000 AXNT20 KNHC 231740 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SUN DEC 23 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 4N25W 4N35W...EQUATOR AT 50W INTO SOUTH AMERICA. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 150 NM N OF THE AXIS BETWEEN 30W-50W AND WITHIN 90 NM S OF THE AXIS BETWEEN 29W-38W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG THE EQUATOR BETWEEN THE PRIME MERIDIAN AND 8W. ...DISCUSSION... THE GULF OF MEXICO... A STRONG COLD FRONT IS MOVING ACROSS THE GULF THIS AFTERNOON. AS OF 1500 UTC...THIS FEATURE STRETCHES FROM THE FLORIDA PANHANDLE ACROSS THE CENTRAL GULF NEAR 24N90W TO THE BAY OF CAMPECHE AND SOUTH MEXICO. GALE FORCE WINDS OF 30 TO 35 KT ARE BLOWING BEHIND THE FRONT. AS A RESULT...A GALE WARNING HAS BEEN POSTED S OF 28N AND WEST OF THE FRONT WITH SEAS BUILDING UP TO 12 FT. A QUIKSCAT PASS FROM THIS MORNING CONFIRMED THESE STRONG WINDS. A WELL DEFINED LINE OF CONVECTION MARKS THE FRONTAL BOUNDARY WITH BROKEN TO OVERCAST COLD AIR STRATOCUMULUS CLOUDS BEHIND THE FRONT. A DEEP LAYERED TROUGH OVER THE CENTRAL PLAINS SUPPORTS THE FRONT WITH A MID/UPPER-LEVEL RIDGE DOMINATING THE ENTIRE GULF. AHEAD OF THE FRONT A WARM AND HUMID AIRMASS REMAINS IN PLACE. THE COLD FRONT WILL EXTEND FROM THE CENTRAL FLORIDA PENINSULA TO THE YUCATAN CHANNEL LATE TONIGHT AND EXIT THE GULF ON MONDAY. HIGH PRESSURE WILL BUILD OVER THE ENTIRE GULF MONDAY AND TUESDAY USHERING A COOL AND DRY AIRMASS. THE CARIBBEAN SEA... A MID/UPPER RIDGE CONTROLS THE ENTIRE BASIN. AT MID LEVEL... IT IS ANCHORED ON A HIGH OVER CENTRAL CUBA. SWLY WINDS ON THE WESTERN PERIPHERY OF THE UPPER RIDGE ARE TRANSPORTING UPPER LEVEL MOISTURE FROM THE EPAC ACROSS PANAMA/COSTA RICA INTO THE SW CARIBBEAN. THESE WINDS...PAIRED WITH THE CLOSE PROXIMITY OF THE EPAC ITCZ ARE ENHANCING MODERATE TO STRONG CONVECTION OVER THE AREA...BUT PARTICULARLY OVER E PANAMA. STRONG SUBSIDENCE IS NOTED OVER THE REMAINDER OF THE SEA PROVIDING NICE WEATHER CONDITIONS. A WEAK SFC TROUGH IS OVER THE CENTRAL CARIBBEAN ALONG 72W SOUTH OF 15N GENERATING SOME SHOWER ACTIVITY OVER WESTERN VENEZUELA...INCLUDING THE AREA OF LAKE MARACAIBO. LIGHT TO MODERATE TRADE WINDS ARE OVER THE CARIBBEAN WITH THE STRONGEST WINDS JUST N OF THE COLOMBIAN COAST. THE ATLANTIC OCEAN... MAIN FEATURE IN THE W ATLC IS A 1011 MB DEVELOPING GALE CENTER LOCATED NEAR 27N69W AT 23/1200 UTC. THIS LOW IS FORECAST TO MOVE SE AND SLIGHTLY WEAKEN. A MID/UPPER-LEVEL TROUGH ALONG 62W/63W N OF 16N SUPPORTS THIS LOW THAT HAS A TROUGH HANGING WSW ACROSS THE CENTRAL BAHAMAS. MOST OF THE DEEP CLOUDINESS...SCATTERED SHOWERS AND TSTMS ARE SITUATED TO THE E OF THE CENTER IN AN UPPER DIFFLUENT ZONE FROM 22N-32N BETWEEN 52W-61W. THE ATTACHED COLD FRONT EXTENDS FROM 28N65W TO 21N68W. A WARM FRONT ALSO EXTENDS FROM THE LOW TO 27N56W. AT THIS POINT...A SFC TROUGH CONTINUES MAINLY EWD AND CONNECTS WITH A COLD FRONT N OF AREA. VIS SATELLITE IMAGERY SHOWS DISTINCT TURNING IN THE LOW-LEVEL CLOUDS ASSOCIATED WITH THE LOW. ANOTHER SWIRL OF LOW CLOUDS IS NEAR 27N72W...JUST E OF THE BAHAMAS. AN AREA OF SHOWERS WITH EMBEDDED TSTMS HAS DEVELOPED NE OF THE LEEWARD ISLANDS NEAR 20N57W. UPPER DIFFLUENCE ASSOCIATED WITH THE ABOVE MENTIONED TROUGH IS HELPING TO INDUCE THIS ACTIVITY. THE E ATLC IS QUIET UNDER THE INFLUENCE OF A SFC HIGH PRES AND ZONAL FLOW ALOFT DOMINATING THE WX PATTERN. THIS IS PRODUCING PATCHES OF LOW/MID CLOUD WITH MAINLY LIGHT SHOWERS...AND MODERATE NE TO E TRADES. $$ GR