000 AXNT20 KNHC 102338 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE OCT 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ADDED TO THE 18 UTC ANALYSIS ALONG 31W/32W S OF 18N. LOW TO MID LEVEL CLOUDS ARE FLOWING CYCLONICALLY ABOUT THE WAVE AXIS WITH A SWIRL NEAR 12.5N. THIS WAVE IS ALSO TRACKABLE USING THE MET 9 HOVMOLLER DIAGRAMS. GFS HAS A FAIR HANDLE ON INITIALIZING THIS FEATURE...BUT THE AXIS IN THE MODEL IS A DEGREE OR TWO FURTHER EAST. THE ATMOSPHERIC ENVIRONMENT IS NOT FAVORABLE ALONG AND TO THE E OF THE WAVE AT THE MOMENT WITH MODERATE TO STRONG UPPER LEVEL SWLY WINDS SHEARING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 300 NM TO THE E OF THE WAVE. A TROPICAL WAVE IS LOCATED ABOUT 150 TO 200 NM E OF THE LESSER ANTILLES ALONG 58W S OF 24N. THIS WAVE HAS BEEN WELL-DEFINED OVER THE PAST SEVERAL DAYS AS IT TRACKS W 10 TO 15 KT. SCATTERED SHOWERS AND TSTMS ARE MOSTLY WITHIN 400 NM TO THE E OF THE WAVE AXIS. SFC OBSERVATIONS CLEARLY SHOW WINDS VEERING FROM THE SE E OF THE AXIS TO THE ENE W OF THE AXIS. SOME OF THESE OBS ARE RECORDING 20 KT WINDS WITHIN 200 NM E OF THE WAVE. FURTHER DEVELOPMENT...IF ANY...IS EXPECTED TO BE SLOW TO OCCUR. A TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 70W S OF 20N MOVING W 10 TO 15 KT. SLIGHT LOW TO MID LEVEL CYCLONIC TURNING IS NOTED ABOUT THE WAVE AXIS. OTHERWISE...LITTLE WAVE STRUCTURE IS APPARENT. UPPER DIFFLUENCE ALONG WITH SOME LOW LEVEL CONVERGENCE NEAR THE WAVE AXIS HAS GENERATED SCATTERED MODERATE CONVECTION ACROSS THE DOMINICAN REPUBLIC AND THE MONA PASSAGE. A TROPICAL WAVE HAS BEEN RELOCATED ALONG 89W S OF 16N ESTIMATED TO BE MOVING 10 TO 15 KT. THIS PSN PUTS THIS WAVE IN THE EPAC EXCEPT FOR THE NRN EXTENSION WHICH LIES ACROSS CENTRAL AMERICA. THIS RELOCATION WAS BASED MOSTLY ON BROAD LOW TO MID LEVEL CLOUD TURNING ON VIS IMAGES. THIS WAVE HAS BEEN CHALLENGING TO TRACK OVER THE PAST SEVERAL DAYS...AND THIS PSN APPEARS TO BE IN BETTER AGREEMENT WITH A WAVE-LIKE FEATURE. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N15W 12N25W 10N45W 13N57W 10N63W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES DISCUSSED ABOVE...ISOLATED MODERATE IS WITHIN 240 NM EITHER SIDE OF THE AXIS E OF 24W. THIS ACTIVITY MIGHT BE ASSOCIATED WITH A LOW AMPLITUDE TROPICAL WAVE...BUT IT HAS NOT BEEN INDICATED ON THE 18 UTC ANALYSIS DUE TO INCONCLUSIVE DATA. ...DISCUSSION... THE GULF OF MEXICO... A BROAD MID TO UPPER LEVEL RIDGE COVERS MUCH OF THE GULF OF MEXICO WITH THE HIGH CENTER OVER CENTRAL MEXICO. A PRONOUNCED SHORTWAVE TROUGH IS DIGGING ACROSS THE SOUTH CENTRAL U.S. GENERATING CONVECTIVE ACTIVITY ACROSS SE TEXAS AND LOUISIANA. A SQUALL LINE WAS ANALYZED AT 21 Z FROM 30N94W TO 28N96W...THIS ACTIVITY IS QUICKLY PRESSING TO THE ESE. THE REMAINDER OF THE GULF IS QUIET THIS EVENING. WESTERLY UPPER LEVEL FLOW ON THE NRN SIDE OF THE RIDGE IS SPREADING PATCHES OF HIGH LEVEL DEBRIS MOISTURE INTO THE GULF...BUT MOST OF IT IS NOT DEEP IN NATURE AS MODERATE DRY AIR LIES ACROSS