000 AXNT20 KNHC 171135 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT NOV 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...TROPICAL WAVES... TROPICAL WAVE APPEARS TO HAVE PICKED UP SOME SPEED AS IT APPROACHES THE WINDWARD ISLANDS NOW CLOSE TO 60W S OF 16N MOVING W 15-20 KT. THIS WAVE HAS GAINED CONVECTION OVERNIGHT WITH LATEST IR IMAGES REVEALING SCATTERED MODERATE FROM 9N-12N BETWEEN 57W-61W. BUOY DATA IN THE REGION SHOWS A PRES MINIMUM NEAR THE WAVE AXIS AND AN EARLIER QSCAT PASS DEPICTED A SLIGHT INCREASE IN THE ELY TRADES ALONG AND TO THE E OF THE WAVE AXIS. TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 76W S OF 17N MOVING W 10-15 KT. THE MIMIC TPW ANIMATION PROVIDES A BIT OF HISTORY ON THIS WAVE SHOWING A WELL DEFINED...ALBEIT NARROW...MOISTURE PLUME TRACKING WWD ACROSS THE CARIB THU AND EARLY FRI. THIS MOISTURE AREA...WHICH IS THOUGHT TO REPRESENT MUCH OF THE WAVE ENERGY...HAS BEEN PULLED TO THE NE BY A STRONG COLD FRONT OVER THE LAST 12-18 HOURS. THE LEFT OVER PORTION OF THE WAVE IS WEAK AND IS ONLY PRODUCING ISOLATED SHOWERS IN ITS VICINITY. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 6N26W 7N40W 8N56W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N OF THE AXIS BETWEEN 26W-33W AND WITHIN 240 NM S OF THE AXIS BETWEEN 33W-39W. SCATTERED MODERATE IS ALSO WITHIN 120 NM N OF THE AXIS BETWEEN 47W-53W. DISCUSSION... THE GULF OF MEXICO... SFC HIGH PRES CONTINUES TO SHIFT E CENTERED OVER THE GEORGIA/FLORIDA BORDER NEAR 31N85W...ANALYZED 1022 MB. ITS A VERY CHILLY MORNING E OF THE HIGH ACROSS PORTIONS OF THE SOUTHEAST WITH TEMPS AS COLD AS THE MID TO UPPER 20'S F IN THE TYPICAL COOLER INLAND PORTIONS OF NW FLORIDA. THE AIRMASS MODIFIES FURTHER W ESPECIALLY W OF 90W WHERE LOW-LEVEL RETURN FLOW HAS SET UP. FAIR WEATHER EXISTS ACROSS THE ENTIRE AREA WITH SATELLITE IMAGERY SHOWING COOL AIR STRATOCUMULUS CLOUDS AS THE PRIMARY MOISTURE SOURCE IN THE CENTRAL AND E GULF AND SOME PATCHY LOW TO MID LEVEL CLOUDS IN FAR WRN PORTION...PICKED UP BY THE MORE MOIST LOW-LEVEL FLOW. IN THE MID AND UPPER LEVELS ...MODEST RIDGING AND ABUNDANT STABLE AIR COVERS THE REGION. LOOKING AHEAD A DAY OR TWO...SFC HIGH PRES IS EXPECTED TO CONTINUE TRACKING EWD ALLOWING E TO SE FLOW TO DEVELOP WHICH WILL ALLOW TEMPS TO RECOVER BACK TOWARD NORMAL. THE CARIBBEAN SEA... STRONG COLD FRONT THAT SWEPT THROUGH THE GULF OF MEXICO THU AND FRI IS GRADUALLY LOSING ITS IDENTITY IN THE NW CARIBBEAN ...ANALYZED FROM ERN CUBA TO THE CENTRAL