000 AXNT20 KNHC 181100 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST THU JAN 18 2007 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N11W 5N20W 3N30W 2N52W. ISOLATED CLUSTERS OF MODERATE CONVECTION ARE WITHIN 120NM OF THE AXIS BETWEEN 22W-33W AND BETWEEN 41W-52W. ...DISCUSSION... GULF OF MEXICO... THIS MORNINGS WV IMAGERY CONTINUES TO SHOW SUBTROPICAL JET SPREADING SIGNIFICANT AMOUNT OF MID TO UPPER MOISTURE FROM THE NE PAC...THROUGH NRN MEXICO...TEXAS...AND CLIPPING THE NRN GULF WATERS. MUCH DRIER AIR IS PRESENT SE OF A LINE FROM TAMPICO MEXICO TO TAMPA FLORIDA. UPPER PATTERN REMAINS DOMINATED BY RIDGING. SHORTWAVE IR IMAGERY DEPICTS BROKEN TO OVERCAST LOW CLOUDS BEHIND THE LINGERING SFC FRONTAL BOUNDARY...WHICH AS OF 0900 UTC EXTENDS W AS A COLD FRONT FROM S FLORIDA TO 26N85W...THANKS TO THE RECENTLY FORMED SFC LOW NEAR COCOA BEACH. FRONT THEN EXTENDS W AS A STATIONARY FRONT TO 26N95W...THEN SSE THROUGH THE CENTRAL BAY OF CAMPECHE. LIGHT RAIN CAN BE EXPECTED BEHIND THE FRONT WITH THE ISENTROPIC LIFT OCCURRING. WINDS AND SEAS WILL CONTINUE TO RELAX ACROSS THE GULF TODAY AS THE HIGH OVER NE MEXICO WEAKENS...IN ADDITION TO THE NEW LOW OFF FLORIDA AND COASTAL FRONT OFF THE SE COAST PRODUCING A WEAKNESS IN THE ONCE WELL ESTABLISHED SFC RIDGE OVER THE AREA. HOWEVER...NE WINDS AND WIND WAVES TO INCREASE AGAIN IN NW PORTION TONIGHT THROUGH SAT AS LINGERING TROUGH INTERACTS WITH REINFORCING CONTINENTAL HIGH PRESSURE. CARIBBEAN SEA... EXTENSIVE DRY AIR IN THE MID TO UPPER LEVELS CONTINUES TO SUPPRESS CONVECTION OVER THE ENTIRE CARIBBEAN. MODERATE TO STRONG TRADE WINDS ALSO CONTINUE OVER THE CARIBBEAN BASIN WITH THE MAXIMA REMAINING NEAR THE COLOMBIAN COAST AROUND 30 KT. THE TRADES ARE ADVECTING TYPICAL PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED SHOWERS ACROSS THE AREA. SIMILAR CONDITIONS EXPECTED ACROSS THE CARIBBEAN THROUGH THE WEEKEND. ATLANTIC OCEAN... UPPER RIDGE IS BUILDING INTO THE SW N ATLC BEHIND A WEAKENING UPPER TROUGH. THIS IS ADVECTING HIGH CLOUDS/MOISTURE EWD FROM THE SE U.S. COAST INTO THE ATLC WATERS N OF 26N W OF 55W. SIGNIFICANT DRY UPPER AIR IS OVER THE SW N ATLC S OF 26N THROUGH THE CARIBBEAN. STRONG SFC HIGH PRESSURE REMAINS OVER THE W ATLC BEHIND THE COLD FRONT THAT ENTERS THE AREA AT 32N57W AND CONTINUES SW TO 27N72W WHERE IT CONTINUES WNW AS A WARM FRONT TO THE NEWLY FORMED WEAK SFC LOW NEAR COCOA BEACH. BROKEN LOW CLOUDS/LIGHT RAIN SEEN OVER THE AREA BEHIND THE FRONT...IN ADDITION TO MODERATE TO STRONG NE TO E WINDS/WAVES. WINDS WILL BACK OFF DURING THE DAY AS THE LOW LIFTS NE AND PRODUCES A WEAKNESS IN THE RIDGE. HOWEVER...ASSOCIATED MODERATE NLY SWELL WILL STILL BE FELT FROM THE OLD FRONT AS IT SPREADS E THROUGH THE AREA...PEAKING IN THE SE BAHAMAS TONIGHT AND AT EXPOSED PUERTO RICO BEACHES DURING SAT...THEN SUBSIDING FROM W TO E. CENTRAL ATLC IS DOMINATED BY THE 1016 MB SFC LOW NEAR 23N52W. THIS HAS A MERIDIONAL SFC TROUGH WITH IT FROM 14N-29N...AND IS A REFLECTION OF THE UPPER TROUGH EXTENDING THROUGH THE AREA. ASSOCIATED SCATTERED MODERATE CONVECTION IS FROM 20N-26N BETWEEN 45W-52W. ABUNDANT MOISTURE WITH POSSIBLE SCATTERED SHOWERS ARE ELSEWHERE FROM 11N-21N BETWEEN 37W-47W. ANOTHER UPPER LOW IS OVER THE E ATLC NEAR 22N27W...THAT ALSO HAS SIGNIFICANT MOISTURE WITH EMBEDDED SHOWERS MAINLY TO ITS E FROM 12N-27N BETWEEN AFRICA AND 27W. THERE MAY BE A WEAK REFLECTION OF THIS AT THE SFC...THOUGH THE E ATLC SFC PATTERN IS GENERALLY DOMINATED BY MODERATE E TO NE WINDS S OF THE RIDGING FROM SW EUROPE. $$ WILLIS