000 AXNT20 KNHC 190003 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI JAN 18 2008 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 8N13W 4N20W 1N30W EQ40W 1S48W. CLUSTERS OF SCATTERED MODERATE CONVECTION LIE NORTH OF THE ITCZ FROM 1N-4N BETWEEN 25W-40W. ...DISCUSSION... GULF OF MEXICO... A VIGOROUS SRN STREAM SHORTWAVE IMPULSE ROTATING THROUGH A LARGER-SCALE TROUGH OVER THE W CNTRL CONUS IS CAUSING THE DEVELOPMENT OF A BROAD AREA OF SFC LOW PRESSURE OVER THE WRN GULF OF MEXICO. AS OF 2100 UTC...THE BROAD 1008 MB SFC LOW IS LOCATED NEAR 25N95W OVER THE W CNTRL GULF OF MEXICO AND IS SLOWLY RIDING N/NE WHILE DRAGGING THE POLAR FRONT WITH IT. THE POLAR FRONT EXTENDS EAST OF THE SFC LOW TO 24N90W 25N85W TO A PSN SOUTH OF LAKE OKEECHOBEE AND THEN N OF THE NWRN BAHAMAS. A MODERATELY STRONG S TO SELY FLOW FROM THE NW CARIBBEAN AND SERN GULF IS DRAWING COPIOUS MOISTURE TO THE FRONT...RESULTING IN A WELL-DEFINED OVERRUNNING PCPN PATTERN OVER THE NWRN AND NOW CNTRL GULF OF MEXICO. IN FACT...STRONG UPPER-LEVEL DIVERGENCE AND POTENTIAL VORTICITY ADVECTION ACTING ON PRECIPITABLE WATER VALUES IN EXCESS OF 1.5 INCHES OVER THE WRN AND CNTRL GULF OF MEXICO ARE CREATING A LARGE SHIELD OF LGT/MDT PCPN IN THE COLD SECTOR N AND W OF THE SFC LOW. IN ADDITION...SATELLITE AND RADAR TRENDS INDICATE A RAPIDLY EXPANDING AREA OF CONVECTION WITHIN ABOUT 150 NM NE OF THE SFC WAVE AND N OF THE ASSOCIATED WARM FRONT. MODELS SUGGEST THAT THE SFC WAVE HAS THE POTENTIAL TO DEVELOP INTO A GALE CTR AS IT TRACKS RAPIDLY ENE THROUGH THE N CNTRL/NERN GULF OF MEXICO SAT MORNING AND AFTERNOON...BEFORE REFORMING OFF THE SE CONUS SAT NIGHT. AS THIS OCCURS...THE POLAR FRONT SHOULD AGAIN SWEEP THROUGH MOST OF THE GULF BY SUN MORNING...WITH STG SFC HIGH PRESSURE FORECAST TO BUILD INTO THE WRN/CNTRL GULF IN THE WAKE OF THE GALE BY SAT NIGHT. THIS SHOULD LEAD TO A STG NLY FLOW OF 2O TO POSSIBLY 40 KTS FROM THE NWRN GULF COAST THROUGH THE BAY OF CAMPECHE. CARIBBEAN SEA... A STRONG MID TO UPPER LEVEL ANTICYCLONE REMAINS ANCHORED ACROSS SRN COLOMBIA...WITH A RIDGE AXIS EXTENDING NWD ROUGHLY ALONG 75W INTO THE CARIBBEAN BASIN. STRONG SUBSIDENCE AND A RELATIVELY HIGH ATMOSPHERIC STABILITY ASSOCIATED WITH THIS FEATURE CONTINUES TO HOLD SWAY ACROSS MOST OF THE AREA ...ESPECIALLY FROM THE SOUTHWESTERN THROUGH THE SOUTHEASTERN CARIBBEAN SEA. DESPITE THE HIGH ATMOSPHERIC STABILITY ALOFT...A MODERATE TO OCCASIONALLY STRONG TRADE WIND FLOW AND STRONG SHEAR OF THE LOW-LEVEL WIND CONTINUES TO GENERATE VARIABLE CLOUDINESS AND STREAKS OF SHOWERS FROM THE E CNTRL THROUGH THE W CNTRL CARIBBEAN