000 AXNT20 KNHC 041049 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT OCT 04 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 20W S OF 18N MOVING W NEAR 10 KT. WAVE IS EMBEDDED WITHIN DEEP LAYERED MOISTURE AS INDICATED BY MIMIC TPW ANIMATION. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 11N-19N BETWEEN 17W-24W. TROPICAL WAVE IS TILTED FROM 20N49W TO 10N51W BASED ON MIMIC TPW ANIMATION... SATELLITE IMAGERY...AND LATEST QUIKSCAT PASS MOVING W 10-15 KT. DEEP CONVECTION IS WELL E OF THE WAVE AXIS DUE TO UPPER LEVEL FEATURES. TROPICAL WAVE IS TILTED FROM 19N60W TO 9N61W MOVING W NEAR 10 KT. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 13N TO THE COAST OF SOUTH AMERICA BETWEEN 60W-64W WITH ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE REMAINDER OF THE WAVE. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 13N15W 14N21W 7N39W 13N52W 12N60W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE WITHIN 180 NM N OF THE ITCZ FROM 24W-30W AND FROM 3N TO THE ITCZ FROM 20W-43W. ...DISCUSSION... GULF OF MEXICO... A DEEP LAYERED TROUGH IS MOVING INTO THE NW ATLC BUT CONTINUES TO DOMINATE THE GULF WITH DRY STABLE AIR OVER THE GULF WATERS WITH THE EXCEPTION OF S FLORIDA AND THE FLORIDA STRAITS S OF 25N E OF 83W. THIS DEEP TROUGH CONTINUES TO SUPPORT A QUASI- STATIONARY FRONT IN THE W ATLC INTO THE FLORIDA STRAITS WHERE A 1014 MB LOW HAS DEVELOPED NEAR 24N81W AND A SURFACE TROUGH CONTINUING SW TO THE N COAST OF CUBA NEAR 23N83W AND GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 26N E OF 85W. LOW LEVEL CONVERGENCE CONTINUES IN THE BAY OF CAMPECHE GIVING THE AREA LOW CLOUDS AND POSSIBLE ISOLATED SHOWERS S OF 20N W OF 92W. THE REMAINDER OF THE GULF REMAINS RATHER CLEAR AGAIN THIS MORNING WITH DEW POINTS REMAINING IN THE 60 DEG RANGE ACROSS THE GULF N OF 26N. CARIBBEAN SEA... A WEAK 1010 MB SURFACE LOW REMAINS IN THE NW CARIBBEAN NEAR 18N86W WITH AN UPPER RIDGE ANCHORED NEAR THE CAYMAN ISLANDS COVERING THE NW CARIBBEAN. THIS UPPER RIDGE COUPLED WITH THE DEEP LAYERED TROUGH OVER THE GULF OF MEXICO CONTINUES TO PROVIDE MOIST UPPER FLOW OVER THE NW CARIBBEAN AND GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE AREA W OF 77W TO OVER CUBA AND CENTRAL AMERICA AND TO THE YUCATAN CHANNEL. AN UPPER LOW IS S OF THE MONA PASSAGE NEAR 17N67W COVERING THE CENTRAL CARIBBEAN BETWEEN THE LESSER ANTILLES AND 76W GENERATING ISOLATED SHOWERS WITHIN 200 NM OF THE UPPER LOW. DIFFLUENCE ALOFT IS GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE S/CENTRAL CARIBBEAN S OF 15N TO INLAND OVER COLOMBIA BETWEEN 70W-76W. THIS UPPER FLOW IS ALSO DRAWING THE DRIER STABLE AIR FROM THE W ATLC OVER THE N/CENTRAL CARIBBEAN. ATLANTIC OCEAN... DEEP LAYERED TROUGH OVER THE FAR E US CONTINUES TO MOVE OVER THE NE ATLC AND THE CANADIAN MARITIMES CLIPPING THE W ATLC N OF 27N W OF 74W WITH THE ASSOCIATED QUASI-STATIONARY FRONT ENTERING THE REGION FROM A 1018 MB LOW NEAR 33N72W ALONG 28N75W EXTENDING INTO THE FLORIDA STRAITS WHERE A 1014 MB LOW HAS DEVELOPED NEAR 24N81W AND A SURFACE TROUGH CONTINUES SW TO THE N COAST OF CUBA NEAR 23N83W. DRY STABLE AIR REMAINS N OF 28N W OF 76W TO OVER THE SE US WITH MOIST SW UPPER FLOW FROM THE CARIBBEAN ACROSS CUBA GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 27N W OF 77W TO INLAND OVER S FLORIDA AND ISOLATED SHOWERS WITHIN 90 NM OF THE REMAINDER OF THE FRONTAL BOUNDARY. AN UPPER RIDGE COVERS THE REMAINDER OF THE W ATLC ANCHORED NEAR 33N55W SUPPORTING DRY STABLE AIR ACROSS THE W ATLC INTO THE CENTRAL ATLC. AN UPPER LOW CONTINUES TO UNDERCUT THIS UPPER RIDGE CENTERED IN THE CARIBBEAN S OF THE MONA PASSAGE AND COVERS THE SW ATLC S OF 23N FROM 60W-75W INCLUDING THE TURKS AND CAICOS. A SECOND CUT-OFF UPPER LOW IN THE CENTRAL ATLC IS CENTERED NEAR 23N49W GENERATING ISOLATED SHOWERS FROM 19N-26N BETWEEN 46W-51W. A SURFACE TROUGH IS JUST TO THE N EXTENDING FROM 32N48W ALONG 28N49W TO 24N49W. DIFFLUENCE ALOFT TO THE SE OF THIS UPPER LOW IS GENERATING SCATTERED MODERATE/STRONG CONVECTION WITHIN 90/120 NM OF LINE FROM 15N49W TO 19N39W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM WITHIN 120 NM OF LINE FROM 20N42W TO 26N47W. AN UPPER TROUGH IS OVER THE NE ATLC EXTENDING THROUGH 32N14W SW TO 27N26W COVERING THE AREA N OF 24N FROM 27W TO OVER NW AFRICA. THE TYPICAL E/W UPPER RIDGE AXIS EXTENDS FROM W AFRICA ALONG 14N16W TO NEAR 10N36W PUSHING THE ITCZ FURTHER TO THE SOUTH. $$ WALLACE