000 AXNT20 KNHC 142342 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST WED NOV 14 2007 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. ...TROPICAL WAVES... TROPICAL WAVE IS OVER CENTRAL AMERICA ALONG 85W S OF 16N MOVING W 10-15 KT. LAST SEVERAL VISIBLE IMAGES OF THE DAY SHOWED AN AREA OF LOW-LEVEL TURNING JUST OFF THE PACIFIC COAST OF COSTA RICA. THERE IS A FAIR AMOUNT OF CLOUDINESS AND EMBEDDED ISOLATED SHOWERS AND TSTMS OVER CENTRAL AMERICA AND THE FAR WRN CARIB WATERS. THIS MOISTURE APPEARS PARTIALLY ASSOCIATED WITH THIS WAVE AND DIFFLUENCE ALOFT ALONG AN ELONGATED UPPER RIDGE AXIS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 6N28W 8N45W 10N62W. SATELLITE IMAGES AND THE MIMIC TPW ANIMATION REVEAL WELL DEFINED LOW-LEVEL TROUGHING...WHICH COULD BE CLASSIFIED AS A TROPICAL WAVE...ALONG 45W/46W FROM 4N-14N. SCATTERED SHOWERS AND TSTMS TRAIL THE TROUGH AXIS FROM 7N-12N BETWEEN 37W-44W. SIMILAR ACTIVITY IS WITHIN 120 NM S OF THE AXIS BETWEEN 27W-34W. DISCUSSION... GULF OF MEXICO... WEAK SFC HIGH PRES...ANALYZED 1019 MB...HAS BEEN NEARLY STATIONARY OVER THE PAST DAY CENTERED ABOUT 150 NM S OF MOBILE ALABAMA NEAR 28N87W. THIS HAS ALLOWED WINDS TO BE FAIRLY LIGHT AND ANTICYCLONIC ACROSS THE REGION. HOWEVER...A CHANGE IS NOT FAR AWAY AS A COLD FRONT MAKES ITS WAY INTO THE REGION. THIS FRONT IS CURRENTLY OVER SE TEXAS EXPECTED TO ENTER THE NW WATERS TONIGHT. WINDS WILL SHIFT NLY AND INCREASE SIGNIFICANTLY BEHIND THE BOUNDARY. THIS FLOW WILL ADVECT A COOLER AND DRIER AIRMASS INTO THE REGION. CURRENT DEWPOINTS BEHIND THE BOUNDARY ARE AS LOW AS THE SINGLE DIGITS F IN THE TEXAS PANHANDLE. THIS AIRMASS...OF COURSE VERY MUCH MODIFIED...WILL MOVE INTO THE REGION TONIGHT AND TOMORROW. ALOFT...A MID TO UPPER LEVEL RIDGE HAS BUILT NWD INTO THE SW GULF WHILE A SERIES OF UPPER SHORTWAVES PROPAGATE THROUGH THE EXTREME NE PORTION. ABUNDANT SUBSIDENCE LIES OVER THE BULK OF THE REGION PROVIDING WIDESPREAD FAIR WEATHER. CARIBBEAN SEA... THE WEATHER ACROSS THE WRN CARIB HAS SIGNIFICANTLY QUIETED DOWN...COMPARED TO THE PAST COUPLE OF DAYS...AS LOW-LEVEL TROUGHING HAS MOVED W OF THE AREA. THERE STILL IS SOME ISOLATED SHOWERS AND TSTMS S OF 18N W OF 80W ASSOCIATED WITH A TROPICAL WAVE OVER CENTRAL AMERICA AND A DIFFLUENT PATTERN ALOFT ALONG A STRETCHED UPPER RIDGE AXIS. A WEAK SFC TROUGH...OR POSSIBLE TROPICAL WAVE...IS IN THE E CARIB ALONG 66W S OF 17N. IR IMAGERY SUGGESTS ISOLATED SHOWERS WITHIN 90 NM OF THE AXIS. THE REMAINDER OF THE AREA IS RATHER TRANQUIL UNDER MODERATE TO FRESH TRADE WIND FLOW AND STABLE MID AND UPPER LEVEL AIR ADVECTED BY W TO NWLY FLOW. ATLANTIC OCEAN... SATELLITE IMAGERY SHOWS DEEP LAYER TROUGHING OVER THE SW ATLC WITH THE UPPER SHORTWAVE EXTENDING FROM NEAR BERMUDA TO THE BAHAMAS. THIS SHORTWAVE IS SUPPORTING A NEW 1012 MB SFC LOW CENTERED OVER THE WRN BAHAMAS NEAR 25N78W...ADDED TO THE SFC MAP AT 21Z. WHILE LOW-LEVEL TURNING IS EASILY APPARENT IN NIGHT CHANNEL VIS IMAGES AND TO SOME DEGREE IN SFC DATA...MUCH OF THE THICK CLOUDINESS IS SHEARED WELL TO THE E OF THE LOW BY STRONG UPPER WLYS. MIAMI DOPPLER RADAR DEPICTS ISOLATED PATCHES OVER S FLA...MORE SCATTERED IN NATURE ACROSS THE FL KEYS. THE AFOREMENTIONED THICKER CLOUDS AND EMBEDDED SCATTERED SHOWERS AND TSTMS ARE FROM 23N-30N BETWEEN 70W-75W. THE BROAD UPPER TROUGHING OVER THE CENTRAL AND W ATLC IS SUPPORTING A COLD FRONT WHICH EXTENDS ALONG 32N34W 23N47W THEN DISSIPATING TO 20N55W. LOW-LEVEL CONVERGENCE NEAR THE FRONT COUPLED WITH EXTENSIVE MID AND UPPER LEVEL SWLY FLOW IS PRODUCING SCATTERED SHOWERS AND TSTMS N OF 27N BETWEEN 34W-41W. ISOLATED ACTIVITY IS ELSEWHERE WITHIN 120 NM OF THE BOUNDARY. SHORTWAVE IR IMAGES SUGGEST A POSSIBLE WEAK FRONTAL LOW FORMING...WILL ASSESS THIS AT 00Z. THE REMAINDER OF THE CENTRAL AND E ATLC IS UNDER WEAK SFC RIDGING ANCHORED BY A 1020 MB HIGH NEAR 28N28W. THIS PATTERN IS ALLOWING WINDS TO BE LIGHT TO MODERATE ACROSS THE REGION. IN THE MID AND UPPER LEVELS...A BROAD RIDGE COVERS MOST OF THE AREA WITH THE AXIS EXTENDING FROM AN ELONGATED ANTICYCLONE NEAR 10N37W TO 32N29W. A ELONGATED TROUGH CUTS ACROSS THE FAR E PORTION EXTENDING SW FROM A LARGE CUT OFF OVER CENTRAL EUROPE. A WEAKENED SWLY JET ORIGINATES JUST E OF THE TROUGH BASE NEAR 11N29W AND EXTENDS NE TO AFRICA NEAR 17N16W. DIFFLUENCE TO THE SE OF THE JET IS ONLY PRODUCING HIGH CLOUDINESS WITHIN 90 NM OF THE JET AXIS. $$ CANGIALOSI