SEA. THE MOST CONCENTRATED ACTIVITY HAS BEEN OCCURRING IN THE VICINITY OF PUERTO RICO AND HISPANIOLA LATE THIS AFTERNOON ...WITH MORE WIDELY SCATTERED ACTIVITY ELSEWHERE ACROSS THE AREA. A QUIKSCAT PASS INDICATES THE STRONG WINDS LIE FROM THE NRN COLOMBIA COAST TO ABOUT 14N BETWEEN 72W-78W. OTHER LESS DEFINED BANDS OF CLOUDS AND OCCASIONAL SHOWERS CONTINUE TO AFFECT PARTS OF THE WRN AND NWRN CARIBBEAN...LIKELY RELATED TO SHEAR OF THE LOW-LEVEL WIND AND SPEED CONVERGENCE. GOING FORWAR... MODEL GUIDANCE INDICATES THAT THE POLAR FRONT... CURRENTLY OVER THE GULF OF MEXICO ...SHOULD DESCEND INTO THE EXTREME NWRN CARIBBEAN BY SUN MORNING ...ACCOMPANIED BY STRONG N TO NE WINDS OF UP TO 30 KTS AND BUILDING SEAS. AS THIS OCCURS...WINDS AHEAD OF THE FRONT SHOULD SLACKEN QUITE A BIT OVER THE REMAINDER OF THE NWRN CARIBBEAN. HOWEVER...AS BROAD SFC HIGH PRESSURE OVER THE CNTRL ATLANTIC WILL BEGIN DRIFTING EWD THROUGH THE PD...A STRONG EARLY FLOW SHOULD CONTINUE TO PREVAIL FROM THE E CNTRL TO THE W CNTRL CARIBBEAN...AS STRONG OR PERHAPS STRONGER THAN THE CURRENT REGIME. ATLANTIC OCEAN... A COLD FRONT EXTENDING ALONG A LINE FROM 30N75W 29N77W CONTINUES MOVING SLOWLY E AND SE...WHILE THE WRN END REMAINS STATIONARY FROM 29N77W TO JUST N OF FT PIERCE FL AND SWWD TO N OF NAPLES FL. SCATTERED TO BROKEN CLOUDINESS AS WELL AS A FEW SHOWERS ARE LOCATED WITHIN 90NM NW THIS FEATURE. ANOTHER COLD FRONT EXTENDS ACROSS THE CNTRL ATLANTIC FROM 32N34W 24N45W 2160W...WITH A 1026 MB SFC HIGH NEAR 32N60W BUILDING IN BEHIND IT. THE FRONT IS DEFINED BY A BAND OF MOSTLY SCATTERED LOW CLOUDS SW OF 27N35W...WHILE MORE CONCENTRATED CLOUDS AND A FEW SHOWERS ACCOMPANY THE NRN END THROUGH 32N34W. TO THE EAST...A 1033 MB HIGH LOCATED OVER PORTUGAL AND WRN SPAIN DOMINATES THE NE ATLANTIC...AHEAD OF THE ABOVE MENTIONED FRONT....WITH A RIDGE AXIS EXTENDING AS FAR S AND W AS 27N25W. MEANWHILE...AT UPPER LEVELS...RIDGING FROM THE WRN CARIBBEAN BUBBLES NWD THROUGH THE SWRN ATLANTIC...WHILE A BROAD LONGWAVE TROUGH COVERS THE REMAINDER OF THE ATL E OF ABOUT 65W. IN THE BASE OF THE ABOVE LONGWAVE TROUGH...A STRONG 70-90KT JET CONTINUES TO TRANSPORT CONSIDERABLE UPPER-LEVEL MOISTURE/HIGH CLOUDS FROM NORTHERN SOUTH AMERICA NE TO THE NWRN COAST OF AFRICA. LOOKING AHEAD...MODELS DRIVE THE COLD FRONT CURRENTLY OVER THE SWRN ATL THROUGH THE BAHAMAS AND INTO THE NRN CARIBBEAN BY SUN NIGHT ...FOLLOWED BY A STRONG AND COLD SFC RIDGE BUILDING IN BEHIND IT OVER THE ERN CONUS. EXPECT A GENERALLY NE FLOW OF 20-30 KTS TO COVER THE AREA W OF 70W TO THE COAST OF FL SUN AFTERNOON AND EVENING. $$ KIMBERLAIN