000 AXPZ20 KNHC 062159 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC MON OCT 06 2008 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...SPECIAL FEATURES... TROPICAL STORM NORBERT AT 14.5N 105.3W AT 06/2100 UTC OR 320 NM S-SW OF MANZANILLO MEXICO MOVING W-NW OR 285 DEG AT 7 KT. ESTIMATED MINIMUM CENTRAL PRES 990 MB. MAXIMUM SUSTAINED WIND SPEED 60 WITH GUSTS TO 75 KT. REFER TO LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC AND INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP5/ WTPZ35 KNHC FOR MORE DETAILS. NORBERT CONTINUE SHOWING SIGNS OF INTENSIFICATION APPROACHING HURRICANE STRENGTH THRESHOLD AND EXPECTED TO BECOME ONE WITHIN NEXT 12 HRS. CLOUD BANDS LENGTH AND CURVATURE INDICATE WELL ORGANIZED CYCLONE. UPPER LEVEL OUTFLOW IS WELL ROUNDED AND EMBEDDED IN FAVORABLE ENVIRONMENT. NORBERT TRACK AND INTENSITY BECOMES REAL CHALLENGE AS GUIDANCE PRESENT SEVERAL DIVERGING SCENARIOS. SOUTHWESTWARD DIGGING UPPER LEVEL TROUGH COULD INFLUENCE NORBERT INTO A MORE NORTHERLY TRACK...APPROACHING THE COAST AND COOLER WATERS...OR A MORE WESTERLY COURSE WITH WARM SEA SURFACE TEMPERATURES AND MORE FAVORABLE UPPER SUPPORT. OFFICIAL FORECAST TURNS NORBERT MORE NW THEN N AT AN UNDISTURBED DISTANCE FROM THE COAST WHILE INTENSIFYING. TROPICAL DEPRESSION MARIE AT 18.9N 123.7W AT 06/2100 UTC OR 930 NM W-SW OF SRN TIP OF BAJA CALIFORNIA MOVING W OR 280 DEG AT 3 KT. ESTIMATED MINIMUM CENTRAL PRES 1007 MB. MAXIMUM SUSTAINED WIND SPEED 25 WITH GUSTS TO 35 KT. LAST NHC FORECAST/ADVISORY IS UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC AND INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPEP4/WTPZ34 KNHC FOR MORE DETAILS. MARIE IS TAKING HER LAST BREATHS AS TROPICAL CYCLONE AS IT HAS DRIFTED INTO COOL SEA SURFACE TEMPERATURES WITH A DRIER AND STABLE AIR MASS. ITS DEMISE IS NOW MEASURED IN HOURS SINCE MOST DEEP CONVECTION IS ALL BUT GONE AT PRESENT. MARIE SHOULD BECOME A REMNANT LOW PRES WITHIN 12 HRS. NO MORE ADVISORIES WILL BE ISSUED BY NHC. AREA OF LOW PRES 1008 MB AT 12N89W HAS BARELY MOVED LAST 12 HRS. SYSTEM APPEARS TO BE LOSING ITS BATTLE AGAINST INCREASED NE WIND SHEAR ALOFT AND CONTINUES UNDER INCREASINGLY HOSTILE ENVIRON. WITH ITS DEEP CONVECTION GONE...CLOUD TOPS WARMED AND DISTURBED OUTFLOW...CHANCES OF INTENSIFICATION BECOME LESS PROBABLE... ALTHOUGH 12Z GFS GUIDANCE STILL KEEPS IT ALIVE. ...ITCZ... ITCZ AXIS ALONG 06N77W TO 08N105W TO 05N120W TO 07N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM OF 07N89W. SCATTERED MODERATE CONVECTION WITHIN 40 NM OF AXIS FROM 105W-115W. ...DISCUSSION... UPPER LEVEL RIDGE FROM ANTICYCLONE OVER YUCATAN PENINSULA TO SECOND ANTICYCLONE AT 18N126W DISRUPTED BY SW DIGGING UPPER LEVEL TROUGH EXTENDING FROM N TEXAS ACROSS TIP OF BAJA CALIFORNIA TO 15N117W. THIS TROUGH IS CONTRIBUTING TO DIFFLUENT FLOW ALOFT ENHANCING INTENSIFICATION OF NORBERT AND LIKELY INFLUENCING ITS STEERING. DRY AND STABLE SUBSIDING AIR MASS OVER E PAC W OF 115W HELPING IN DEMISE OF TROPICAL DEPRESSION MARIE. ELSEWHERE AT THE SURFACE... TROPICAL STORM MARCO OVER BAY OF CAMPECHE COULD FORCE N WINDS ACROSS ISTHMUS OF TEHUANTEPEC AND INCREASE WINDS INTO GULF OF TEHUANTEPEC. WITH LOW PRES AT 12N89W DRIFTING INTO PICTURE JUST S OF TEHUANTEPEC...SOLUTION BECOMES MORE COMPLICATED AND MODEL GUIDANCE HIGHLY UNRELIABLE. WHILE N WINDS 20-30 KT FOR SHORT PERIOD OF TIME ARE FORECAST...CONFIDENCE REMAIN VERY LOW. HIGH PRES 1025 MB ALONG 31N PRODUCED A NOW SUBSIDING SWELL TRAIN INTO NW CORNER OF E PAC SPREADING SW. SHIP REPORTS INDICATE SEAS TO 10 FT WHILE MODEL GUIDANCE HAS LOWER HEIGHTS AND LESS WIDESPREAD AS FORECAST. LONG PERIOD SW SWELL OVER SW HALF OF BASIN SUBSIDING...BUT MERGING WITH SEA HEIGHTS PRODUCED BY TROPICAL CYCLONES...NORBERT AND 1008 MB LOW PRES AT 12N89W...FORECAST ADDRESSES THE LATTER. $$ WALLY BARNES