000 AXNT20 KNHC 260554 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED SEP 26 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...SPECIAL FEATURES... TROPICAL STORM KAREN REMAINS A LOW END TROPICAL STORM OVER THE TROPICAL ATLANTIC AND IS NO IMMEDIATE THREAT TO LAND. AT 26/0300 UTC KAREN WAS NEAR 11.1N 41.0W OR ABOUT 1175 NM...2185 KM...EAST OF THE WINDWARD ISLANDS...MOVING W-NW AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WINDS ARE 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. THE CONVECTIVE PATTERN ASSOCIATED WITH KAREN HAS BECOME A LITTLE BETTER ORGANIZED OVER THE LAST FEW HOURS WITH DEEP CONVECTION NOW MORE PRONOUNCED NEAR THE CENTER AND BANDING FEATURES A LITTLE BETTER DEFINED. NUMEROUS MODERATE TO STRONG CONVECTION IS WITHIN 60 NM OF THE CENTER. SCATTERED MODERATE IS ELSEWHERE FROM 8N-16N BETWEEN 36W-45W...WITH THE MOST PRONOUNCED BAND N OF THE CENTER FROM 13N-16N BETWEEN 37W-44W. KAREN IS EXPECTED TO CONTINUE MOVING W-NW OVER THE NEXT 24 HOURS WITH SOME ADDITIONAL STRENGTHENING EXPECTED. TROPICAL DEPRESSION THIRTEEN AT 26/0300 UTC WAS NEAR 21.7N 95.4W OR ABOUT 145 NM...265 KM...EAST-SOUTHEAST OF TAMPICO MEXICO...MOVING TOWARD THE W SLOWLY AT 4 KT. A SLOW AND ERRATIC MOTION IS EXPECTED OVER THE NEXT DAY OR SO. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WINDS ARE 25 KT WITH GUSTS TO 35 KT. SEE LATEST NHC FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT3/WTNT33 KNHC FOR MORE DETAILS. DEEP CONVECTION IS OVERALL MINIMAL WITH THE DEPRESSION...WITH SCATTERED SHOWERS/ISOLATED TSTMS GENERALLY FROM 20N-25N BETWEEN 92W-97W. SLOW STRENGTHENING IS POSSIBLE DURING THE NEXT 24 HOURS. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE E ATLC ALONG 20W S OF 16W...ESTIMATED TO BE MOVING W 10-15 KT. THE WAVE SHOWS UP WELL IN LOW LEVEL SATELLITE DERIVED WINDS AND VORTICITY...AND THE UW CIMSS TPW PRODUCTS. SCATTERED CLUSTERS OF MODERATE CONVECTION ARE GENERALLY WITHIN 180 NM EITHER SIDE OF THE AXIS. A MORE CONCENTRATED AREA OF MODERATE TO STRONG CONVECTION IS EMBEDDED IN THE ITCZ JUST TO THE E OF THE WAVE...WITHIN 150 NM OF 6N27W. A 1013 MB LOW PRESSURE AREA IS NEAR THE VIRGIN ISLANDS NEAR 17N64W...ASSOCIATED WITH A TROPICAL WAVE ALONG 64W SOUTH OF 21N. THIS SYSTEM IS POORLY ORGANIZED...AND UPPER-LEVEL WINDS ARE EXPECTED TO BE UNFAVORABLE FOR DEVELOPMENT FOR THE NEXT COUPLE OF DAYS. THE MOST CONCENTRATED AREA OF TSTMS IS JUST SE OF PUERTO RICO FROM 16N-18N BETWEEN 64W-66W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ELSEWHERE WITHIN 120NM EITHER SIDE OF THE WAVE AXIS...MAINLY N OF 15N. THIS MOISTURE WILL SPREAD THROUGH PUERTO RICO THROUGH LATER TODAY...AND EVENTUALLY HISPANIOLA THROUGH THU. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 9N19W 6N26W 12N37W 5N53W. BESIDES FOR THE ACTIVITY ASSOCIATED WITH T.S. KAREN AND THE TROPICAL WAVE OVER THE E ATLC...NUMEROUS MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150NM EITHER SIDE OF THE AXIS BETWEEN 23W-31W. DISCUSSION... GULF OF MEXICO... THE MAIN WEATHER FEATURE ACROSS THE GULF OF MEXICO IS TROPICAL DEPRESSION THIRTEEN LOCATED IN THE SW PORTION. SEE SPECIAL FEATURES ABOVE. ABUNDANT TROPICAL MOISTURE WITH PATCHY SHOWER ACTIVITY IS OVER THE BASIN BETWEEN THE BAY OF CAMPECHE AND LOUISIANA. AN UPPER LOW IS NEAR TAMPICO MEXICO WHICH IS STILL PRODUCING SOME SWLY SHEAR OVER T.D. 13...BUT IS EXPECTED TO BE REPLACED BY AN UPPER HIGH OVER THE NEXT COUPLE OF DAYS. SCATTERED SHOWERS/TSTMS ARE OFFSHORE TAMPA FROM 26N-28N BETWEEN 83W-87W. SHOWER ACTIVITY WITH EMBEDDED TSTMS ALSO PERSIST OVER THE STRAITS OF FLORIDA AND NEAR THE KEYS. THIS ACTIVITY IS PRIMARILY ASSOCIATED WITH A MID TO UPPER LEVEL TROUGH OVER W FLORIDA AND THE FAR ERN GULF...THOUGH SOME SUBTLE LOW LEVEL CYCLONIC TURNING IS NOTED IN THE VICINITY AND THUS A WEAK SFC TROUGH IS ANALYZED ALONG 27N82W 22N84W. THIS MOISTURE EXPECTED TO LIFT SLOWLY NE OVER THE NEXT COUPLE OF DAYS. CARIBBEAN SEA... THE MAIN WEATHER FEATURE IN THE CARIBBEAN IS ASSOCIATED WITH THE TROPICAL WAVE AND ASSOCIATED LOW PRESSURE AREA AFFECTING THE NE PORTION. SEE TROPICAL WAVE SECTION. OTHERWISE THE BASIN IS FAIRLY TRANQUIL. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OVER WRN CUBA AND THE NW CARIBBEAN N OF 18N BETWEEN 76W-82W...ASSOCIATED WITH THE MID TO UPPER TROUGH EXTENDING INTO THE REGION FROM FLORIDA AND THE ERN GULF. UPPER SLY FLOW AHEAD OF THIS UPPER TROUGH...AND TO THE W OF THE UPPER HIGH OVER THE ERN CARIB...IS ADVECTING HIGH CLOUDS/MOISTURE NEWD OVER THE CENTRAL CARIBBEAN. TRADES REMAIN LIGHT TO MODERATE ACROSS THE BASIN...BUT WINDS/SEAS COULD BE HIGHER AT TIMES IN SQUALLS NEAR THE LOW/WAVE MOVING THROUGH THE EASTERN CARIBBEAN. ATLANTIC OCEAN... AN AREA OF DISTURBED WEATHER PERSISTS OVER SOUTH FLORIDA... WEST-CENTRAL CUBA AND THE WESTERN BAHAMAS...PRIMARILY ASSOCIATED WITH LIFT AHEAD OF THE MID TO UPPER TROUGHING EXTENDING S THROUGH THE WRN FLORIDA PENINSULA. SCATTERED SHOWER AND TSTM ACTIVITY IS GENERALLY OVER THE AREA S OF 28N W OF 75W. SLOW DEVELOPMENT IN THIS AREA IS POSSIBLE OVER THE NEXT DAY OR TWO...AND THIS SYSTEM COULD BRING LOCALLY HEAVY RAINS TO SOUTH FLORIDA AND THE KEYS DURING THIS PERIOD. THE NRN PORTION OF THE TROPICAL WAVE OVER THE ERN CARIBBEAN IS ENHANCING SCATTERED SHOWERS/ISOLATED TSTMS S OF 25N BETWEEN 6OW-66W. A SMALL...MOSTLY BENIGN LOW TO MID LEVEL VORTICITY MAXIMUM IS NOTED JUST W OF THIS WEATHER NEAR 25N68W...AND IS NOT EXPECTED TO AMOUNT TO MUCH OVER THE NEXT COUPLE OF DAYS. THIS SWIRL IS EMBEDDED IN THE LIGHT TO MODERATE ELY FLOW OVER THE WRN ATLC S OF WEAK SFC RIDGING. THE REMAINDER OF THE CENTRAL ATLC IS DOMINATED BY A SFC TROUGH ENTERING THE AREA NEAR 32N37W AND CONTINUING SW TO 26N50W AND THEN WNW TO 29N65W. SHOWER ACTIVITY IS GENERALLY ISOLATED WITHIN 60NM OF THIS BOUNDARY. MODERATE SFC RIDGING REMAINS ANCHORED OVER THE E ATLC...PRODUCING LIGHT TO MODERATE NE TRADES E OF 33W. A WELL DEFINED UPPER LOW IS JUST NW OF THE CANARY ISLANDS NEAR 31N19W. THIS APPEARS TO BE GENERATING SCATTERED SHOWERS AND POSSIBLY ISOLATED TSTMS FROM 29N-32N BETWEEN 16W-21W. $$ WILLIS