000 AXNT20 KNHC 211713 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SUN DEC 21 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1700 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH CROSSES THE COAST OF AFRICA NEAR 05N09W TO 06N14W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 05N30W 05N40W TO THE COAST OF SURINAME NEAR 04N51W. ISOLATED MODERATE CONVECTION IS FROM 03N-09N E OF 30W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 03N-08N W OF 30W. ...DISCUSSION... GULF OF MEXICO... SOUTHWESTERLY FLOW ALOFT BETWEEN A MIDDLE-LEVEL TROUGH WITH AXIS ALONG THE CENTRAL U.S. AND A BROAD ANTICYCLONE ANCHORED N OF THE MONA PASSAGE CONTINUES TO ADVECT MOISTURE FROM THE EPAC ITCZ TO THE GULF N OF A LINE FROM 28N82W TO 25N90W TO 18N95W. AHEAD OF THIS PLUME OF MOISTURE STREAMING INTO THE GULF...A STATIONARY FRONT EXTENDS FROM ACROSS NORTHERN FLORIDA TO 28N85W SW TO THE GULF OF CAMPECHE ALONG 25N92W TO 20N96W. THE WIND PATTERN ALOFT ALLOWS FOR A DIFFLUENT ENVIRONMENT THAT ENHANCES SCATTERED SHOWERS AND ISOLATED TSTMS N OF THE FRONTAL BOUNDARY. A PRE- FRONTAL SURFACE TROUGH IS FROM 26N86W TO 21N87W SUPPORTING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS WITHIN 160 NM E OF ITS AXIS FROM 21N-25N. OTHERWISE...VARIABLE WIND OF 5-15 KT DOMINATE THE GULF WATERS. THE STATIONARY FRONT WILL WEAKEN TONIGHT ALONG WITH THE SURFACE TROUGH AS HIGH PRESSURE BUILDING IN THE SW N ATLC EXTENDS A RIDGE AXIS SW ACROSS THE GULF. A STRONG COLD FRONT WILL BE ENTERING THE NW BASIN TUESDAY NIGHT WITH GALE FORCE WINDS N OF THE BOUNDARY. CARIBBEAN SEA... A VERY STABLE ENVIRONMENT CONSISTING OF A BROAD MIDDLE-LEVEL ANTICYCLONE...A RIDGE AT THE UPPER-LEVELS AND DRY AIR SUBSIDENCE FROM ALOFT SUPPORTS FAIR WEATHER ACROSS GREAT PORTIONS OF THE BASIN. SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW MAY ENHANCE ISOLATED SHOWERS ACROSS THE CENTRAL AND EASTERN BASIN WHILE A SURFACE TROUGH ALONG 18N82W TO 10N82W ENHANCE SIMILAR SHOWER ACTIVITY S OF 18N WITHIN 100 NM OF THE CENTRAL AMERICA COAST. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE IN THE YUCATAN CHANNEL ASSOCIATED WITH A SURFACE TROUGH IN THE SE GULF OF MEXICO WHICH WILL DISSIPATE THIS EVENING LEAVING LINGERING SHOWERS THROUGH LATE TONIGHT. LIGHT TRADES OF 5-10 KT ARE IN THE NW CARIBBEAN WHILE TRADES OF 15-20 KT DOMINATE ELSEWHERE...INCREASING TO 25 KT ALONG THE COAST OF COLOMBIA. TRADES OVER THE CENTRAL AND EASTERN CARIBBEAN ARE FORECAST TO REMAIN ON THE 20-25 KT THE NEXT THREE DAYS...HOWEVER SPREADING WESTWARD TO THE REMAINDER BASIN AS HIGH PRESSURE OVER THE SW N ATLC STRENGTHENS FROM MON TO TUE. HISPANIOLA... A VERY STABLE ENVIRONMENT ALOFT CONTINUES TO SUPPORT FAIR WEATHER ACROSS THE ISLAND...HOWEVER A SHALLOW MOIST AIRMASS OVER THE EASTERN BASIN CARIBBEAN WILL START MOVING ACROSS THE CENTRAL AND SOUTHERN ISLAND TONIGHT...THUS SUPPORTING CLOUDINESS AND POSSIBLE ISOLATED SHOWERS THROUGH MONDAY AFTERNOON. ATLANTIC OCEAN... A STATIONARY FRONT CONTINUES TO EXTEND FROM THE GULF OF MEXICO ACROSS THE NORTHERN FLORIDA PENINSULA REACHING THE SW N ATLC WATERS FROM 29N81W TO 30N76W. THE CURRENT OF UPPER-LEVEL MOISTURE ACROSS THE GULF OF MEXICO REACHES THIS PORTION OF THE ATLC...THUS SUPPORTING ISOLATED SHOWERS N OF 22N W OF 70W. OVER THE CENTRAL BASIN...A NARROW AND ELONGATED TROUGH ALOFT WITH BASE NEAR 25N36W SUPPORT A COLD FRONT N OF THE AREA OF DISCUSSION THAT STARTS TO DISSIPATE ALONG 29N41W SW TO 23N50W. AHEAD OF THE FRONT...A SURFACE TROUGH EXTENDS FROM 30N38W TO 23N38W ENHANCING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS WITHIN 90 NM EITHER SIDE OF ITS AXIS. SURFACE RIDGING DOMINATES OVER THE EASTERN BASIN N OF 22N. SURFACE RIDGING WILL BECOME THE DOMINANT FEATURE ACROSS THE ENTIRE ATLC BY TUE NIGHT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS