000 AXNT20 KNHC 280605 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 40W/41W S OF 13N MOVING W NEAR 10 KT. THIS WAVE REMAINS RATHER LOW AMPLITUDE AND HAS BECOME LESS DEFINED THAN IT WAS...WITH LITTLE CURVATURE NOTED IN SAT IMAGES AND AVAILABLE SFC DATA. HOWEVER...ANALYSIS OF A HOVMOLLER DIAGRAM STILL SHOWS THE FEATURE TRACKING SLOWLY TO THE W. A CLUSTER OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 9N-11N BETWEEN 38W-41W...WITH ISOLATED SHOWERS/TSTMS NOTED ELSEWHERE WITHIN 150NM OF THE AXIS. A TROPICAL WAVE IS ALONG 59W/60W S OF 21N MOVING W 10 TO 15 KT. A 1009 MB LOW IS ALONG THE WAVE NEAR 14N. THE AXIS IS CURRENTLY BETWEEN BARBADOS AND THE MAIN WINDWARD ISLAND CHAIN...AND IS WELL REPRESENTED WITH THE AVAILABLE SURFACE OBSERVATIONS ALONG WITH PRONOUNCED CYCLONIC CURVATURE SEEN IN SATELLITE IMAGERY. SCATTERED MODERATE CONVECTION STILL NOTED FROM 9N-15N BETWEEN 58W-64W. ALTHOUGH SHOWER AND THUNDERSTORM ACTIVITY HAS CHANGED LITTLE THIS EVENING...UPPER-LEVEL WINDS ARE EXPECTED TO BECOME SOMEWHAT MORE FAVORABLE FOR SOME ADDITIONAL DEVELOPMENT DURING THE NEXT DAY OR SO. THIS SYSTEM COULD PRODUCE LOCALLY HEAVY RAINS AND GUSTY WINDS AS IT MOVES ACROSS MUCH OF THE LESSER ANTILLES AND ADJACENT WATERS TONIGHT AND SATURDAY. A WEAK TROPICAL WAVE IS EXTENDING S FROM HAITI ALONG 72W/73W 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 ZONES TO ITS N AND NW. DEEP CONVECTION REMAINS MINIMAL WITHIN 200NM OF THE EITHER SIDE OF THE AXIS. ...THE ITCZ... ITCZ AXIS IS ALONG 10N14W 7N25W 6N44W 12N58W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE IS WITHIN 200 NM N AND 140 NM S OF THE AXIS BETWEEN 22W-38W. SIMILAR ACTIVITY IS WITHIN 150 NM EITHER SIDE BETWEEN 45W-55W. ...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 28/2100 UTC...THE FRONT WAS ANALYZED FROM THE SW TIP OF GEORGIA TO THE CENTRAL GULF NEAR 23N90W...TO NEAR THE ISTHMUS OF TEHUANTEPEC NEAR 18N95W THEN NWD ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS NEAR 24N99W. SCATTERED MODERATE CONVECTION ASSOCIATED WITH THE FRONT IS NOTED IN THE CENTRAL BAY OF CAMPECHE...BUT MORE CONVECTIVE WEATHER LIES FURTHER E IN THE WARM SECTOR MOVING ACROSS NE FLORIDA AND THE APALACHEE BAY WHERE A SQUALL LINE IS ANALYZED. A PREFRONTAL TROUGH IS ALSO SPARKING NUMEROUS MODERATE/ISOLATED STRONG CONVECTION FROM THE YUCATAN CHANNEL NNE TO NEAR TAMPA. STRONG NW/N WINDS BETWEEN 20 AND 30 KT ARE COMMON BEHIND THE FRONT AND SIMILAR MAGNITUDE SWLY WINDS AHEAD OF THE FRONT AS STRONG SFC HIGH PRES BUILD IN. FOR MORE DETAILS IN WINDS AND WAVES ASSOCIATED WITH THIS FRONTAL SYSTEM REFER TO MIAOFFNT4 AND MIAHSFAT2. THIS FAST MOVING FRONT WILL LIKELY CLEAR THE ENTIRE GULF BY EARLY THIS AFTERNOON. THE CARIBBEAN SEA... A PREFRONTAL TROUGH ASSOCIATED WITH THE STRONG COLD FRONT MOVING THROUGH THE GULF CLIPS THE CARIBBEAN WATERS THROUGH THE YUCATAN CHANNEL...PRODUCING CLUSTERS OF MODERATE CONVECTION IN THE AREA. 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 21N77W THAT HAS RIDGING EXTENDING E TO 60W ALONG 20N. MOST OF THE SHOWERS/TSTMS NOTED FROM 13N-20N BETWEEN 75W-82W...WHICH IS AN UPPER DIFFLUENT REGION BETWEEN THE UPPER HIGH OVER CUBA AND A WEAK UPPER LOW IN THE NW CARIBBEAN NEAR 17N81W. SIMILAR SHOWERS NOTED JUST S OF THE DOMINICAN REPUBLIC TO 15N...ANOTHER UPPER DIFFLUENT ZONE. MUCH OF THE SRN CARIBBEAN 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. 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. HEAVY SHOWERS WITH EMBEDDED TSTMS ALSO MOVING OFF THE COAST OF FLORIDA AND SE COAST OF FLORIDA IN THE WARM SECTOR OF THE FRONTAL SYSTEM. SEE MIAOFFNT3 FOR DETAILS SURROUNDING THE WINDS/SEAS ASSOCIATED WITH THIS FRONT. THE OLDER COLD FRONT BOUNDARY LINGERS IN THE CENTRAL ATLC WATERS ALONG 32N44W 25N55W AND THEN EXTENDS WSW AS A TROUGH TO THE TIP OF ERN CUBA. ISOLATED SHOWERS/TSTMS NOTED WITHIN 100NM OF THIS BOUNDARY. VERTICALLY STACKED HIGH PRESSURE CONTINUES TO DOMINATED MUCH OF THE ERN ATLC WITH THE UPPER HIGH CENTERED NEAR 26N32W AND A 1024 MB SFC HIGH CENTERED NEAR 34N27W. THIS AREA ALSO DOMINATED BY DRY STABLE AIR AND SCATTERED TO BROKEN STRATOCUMULUS. 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/CANGIALOSI