000 AXNT20 KNHC 192343 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU DEC 19 2013 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. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE WEST AFRICAN COAST AT 07N12W TO 06N34W TO ALONG 04N13W TO 04N24W TO 06N34W TO THE EQUATOR NEAR 49W. WHILE NO SIGNIFICANT CONVECTION IS NOTED ALONG THE ITCZ AXIS...A SURFACE THE EQUATOR AT 49W AT THE COAST OF BRAZIL. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE ITCZ AT THIS TIME. IN THE SOUTHWESTERN CARIBBEAN...THE MONSOON TROUGH EXTENDS ACROSS PANAMA TO 09N76W AT THE COAST OF COLOMBIA. NO SIGNIFICANT DEEP CONVECTION IS ASSOCIATED WITH THE MONSOON TROUGH AT THIS TIME. ...DISCUSSION... GULF OF MEXICO... 1027 MB SURFACE HIGH IS CENTERED NORTHEAST OF THE GULF NEAR 33N82W ALONG THE BORDER OF GEORGIA AND SOUTH CAROLINA. SURFACE WINDS ARE GENERALLY SOUTHEASTERLY TO SOUTHERLY OVER THE GULF AT 15 TO 20 KT. NO DEEP CONVECTION IS OCCURRING OVER THE GULF OF MEXICO AT THIS TIME AND ONLY WIDELY SCATTERED SHOWERS ARE APPARENT ON RADAR ALONG THE UPPER TEXAS COAST. IN THE UPPER- LEVELS...A WEAK TROUGH IN THE WESTERLIES IS SEEN ALONG THE EAST MEXICAN COAST...THOUGH IT IS NOT ASSOCIATED WITH ANY COHERENT SURFACE FEATURE. ALSO A WEAK FAST-MOVING TROUGH IN THE UPPER LEVELS IS MOVING ALONG THE FLORIDA PANHANDLE. THIS SYSTEM MAY BE ENHANCING SOME UPPER-LEVEL CLOUDINESS...BUT NOT CONTRIBUTING TOWARD ANY SHOWER ACTIVITY AT THIS TIME. DURING THE NEXT DAY...THE SURFACE CIRCULATION SHOULD REMAIN ABOUT THE SAME...BUT THERE WILL BE ADDITIONAL MOISTURE ADVECTION IN THE SOUTHEASTERLIES IN THE WESTERN HALF OF THE GULF. THIS ENHANCE THE CHANCE FOR SOME SHOWER ACTIVITY ON FRIDAY IN THE REGION. CARIBBEAN SEA... A MODERATE PRESSURE GRADIENT EXISTS OVER THE CARIBBEAN SEA BETWEEN THE SEMI-PERMANENT LOW OVER SOUTH AMERICA AND A 1027 MB BERMUDA HIGH. THIS IS PRODUCING EAST TO NORTHEASTERLY TRADEWINDS OF GENERALLY 15 TO 25 KT WITH THE TYPICAL ENHANCEMENT OF THE WINDS ALONG THE COAST OF COLOMBIA TO 30 KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATES THREE LOCAL MAXIMA OF MOIST CONDITIONS IN THE LOW-LEVELS...85W...75W...AND 65W. DESPITE THESE MOISTURE MAXIMA...NO SIGNIFICANT DEEP CONVECTION IS OCCURRING OVER THE CARIBBEAN TODAY INCLUDING THE GREATER ANTILLES AND CENTRAL AMERICA. IN THE UPPER LEVELS...A SUBSIDENT HIGH IS CENTERED OVER COLOMBIA AND ANTICYCLONICALLY TURNING FLOW DOMINATES OVER THE CARIBBEAN. SOME UPPER-LEVEL MOISTURE AND CLOUDINESS IS BEING ADVECTED NORTHEASTWARD OVER THE WESTERN CARIBBEAN FROM SOME EARLIER DEEP CONVECTION OVER CENTRAL AMERICA AND THE NORTHEAST PACIFIC. DURING THE NEXT DAY...NO SIGNIFICANT CHANGE IN THE SURFACE WINDS IS ANTICIPATED THOUGH THE MOISTURE MAXIMA OVER 75W MAY ENHANCE CHANCES FOR SHOWERS OVER CENTRAL AMERICA. ...HISPANIOLA... AS WITH THE REST OF THE CARIBBEAN...NO SIGNIFICANT DEEP CONVECTION HAS BEEN OCCURRING OVER HISPANIOLA TODAY. EASTERLY TRADEWINDS MAY PRODUCE SOME SCATTERED SHOWERS IN THE DOMINICAN REPUBLIC AND ALONG THE SOUTHERN COAST OF HAITI ON FRIDAY DUE TO THE COMBINATION OF UPSLOPE FLOW AND AFTERNOON HEATING. HOWEVER...NO LARGE AMOUNTS OF PRECIPITATION ARE EXPECTED. ATLANTIC OCEAN... A COLD FRONT EXTENDS FROM 32N54W WEST-SOUTHWESTWARD TO 27N73W. NO SHOWER ACTIVITY IS ASSOCIATED WITH THE FRONT AT THIS TIME. AHEAD OF THE FRONT IS A TROUGH...AN EX-FRONTAL BOUNDARY... EXTENDING FROM 30N56W WEST-SOUTHWESTWARD TO 24N76W IN THE CENTRAL BAHAMAS. SCATTERED SHOWERS EXIST WITHIN 60 NM OF THE TROUGH AXIS. NEITHER THE FRONT NOR THE TROUGH ARE ASSOCIATED WITH MORE THAN 20 KT OF WIND. THE ASSOCIATED SHORT-WAVE TROUGH IN THE UPPER LEVELS HAS ALREADY MOVED TO 60W AT 30N...SO LITTLE DYNAMICAL SUPPORT FOR THE FRONT OR SURFACE TROUGH IS EXPECTED. THE TROUGH AND FRONT WILL LIKELY MERGE WITHIN THE NEXT DAY...BUT ONLY SCATTERED SHOWERS SHOULD PERSIST IN ASSOCIATION WITH THESE FEATURES. WELL TO THE EAST...ANOTHER TROUGH AXIS EXISTS FROM 06N35W TO 15N33W WITH NE WINDS 20 TO 30 KT EAST OF THE TROUGH AXIS. THE SURFACE TROUGH IS ASSOCIATED WITH A VIGOROUS UPPER- LEVEL LOW CENTERED NEAR 21N34W...WHICH IS RETROGRADING WESTWARD. LITTLE DEEP CONVECTION IS ASSOCIATED WITH THE SURFACE TROUGH/UPPER LOW...BUT WIDESPREAD SHOWERS AND MID-TO UPPER-LEVEL CLOUDINESS EXTENDS FROM 10N TO 25N AND 20W TO 33W. THIS TROUGH IS LIKELY TO WEAKEN SOME...BUT THE SHOWERS WILL PERSIST FOR THE NEXT DAY OR SO. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LANDSEA