000 AXNT20 KNHC 292322 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI DEC 29 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA... CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA... NORTHEASTERN 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ... ITCZ IS CENTERED ALONG 5N9W 3N25W 2N42W TO THE EQUATOR AND 51W. ISOLATED MODERATE CONVECTION IS WITHIN 180 NM N AND 120 NM S OF THE AXIS BETWEEN 22W-40W. ...DISCUSSION... THE GULF OF MEXICO... LITTLE CHANGE HAS OCCURRED OVER THE PAST 24 HOURS IN THE GULF OF MEXICO. THE MAIN WEATHER FACTOR THIS EVENING CONTINUES TO BE THE STRONG SELY WINDS IN THE WRN GULF. SFC OBSERVATIONS INDICATE SE FLOW FROM 20-25 KT ACROSS THE W PORTION WHERE A FAIRLY TIGHT PRES GRAD PERSISTS BETWEEN A SLOW MOVING LARGE LOW PRES SYSTEM IN THE S CENTRAL U.S. AND HIGH PRES CENTERED ACROSS THE MID-ATLANTIC STATES. THE SFC FLOW GRADUALLY RELAXES AND VEERS MORE TO THE E IN THE E GULF...CLOSER TO THE SFC HIGH. THE MID AND UPPER LEVEL PATTERN IS HIGHLY AMPLIFIED WITH A LARGE LOW CENTERED OVER NEW MEXICO...WHICH IS ASSOCIATED WITH THE SFC LOW PRES SYSTEM MENTIONED ABOVE...AND A RIDGE AXIS ALONG 82W. WIDESPREAD DRY AIR IS NOTED ON WATER VAPOR IMAGERY PROVIDING A STABLE ENVIRONMENT ACROSS MUCH OF THE GULF OF MEXICO. HOWEVER...STABLE CONDITIONS ARE NOT FOUND ACROSS E TEXAS WHERE STRONG SLY UPPER LEVEL WINDS AND A SHARP AIRMASS CONTRAST IS PRODUCING STRONG TSTMS AND POSSIBLE TORNADOES. LOOKING AHEAD...THE TRAILING COLD FRONT...CURRENTLY IN NE MEXICO...WILL ENTER THE NW GULF LATE TONIGHT/EARLY SAT AND WILL WEAKEN AS IT TRACKS ESE ACROSS THE AREA. THE ATMOSPHERE WILL MOISTEN AHEAD OF THE FRONT AND WINDS WILL TURN MORE TOWARD THE S. ONCE THE FRONT PASSES...A SLIGHTLY COOLER AND DRIER AIRMASS WILL ADVECT IN. THE CARIBBEAN SEA... THE CARIBBEAN IS QUIET THIS EVENING. SOME DEBRIS MID-HIGH LEVEL CLOUDINESS WITH POSSIBLE ISOLATED SHOWERS ARE STREAMING NEWARD INTO S MEXICO...EL SALVADOR AND GUATEMALA. THIS CLOUDINESS IS ASSOCIATED WITH A STRONGLY SHEARED AREA OF LOW PRES IN THE EPAC. OTHERWISE...NO DEEP MOISTURE IS APPARENT ON SATELLITE IMAGERY WITH A BROAD MID TO UPPER LEVEL RIDGE AND PLENTY OF DRY STABLE AIR ALOFT COVERING THE REGION. THE DRIEST AIR LIES E OF 70W S OF 16N WHERE UPPER LEVEL CONFLUENCE IS QUIET STRONG. TRADE WINDS REMAIN ON THE STRONG SIDE MAINLY IN THE 20 TO 25 KT RANGE EXCEPT TO 30 KT IN THE SW CARIB. THESE WINDS WILL LIKELY REMAIN THAT WAY OVER THE NEXT FEW DAYS AS THE PRES GRAD IN THE AREA CHANGES LITTLE. MODELS ALSO SHOW LITTLE CHANGE IN MOISTURE AND THE UPPER LEVEL PATTERN. THE ATLANTIC OCEAN... A LONG WAVE UPPER LEVEL RIDGE/TROUGH/RIDGE PATTERN HAS SET UP ACROSS THE SUBTROPICAL ATLC. STARTING IN THE W ATLC...PLENTY OF DRY AIR IN THE MID AND UPPER LEVELS IS SPREADING EWARD COVERING THE AREA W OF 65W. THIS STABLE AIR IS ASSOCIATED WITH AN UPPER RIDGE CENTERED ALONG 80W-82W. A RATHER FLAT UPPER TROUGH COVERS THE REGION BETWEEN 45W-65W. AN ASSOCIATED COLD FRONT EXTENDS ALONG 32N40W 27N54W. UPPER DIFFLUENCE ENHANCED BY SFC FORCING IS PRODUCING A SWATH OF MAINLY MID-HIGH LEVEL MOISTURE N OF 23N BETWEEN 49W-63W. THE REMAINDER OF THE SUBTROPICAL ATLC IS DOMINATED BY A LARGE STACKED RIDGE. THE MID TO UPPER LEVEL CENTER IS LOCATED NEAR 26N33W WITH THE ASSOCIATED 1028 MB SFC HIGH ANALYZED FARTHER TO THE NE NEAR 31N23W. WIDESPREAD DRY SINKING AIR ALONG WITH HIGH PRESSURE IS PRODUCING FAIR WEATHER ACROSS A LARGE PORTION OF THE ATLC...BASICALLY E OF 50W. IN THE TROPICAL E ATLC...A CUT OFF UPPER LOW IS LOCATED TO THE S OF THE LARGE SUBTROPICAL RIDGE NEAR 16N31W. STRONG SW TO WLY UPPER LEVEL WINDS IS GENERATING ABUNDANT CLOUDINESS AND LIKELY EMBEDDED SCATTERED SHOWERS E OF 30W FROM 10N-21N. $$ CANGIALOSI