000 AXPZ20 KNHC 180324 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON SEP 18 2006 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...SPECIAL FEATURES... TROPICAL STORM MIRIAM IS CENTERED NEAR 19.4N 114.1W...OR 300 NM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA...AT 18/0300 UTC MOVING N NW AT 4 KT. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1001 MB. MIRIAM IS EMBEDDED IN NE MID TO UPPER LEVEL FLOW SE OF AN UPPER RIDGE WITH THE RESULTANT NLY SHEAR EXPOSING THE LOW LEVEL CENTER...CURRENTLY SCATTERED MODERATE CONVECTION IS OBSERVED WELL TO THE SW OF CENTER...WITHIN 120 NM OF 17.5N118.5W. MIRIAM IS EXPECTED TO MOVE INTO AN AREA OF INCREASED WIND SHEAR AND COOLER WATERS OVER THE NEXT COUPLE OF DAYS THUS A GRADUAL WEAKENING TREND IS FORECAST. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE ALONG 88.5W N OF 4N MOVING W 12 KT. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS ENHANCED FROM 4N TO 16N BETWEEN 80W AND 86W WITH THE STRONGEST CONVECTION MOVING ACROSS NICARAGUA AT THE MOMENT. TROPICAL WAVE ALONG 96W N OF 4N HAS BEEN RELOCATED BUT IS ESTIMATED TO BE MOVING W AT 12 KT. BROAD CYCLONIC TURNING IS NOTED N OF 10N ALONG THE WAVE WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION OBSERVED ALONG 12N BETWEEN 92W AND 97W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N85W 7N104W 15N117W 10N130W 10N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 120 NM EITHER SIDE OF LINE 8N81W 5N93W AND FROM 4N TO 10N BETWEEN 104W AND 116W. ...DISCUSSION... AN UPPER CYCLONE IS NEAR 32N131W WITH ITS ENVELOPE OF UPPER CYCLONIC FLOW SHRINKING WITH TIME AND CURRENTLY ABOUT 420 NM DIAMETER. A TROUGH EXTENDS SW FROM THE CYCLONE TO NEAR 22N133W. AN UPPER ANTICYCLONE IS QUASI-STATIONARY AT 22N123W WITH A RIDGE EXTENDING SW TO A SHARP CREST NEAR 17N142W. A RIDGE ALSO EXTENDS E TO CREST NEAR 23N110W. TO THE N OF THIS RIDGE...A SHORTWAVE TROUGH OVER WRN N AMERICA EXTENDS S INTO THE DISCUSSION AREA FROM 34N108W TO A BASE AT 25N106W. A BAND OF VERY DRY UPPER AIR IS INDICATED WITHIN 90 NM EITHER SIDE OF LINE 31N102W 18N135W AND IS SURROUNDED BY RELATIVELY DRY AIR OVER THE DISCUSSION AREA NW OF LINE 11N140W 21N118W 27N103W. SOME OF THE UPPER DEBRIS MOISTURE FROM MIRIAM IS ADVECTED SW WITHIN 120 NM EITHER SIDE OF LINE 24N102W 6N134W. A TUTT EXTENDS FROM A DEEP LAYERED CYCLONE OVER THE SW ATLC NEAR 35N69W THROUGH 24N80W TO ANOTHER WEAK CYCLONE NEAR 21N96W THEN ACROSS CENTRAL AMERICA TO A WEAK INVERTED UPPER TROUGH ALONG 12N105W AND S OF THE EQUATOR AT 107W. ELSEWHERE AT THE SURFACE A RIDGE EXTENDS ALONG 32N134W 23N117W. $$ NELSON