000 AXNT20 KNHC 121725 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI DEC 12 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 1645 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE ITCZ BEGINS AT THE COAST OF WEST AFRICA NEAR 05N09W AND CONTINUES WESTWARD TO 04N52W. SCATTERED MODERATE CONVECTION EXISTS EAST OF 30W WITHIN 60 NM OF THE ITCZ AXIS. ...DISCUSSION... GULF OF MEXICO... A 1030 MB HIGH CENTERED OVER TENNESSEE-KENTUCKY ALONG WITH A MODERATE N-S PRESSURE GRADIENT IS ALLOWING CONTINUED COLD AIR ADVECTION WITH WINDS OF 5 TO 15 KT ACROSS THE EASTERN HALF OF THE GULF OF MEXICO. WEAK SE RETURN FLOW CONTINUES IN THE WESTERN GULF. NO SIGNIFICANT DEEP CONVECTION IS OCCURRING UNDER GENERALLY DRY AND SUBSIDENT FLOW. LITTLE CHANGE IS EXPECTED AT THE SURFACE FOR THE NEXT COUPLE OF DAYS AS THE HIGH REMAINS RATHER LOCKED IN PLACE OVER THE SOUTHEAST UNITED STATES. IN THE UPPER-LEVELS...STRONG WEST-SOUTHWESTERLIES AS PART OF THE SUBTROPICAL JET STREAM ARE OBSERVED OVER THE GULF...ADVECTING MOISTURE AND HIGH CLOUDS BUT NO SIGNIFICANT PRECIPITATION. CARIBBEAN SEA... THE COLD AIR ADVECTION OVER THE GULF CONTINUES SOUTHWARD... COVERING THE WESTERN CARIBBEAN...THOUGH THE ORIGINATING FRONTAL BOUNDARY HAS DISSIPATED. WINDS ARE PEAKING AT 25-30 KT IN THE SOUTHWESTERN CARIBBEAN...AS SEEN BY THE 1504Z ASCAT SCATTEROMETER...WITH A CONTRIBUTION FROM GRADIENT INDUCED BY THE SEMI-PERMANENT LOW OVER PANAMA-COLOMBIA. ELSEWHERE...THE TRADEWINDS ARE GENERALLY 10-20 KT ACROSS THE CARIBBEAN. ADDITIONALLY...SCATTERED MODERATE CONVECTION IS OBSERVED FROM 10- 14N BETWEEN 80-84W ALONG THE EASTERN END OF THE NORTHEAST PACIFIC MONSOON TROUGH. ELSEWHERE...NO SIGNIFICANT DEEP CONVECTION IS OCCURRING OVER THE CARIBBEAN UNDER TYPICALLY SUBSIDENT AND DRY MID TO UPPER LEVEL WESTERLY FLOW. CONTINUED COOL AIR ADVECTION SHOULD OCCUR ACROSS THE NW CARIBBEAN DURING THE NEXT TWO DAYS...THOUGH THE PRESSURE GRADIENT WILL RELAX SOME...ALLOWING THE WINDS IN THE SW CARIBBEAN TO DIMINISH. HISPANIOLA... A STATIONARY TROUGH...THE REMNANTS OF A COLD FRONT...IS LOCATED JUST NORTH OF HISPANIOLA TODAY. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH IT...THOUGH ISOLATED LOW-TOPPED SHOWERS ARE POSSIBLE DURING THE NEXT TWO DAYS. WINDS ARE E 10-15 KT ALONG THE SOUTHERN COAST OF HISPANIOLA WITH WEAKER WINDS ALONG THE NORTHERN COAST. OVER THE NEXT TWO DAYS...ISOLATED SHOWERS ARE POSSIBLE BUT THESE SHOULD NOT BE WIDESPREAD NOR BECOME DEEP CONVECTION. THE COASTAL WINDS SHOULD REMAIN WEAK DURING THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... A DISSIPATING STATIONARY FRONT EXTENDS FROM 32N57W SOUTHWESTWARD TO 26N63W AND BECOMES A TROUGH THAT EXTENDS TO EASTERN CUBA. NO SIGNIFICANT DEEP CONVECTION EXISTS ALONG THE FRONT/TROUGH... THOUGH ISOLATED SHOWERS MAY BE OCCURRING WITHIN 60 NM OF THE FRONT/TROUGH. THE FRONT/TROUGH SHOULD DISSIPATE WITHIN THE NEXT DAY. A NEW COLD FRONTAL BOUNDARY HAS REACHED OUR NORTHEASTERN BOUNDARY EXTENDING FROM 32N70W TO 30N76W. THIS SHOULD QUICKLY PROGRESS SOUTHEASTWARD...BUT WITHOUT PRODUCING ANY SIGNIFICANT WINDS IN OUR AREA. A 1015 MB SURFACE LOW IS LOCATED NEAR 23N44W. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THIS LOW...THOUGH NORTHEASTERLY WINDS OF 20 KT ARE PRESENT WITHIN THE NORTHERN SEMICIRCLE. THIS LOW SHOULD DISSIPATE BY SATURDAY. A BUILDING AND SOUTHWARD MOVING AZORES HIGH SHOULD HELP INDUCE A LARGE AREA OF 20-30 KT WINDS IN THE EASTERN ATLANTIC BY SUNDAY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LANDSEA