000 AXNT20 KNHC 300547 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON SEP 30 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 0315 UTC. ...SPECIAL FEATURES... SUBTROPICAL STORM LAURA IS CENTERED NEAR 39.0N 48.4W AT 30/0300 UTC OR ABOUT 510 NM SSE OF CAPE RACE NEWFOUNDLAND MOVING N AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 995 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/ WTNT32 KNHC FOR MORE DETAILS. LAURA IS EXPECTED TO TURN TOWARD THE NNE WITH AN INCREASE IN FORWARD SPEED DURING THE NEXT COUPLE OF DAYS WITH LITTLE CHANGE IN STRENGTH. LAURA IS EMBEDDED WITHIN AN UPPER LOW/TROUGH AND OVER THE NEXT DAY OR SO THE UPPER LOW IS EXPECTED TO WEAKEN AS LAURA MOVES INTO THE WESTERLIES...AND LAURA STILL COULD BECOME A TROPICAL CYCLONE BEFORE MOVING INTO AN AREA OF LOWER SEA SURFACE TEMPERATURES DURING THE NEXT 24 HOURS. IN THE REGION...CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90/120 NM OF LINE FROM 22N42W 29N30W TO BEYOND 32N30W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 29W/30W S OF 15N MOVING W 15 KT. WAVE IS WELL DEFINED INVERTED-V CURVATURE OBSERVED IN THE LOW LEVEL CLOUDS EMBEDDED WITHIN DEEP LAYERED MOISTURE AS INDICATED BY MIMIC TPW ANIMATION. SMALL CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION FROM 8N-16N BETWEEN THE WAVE AXIS AND 33W. TROPICAL WAVE IS ALONG 43W/44W FROM 10N-20N MOVING W 5-10 KT. WELL DEFINED BROAD SWIRL IN THE LOW LEVEL CLOUDS ALONG THE WAVE AXIS NEAR 15N. DEEP LAYER MOISTURE IS ALSO BROADLY DISTRIBUTED AROUND WAVE AS INDICATED BY MIMIC TPW ANIMATION. SCATTERED MODERATE CONVECTION IS WITHIN 30/45 NM OF 18N FROM 40W TO THE WAVE AXIS. TROPICAL WAVE IS ALONG 57W/58W S OF 16N MOVING W 10-15 KT. WEAK LOW AMPLITUDE INVERTED-V CURVATURE. ALTHOUGH THIS WAVE IS EMBEDDED WITHIN DEEP LAYERED MOISTURE AS INDICATED BY MIMIC TPW ANIMATION...WATER VAPOR SATELLITE IMAGERY INDICATES STRONG SUBSIDENCE AND THUS DRY STABLE AIR. RESULTS IS NO ASSOCIATED SHOWERS/CONVECTION. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 12N14W 10N26W 6N39W 8N50W 10N60W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N-9N BETWEEN 36W-38W. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 2N-10N BETWEEN 30W-45W AND MOVING OFF W AFRICA WITHIN 75 NM ALONG THE COAST FROM 8N-11N. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH DOMINATES THE CENTRAL US AND THE W GULF W OF 86W WITH A COMPLICATED SYSTEM OVER THE E GULF CONSISTING OF A 1011 MB LOW N OF THE YUCATAN NEAR 23N89W AND A SURFACE TROUGH EXTENDING SW OVER THE E BAY OF CAMPECHE TO 19N92W AND NE ACROSS CENTRAL FLORIDA NEAR NAPLES. BROAD UPPER RIDGE ANCHORED IN THE W ATLC COVERS THE REMAINDER OF THE GULF DRAWING MOIST UPPER FLOW N OVER THE E GULF PROVIDING UPPER LEVEL SUPPORT FOR HEAVY SHOWERS/THUNDERSTORMS MAINLY ALONG THE W COAST OF FLORIDA FROM JUST N OF TAMPA TO OVER THE FLORIDA KEYS BETWEEN 81W-84W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE REMAINDER OF THE AREA S AND E OF THE SURFACE TROUGH AS WELL AS N OF THE SURFACE TROUGH E OF 88W. THE REMAINDER OF THE GULF IS UNDER STRONG SUBSIDENCE AND DRY UPPER AIR BUT ENOUGH LOW LEVEL MOISTURE TO CREATE LOW LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS E OF 94W AND REMARKABLE CLEAR SKIES ALONG THE COAST OF TEXAS AND W LOUISIANA. CARIBBEAN SEA... WEAK UPPER LOW IS IN THE NW CARIBBEAN JUST W OF JAMAICA EMBEDDED WITH THE STRONGER UPPER RIDGE ANCHORED IN THE W ATLC THAT COVERS THE REMAINDER OF THE CARIBBEAN. THE UPPER RIDGE IS BRINGING STRONG SUBSIDENCE AND DRY STABLE AIR TO THE E CARIBBEAN E OF 75W LEAVING THE W CARIBBEAN UNDER DEEP LAYERED MOISTURE AND MOSTLY FAIR WEATHER WITH ONLY ISOLATED SHOWERS USHERED IN ON MODERATE TRADE WINDS OVER THE E CARIBBEAN. MEANWHILE THE W CARIBBEAN REMAINS MOISTURE LADEN AND WITH THE UPPER DIFFLUENCE IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS W OF 75W WITH THE HIGHEST CONCENTRATION OVER CENTRAL AMERICA. ATLANTIC OCEAN... SUBTROPICAL STORM LAURA IS LOCATED N OF THE REGION...SEE SPECIAL FEATURES ABOVE. BROAD UPPER RIDGE COVERS THE W ATLC ANCHORED OVER THE BAHAMAS NEAR 24N76W AND A RIDGE AXIS EXTENDING NE TO 33N54W DRAWING UPPER LEVEL MOISTURE FROM THE CARIBBEAN ACROSS CUBA AND THE N BAHAMA ISLANDS GENERATING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS W OF 76W. THE SURFACE TROUGH IN THE GULF OF MEXICO EXTENDS ACROSS FLORIDA FROM NAPLES TO VERO BEACH INTO THE W ATLC TO 30N76W. BENEATH THE UPPER RIDGE IS A 1017 MB SURFACE HIGH NEAR 26N66W AND ALONG WITH STRONG SUBSIDENCE AND DRY AIR IS GIVING THE REMAINDER OF THE AREA FAIR WEATHER TONIGHT. THE UPPER TROUGH ASSOCIATED WITH SUBTROPICAL STORM LAURA EXTENDS INTO THE CENTRAL ATLC N OF 22N FROM 35W-50W AND IS ENHANCING THE CONVECTION ASSOCIATED WITH LAURA. AN UPPER LOW IS MOVING INLAND OVER MOROCCO JUST E OF THE CANARY ISLANDS WITH AN UPPER TROUGH COVERING THE NE ATLC N OF 26N E OF 24W. THE TROPICS IS DOMINATED BY THE TYPICAL E/W UPPER RIDGE ANCHORED OVER THE CAPE VERDE ISLANDS EXTENDING W TO NEAR 50W. $$ WALLACE