WDPN31 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (OMAIS) WARNING NR 
034//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.0N 129.1E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 397 NM SOUTH OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS THAT THE
EARLIER CCC CONVECTIVE PATTERN HAS BROKEN DOWN INTO DISORGANIZED
POCKETS OF FLARING DEEP CONVECTION AROUND A CENTRAL CONVECTIVE
MASS. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED
ON THE PGTW FIX POSITION AND A LOW RESOLUTION 201701Z ATMS PASS
WITH AN ILL-DEFINED LLCC. THE OVERALL DISORGANZATION INDICATES THAT
THE VORTEX CONTINUES TO STRUGGLE TO CONSOLIDATE. HOWEVER, THE
INITIAL INTENSITY WAS RAISED TO 35 KNOTS, WHICH IS SLIGHTLY HIGHER
THAN AGENCY ESTIMATES, BASED ON EARLIER ASCAT AND SMAP DATA, WITH 
HIGHER WINDS ISOLATED TO THE SOUTHEAST QUADRANT. THIS ASSESSMENT IS 
ALSO CONSISTENT WITH CIMSS ADT ESTIMATES.

INITIAL WIND RADII BASIS: SCATTEROMETER AND SMAP DATA 

CURRENT STEERING MECHANISM: EXTENSION OF A DEEP LAYER SUBTROPICAL
RIDGE (STR) CENTERED EAST OF HONSHU

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   CIMSS SATCON: 41 KTS AT 201520Z
   CIMSS ADT: 34 KTS AT 201740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK RADIAL
   OTHER FACTORS: A SHARP UPPER LEVEL TROUGH TO THE NORTH IS
INCREASING VERTICAL SHEAR

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS 16W (OMAIS) HAS CONTINUED TO STEADILY TRACK
TO THE NORTHWEST OVER THE PAST SIX HOURS AS AN EXTENSION OF THE STR
REMAINS FIRMLY ENTRENCHED TO THE NORTHEAST. OMAIS IS EXPECTED TO
TURN ON TO A MORE NORTHWARD TRACK OVER THE COURSE OF THE NEXT 36
HOURS AS IT ROUNDS THE STR, FOLLOWED BY A RECURVATURE TO THE
NORTHEAST AFTER CLEARING THE RYUKU CHAIN. PRIOR TO RECURVATURE, THE
MARGINALLY CONDUCIVE ENVIRONMENT WILL MODERATE THE POTENTIAL FOR
ADDITIONAL INTENSIFICATION. A PEAK OF 40 KNOTS IS FORECAST. BEYOND
TAU 36, THE EASTERN END OF A RIDGE BUILDING TO THE NORTH WILL BRING
SIGNIFICANT NORTHLY SHEAR, IN OPPOSITION TO THE MOTION VECTION.
THIS SHEAR IS EXPECTED TO RESULT IN RAPID DETERIORATION LEADING TO
DISSIPATION AS A SIGNIFICANT TROPICAL CYCLONE BY TAU 72. SOME
MODELS ARE INDICATING THAT ANOTHER CIRCULATION MOVING OFF THE COAST
OF CHINA MAY MERGE WITH THE REMNANTS OF 16W, WITH THE POTENTIAL FOR
A DEVELOPING EXTRA-TROPICAL LOW OVER THE SEA OF JAPAN, BEYOND THIS
FORECAST.

MODEL DISCUSSION: TRACK GUIDANCE CONTINUES TO BE SPLIT, WITH
NAVGEM, GALWEM AND UKMET ENSEMBLE TRAKING MUCH FARTHER WEST PRIOR TO
RECURVATURE. THE REMAINDER OF THE CONSENSUS MODELS INCLUDING EGRR,
GFS, ECMWF AND THEIR ENSEMBLES ARE TIGHTLY CLUSTERED ABOUT THE JTWC
FORECAST TRACK THROUGH TAU 48, WITH INCREASING ALONG TRACK SPREAD
THEREAFTER. THE ECMWF AND ITS ENSEMBLE LOSE THE VORTEX ALTOGETHER
BY TAU 36. THE JTWC FORECAST TRACK IS SHIFTED EAST OF THE
MULTI-MODEL CONSENSUS TO ACCOUNT FOR THE WESTWARD OUTLIERS. THE
INTENSIFY FORECAST IS SLIGHTLY BELOW CONSENSUS, AS WEAKENING IS
EXPECTED TO OCCUR MORE RAPIDLY THAN MODELS INDICATE DUE TO THE HIGH
SHEAR IN THE LATER TAUS. 


FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: ---
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: ---//
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