000 AXPZ20 KNHC 150853 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC TUE OCT 15 2013 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0830 UTC. ...SPECIAL FEATURES... TROPICAL STORM PRISCILLA NEAR 17.1N 116.0W AT 15/0900 UTC OR 491 NM SW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MOVING N AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SEE LATEST NHC FORECAST /ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS WITHIN 180 NM IN THE W QUADRANT...BEING SHEARED BY STRONG E- SE UPPER LEVEL WINDS. PRISCILLA IS FORECAST TO WEAKEN TO A TROPICAL DEPRESSION LATER TODAY...THEN TO A REMNANT LOW BY 48 HOURS AS IT MOVES INTO AN AREA OF MORE STABLE AIR WITH INCREASING UPPER LEVEL WIND SHEAR...DISSIPATING BY LATE FRI. DOWNGRADED TROPICAL DEPRESSION OCTAVE NEAR 25.5N 112.0W AT 15/0900 UTC OR 43 NM NNE OF CABO SAN LAZARO MEXICO MOVING NNE AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. REMAINING SCATTERED MODERATE CONVECTION IS REMOVED TO THE NE OF THE CENTER OVER THE GULF OF CALIFORNIA FROM 25N TO 28N E OF 111W...WITH ADDITIONAL CONVECTION AND LOCALLY HEAVY RAINFALL OVER LAND OVER THE SOUTHERN BAJA CALIFORNIA PENINSULA AS WELL AS SPREADING ACROSS PORTIONS OF NW MEXICO AND SOUTHERN NEW MEXICO AND WESTERN TEXAS. OCTAVE IS FORECAST TO WEAKEN TO A REMNANT LOW OVER LAND WITHIN THE NEXT 12 HOURS...DISSIPATING BY WED AFTERNOON. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM 10N85W TO 07N92W TO 08N107W... THEN RESUMES FROM 11N120W TO LOW PRES NEAR 10N136W TO BEYOND 10N140W. NO ITCZ IS PRESENT E OF 140W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM SW OF A LINE FROM 10N85W TO 06N78W. ...DISCUSSION... A BROAD AND DOMINANT UPPER LEVEL ANTICYCLONE REMAINS OVER NE MEXICO S OF TEXAS NEAR 25N98W WITH A RIDGE AXIS EXTENDING TO THE WSW TO NEAR 18N121W. THIS IS THE ANTICYCLONE INDUCING UPPER LEVEL SHEAR OVER PRISCILLA AS IS DESCRIBED ABOVE...AND IS ALSO RESPONSIBLE FOR ADVECTING THE REMAINING CONVECTION TO THE NE AWAY FROM OCTAVE. ADDITIONAL CONVECTION IS SUPPORTED ON THE S-SW PORTION OF THE ANTICYCLONE FROM 09N TO 16N BETWEEN 106W AND 136W. AN UPPER LEVEL TROUGH IS W OF THE RIDGE AND ANTICYCLONE EXTENDING FROM SOUTHERN CALIFORNIA THROUGH 32N120W TO 12N134W. DRY AND STABLE AIR IS PRESENT W OF A LINE FROM 26N113W TO 00N130W...EXCEPT N OF 19N W OF 131W WHERE DEEP TROPICAL MOISTURE CONTINUES TO BE ADVECTED FROM THE DEEP TROPICS S OF THE HAWAIIAN ISLANDS INTO THE NW CORNER OF THE DISCUSSION WATERS AROUND AN UPPER LEVEL RIDGE. AN INVERTED UPPER LEVEL TROUGH HAS DEVELOPED SE OF THE ANTICYCLONE FROM NEAR THE GULF OF TEHUANTEPEC REGION SW TO 07N104W...MOVING W AS THE ABOVE MENTIONED ANTICYCLONE EXTENDS ANOTHER RIDGE TO THE E OF THE TROUGH FROM THE NW CARIBBEAN SEA TO ACROSS COSTA RICA. ELSEWHERE AT THE SURFACE...WEAK 1008 NM LOW PRES IS NEAR 10N104W. ASSOCIATED WINDS ARE MAINLY LIGHT WITH 4-6 FT SEAS AND NO SIGNIFICANT CONVECTION NEAR THE LOW. NO DEVELOPMENT IS CURRENTLY ANTICIPATED DURING THE NEXT 48 HOURS AS THE LOW MOVES TO THE W AROUND 10 KT. A PINCHED PRES GRADIENT IS INDUCING FRESH TO STRONG WINDS AND RESULTANT 8 FT SEAS IN THE GULF OF TEHUANTEPEC AS INDICATED BY RECENT ASCAT...OSCAT...AND WINDSAT SCATTEROMETER PASSES. THESE CONDITIONS ARE FORECAST TO DIMINISH AND SUBSIDE LATER THIS MORNING AS THE GRADIENT SLACKENS. A SURFACE RIDGE EXTENDS FROM 32N136W TO THE SE TO JUST NW OF PRISCILLA. OUTSIDE OF THE TROPICAL CYCLONE AREAS...MODERATE WINDS AND 4-7 FT SEAS DOMINATE THE REMAINDER OF THE DISCUSSION WATERS. GULF OF CALIFORNIA...A BRIEF SPELL OF FRESH TO STRONG NORTHERLY WINDS IS FORECAST IN THE EXTREME NORTHERN GULF OF CALIFORNIA N OF 30N BY LATE TUE NIGHT AS TROUGHING SETS UP ACROSS NW MEXICO. WINDS WILL THEN DIMINISH TO 20 KT OR LESS BY WED EVENING AS THE TROUGHING BROADENS. $$ LEWITSKY