000 AXPZ20 KNHC 201025 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SUN NOV 20 2011 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 0945 UTC. ...SPECIAL FEATURE... TROPICAL DEPRESSION THIRTEEN-E NEAR 10.4N 103.7W AT 20/0900 UTC MOVING W AT 13 KT. ESTIMATED MINIMUM PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTPZ33 FOR MORE DETAILS. CONVECTION HAS CONTINUED TO DEEPEN MAINLY NE OF THE CENTER WHERE THE SCATTERED STRONG TYPE EXISTS OUT TO ABOUT 21O NM FROM THE CENTER. SIMILAR CONVECTION IS WITHIN 120 NM OF THE CENTER IN THE SE QUADRANT. A DEVELOPING OUTER RAIN BAND IS DENOTED BY SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 30 NM OF A LINE FROM 14N104W TO 12.5N106W. CLUSTERS OF SIMILAR TYPE CONVECTION ARE SW OF THE CENTER WITHIN 45 NM OF 9N105W...AND 08N108W. THE DEPRESSION REMAINS UNDER THE SOUTHERN PERIPHERY OF A DEEP LAYER SUBTROPICAL RIDGE. THIS ALONG WITH VERTICAL SHEAR FORECAST TO REMAIN RATHER LOW THROUGH THE NEXT 24-48 HRS WILL ALLOW THE DEPRESSION TO GRADUALLY INTENSIFY INTO A TROPICAL STORM BY 24 HRS ...AND CONTINUE TO INTENSIFY INTO 48 HRS AS IS TRACKS TO THE W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM NORTHERN COSTA RICA TO WEAK LOW PRES NEAR 8N89W 1010 MB AND CONTINUES TO 9N96W WHERE IT ENDS. LOW LEVEL WINDS INDICATE THAT THE INTERTROPICAL CONVERGENCE ZONE BEGINS AT 8N112W AND CONTINUES TO 9N120W TO 10N129W TO 9N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 45 NM EITHER SIDE OF 08N106W 08N113W. ...DISCUSSION... A RATHER VIGOROUS UPPER LOW N OF THE AREA NEAR 38N126W IS RAPIDLY SWINGING SE WITH A TROUGH EXTENDING FROM IT SW TO 32N127W TO 27N132W TO BEYOND THE AREA AT 26N140W. THE ASSOCIATED COLD FRONT IS JUST N OF THE AREA ALONG 31N AND W OF 127W. THE TROUGH WILL MOVE INLAND THE WESTERN U.S. TONIGHT PUSHING THE COLD FRONT TO A POSITION FROM NEAR 32N119W TO 27N126W TO 26N140W TONIGHT...AND TO E OF THE AREA WHERE IT DISSIPATES BY LATE MON NIGHT. LATEST SATELLITE WATER VAPOR IMAGERY SHOWS PLENTIFUL MID TO UPPER LEVEL MOISTURE BEING ADVECTED TO THE NE TO THE SE OF THE DEEP LAYER TO NEAR 19N. ADDITIONAL MID TO UPPER LEVEL MOISTURE IS STREAMING INTO THE AREA IN PERSISTENT WLY FLOW OVER THE PORTION OF THE AREA FROM 10N TO 19N W OF 120W. THIS MOISTURE IS BEING CHANNELED INTO THE AREA FROM THE DEEP TROPICS S OF THE HAWAIIAN ISLANDS. AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR THE VICINITY OF THE GULF OF TEHUANTEPEC WITH A RIDGE AXIS EXTENDING FROM IT TO NEAR 13N121W. UPPER LEVEL DIFFLUENCE ALONG THE RIDGE IS ENHANCING CONVECTION ALONG THE ITCZ AS IS DESCRIBED IN THE SECTION ABOVE. IN ADDITION...THE RIDGE IS HELPING TO SUSTAIN THE DEVELOPING TREND OF CONVECTION ASSOCIATED WITH TROPICAL DEPRESSION THIRTEEN-E. ELSEWHERE OUTSIDE ITCZ CONVECTION AND MOISTURE ASSOCIATED WITH THE DEPRESSION...SATELLITE WATER VAPOR IMAGERY INDICATES DRY AND STABLE AIR UNDER MODERATE TO STRONG SUBSIDENCE SE OF A LINE FROM SRN BAJA CALIFORNIA TO 10N120W TO 6N126W. ELSEWHERE AT THE SURFACE...HIGH PRES CENTERED WELL NW OF THE REGION EXTENDS A RIDGE THROUGH 29N140W SE TO 26N131W AND TO NEAR 24N118W. HIGH PRES COVERS THE AREA N OF ABOUT 16N AND W OF 117W. LARGE NW SWELLS WITH PEAK WAVE PERIODS OF 14-17 SECONDS ARE RESULTING IN SEAS OF 9-14 FT TO EXIST N OF 29N BETWEEN 119W-124W. AS THE ABOVE MENTIONED COLD FRONT SWEEPS INTO THE AREA OVER THE NEXT 48 HRS...A NEW SET OF SIMILAR NW SWELLS WILL PROPAGATE SE AND S INTO MAINLY THE N CENTRAL PORTION OF THE DISCUSSION AREA. A SURFACE TROUGH IS ANALYZED ALONG THE ITCZ EXTENDING FROM 13N127W TO 10N130W. THE PRES GRADIENT BETWEEN ASSOCIATED LOW PRES AND THAT ASSOCIATED WITH THE ITCZ...AND THE RIDGE TO THE N IS ALLOWING FOR NE 20 KT TRADES WITH SEAS OF 8 FT TO BE LOCATED FROM 10N-24N AND W OF 129W. THIS AREA OF TRADES WILL EXPAND SOME EASTWARD OVER THE NEXT 48 HRS AS THE TROPICAL STORM THIRTEEN-E MOVES FURTHER WESTWARD. GAP WINDS... N-NE WINDS OF 20 KT ARE FORECAST TO FILTER INTO THE GULF OF TEHUANTEPEC IN ABOUT 24 HOURS...BUT DIMINISH EARLY MON EVENING. GULF OF PAPAGAYO NE-E 20 KT WINDS ARE EXPECTED TO PULSATE ON AND OFF THROUGH MON EVENING. $$ AGUIRRE