000 AXNT20 KNHC 272346 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT DEC 27 2008 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ... ITCZ IS ANALYZED ALONG 7N9W 1N30W CROSSING THE EQUATOR NEAR 37W AND INTO NE BRAZIL NEAR 1S50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-5N BETWEEN 10W-17W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 2N-7N BETWEEN 21W-33W. ...DISCUSSION... GULF OF MEXICO... THE GULF IS DOMINATED BY AN UPPER RIDGE THAT EXTENDS FROM THE CARIBBEAN ACROSS W CUBA AND THE E GULF TO OVER THE ERN U.S. SEABOARD WITH MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR NOTED E OF A LINE FROM LAFAYETTE LOUISIANA TO TAMPICO MEXICO. AN UPPER LEVEL TROUGH IS MOVING ACROSS THE CENTRAL U.S. PLAIN STATES TO OVER NW MEXICO AND SUPPORTS AN APPROACHING COLD FRONT POSITIONED ALONG THE TEXAS COAST. SOUTHERLY RETURN FLOW IS OBSERVED ACROSS THE ENTIRE GULF WITH PATCHES OF SCATTERED LOW CLOUDS STREAMING NWD. CARIBBEAN SEA... A BROAD UPPER RIDGE DOMINATES THE CARIBBEAN W OF 65W AND IS ANCHORED OVER SOUTH AMERICA WITH AXIS EXTENDING NW ACROSS W CUBA AND ACROSS THE FLORIDA PENINSULA. THE BASE OF AN UPPER LEVEL TROUGH IS E OF 65W AND EXTENDS NE INTO THE CENTRAL ATLC. STRONG SUBSIDENCE AND DRY AIR IS NOTED ACROSS THE ENTIRE BASIN. A SURFACE RIDGE REMAINS OVER THE W ATLC AND WITH LOWER PRESSURE OVER SOUTH AMERICA THE PRESSURE GRADIENT ACROSS THE CARIBBEAN IS PRODUCING MODERATE/STRONG ELY TRADE WINDS. THESE TRADE WINDS COUPLED WITH LOW LEVEL CONVERGENCE ARE GENERATING FAST MOVING ISOLATED SHOWERS THAT DOT MUCH OF THE CARIBBEAN. MOST NOTABLE AREA IS N OF 15N AND E OF 71W. THE MODERATE/STRONG TRADE WINDS WILL CONTINUE THROUGH MON THEN DIMINISH GRADUALLY AS HIGH PRESSURE OVER THE ATLC WEAKENS. ATLANTIC OCEAN... THE UPPER RIDGE THAT DOMINATES THE CARIBBEAN EXTENDS OVER THE W ATLC W OF 65W WITH A DEEP LAYERED TROUGH EXTENDING OVER THE CENTRAL ATLC WITH AXIS ALONG 32N45W SW TO THE NRN LEEWARD ISLANDS. THE ACCOMPANYING COLD FRONT ENTERS THE REGION NEAR 32N34W EXTENDING W-SW TO 27N50W TO 26N65W WEAKENING TO A SURFACE TROUGH EXTENDING W TO NEAR 27N75W. BROKEN/OVERCAST LOW CLOUDS WITH ISOLATED SHOWERS ARE WITHIN 60/75 NM OF THE FRONT. HIGH PRESSURE CONTINUES TO IMPACT THE W AND CENTRAL ATLC BRIDGING THE ABOVE FRONTAL BOUNDARY. A SECOND COLD FRONT ENTERS THE FAR NE ATLC NEAR 32N13W THROUGH THE CANARY ISLANDS TO 26N17W WITH ANY SHOWER ACTIVITY WELL N OF THE AREA. THE ASSOCIATED UPPER TROUGH IS N OF 31N AND E OF 8W. UPPER DIFFLUENCE AND SW UPPER FLOW ARE ACROSS THE TROPICAL ATLC E OF 55W TO OVER NW AFRICA. MULTI- LAYERED CLOUDINESS WITH ISOLATED SHOWERS COVER MUCH OF THE TROPICAL ATLC S OF A LINE FROM WRN SAHARA SW TO NEAR BARBADOS. $$ HUFFMAN