000 AXNT20 KNHC 281042 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT OCT 28 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 41W/42W S OF 13N MOVING W 10 TO 15 KT. THIS WAVE REMAINS RATHER LOW AMPLITUDE AND IS LESS DEFINED THAN IT WAS A COUPLE DAYS AGO...WITH LITTLE CURVATURE NOTED IN SAT IMAGES AND AVAILABLE SFC DATA. HOWEVER...ANALYSIS OF A HOVMOLLER DIAGRAM STILL SHOWS THE FEATURE TRACKING TO THE W. ISOLATED MODERATE CONVECTION NOTED WITHIN 150 NM OF EITHER SIDE OF THE AXIS. A TROPICAL WAVE IS MOVING THROUGH THE WINDWARD ISLANDS...ALONG 60W S OF 21N MOVING W 10 TO 15 KT. A 1010 MB LOW IS ALONG THE WAVE NEAR 13N. CLUSTERS OF SCATTERED MODERATE CONVECTION SEEN FROM 10N-17N BETWEEN 55W-65W. SOME SLOW DEVELOPMENT IS POSSIBLE WITH THIS SYSTEM DURING THE NEXT DAY OR SO. LOCALLY HEAVY RAINS AND GUSTY WINDS WILL ALSO BE POSSIBLE AS THE SYSTEM MOVES ACROSS MUCH OF THE LESSER ANTILLES AND ADJACENT EASTERN CARIBBEAN WATERS TODAY AND TONIGHT. A WEAK TROPICAL WAVE IS EXTENDING S FROM WRN HAITI ALONG 74W S OF 18N MOVING W 10 TO 15 KT. THE POSITION IS BASED ON CONTINUITY AS THE WAVE LACKS A CLEAR CUT SIGNATURE...AND MAY NEED TO BE DROPPED EVENTUALLY AS IT INTERACTS WITH THE FRONTAL ZONE ABOUT TO MOVE INTO THE NW CARIBBEAN. DEEP CONVECTION REMAINS MINIMAL WITHIN 200NM OF THE EITHER SIDE OF THE AXIS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N13W 8N38W 8N50W 12N58W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE/ISOLATED STRONG IS WITHIN 175 NM N OF THE AXIS BETWEEN 18W-38W. ISOLATED MODERATE CONVECTION NOTED IN THE SAME AREA EXCEPT WITHIN 200NM S OF THE AXIS. SCATTERED MODERATE/ISOLATED STRONG PATCHES NOTED FROM 6N-11N BETWEEN 44W-56W. ...DISCUSSION... THE GULF OF MEXICO... A STRONG COLD FRONT...ASSOCIATED WITH A SHARP UPPER TROUGH EXTENDING SSW FROM THE GREAT LAKES...CONTINUES TO MOVE QUICKLY SOUTHEASTWARD IN THE GULF. AS OF 28/0900 UTC...THE FRONT WAS ANALYZED FROM THE FLORIDA BIG BEND TO NEAR COASTAL YUCATAN NEAR 21N90W...TO NEAR THE ISTHMUS OF TEHUANTEPEC NEAR 17N95W. A CLUSTER OF MODERATE TO STRONG CONVECTION ASSOCIATED WITH THE FRONT IS NOTED IN THE SOUTHERN BAY OF CAMPECHE AND SE MEXICO...WITH MORE CONVECTIVE WEATHER FURTHER E IN THE WARM SECTOR MOVING ACROSS THE SE GULF AND SE FLORIDA. THIS AREA AHEAD OF THE FRONT WAS PREVIOUSLY ANALYZED AS A PREFRONTAL TROUGH...BUT IT APPEARS THE MAIN COLD FRONT HAS CAUGHT UP AND THUS THE TROF WAS LEFT OFF THE 0900 UTC MAP. STRONG NW/N WINDS BETWEEN 20 AND 30 KT ARE COMMON BEHIND THE FRONT AS STRONG HIGH PRESSURE BUILDS FROM THE NW...AND SHOULD DOMINATE THE ENTIRE GULF BY THIS AFTERNOON. ASSOCIATED STEEP NW/N WIND WAVES WILL RAPIDLY REPLACE THE PREFRONTAL WIND WAVES FROM THE SOUTH. FOR MORE DETAILS IN WINDS AND WAVES ASSOCIATED WITH THIS FRONTAL SYSTEM REFER TO MIAOFFNT4 AND MIAHSFAT2. THE CARIBBEAN