLD FRONT EXTENDING TO ITS SOUTH AND WEST. THIS SHOULD PUSH EASTWARD WITHOUT REACHING MUCH FARTHER SOUTH AND GRADUALLY WEAKEN. ELSEWHERE...A PAIR OF 1025 MB SURFACE HIGHS AT 27N43W AND 30N34W ANCHOR A RIDGE THAT EXTENDS ACROSS THE ATLANTIC NEAR 28N. THE RESULTING MODERATE PRESSURE GRADIENT ON THE EQUATORWARD SIDE ARE GENERALLY PRODUCING EASTERLY TRADEWINDS OF ABOUT 15 KT. LITTLE CHANGE IS ANTICIPATED DURING THE NEXT COUPLE OF DAYS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LANDSEA