000 AXNT20 KNHC 241803 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE OCT 24 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 36W/37W S OF 18N MOVING W NEAR 15 KT. INVERTED V PATTERN/CYCLONIC TURNING OF THE LOW CLOUD FIELD NOTED ABOUT THE WAVE AXIS...UNDERNEATH THE HIGHER CLOUDS STREAMING ANTICYCLONICALLY AROUND THE UPPER HIGH JUST TO THE W. SCATTERED MODERATE CONVECTION FROM 9N-14N BETWEEN 34W-43W. TROPICAL WAVE IS ALONG 58W...JUST E OF THE WINDWARD ISLANDS...S OF 19N MOVING W 10-15 KT. BROAD CYCLONIC TURNING EVIDENT IN THE LOW TO MID CLOUD FIELD...WITH NUMEROUS MODERATE/ISOLATED STRONG CONVECTION FROM 12N-18N BETWEEN 54W-61W. TROPICAL WAVE IS ALONG 75W/76W S OF 19N DRIFTING SLOWLY TO THE W. IT APPEARS THIS WAVE IS SLOWING AND BECOMING TILTED FROM SE TO NW...AND MAY BECOME EVEN MORE DIFFICULT TO TRACK AS IT INTERACTS WITH THE APPROACHING FRONTAL SYSTEM FROM THE NW. DEEP CONVECTION IS MINIMAL WITH A FEW ISOLATED SHOWERS/TSTMS NOTED WITHIN 100NM OF THE AXIS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 8N24W 11N35W 10N48W 14N55W TO INLAND OVER THE S AMERICAN COAST NEAR 10N62W. NARROW BAND OF SCATTERED MODERATE CONVECTION WITHIN 100NM OF THE LINE ALONG 5N13W 4N22W 9N31W. SCATTERED SHOWERS/TSTMS FROM 7N-15N BETWEEN 45W-55W. ...DISCUSSION... GULF OF MEXICO... MUCH OF THE GULF IS EXPERIENCING COOL FALL WEATHER THIS AFTERNOON IN WAKE OF THE RECENT COLD FRONT PASSAGE. THE TAIL END OF THE FRONTAL BOUNDARY IS PRODUCING SCATTERED SHOWERS/TSTMS IN THE BAY OF CAMPECHE FROM 19N-23N BETWEEN 92W-97W. UPPER HIGH PRESSURE OVER THIS AREA IS ALSO SUPPORTING THIS ACTIVITY. ELSEWHERE IN THE UPPER LEVELS...VERY DRY AIR MOVING OVER THE NE GULF AND FLORIDA AROUND THE LARGE TROF PUSHING OFF THE EAST COAST. SURFACE HIGH PRESSURE N OF THE AREA IS PRODUCING 15-25KT N/NE WINDS FOR THE ERN GULF WITH MORE OF AN E FLOW IN THE WRN GULF. ASSOCIATED SHORT TO MEDIUM PERIOD WIND WAVES HAVE ALSO BUILT...LARGEST S AND W PORTIONS AT THE TAIL END OF THE FETCH. WINDS AND SEAS WILL GRADUALLY VEER IN DIRECTION AND SLOWLY RELAX OVER THE NEXT COUPLE OF DAYS WITH THE HIGH MOVING EAST NORTH OF THE AREA...SEE MIAOFFNT4 FOR DETAILS. CARIBBEAN SEA... AN UPPER LOW REMAINS OVER THE NW CARIBBEAN NEAR 18N82W. THERE IS A WEAK REFLECTION OF THIS AT THE SURFACE AS A TROUGH EXTENDING NNE FROM COASTAL HONDURAS ALONG 14N85W 19N82W. SHOWER/TSTM ACTIVITY IN THE VICINITY IS OVERALL MINIMAL ASIDE FROM A FEW ISOLATED CELLS FROM 19N-21N BETWEEN 82W-87W. HOWEVER...THIS MAY BE MORE ASSOCIATED WITH PREFRONTAL LIFT AHEAD OF THE COLD FRONT NOW EXTENDING THROUGH CENTRAL CUBA TO THE YUCATAN. THIS FRONT WILL SLOW AND BEGIN TO DRIFT SE OVER THE NW WATERS DISSIPATING THROUGH THU. A FEW CLUSTERS OF SCATTERED MODERATE CONVECTION NOTED IN THE SW CARIBBEAN AND COASTAL PANAMA FROM 9N-13N BETWEEN 76W-82W...LIKELY ASSOCIATED WITH THE ITCZ AND WEAK UPPER DIFFLUENCE. LARGE SCALE...BROAD UPPER RIDGING DOMINATES THE CARIBBEAN BETWEEN 59W-78W. A FEW OTHER SMALL SCALE UPPER FEATURES EMBEDDED IN THIS REGION BUT GENERATING LITTLE IF ANY SIGNIFICANT WEATHER. THE TROPICAL WAVE JUST E OF THE WINDWARD ISLANDS IS EXPERIENCING WLY SHEAR S OF AN UPPER LOW...AND WILL MOVE THROUGH THE ERN CARIBBEAN THROUGH THE SECOND HALF OF THE WORKWEEK. ATLANTIC OCEAN... WRN ATLC DOMINATED BY STRONG SURFACE COLD FRONT PUSHING THROUGH THE AREA ASSOCIATED WITH LARGE DEEP LAYER TROUGHING PUSHING OFF THE EAST COAST. THIS HAS USHERED IN SOME OF THE COOLEST AIR OF THE SEASON THUS FAR...ALONG WITH INCREASING N/NW FLOW AND RISING SHORT TO MEDIUM PERIOD SWELL. ASSOCIATED SWELL WILL SPREAD E THROUGH THE CARIBBEAN THROUGH THE END OF THE WORKWEEK BRINGING THE FIRST APPRECIABLE WINTER-LIKE SWELL EVENT OF THE SEASON...SEE STATEMENTS FROM LOCAL WEATHER SERVICE OFFICES AND MIAOFFNT3 FOR MORE DETAILS. PREFRONTAL TROUGH ANALYZED ALONG 21N70W 28N67W AND HAS A MORE PRONOUNCED CONFLUENT ZONE WITH IT. ASSOCIATED SCATTERED MODERATE CONVECTION FROM 22N-30N BETWEEN 62W-67W...AND MOVING FAIRLY QUICKLY TO THE E. UPPER TROUGHING NOTED FROM 15N-25N BETWEEN 45W-60W...HAS A WELL DEFINED UPPER LOW CENTER NEAR 21N50W. CONVECTION IN THIS REGION IS MINIMAL ASIDE FROM THAT DESCRIBED WITH THE TROPICAL WAVE JUST E OF THE WINDWARD ISLANDS. AN UPPER HIGH NEAR 28N43W IS SURROUNDED BY VERY DRY AIR...AND ALSO HAS A 1019MB SURFACE HIGH NEARBY AT 28N48W. ANOTHER UPPER HIGH NOTED FURTHER S NEAR 13N40W. UPPER LOW SEEN SPINNING NEAR 19N28W WITH THE ASSOCIATED MOISTURE LIMITED TO 200NM E OF THE ASSOCIATED UPPER TROUGH AXIS. ERN ATLC ALSO DOMINATED BY A 1018MB SURFACE HIGH NEAR 22N28W THAT LOOKS TO DISSIPATE AS THE SURFACE HIGH FURTHER NW NEAR 28N48W TAKES OVER. THUS...THE TROUGH ANALYZED BETWEEN THESE TWO SFC HIGHS ALSO LIKELY TO DISSIPATE. $$ WILLIS