000 AXPZ20 KNHC 210330 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN AUG 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. ...SPECIAL FEATURE... ...ITCZ/MONSOON TROUGH... FROM 14N92W TO 15N97W TO 1011 MB LOW PRES AT 12N105W TO 10N111W THEN FROM 16N124W TO 11N137W TO 10N140W. SCATTERED MODERATE CONVECTION WITHIN 180 NM SE OF AXIS FROM 123W TO 130W. ...DISCUSSION... TROPICAL DEPRESSION GREG AT 20.1N 121.0W AT 21/0300 UTC MOVING W-NW AT 06 KT. MAXIMUM SUSTAINED WIND 30 GUSTS TO 40 KT WITH MINIMUM CENTRAL PRESSURE OF 1008 MB. GREG JUST WEAKENED TO A TROPICAL DEPRESSION EARLIER TONIGHT AND FORECAST TO BECOME POST-TROPICAL REMNANT LOW EARLY SUN. DEEP CENTRAL CONVECTION HAS DECREASED IN INTENSITY AND COVERAGE. REFER TO NHC HIGH SEAS FORECAST UNDER WMO HEADER FZPN03 KNHC AND AWIPS HEADER MIAHSFEP2 FOR FURTHER DETAILS. VERY DRY AIR MASS DUE TO MODERATE TO STRONG SUBSIDENCE REIGNS OVER BASIN N OF 15N W OF 122W WITH MOISTURE ASSOCIATED WITH T.D. GREG AS ONLY MOISTURE SLOT ALBEIT DIMINISHING VERY FAST. DRYNESS, COOL TEMPERATURES AND ADVERSE UPPER LEVEL ENVIRONMENT SPELLED DOOM FOR GREG. LARGE RIDGE OVER TEXAS MAINTAINS ANTICYCLONIC FLOW OVER REMAINDER OF BASIN WITH E OR SE FLOW ALOFT STRONG ENOUGH TO CURTAIL ORGANIZED DEEP CONVECTION ALONG MONSOON TROUGH AND WEAKENING SURFACE LOW PRES 1011 MB AT 12N105W. GLOBAL MODEL GUIDANCE INDICATED A TAIL OF STRONG SW WINDS SE OF GREG BUILDING SEAS TO 10 FT SE OF GREG CENTER THROUGH LATE SUN. GREG EXPECTED TO DISSIPATE COMPLETELY WITHIN 72 HOURS WITH LOW LEVEL CENTER BEING ABSORBED IN LARGER SCALE MONSOON CIRCULATION OVER W PORTION OF BASIN. LOW PRES AT 12N105W SHOWS CYCLONIC TURNING AND MOST MODELS FLIRT WITH IT BUT EVENTUALLY LOSE IT IN THE MONSOON TROUGH FLOW ALSO. THIS IS CREDIBLE GIVEN THE ADVERSITY OF UPPER LEVEL ENVIRONMENT. FRESH SW FLOW WITH SEAS TO 8 FT NOTED IN SE QUADRANT OF LOW PRES. LONG PERIOD CROSS EQUATORIAL SWELLS 8-9 FT SPREAD INTO E PAC S OF 10N FROM 95W TO 120W. $$ WALLY BARNES 000 AXPZ20 KNHC 210330 RRA TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN AUG 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0300 UTC. ...ITCZ/MONSOON TROUGH... FROM 14N92W TO 15N97W TO 1011 MB LOW PRES AT 12N105W TO 10N111W THEN FROM 16N124W TO 11N137W TO 10N140W. SCATTERED MODERATE CONVECTION WITHIN 180 NM SE OF AXIS FROM 123W TO 130W. ...DISCUSSION... TROPICAL DEPRESSION GREG AT 20.1N 121.0W AT 21/0300 UTC MOVING W-NW AT 06 KT. MAXIMUM SUSTAINED WIND 30 GUSTS TO 40 KT WITH MINIMUM CENTRAL PRESSURE OF 1008 MB. GREG JUST WEAKENED TO A TROPICAL DEPRESSION EARLIER TONIGHT AND FORECAST TO BECOME POST-TROPICAL REMNANT LOW EARLY SUN. DEEP CENTRAL CONVECTION HAS DECREASED IN INTENSITY AND COVERAGE. REFER TO NHC HIGH SEAS FORECAST UNDER WMO HEADER FZPN03 KNHC AND AWIPS HEADER MIAHSFEP2 FOR FURTHER DETAILS. VERY DRY AIR MASS DUE TO MODERATE TO STRONG SUBSIDENCE REIGNS OVER BASIN N OF 15N W OF 122W WITH MOISTURE ASSOCIATED WITH T.D. GREG AS ONLY MOISTURE SLOT ALBEIT DIMINISHING VERY FAST. DRYNESS, COOL TEMPERATURES AND ADVERSE UPPER LEVEL ENVIRONMENT SPELLED DOOM FOR GREG. LARGE RIDGE OVER TEXAS MAINTAINS ANTICYCLONIC FLOW OVER REMAINDER OF BASIN WITH E OR SE FLOW ALOFT STRONG ENOUGH TO CURTAIL ORGANIZED DEEP CONVECTION ALONG MONSOON TROUGH AND WEAKENING SURFACE LOW PRES 1011 MB AT 12N105W. GLOBAL MODEL GUIDANCE INDICATED A TAIL OF STRONG SW WINDS SE OF GREG BUILDING SEAS TO 10 FT SE OF GREG CENTER THROUGH LATE SUN. GREG EXPECTED TO DISSIPATE COMPLETELY WITHIN 72 HOURS WITH LOW LEVEL CENTER BEING ABSORBED IN LARGER SCALE MONSOON CIRCULATION OVER W PORTION OF BASIN. LOW PRES AT 12N105W SHOWS CYCLONIC TURNING AND MOST MODELS FLIRT WITH IT BUT EVENTUALLY LOSE IT IN THE MONSOON TROUGH FLOW ALSO. THIS IS CREDIBLE GIVEN THE ADVERSITY OF UPPER LEVEL ENVIRONMENT. FRESH SW FLOW WITH SEAS TO 8 FT NOTED IN SE QUADRANT OF LOW PRES. LONG PERIOD CROSS EQUATORIAL SWELLS 8-9 FT SPREAD INTO E PAC S OF 10N FROM 95W TO 120W. $$ WALLY BARNES