YUCATAN COAST. COOL AIR HAS WORKED ITS WAY AS FAR S AS THE NRN YUCATAN WITH TEMPS IMPRESSIVELY AS LOW AS THE UPPER 50'S F IN CANCUN. THERE IS SOME PATCHY LOW-LEVEL CLOUDINESS AND ISOLATED SHOWERS WITHIN 60 NM OF THE FRONT. FARTHER S...IR IMAGERY SHOWS SMALL CLUSTERS OF SHOWERS AND ISOLATED TSTMS IN THE SW CARIB FROM 9N-12N BETWEEN 79W-83W ASSOCIATED WITH LOW-LEVEL CONFLUENCE NEAR THE ITCZ. SIMILAR WEATHER IS OCCURRING OVER HISPANIOLA AND NEARBY WATERS TIED TO THE TAIL END OF A PRE-FRONTAL TROUGH. SAN JUAN DOPPLER RADAR...WHICH WAS ACTIVE EARLIER...SHOWS NEARLY ALL OF THE ACTIVITY W OF THE ISLAND. SCATTERED SHOWERS AND TSTMS ARE ALSO MAKING THEIR WAY TOWARD THE WINDWARD ISLANDS TRIGGERED BY APPROACHING TROPICAL WAVE. THE REMAINDER OF THE AREA IS RELATIVELY TRANQUIL WITH MODERATE DRY AIR AND SW TO ZONAL FLOW OVERHEAD. THE ATLANTIC OCEAN... MID AND UPPER LEVEL TROUGHING DOMINATES MUCH OF THE WRN ATLC EXTENDING SWD FROM A POLAR VORTEX. THIS UPPER SYSTEM IS SUPPORTING A FAIRLY STRONG COLD FRONT WHICH STRETCHES FROM 32N58W ACROSS THE SE BAHAMAS. THE COMBINATION OF SFC HIGH PRES BEHIND THE FRONT AND A VERY DRY ENVIRONMENT ALOFT IS PROVIDING FAIR AND COOL WEATHER ACROSS THE SW ATLC. NIGHT CHANNEL VIS IMAGERY SHOWS A LARGE AREA OF SCATTERED STRATOCUMULUS CLOUDS...INDICATIVE OF THE COOL AIRMASS IN PLACE. SOME ACTIVE WEATHER LIES IN A DIFFLUENT ZONE ALOFT BETWEEN THE TROUGH AND A RIDGE AXIS ALONG 50W/51W. IR IMAGES AND LIGHTNING DATA REVEAL SCATTERED SHOWERS AND TSTMS N OF 23N BETWEEN 52W-60W AND S OF 20N BETWEEN 66W-70W. A SFC PRE-FRONTAL TROUGH FROM 26N58W TO THE DOMINICAN REPUBLIC IS ENHANCING SOME OF THIS WEATHER ESPECIALLY S OF 20N. PART OF THE CENTRAL ATLC...BETWEEN 40W AND 53W...IS DOMINATED BY DEEP LAYER RIDGING AND DEBRIS HIGH LEVEL CLOUDINESS. THE PATTERN QUICKLY CHANGES THEME IN THE E ATLC WHERE LARGE SCALE DEEP LAYER TROUGHING IS IN PLACE ANCHORED BY AN OCCLUDED LOW NEAR 35N28W. A MID-LEVEL DISTURBANCE TO THE S OF THE OCCLUDED LOW APPEARS TO HAVE BUILT DOWN TO THE SFC AND A 1011 MB LOW WAS ADDED TO THE MAP NEAR 25N31W AT 06Z. THIS LOW LIES ALONG A FRONT EXTENDING FROM A 1005 MB LOW W OF THE MADEIRA ISLANDS NEAR 34N20W TO 24N42W. ASSOCIATED SCATTERED SHOWERS AND TSTMS HAVE BECOME INCREASINGLY STRETCHED FROM 23N-29N BETWEEN 26W-32W. A SWLY JET BRANCH HAS SET UP NEAR THE BASE OF THE TROUGH AND THEN RUNS NE ALONG 14N47W 17N30W 24N22W GENERATING AND ADVECTING MID-HIGH LEVEL CLOUDINESS WITHIN 150 NM SE OF THE JET AXIS. $$ CANGIALOSI