000 AXNT20 KNHC 071726 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT OCT 07 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 1715 UTC. ...TROPICAL WAVES... A FAIRLY HIGH AMPLITUDE TROPICAL WAVE IS ALONG 39W S OF 21N MOVING W ABOUT 15 KT. THE WAVE AXIS IS EASILY IDENTIFIABLE ON SATELLITE IMAGERY WITH A LARGE INVERTED-V SIGNATURE NOTED. SCATTERED MODERATE CONVECTION IS EMBEDDED IN THE ITCZ WITHIN SEVERAL HUNDRED NM OF THE WAVE AXIS...DISCUSSED IN THE ITCZ SECTION. ONLY ISOLATED TO SCATTERED HIGHLY SHEARED SHOWERS ARE WITHIN 180 NM E OF THE WAVE AXIS N OF 12N. A TROPICAL WAVE IS ALONG 57W S OF 16N MOVING W NEAR 15 KT OVER THE PAST 24 HOURS. THIS WAVE HAS LITTLE SIGNATURE ASSOCIATED WITH IT. SOME SLIGHT LOW-MID LEVEL CYCLONIC TURNING IS LOCATED E OF THE AXIS...HOWEVER NO ADJUSTMENT IN THE WAVE PSN WAS MADE DUE TO LACK OF STRONG EVIDENCE IN SFC AND UPPER AIR OBS/MODEL DATA. SCATTERED SHOWERS AND TSTMS ARE WITHIN 240 NM EITHER SIDE OF THE WAVE AXIS. A TROPICAL WAVE IS IN THE ERN CARIBBEAN ALONG 66W S OF 17N MOVING W 10 TO 15 KT. LITTLE WAVE STRUCTURE IS NOTED ON VIS IMAGES. WESTERLY UPPER LEVEL FLOW IS SHEARING SCATTERED SHOWERS AND TSTMS TO THE WINDWARD ISLANDS...BUT EVEN THIS ACTIVITY HAS BEEN DISSIPATING OVER THE LAST FEW HOURS. A TROPICAL WAVE HAS EXITED THE CARIBBEAN SEA ALONG 89W S OF 19N MOVING W 10 TO 15 KT. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 400 NM EITHER SIDE OF THE WAVE AXIS. THE MOST IMPRESSIVE CLUSTER IS IN THE WRN CARIBBEAN SEA FROM 16N-20N BETWEEN 83W-86W. THIS ACTIVITY IS BEING ENHANCED BY UPPER DIFFLUENT FLOW BETWEEN A LARGE TROUGH IN THE GULF AND A RIDGE IN THE SRN CARIBBEAN. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N15W 7N30W 9N38W 6N50W 7N57W. BESIDES FOR THE CONVECTION DISCUSSED IN THE TROPICAL WAVES SECTION...SCATTERED MODERATE IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 30W AND 48W. SIMILAR CONVECTION LIES E OF 18W FROM 7N-11N. ...DISCUSSION... THE GULF OF MEXICO... THE MAIN FEATURE IN THE GULF IS A LARGE DEEP UPPER TROUGH THAT COVERS MUCH OF THE CENTRAL AND EASTERN PORTION OF THE AREA. A LARGE CUT OFF LOW HAS DEVELOPED OVER NORTH CAROLINA...EMBEDDED IN THIS BROAD TROUGHING. STRONG SUBSIDENCE ACCOMPANIES THE TROUGH WITH VERY DRY AIR ALOFT NOTED ON WATER VAPOR IMAGES E OF 90W N OF 24N. A NARROW SQUASHED RIDGE LIES TO THE W OF THE TROUGH EXTENDING FROM THE YUCATAN PENINSULA NNW TO THE MIDWESTERN STATES OF THE U.S. A FAIR AMOUNT OF MOISTURE IS IN THE WRN GULF ASSOCIATED WITH THE MOIST SLY FLOW OF THE UPPER RIDGE. THIS MOISTURE IS THEN ADVECTED EASTWARD ACROSS THE SRN GULF AND NRN CARIBBEAN BY A WESTERLY JET WITH CORE WINDS NEAR 60 KT BASED ON CIMSS DERIVED UPPER LEVEL WINDS. A SFC TROUGH IS EMBEDDED IN THE HIGH LEVEL MOISTURE IN THE WRN GULF ALONG 94W FROM 