AXNT20 KNHC 090600 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST MON NOV 09 2009 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 0515 UTC. ...SPECIAL FEATURES... HURRICANE IDA IS CENTERED NEAR 24.4N 87.5W AT 09/0600 UTC OR ABOUT 295 NM SSE OF THE MOUTH OF THE MISSISSIPPI RIVER MOVING NNW AT 12 KT. ESTIMATED MINIMUM PRESSURE BASED ON DATA FROM THE HURRICANE HUNTER AIRCRAFT IS 987 MB. MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. SCATTERED/NUMEROUS STRONG CONVECTION IS WITHIN A 60 NM RADIUS OF 24.5N87W. SCATTERED MODERATE CONVECTION COVERS THE REMAINDER OF THE AREA FROM 23N-27N BETWEEN 82W-89W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 52W S OF 18N MOVING W NEAR 15 KT. WAVE RESIDES BENEATH A DRY UPPER LEVEL TROUGH AXIS JUST TO THE E. NO SIGNIFICANT DEEP CONVECTION ACCOMPANIES THE WAVE. TROPICAL WAVE IS ALONG 70W S OF 17N MOVING W NEAR 15 KT. WAVE CONTINUES TO BE ILL-DEFINED AND DIFFICULT TO TRACK AS IT MOVES WESTWARD BENEATH DRY AND STABLE AIR. NO SIGNIFICANT DEEP CONVECTION ACCOMPANIES THE WAVE. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 5N31W 8N49W 8N61W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 6N-11N BETWEEN 38W-42W AND FROM 11N-13N BETWEEN 36W-40W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM OF LINE FROM THE COAST OF W AFRICA NEAR 7N12W ALONG 5N24W TO 7N34W AND FROM 13N18N BETWEEN 36W-41W. ...DISCUSSION... GULF OF MEXICO... HURRICANE IDA IS THE PRIMARY CONCERN TONIGHT FOR THE GULF OF MEXICO...SEE SPECIAL FEATURES ABOVE. CONVECTION ASSOCIATED WITH IDA REMAINS ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL RIDGE EXTENDING FROM THE WESTERN CARIBBEAN NORTHWARD ACROSS CUBA JUST W OF THE FLORIDA PENINSULA AND AN UPPER LEVEL TROUGH THAT EXTENDS FROM TEXAS NEAR 29N97W TO THE E BAY OF CAMPECHE NEAR 19N91W. THE UPPER LEVEL TROUGH ALSO SUPPORTS A SURFACE TROUGH THAT EXTENDS FROM 28N95W THROUGH A ELONGATING 1008 MB LOW NEAR 23N95W THEN TO THE E BAY OF CAMPECHE NEAR 19N91W. WIND SHIFT IS MAINLY ASSOCIATED WITH THE SURFACE TROUGH AXIS. HOWEVER...UPPER LEVEL DIFFLUENCE N OF 25N W OF 90W IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE AREA TO INLAND OVER LOUISIANA AND TEXAS. THE INCREASED PRESSURE GRADIENT CREATED BETWEEN HURRICANE IDA AND THE SURFACE RIDGE OVER THE W ATLC INTO THE SE U.S. IS PRODUCING GALE FORCE WINDS IN THE STRAITS OF FLORIDA. CARIBBEAN SEA... HURRICANE IDA HAS MOVED INTO THE SE GULF OF MEXICO THROUGH THE YUCATAN CHANNEL BUT CONTINUES TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 18N ACROSS CUBA BETWEEN 77W-85W. THIS ACTIVITY IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE ASSOCIATED WITH AN UPPER LEVEL RIDGE ANCHORED IN THE NEAR 16N82W EXTENDING N ACROSS CUBA INTO THE E GULF OF MEXICO. THE SOUTHERN RIDGE AXIS EXTENDS S TO OVER E PANAMA PROVIDING DIFFLUENCE ALOFT TO PRODUCE ISOLATED SHOWERS/THUNDERSTORMS MAINLY S OF 12N W OF 73W AND IN THE GULF OF HONDURAS S OF 18N BETWEEN 84W-87W. AN UPPER TROUGH FROM THE W/CENTRAL ATLC DIPS S OVER THE E CARIBBEAN E OF 80W GIVING THE AREA NW UPPER LEVEL FLOW AND GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 17N-20N E OF 77W TO ACROSS THE LEEWARD ISLANDS INCLUDING THE VIRGIN ISLANDS TO HISPANIOLA. PRIMARILY MODERATE SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY FROM 11N-16N WITH SOME ISOLATED SHOWERS LOW LEVEL FAST MOVING SHOWERS ARE BEING USHERED IN ON MODERATE EASTERLY TRADEWINDS. ATLANTIC OCEAN... A SURFACE RIDGE REMAINS IN CONTROL OF THE W ATLC N OF 22N W OF 60W ANCHORED BY SEVERAL SURFACE HIGHS N OF THE REGION. A COLD FRONT ENTERS THE CENTRAL ATLC NEAR 32N45W EXTENDING SW TO 28N51W WHERE IT BECOMES STATIONARY TO 24N60W THEN CONTINUES AS SURFACE TROUGH TO 21N68W. THE FRONT IS SUPPORTED ALOFT BY A UPPER LEVEL TROUGH THAT EXTENDS S INTO THE E CARIBBEAN COVERING THE AREA BETWEEN 50W-80W. JUST TO THE E IS A NARROW HIGHLY AMPLIFIED UPPER RIDGE THAT EXTENDS FROM 16N56W TO BEYOND 32N40W PROVIDING DIFFLUENCE ALOFT TO GENERATE A BROAD AREA OF SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS FROM 15N-22N BETWEEN 55W-62W AND FROM 23N-27N BETWEEN 49W-55W. A NARROW UPPER LEVEL TROUGH IS OVER THE E/CENTRAL ATLC EXTENDING FROM 32N33W DIPPING INTO THE TROPICS NEAR 12N52W AND CONTINUES TO ENHANCE CONVECTION N OF THE ITCZ. THE E ATLC IS REMAINS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED ON A 1032 MB HIGH ANCHORED E OF THE AZORES. $$ WALLACE
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