SEA... SCATTERED MODERATE/ISOLATED STRONG CONVECTION ASSOCIATED WITH A RAPIDLY APPROACHING COLD FRONT FROM THE SE GULF IS AFFECTING THE YUCATAN CHANNEL AND ADJACENT CARIBBEAN WATERS. THE TAIL END OF AN OLD ATLC FRONTAL BOUNDARY/TROUGH CONTINUES TO LOOSE ITS IDENTITY OVER THE N CARIBBEAN AND NRN HISPANIOLA. THERE ARE STILL ISOLATED SHOWERS/TSTMS OVER THE WATERS SURROUNDING CUBA...JAMAICA...AND HISPANIOLA ASSOCIATED WITH THIS OLD FRONTAL SYSTEM. THIS ACTIVITY ALSO BEING SUPPORTED BY THE UPPER HIGH OVER ERN CUBA NEAR 21N76W THAT HAS RIDGING EXTENDING E TO 60W ALONG 20N. THE ISOLATED SHOWERS/TSTMS NOTED FROM 13N-20N BETWEEN 74W-85W ALSO BEING SUPPORTED BY UPPER DIFFLUENCE BETWEEN THE UPPER HIGH OVER CUBA AND A WEAK UPPER LOW IN THE NW CARIBBEAN NEAR 17N80W. SIMILAR SHOWERS NOTED JUST S OF THE DOMINICAN REPUBLIC TO 15N...ANOTHER UPPER DIFFLUENT ZONE. MUCH OF THE SRN CARIBBEAN S OF 15N BETWEEN 67W-83W IS EXPERIENCING FAIR WEATHER WITH DRY MID TO UPPER AIR IN PLACE. THE TROPICAL WAVE/LOW MOVING THROUGH THE WINDWARD ISLANDS IS BEGINNING TO AFFECT THE ERN CARIBBEAN AND WILL SPREAD MOISTURE THROUGH THE REGION OVER THE NEXT COUPLE OF DAYS. MEANWHILE...THE FRONT IN THE GULF WILL MOVE INTO THE NW CARIBBEAN AND SLOW DOWN. SEE MIAOFFNT3 FOR MORE INFO. THE ATLANTIC OCEAN... FROM W TO E...A HIGHLY AMPLIFIED RIDGE/TROUGH/RIDGE PATTERN REMAINS ESTABLISHED ACROSS THE ATLC. SURFACE HIGH PRESSURE THAT HAS PUSHED OFF THE EAST COAST IS INTERACTING WITH THE NEXT STRONG FRONTAL SYSTEM TO PRODUCE WIDESPREAD 20-30 KT S WINDS IN THE SW NORTH ATLC OFF THE COAST OF FLORIDA/BAHAMAS. THESE WINDS WILL SHIFT W TO NW AT A SIMILAR MAGNITUDE BEHIND THE FRONT. HEAVY SHOWERS WITH EMBEDDED TSTMS ALSO MOVING OFF THE COAST OF FLORIDA AND THE SOUTHEAST STATES IN THE WARM SECTOR OF THE FRONTAL SYSTEM. SEE MIAOFFNT3 FOR DETAILS SURROUNDING THE WINDS/SEAS ASSOCIATED WITH THIS FRONT. OUR OLDER COLD FRONT BOUNDARY LINGERS IN THE CENTRAL ATLC WATERS ALONG 32N43W 23N57W AND THEN EXTENDS WSW AS A TROUGH TO THE TIP OF ERN CUBA. ISOLATED SHOWERS/TSTMS NOTED WITHIN 100NM OF THIS BOUNDARY...BUT OVERALL THE BOUNDARY SEEMS TO BE LOSING ITS IDENTITY. VERTICALLY STACKED HIGH PRESSURE CONTINUES TO DOMINATED MUCH OF THE ERN ATLC WITH THE UPPER HIGH CENTERED NEAR 27N34W AND A 1024 MB SFC HIGH CENTERED NEAR 31N30W. THIS AREA ALSO DOMINATED BY DRY STABLE AIR AND SCATTERED TO BROKEN STRATOCUMULUS. A WEAK 1012MB LOW NOTED N OF THE CANARY ISLANDS NEAR 30N15W BUT LITTLE CONVECTION IS ASSOCIATED WITH IT. IN THE DEEP TROPICS...UPPER HIGH PRESSURE NOTED JUST E OF THE WINDWARD ISLANDS. UPPER DIFFLUENCE BETWEEN THIS FEATURE AND A TROUGH EXTENDING NW FROM NE SOUTH AMERICA IS HELPING SUPPORT THE CONVECTION WITH THE WAVE ALONG 60W. AN UPPER LOW IS NOTED NEAR 16N40W WITH MINIMAL SHOWER ACTIVITY NOTED NEAR THIS FEATURE. $$ WILLIS