000 AXPZ20 KNHC 230330 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC WED SEP 23 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0315 UTC. ...SPECIAL FEATURE... THE AREA OF LOW PRES EARLIER NOTED ABOUT 600 NM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA HAS INTENSIFIED INTO NEWLY FORMED TROPICAL DEPRESSION SEVENTEEN-E NEAR 15.7N 115.7W AT 23/0300 UTC MOVING NW OR 320 DEG AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC FOR MORE DETAILS. CONVECTION ASSOCIATED WITH TROPICAL DEPRESSION SEVENTEEN-E HAS INCREASED IN INTENSITY. DURING THE PAST 12-24 HOURS...WHILE THE OVERALL CLOUD PATTERN HAS INDICATED SOME CONSOLIDATION NOTED BY THE MORE SYMMETRICAL APPEARANCE OF THE CLOUDS MAINLY ON THE W SEMICIRCLE OF THE SYSTEM. THE LAST FEW VISIBLE IMAGES SHOWED A BANDING FEATURE CONSISTING OF NUMEROUS CONVECTION WITHIN 60 NM NW OF THE CENTER. SCATTERED MODERATE TO STRONG CONVECTION IS ELSEWHERE WITHIN 180 NM N QUADRANT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF LINE 14N117W TO 16N117W TO 17N117W AND OF LINE FROM 13N117W TO 14N119W. THE DEPRESSION IS FORECAST INTENSIFY INTO A TROPICAL STORM BY WED MORNING AS IT MOVES NW...AND CONTINUE AT THIS INTENSITY FOR ABOUT 24 HOURS BEFORE WEAKENING BACK INTO A TROPICAL DEPRESSION UNDER STRONG SW VERTICAL WIND SHEAR AND SURROUNDED BY A RATHER STABLE ENVIRONMENT. ...THE ITCZ... THE INTERTROPICAL CONVERGENCE ZONE IS ALONG 8N78W TO 8N90W TO 08N100W TO 12N115W TO 08N127W TO 8N140W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 180 NM S OF THE AXIS BETWEEN 81W-84W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS 120 NM S OF THE AXIS BETWEEN 120W-124W AND ALSO BETWEEN 131W-134W AND N OF THE AXIS FROM 8N-11N BETWEEN 109W-112W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM S OF THE AXIS BETWEEN 88W-90W AND 92W-96W. ...DISCUSSION... N OF 20N... THE REMNANTS OF FORMER TROPICAL STORM MARTY ARE STILE VISIBLE AS A TROUGH ALONG 133W FROM 20N TO 26N MOVING W ABOUT 10 KT. NE WINDS TO 20 KT ARE AT TIMES OCCURRING WITHIN 60 NM W OF THE TROUGH. WEAK HIGH PRES AND MOSTLY BROKEN STRATOCUMULUS WILL PERSIST ELSEWHERE OVER N WATERS THROUGH THE PERIOD WITH SOME CIRRUS NOTED ALONG THE EDGE OF A 60 KT WESTERLY JET CUTTING THROUGH 22N140W 23N125W INTO THE SOUTHERN EDGE OF THE POSITIVELY TILTED UPPER TROUGH OVER THE SOUTHWEST U.S. AND NW MEXICO. THE UPPER TROUGH AND JET AXIS ARE EXPECTED TO REMAIN STATIONARY THE NEXT FEW DAYS. THE COLD FRONT ASSOCIATED WITH THIS TROUGH WILL MOVE S INTO NORTHERN MEXICO LATER TODAY. MODELS SHOW INCREASING AGREEMENT ON WINDS INCREASING TO 20 KT OVER THE NORTHERN GULF OF CALIFORNIA ON WED. FOR NOW HOWEVER HELD OFF ON ANY MENTION OF WINDS ABOVE 20 KT IN THE HIGH SEAS FORECAST SINCE IT APPEARS THAT THESE WINDS WILL BE RELATIVELY SHORT-LIVED. A COLD FRONT NEARING THE NW CORNER OF THE AREA IN ASSOCIATION WITH A DEEP LAYER TROUGH IS EXPECTED TO STALL AND WEAKEN N OF THE AREA THROUGH THE NEXT 48 HOURS AS A RIDGE HOLDS FIRM ACROSS THE AREA NW OF TROPICAL DEPRESSION SEVENTEEN-E. S OF 20N... A WELL PRONOUNCED MID/UPPER ANTICYCLONE CENTERED OVER INLAND MEXICO NEAR 21N100W EXTENDS A RIDGE SW TO OVER NEWLY FORMED TROPICAL DEPRESSION SEVENTEEN-E...AND TO NEAR 14N122W. SLY UPPER LEVEL WINDS ON THE WESTERN PERIPHERY OF THE RIDGE IS LEADING TO SLY SHEAR OVER THE DEPRESSION. TO THE S OF THE RIDGE...AN UPPER LEVEL DIFFLUENT PATTERN IS NOTED WHICH IS ENHANCING ITCZ CONVECTION BETWEEN 108W-115W. WHILE CONDITIONS SHOULD STILL REMAIN BROADLY DIFFLUENT OVER THIS AREA ALOFT. THE GFS HAS BACKED OFF ON THE FORECAST OF A 1005 MB LOW PRES SYSTEM OFF THE SOUTHERN TIP OF PANAMA. THE SYSTEM THAT IS FORECAST IS WEAKER WITH SOUTHWESTERLY WINDS OF 20 KT AND SEAS TO 8 FT OVER THE AREA LATER TODAY. THIS MAY BE AN OVERESTIMATE BUT IS NOW IN LINE WITH OTHER MODELS. ELSEWHERE ASIDE FROM THE PREVIOUSLY MENTIONED SYSTEMS...A WEAK SURFACE TROUGH FOUND ALONG 133W FROM 07N TO 13N IS CAUSING A WEAK PERTURBATION ALONG THE ITCZ...AND N OF THE ITCZ NOTED AS SCATTERED STRONG CONVECTION WITHIN 30 NM OF 11N133W. GAP WINDS... THE COLD FRONT PASSING SOUTH INTO MEXICO TODAY IS EXPECTED TO BRING 20 KT NORTHERLY FLOW THROUGH THE BAY OF CAMPECHE INTO THE GULF OF TEHUANTEPEC IN ABOUT 24 HOURS AND CONTINUE THROUGH 48 HOURS. WINDS ARE EXPECTED TO SLIGHTLY INCREASE JUST AFTER THE FORECAST PERIOD. $$ AGUIRRE