000 AXNT20 KNHC 262354 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT DEC 26 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... A STRONG PRESSURE GRADIENT EXISTS BETWEEN LOWER PRESSURE ACROSS NORTHWESTERN SOUTH AMERICA AND A 1029 MB HIGH CENTERED NEAR BERMUDA INFLUENCING THE SW NORTH ATLC. NEAR GALE TO GALE FORCE WINDS ACROSS THE SOUTH-CENTRAL AND SW CARIBBEAN ARE OCCURRING FROM 11N-14N BETWEEN 73W-77W. THESE CONDITIONS ARE FORECAST TO PERSIST THROUGH EARLY MONDAY. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. AN AREA OF DEVELOPING LOW PRESSURE IS CURRENTLY ANALYZED ACROSS WESTERN TEXAS AND NORTH-CENTRAL MEXICO FOCUSED ON A 1000 MB LOW CENTERED NEAR 31N105W. THE ASSOCIATED COLD FRONT IS EXPECTED TO EMERGE OFF THE TEXAS GULF OF MEXICO COAST LATE SUNDAY INTO EARLY MONDAY WITH NEAR GALE TO GALE FORCE NORTHERLY WINDS FORECAST TO MATERIALIZE BY 27/1800 UTC WEST OF THE FRONT. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE EQUATOR AT THE PRIME MERIDIAN TO 03N12W TO 01N27W TO THE EQUATOR NEAR 40W THEN ALONG THE EQUATOR TO 43W. ISOLATED MODERATE CONVECTION IS FROM THE EQUATOR TO 09N BETWEEN 12W-41W. ...DISCUSSION... GULF OF MEXICO... THE GULF BASIN REMAINS UNDER THE INFLUENCE OF GENERALLY SOUTHWESTERLY FLOW ALOFT WITH AN EMBEDDED SHORTWAVE TROUGH AXIS NOTED ON WATER VAPOR IMAGERY ALONG 90W. THIS SW FLOW REGIME COMES ON THE HEELS OF AN APPROACHING VIGOROUS MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE NW MEXICO NEAR 31N109W. THE UPPER LEVEL DYNAMICS ARE INDUCING A BROAD AREA OF LOW PRESSURE FOCUSED ON A 1000 MB LOW CENTERED OVER FAR WESTERN TEXAS. AS THE LOW CONTINUES TO DEVELOP ACROSS NORTHERN MEXICO AND SOUTHERN TEXAS...SOUTHEASTERLY SURFACE WINDS PREVAIL ACROSS THE GULF BASIN THIS EVENING WITH GENERALLY MODERATE TO FRESH BREEZE CONDITIONS E OF 90W AND FRESH TO STRONG BREEZE CONDITIONS W OF 90W. AS THE LOW MOVES EASTWARD ACROSS EASTERN TEXAS BY SUNDAY AFTERNOON...THE ASSOCIATED COLD FRONT IS EXPECTED TO SWEEP ACROSS THE WESTERN GULF THROUGH EARLY MONDAY MORNING WITH NEAR GALE TO GALE FORCE NW TO N WINDS OCCURRING IN WAKE OF THE FRONT. THE FRONT IS FORECAST TO STALL FROM THE FLORIDA PANHANDLE S-SW TO THE SW GULF BY TUESDAY WITH WINDS DECREASING AS THE FRONTAL BOUNDARY BECOMES DIFFUSE. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR AND SUBSIDENCE ALOFT OVER A MAJORITY OF THE BASIN THIS EVENING RESULTING IN MOSTLY CLEAR SKIES. THE ONLY AREA OF SIGNIFICANT CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ARE OCCURRING ACROSS THE SE CARIBBEAN...INCLUDING THE WINDWARD ISLANDS. OTHER PASSING ISOLATED SHOWERS ARE POSSIBLE ACROSS PUERTO RICO...THE US/UK VIRGIN ISLANDS...AND PORTIONS OF HISPANIOLA. WHILE OVERALL TRANQUIL SKIES PREVAILS...THE PRIMARY MARINE IMPACT TO THE BASIN IS THE STRONG TO OCCASIONAL NEAR GALE TRADES OCCURRING DUE TO A STRENGTHENED PRESSURE GRADIENT BETWEEN LOWER PRESSURE ACROSS NW SOUTH AMERICA AND A STRONG SURFACE RIDGE ANCHORED IN THE VICINITY OF BERMUDA. GALE FORCE CONDITIONS ARE EXPECTED TO PERSIST THROUGH EARLY MONDAY WITHIN CLOSE PROXIMITY TO THE COAST OF COLOMBIA AS MENTIONED ABOVE IN THE SPECIAL FEATURES SECTION. OTHERWISE...BY EARLY NEXT WEEK...THE SW NORTH ATLC RIDGING IS FORECAST TO WEAKEN SLIGHTLY ON MONDAY RELAXING THE PRESSURE GRADIENT SOMEWHAT...HOWEVER RE-STRENGTHENING LATE TUESDAY INTO WEDNESDAY INCREASING THE TRADES ONCE AGAIN. ...HISPANIOLA... DRY AIR AND STABILITY ALOFT ARE PROVIDING FOR OVERALL FAIR CONDITIONS ACROSS THE ISLAND THIS EVENING. A STRAY LOW-TOPPED ISOLATED SHOWER WITHIN THE EASTERLIES CANNOT BE RULED OUT HOWEVER. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL RIDGE IS NOTED ON WATER VAPOR IMAGERY ANCHORED NEAR 28N70W. THE RIDGING ALOFT SUPPORTS A STRONG 1029 MB HIGH CENTERED NEAR BERMUDA PROVIDING OVERALL FAIR CONDITIONS FOR MUCH OF THE SW NORTH AND CENTRAL ATLC WATERS THIS EVENING. THE PRIMARY IMPACT FROM THE ANTICYCLONE IS STRONG WINDS WITHIN THE SOUTHERN PERIPHERY DUE TO A STRENGTHENED PRESSURE GRADIENT BETWEEN THE HIGH AND LOWER PRESSURE ASSOCIATED WITH THE INTERTROPICAL CONVERGENCE ZONE REGION ACROSS NORTHERN SOUTH AMERICA. FRESH TO STRONG EASTERLY WINDS ARE FOUND GENERALLY FROM 12N-24N BETWEEN 55W-77W. OTHERWISE...MODERATE TO FRESH ANTI- CYCLONIC FLOW PREVAILS N OF 24N W OF 50W. ELSEWHERE...THE EASTERN ATLC IS UNDER RELATIVELY QUIET CONDITIONS AS WELL... HOWEVER A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM 34N20W TO 18N30W THAT IS SUPPORTIVE OF A WEAKENING COLD FRONT EXTENDING FROM 32N17W TO 22N30W TO 23N43W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 90 NM EITHER SIDE OF THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN