000 AXNT20 KNHC 281739 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI NOV 28 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 6N11W 3N25W 5N40W 8N48W 6N58W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ AND EXTENDS FROM 13N47W TO 8N50W. SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 120 NM WEST SIDE OF THIS SURFACE TROUGH BETWEEN 10N-12N. ELSEWHERE...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 70 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 20W-37W. SCATTERED MODERATE CONVECTION IS FROM 5N-10N BETWEEN 30W-37W. ...DISCUSSION... GULF OF MEXICO... AS OF 1500 UTC...THE GULF REMAINS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED ON A 1021 MB HIGH LOCATED OVER CENTRAL FLORIDA JUST N OF LAKE OKEECHOBEE. THIS FEATURE IS PRODUCING MOSTLY FAIR WEATHER OVER THE ENTIRE REGION. SLY RETURN FLOW HAS DEVELOPED OVER THE WESTERN GULF AS THIS SFC HIGH CONTINUES TO MOVED EWD. ALOFT...AN UPPER LEVEL RIDGE COVERS THE AREA WITH STRONG UPPER LEVEL WINDS ACROSS THE NORTHERN PERIPHERY OF THE RIDGE OVER THE SE CONUS AND N GULF WATERS. UPPER LEVEL MOISTURE CONTINUES STREAMING ACROSS THE N GULF...WHILE MODERATE TO STRONG SUBSIDENCE IS PRESENT OVER THE S GULF. LOOKING AHEAD...A STRONG COLD FRONT IS FORECAST TO MOVE OUT OF THE TEXAS COAST SATURDAY MORNING...AND WILL EXTEND FROM THE FLORIDA PANHANDLE TO THE BAY OF CAMPECHE SUNDAY AFTERNOON. WINDS ARE EXPECTED TO INCREASE ON EITHER SIDE OF THE FRONT...REACHING NEAR GALE FORCE. IN THE WAKE OF THE FRONT A RELATIVELY COOLER AND DRIER AIR MASS WILL INVADE THE GULF WITH N TO NW SURFACE WINDS. TRANQUIL WEATHER CONDITIONS ARE IN PLACE OVER SOUTH FLORIDA WHERE A VERY STABLE ATMOSPHERE PREVAILS...BUT CHANGES ARE IN STORE FOR SUNDAY AS THE COLD FRONT APPROACHES THE AREA. THE RISK OF TSTMS IS ALREADY IN THE FORECAST DUE TO INCREASING MOISTURE WITH SWLY WINDS ALOFT. CARIBBEAN SEA... IN THE SW CARIBBEAN...A 1010 MB SURFACE LOW IS CENTERED N OF PANAMA NEAR 10N78W. THE CLOUD PATTERN IS EXHIBITING THE CYCLONIC CIRCULATION ASSOCIATED WITH THIS LOW. NLY WINDS ON THE WEST SIDE OF THE LOW ARE ADVECTING LOW LEVEL MOISTURE WITH EMBEDDED SHOWERS INTO WESTERN PANAMA AND COSTA RICA...WHILE CONVECTION IS ON INCREASE ACROSS THE PACIFIC SIDE OF THESE COUNTRIES DUE TO THE CLOSE PROXIMITY OF THE EPAC ITCZ. THE TAIL END OF AN OLD FRONTAL BOUNDARY...ANALYZED AS A SURFACE TROUGH OVER THE TROPICAL CENTRAL ATLC...IS PRODUCING SCATTERED SHOWERS OVER THE SOUTHERN WINDWARD ISLANDS AND THE FAR NE OF VENEZUELA. PATCHES OF LOW LEVEL MOISTURE EMBEDDED IN THE TRADE WIND FLOW ARE NOTED ACROSS THE REMAINDER OF THE BASIN...MORE CONCENTRATED JUST SOUTH OF HISPANIOLA AND NEAR CABO GRACIAS A DIOS NICARAGUA. SIMILAR CLOUDINESS IS ALSO AFFECTING THE ABC ISLANDS...AND THE ISLANDS LOCATED JUST OFFSHORE VENEZUELA. IN THE UPPER LEVELS...A MAINLY ZONAL FLOW DOMINATES THE REGION. THE SURFACE RIDGE N OF THE AREA WILL SHIFT E AND SLOWLY WEAKEN...ALLOWING TRADEWINDS TO DECREASE ACROSS MUCH OF THE BASIN DURING THE UPCOMING WEEKEND. ON THE OTHER HAND...SE TO S WINDS WILL INCREASE OVER THE NW CARIBBEAN BEGINNING ON SUN IN ADVANCE OF A GULF OF MEXICO COLD FRONT EXPECTED TO REACH WESTERN CUBA AND THE NW CARIBBEAN EARLY MON MORNING. NW WINDS OF 15-20 KT WILL FOLLOW THE FRONT...KEEPING TEMPERATES ACROSS CUBA ON THE COOL SIDE. ATLANTIC OCEAN... SURFACE HIGH PRES CENTERED OVER CENTRAL FLORIDA EXTENDS A RIDGE OVER THE W ATLC AND THE BAHAMAS PRODUCING MOSTLY FAIR WEATHER. A WEAKENING COLD FRONT ENTERS THE REGION NEAR 31N54W THEN CONTINUES SW TO NEAR 23N67W. ISOLATED SHOWERS ARE WITHIN 30 NM OF THE FRONT. A 1001 MB LOW CONTINUES TO SPIN OVER THE CENTRAL ATLANTIC AND IS CURRENTLY CENTERED NORTH OF AREA NEAR 32N37W. THIS LOW IS ACCOMPANIED BY SHOWERS AND SQUALLS...AND THE CLOUD PATTERN IS EXHIBITING SOME SUBTROPICAL-LIKE CHARACTERISTICS. THIS SYSTEM IS MOVING NORTHWARD OVER COOLER WATERS AND FURTHER DEVELOPMENT IS NOT ANTICIPATED. A SFC TROUGH EXTENDS FROM THIS LOW INTO THE FORECAST AREA ALONG 31N32W 29N29W 25N26W. AN AREA OF SHOWERS WITH EMBEDDED TSTMS IS WITHIN 120 NM AHEAD OF THIS TROUGH N OF 26N. ANOTHER SURFACE TROUGH...REMNANTS OF AN OLD FRONTAL BOUNDARY...RUNS FROM 18N42W TO 9N60W AND IS GENERATING SOME SHOWER ACTIVITY OVER THE SOUTHERN WINDWARD ISLANDS. THE E ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE CENTERED WELL N OF THE DISCUSSION AREA. IN THE UPPER LEVELS...A RIDGE DOMINATES MUCH OF THE W ATLC. A DEEP LAYERED TROUGH LIES ALONG 62W WITH THE BASE OF THE TROUGH REACHING THE NE CARIBBEAN. A JET STREAM BRANCH WITH CORE WINDS OF AROUND 90 KT ROUNDS THE BASE OF THIS TROUGH WHICH IS SUPPORTING THE AFOREMENTIONED WEAKENING COLD FRONT. A CUT-OFF LOW REMAINS NEAR 32N40W. AN UPPER-LEVEL RIDGE CENTERED NEAR 8N38W DOMINATES THE TROPICS AND IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ AXIS. $$ GR