20N-26N AND IS ENHANCING SCATTERED SHOWERS AND TSTMS WITHIN 90 NM EITHER SIDE OF THE AXIS. A WEAK COLD FRONT IS IN THE NRN GULF STRETCHING FROM CENTRAL FLORIDA TO 27N94W. ONLY SLIGHTLY DRIER AIR AND A FAINT NARROW BAND OF LOW CLOUDS REPRESENT THIS BOUNDARY. GFS SHOWS THE DRY AIRMASS IN THE CENTRAL AND EASTERN GULF TO REMAIN IN PLACE THRU TUE...WITH SOME INCREASE IN MOISTURE IN THE WRN GULF. THE CARIBBEAN SEA... THE MOST ACTIVE WEATHER IN THE CARIBBEAN IS IN THE GULF OF HONDURAS WHERE SCATTERED MODERATE CONVECTION EXISTS FROM 16N TO 20N BETWEEN 83W AND 86W. THIS ACTIVITY IS ASSOCIATED WITH A TROPICAL WAVE ALONG 89W AND UPPER DIFFLUENT AIR S OF A WESTERLY JET BETWEEN AN UPPER HIGH NEAR 15N80W AND A LARGE UPPER TROUGH ACROSS THE CENTRAL/EASTERN GULF. THIS CONVECTION HAS DECREASED IN INTENSITY SLIGHTLY OVER THE PAST FEW HOURS. SIMILAR CONVECTION IS IN THE SW CARIBBEAN S OF 12N W OF 78W ASSOCIATED WITH THE ITCZ. MUCH OF THE CENTRAL AND EASTERN CARIBBEAN IS RATHER QUIET WITH A FAIR AMOUNT OF MODERATELY DRY AIR AND WESTERLY UPPER LEVEL FLOW IN PLACE...EXCEPT FOR SCATTERED SHOWERS AND TSTMS IN THE WINDWARD ISLANDS ASSOCIATED WITH A SHEARED TROPICAL WAVE. MODERATE TO STRONG ELY TRADE WINDS ARE BLOWING ACROSS THE CARIBBEAN WITH THE STRONGEST WINDS OF 20-25 KT OVER THE SOUTH CENTRAL CARIBBEAN. LITTLE CHANGE IN THESE WINDS ARE EXPECTED OVER THE NEXT 24 HOURS. THE ATLANTIC OCEAN... A LARGE UPPER LEVEL TROUGH COVERS MUCH OF THE EASTERN U.S. AND WRN ATLC W OF 70W N OF 24N. MODERATE TO STRONG SUBSIDENCE IS ASSOCIATED WITH THE TROUGH. A WEAK 1018 MB SFC HIGH IS LOCATED UNDERNEATH THE TROUGH NEAR 28N74W. A MID-UPPER LEVEL SUBTROPICAL RIDGE LIES TO THE E OF THE TROUGH AND COVERS THE REGION BETWEEN 38W AND 63W. DRY STABLE AIR IS ALSO IN PLACE UNDERNEATH THE RIDGE LIMITING ANY SHOWER ACTIVITY. A SWLY JET EXISTS BETWEEN THESE FEATURES AND IS ADVECTING A SWATH OF MOISTURE BETWEEN 63W AND 70W. A 1008 MB SFC LOW IS LOCATED NEAR 34N67W WITH A SFC TROUGH EXTENDING SWD FROM THE LOW TO THE ERN BAHAMAS. THIS LOW WAS BEING MONITORED OVER THE LAST DAY OR TWO FOR POSSIBLY BECOMING SUBTROPICAL IN NATURE. HOWEVER IT NOW APPEARS THAT ITS WINDOW FOR BECOMING SUBTROPICAL HAS CLOSED AS IS QUICKLY MOVES TO THE NE. MODERATE TO HEAVY RAINFALL IS OCCURRING IN THIS SLOW MOVING AREA OF WEATHER...BERMUDA HAS RECORED 1.28 INCHES OF RAIN OVER THE PAST 24 HOURS. IN THE EASTERN ATLC...AN ELONGATED UPPER TROUGH AXIS EXTENDS FROM JUST E OF THE AZORES ALONG 27N31W 21N41W 18N55W WITH A COUPLE EMBEDDED UPPER LOW CENTERS ....ESPECIALLY IN THE SE PORTION OF THE TROUGH AXIS. AT THE SURFACE...A BROAD RIDGE DOMINATES THE ATLC EAST OF 65W WITH A 1025 MB HIGH LOCATED NEAR 32N48W. ORGANIZED SHOWERS AND TSTMS IN THE CNTRL AND ERN ATLC ARE CONFINED TO THE ITCZ AND TROPICAL WAVES. $$ CANGIALOSI