000 AXPZ20 KNHC 170947 RRA TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC FRI MAY 17 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 0900 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION ALVIN CENTERED AT 10.3N 112.0W AT 17/0900 UTC IS MOVING WNW AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. SCATTEROMETER WINDS SUGGEST A VERY WEAK SYSTEM AND ALVIN IS DOWNGRADED AT THIS TIME TO A TROPICAL DEPRESSION WITH MAXIMUM SUSTAINED WIND SPEED OF 30 KT WITH GUSTS TO 40 KT WITHIN ABOUT 75 NM OF THE CENTER. CONVECTION INTENSIFIED OVER THE PAST FEW HOURS MAINLY TO THE EAST OF THE SHEARED CENTER...WITH SCATTERED MODERATE TO STRONG CONVECTION NOTED WITHIN 60 NM EITHER SIDE OF A LINE FROM 10N111W TO 13N110W. ALVIN IS FORECAST TO CONTINUE TO TRACK THROUGH AN AREA OF UNFAVORABLE CONDITIONS...AND IT IS FORECAST TO GRADUALLY WEAKEN TO A REMNANT LOW PRESSURE LATER TODAY. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS W FROM THE COAST OF COLOMBIA AT 07N77W TO 1009 MB LOW PRES NEAR 07N83W TO 09N107W WHERE IT LOSES IDENTITY IN THE BROAD CYCLONIC CIRCULATION ASSOCIATED WITH TROPICAL DEPRESSION ALVIN. SCATTEROMETER WINDS INDICATE THE MONSOON TROUGH RESUMES SW OF THE DEPRESSION NEAR 09N113W AND CONTINUES SW TO 07N128W WHERE SCATTEROMETER WINDS SUGGEST A TRANSITION TO AN ITCZ WHICH EXTENDS W TO BEYOND 07N140W. ISOLATED MODERATE AND STRONG CONVECTION IS FLARING ALONG THE EASTERN SEGMENT OF THE MONSOON TROUGH AND THE EMBEDDED LOW PRESSURE WITHIN THE AREA BOUNDED BY 04N-08N TO THE E OF 97W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED ALONG THE WESTERN SEGMENT OF THE MONSOON TROUGH WITHIN 120 NM EITHER SIDE OF A LINE FROM 12N114W TO 07N124W TO 09N134W. THE LOW PRESSURE CENTER NEAR 07N83W IS EXPECTED TO DISSIPATE OVER THE DAY OR SO. ...DISCUSSION... A NEARLY STATIONARY RIDGE EXTENDS FROM 32N136W TO 18N107W. NW WINDS ARE AT 10-15 KT ALONG THE ENTIRE W SHORE OF THE BAJA CALIFORNIA PENINSULA WITH SEAS 4-7 FT. THE GRADIENT WILL TIGHTEN BRIEFLY ON SAT WITH THE NW FLOW INCREASING TO 15-20 KT ALONG THE PENINSULA TO THE N OF 27N. THE GRADIENT WILL RELAX AGAIN ON SUN SUPPORTING MOSTLY W-NW WINDS AT 10 KT WITH LITTLE CHANGE THROUGH TUE. LOOKING A LITTLE FURTHER W NORTHERLY WINDS WILL INCREASE TO 15-20 KT ON SUN ACROSS THE WATERS N OF 29N BETWEEN 118W-125W. THESE CONDITIONS WILL SPREAD S ACROSS THE PACIFIC WATERS N OF 27N BETWEEN 120W-130W BY TUE WITH SEAS TO 10 FT IN MIXED N AND LONG PERIOD CROSS-EQUATORIAL SW SWELL. LONG PERIOD SOUTHERLY SWELLS ARE EXPECTED TO CROSS THE EQUATOR TODAY BETWEEN 108W-120W AND MIX WITH THE CONFUSED SWELLS GENERATED BY ALVIN...PRODUCING SEAS 7-11 FT ACROSS THE WATERS SURROUNDING THE TROPICAL DEPRESSION FROM 16N TO THE EQUATOR BETWEEN 105W AND 120W ON SAT WITH THE SOUTHERLY SWELLS SUBSIDING ON SUN. $$ NELSON