MOST OF THE AREA. AT THE SFC...THE WEAK FRONTAL BOUNDARY THAT HAS BEEN SLOW MOVING IN THE AREA OVER THE PAST FEW DAYS HAS BEGUN DISSIPATING AND IS NEARLY STATIONARY OR DRIFTING N FROM THE FLORIDA STRAITS TO 24N92W. ONLY A NARROW BAND OF LOW CLOUDS REPRESENT THE FRONT. ANOTHER WEAK FRONT MAY ENTER THE NRN GULF LATE TOMORROW FOLLOWED BY A STRONG COLD FRONT LATE THU WITH GALE CONDITIONS EXPECTED ON FRI. THE CARIBBEAN SEA... THERE ARE A FEW AREAS OF ORGANIZED CONVECTION ACROSS THE CARIBBEAN SEA THIS EVENING. STARTING FROM W TO E...SCATTERED MODERATE IS IN THE SW CARIBBEAN S OF 13N W OF 78W...HIGHLY ASSOCIATED WITH THE ITCZ AND POSSIBLY A TROPICAL WAVE TO THE W OF THE AREA. THE SECOND AREA IS OVER THE DOMINICAN REPUBLIC AND WRN PUERTO RICO. SAN JUAN DOPPLER RADAR SHOWS THE BULK OF THE RAIN TO THE NW OF THE ISLAND IN THE MONA PASSAGE. THIS ACTIVITY IS ASSOCIATED WITH A TROPICAL WAVE AND UPPER DIFFLUENCE BETWEEN A RIDGE IN THE CARIBBEAN AND A DEEP TROUGH IN THE WRN ATLC. THE THIRD AREA OF UNSETTLED WEATHER IS JUST TO THE E OF THE AREA...WITH A FEW SHOWERS BEGINNING TO SPREAD INTO THE LESSER ANTILLES. THIS ACTIVITY IS ASSOCIATED WITH A WELL DEFINED TROPICAL WAVE ALONG 58W WITH SOME INSTABILITY ENHANCEMENT FROM AN UPPER TROUGH ALONG 54W. FOR MORE DETAILS...REFER TO THE TROPICAL WAVE SECTION. AS THE WAVE MOVES WESTWARD...MOISTURE WILL INCREASE AND SPREAD ACROSS THE LESSER ANTILLES OVER THE NEXT DAY OR TWO. TRADE WINDS ARE LIGHT TO MODERATE AND WILL LIKELY REMAIN THAT WAY OVER THE COUPLE OF DAYS DUE TO THE WEAK PRES PATTERN. THE ATLANTIC OCEAN... A LARGE SCALE UPPER LEVEL TROUGH/RIDGE/TROUGH PATTERN EXISTS IN THE ATLC BASIN. AN UPPER TROUGH EXTENDS FROM A LOW NEAR 34N70W SWD ACROSS THE BAHAMAS AND ERN CUBA. THE LOW CENTER ITSELF IS GENERATING LITTLE WEATHER AND MUCH OF THE AREA W OF 75W IS UNDER A VERY DRY STABLE AIRMASS. AN ASSOCIATED FRONTAL BOUNDARY HAS BECOME DIFFUSE AND DISSIPATING FROM 31N70W ACROSS THE NRN BAHAMAS INTO THE FLORIDA STRAITS. A LARGE RIDGE COVERS THE AREA BETWEEN 35W AND 62W. UPPER DIFFLUENCE BETWEEN THIS RIDGE AND THE TROUGH TO ITS W IS PRODUCING A SWATH OF MOISTURE BETWEEN 60W AND 73W. SCATTERED SHOWERS AND TSTMS ARE EMBEDDED IN THE MOISTURE PLUME. ANOTHER AREA OF MOISTURE IS IN THE RIDGE BETWEEN 48W AND 58W ASSOCIATED WITH A TROPICAL WAVE AN A WEAK UPPER TROUGH ERODING A PORTION OF THE RIDGE. THE DEEPEST MOISTURE IS S OF 19N BETWEEN 51W AND 58W DIRECTLY ASSOCIATED WITH THE WAVE. THE EASTERN ATLC IS IN A BROAD ELONGATED TROUGH WITH THE HIGHEST AMPLITUDE WELL TO THE NE OF THE AREA. THE UPPER TROUGH EXTENDS FROM THE CANARY ISLANDS SW ALONG 27N27W TO NEAR 13N33W. A 40 TO 60 KT SWLY JET EXISTS NEAR THE BASE OF THE TROUGH TO WRN AFRICA NEAR 18N16W. SCATTERED SHOWERS AND TSTMS EXISTS TO THE E OF THE JET AXIS EMBEDDED IN THE ITCZ...WITH A FAIR AMOUNT OF DRY STABLE AIR WITHIN 360 NM W OF THE JET. AT THE SFC...A BROAD RIDGE IS IN PLACE ACROSS THE AREA E OF 65W WITH A PAIR OF 1021 MB HIGHS NEAR 28N46W AND 32N32W. $$ CANGIALOSI