Tropical Storm NOCK-TEN Update

[Jeb]

WDPN32 PGTW 251500

MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//

SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W

/WARNING NR 47//

RMKS/

1. FOR METEOROLOGISTS.

2. PROGNOSTIC REASONING FOR 251200Z0 TO 281200Z3 OCT 2004.

A. TYPHOON (TY) 28W (NOCK-TEN), LOCATED OFF THE NORTHEAST

COAST OF TAIWAN AND APPROXIMATELY 270 NM WEST OF OKINAWA,

JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 08 KNOTS OVER THE

PAST 06 HOURS. THE WARNING POSITION IS BASED ON 251130Z2

ENHANCED INFRARED SATELLITE IMAGERY, 251200Z0 RADAR IMAGERY

AND RECENT MICROWAVE IMAGERY. THE WARNING INTENSITY IS BASED

ON SATELLITE CURRENT INTENSITY ESTIMATES OF 77 KNOTS WITH A

12 KNOT REDUCTION TO REFLECT GREATER EMPHASIS ON DVORAK

FINAL-T INTENSITY ESTIMATES OF 55 AND 65 KNOTS AND THE RAPID

WEAKENING OF TY 28W. TY 28W HAS STARTED TO RECURVE TO THE

NORTHEAST AND IS WEAKENING. THE CONVECTION ASSOCIATED WITH

TY 28W HAS SIGNIFICANTLY DIMINISHED AND THE SYSTEM HAS LOST

ORGANIZATION OVER THE PAST 06 HOURS. SATELLITE, RADAR AND

MICROWAVE FIX POSITIONS INDICATE THAT THE UPPER LEVEL STRUC-

TURE OF THE SYSTEM MAY BE GETTING DECOUPLED FROM THE LOW

LEVEL CIRCULATION CENTER AS TY 28W ENCOUNTERS STRONG WESTER-

LIES OF THE BAROCLINIC ZONE.

B. TY 28W IS FORECAST TO TRACK NORTHEASTWARD AS IT

CONTINUES TO RECURVE ALONG THE NORTHWESTERN PERIPHERY OF THE

STEERING RIDGE AND ENCOUNTER THE MID-LATITUDE WESTERLIES. TY

28W WILL TRANSITION INTO AN EXTRATROPICAL CYCLONE AS IT

INTERACTS WITH THE BAROCLINIC ZONE. THE AVAILABLE DYNAMIC

AIDS CONSISTING OF NOGAPS, COAMPS, GFDN, NCEP GFS, JGSM, JTYM,

UKMET, AFWA MM5 AND TCLAPS ARE IN GOOD AGREEMENT WITH THIS

SCENARIO THROUGH TAU 24. MODEL FORECASTS OF THE BAROCLINIC

INTERACTION RESULT IN DIVERGENCE OF FORECAST TRACKS BEYOND

TAU 24. UKMET, NCEP GFS, AFWA MM5, JTYM AND NOGAPS EMBED TY

28W INTO THE BAROCLINIC ZONE BY TAU 48. GFDN FORECASTS A

DECOUPLING OF THE SYSTEM, WITH THE MID AND UPPER LEVELS

BECOMING EMBEDDED IN THE MID-LATITUDE FLOW AND THE LOW LEVEL

CIRCULATION TRACKING AROUND THE EASTERN PERIPHERY OF AN ANTI-

CYCLONE THAT DEVELOPS OVER CHINA WITHIN THE NEXT 24 HOURS.

THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC

AIDS WITH LESS EMPHASIS PLACED ON GFDN AFTER TAU 24. TY 28w

IS FORECAST TO COMPLETE TRANSITION INTO AN EXTRATROPICAL

SYSTEM BY TAU 36.

C. THE INTENSITY OF TY 28W IS FORECAST TO RAPIDLY DECREASE

THROUGH THE FORECAST PERIOD AS THE SYSTEM ENCOUNTERS DRY AIR,

COOLER SEA SURFACE TEMPERATURES AND INTERACTS WITH THE MID-

LATITUDE BAROCLINIC ZONE.

D. CURRENT WIND RADII ARE BASED ON A 251058Z1 SSM/I PASS

AND FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVER-

AGE SIZED SYSTEM UNDERGOING EXTRATROPICAL TRANSITION.

FORECAST TEAM: DXION/FJELD/VOHS//

 

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