000 AXNT20 KNHC 201803 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SUN DEC 20 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 1745 UTC. ...SPECIAL FEATURE... THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE CURRENTLY OVER THE ATLC AND LOW PRESSURE OVER NW COLOMBIA CONTINUE TO SUPPORT GALE FORCE WINDS ACROSS THE S-CENTRAL CARIBBEAN FROM 10.5N TO 13N BETWEEN 73W AND 78W WITH SEAS RANGING FROM 10 TO 14 FT. NE TO E WINDS OF 20 TO 30 KT ARE ELSEWHERE FROM 10N TO 17N BETWEEN 69W AND 83W WITH SEAS FROM 8 TO 11 FT. THE WINDS WILL DECREASE SLIGHTLY BELOW GALE FORCE DURING THE AFTERNOON...BUT WILL PULSE BACK TO GALE FORCE AGAIN LATER THIS EVENING. FOR MORE INFORMATION PLEASE REFER TO THE HIGH SEAS FORECAST PRODUCT UNDER AWIPS/WMO HEADER MIAHSFAT2/FZNT02 KNHC. ...ITCZ/MONSOON TROUGH... THE ITCZ EXTENDS FROM 04N08W TO 04N36W TO 05N52W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE FROM 03N TO 06N BETWEEN 25W AND 40W. ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE ITCZ ELSEWHERE. ...DISCUSSION... GULF OF MEXICO... A STRONG AND BROAD RIDGE ANCHORED BY A 1037 MB HIGH OVER NORTH CAROLINA EXTENDS SW ACROSS THE GULF...THUS PROVIDING MODERATE TO FRESH E TO SE WINDS OVER THE NORTHERN BASIN. THE TAIL OF A STATIONARY FRONT EXTENDS FROM WESTERN CUBA TO THE NORTHERN YUCATAN PENINSULA. A TIGHT PRESSURE GRADIENT BETWEEN THE RIDGE AND THE FRONT SUPPORTS NE FRESH TO STRONG WINDS IN THE SE GULF AND NE MODERATE TO FRESH WINDS OVER THE SW BASIN. DRY AIR IN THE MID TO UPPER LEVELS AS WELL AS SUBSIDENCE SUPPORT FAIR WEATHER BASIN-WIDE. ISOLATED SHOWERS ARE POSSIBLE OVER THE SE BASIN S OF 24N ASSOCIATED WITH THE FRONT. BY LATE TODAY THE FRONT WILL DISSIPATE WHILE THE HIGH WILL SLIDE E TO THE MID ATLC WATERS...THUS ALLOWING WINDS TO VEER SLIGHTLY THROUGH EARLY WED. CARIBBEAN SEA... THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE CURRENTLY OVER THE ATLC AND LOW PRESSURE OVER NW COLOMBIA CONTINUE TO SUPPORT GALE FORCE WINDS ACROSS THE S-CENTRAL CARIBBEAN AND MODERATE TO FRESH WINDS ACROSS MOST OF THE REMAINDER BASIN. GALE WINDS ARE EXPECTED TO PULSE AT NIGHT THROUGH TUE. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. AN UPPER TROUGH ALONG THE EASTERN CONUS SEABOARD EXTENDING TO A BASE OVER HONDURAS AND NICARAGUA SUPPORTS A WEAK STATIONARY FRONT FROM WESTERN CUBA...ACROSS THE YUCATAN CHANNEL TO THE NORTHERN YUCATAN PENINSULA. OFF THE YUCATAN PENINSULA AND BELIZE A PRE-FRONTAL TROUGH IS ANALYZED FROM 20N86W TO 15N88W ENHANCING ISOLATED SHOWERS W OF 85W. SIMILAR SHOWER ACTIVITY IS BETWEEN SOUTHERN PANAMA AND COLOMBIA BEING ENHANCED BY A 1008 MB LOW NEAR 08N76W. SHALLOW MOISTURE AND A DIFFLUENT ENVIRONMENT ALOFT SUPPORT ISOLATED SHOWERS AND TSTMS OVER HISPANIOLA AND PASSING SHOWERS ACROSS PUERTO RICO. ELSEWHERE FAIR WEATHER DOMINATES SUPPORTED BY DRY AIR SUBSIDENCE. ...HISPANIOLA... SHALLOW MOISTURE AND A DIFFLUENT ENVIRONMENT ALOFT SUPPORT ISOLATED SHOWERS AND TSTMS OVER HISPANIOLA...MAINLY OVER DOMINICAN REPUBLIC. THIS FEATURE WILL CONTINUE TO GENERATE SCATTERED SHOWERS AND THUNDERSTORMS OVER HISPANIOLA THROUGH TONIGHT. ATLANTIC OCEAN... AN UPPER TROUGH ALONG THE EASTERN CONUS SEABOARD EXTENDING TO A BASE OVER HONDURAS AND NICARAGUA SUPPORTS A WEAK STATIONARY FRONT FROM 30N59W TO THE CENTRAL BAHAMAS NEAR 23N75W TO WESTERN CUBA NEAR 22N79W. DIFFLUENCE ALOFT SUPPORTS SCATTERED SHOWERS AND TSTMS FROM 20N TO 27N BETWEEN 68W AND 76W. FRESH TO STRONG NE WINDS ARE BEHIND THE FRONT. ISOLATED SHOWERS ARE WITHIN 100 NM ELSEWHERE W ALONG THE FRONT. A DISSIPATING COLD FRONT EXTENDS FROM 30N10W TO 22N28W WHERE IT TRANSITIONS TO A DISSIPATING STATIONARY FRONT TO 22N56W...NO CONVECTION ASSOCIATED WITH IT. SURFACE RIDGING DOMINATES ELSEWHERE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR