WDPN31 PGTW 150300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W (SIXTEEN) 
WARNING NR 019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.5N 157.0E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 711 NM EAST OF ANDERSEN AFB
   MOVEMENT PAST 6 HOURS: WESTWARD AT 17 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD,
EXPOSED LOW-LEVEL CIRCULATION (LLC) WITH FLARING DEEP CONVECTION
DISPLACED OVER THE WESTERN SEMICIRCLE. MSI ALSO REVEALS A DEFINED
MID-LEVEL CIRCULATION CENTER POSITIONED WEST OF THE LOW-LEVEL
CIRCULATION CENTER. DUE TO THE LACK OF MICROWAVE IMAGERY AND THE
BROAD NATURE OF THE LLC, THERE IS LOW CONFIDENCE IN THE INITIAL
POSITION. HOWEVER, A 142155Z ASCAT-A PARTIAL IMAGE COVERING THE
SYSTEM CENTER SHOWS A BROAD CIRCULATION WITH EXTENSIVE 5-KNOT WINDS
AND A SWATH OF 20-25 KNOT WINDS DISPLACED 120NM TO THE NORTHEAST.
THE ASCAT-A IMAGE SUPPORTS THE DECISION TO DOWNGRADE THE SYSTEM TO
TD STRENGTH (30 KNOTS) WITH LOW CONFIDENCE. ALTHOUGH VERTICAL WIND
SHEAR VALUES ARE LOW, DIFFLUENT UPPER-LEVEL EASTERLY FLOW OF 20-30 
KNOTS OFFSET BY MODERATE WESTWARD OUTFLOW, ENHANCED BY A TUTT CELL 
TO THE NORTHWEST, AND DRY AIR ENTRAINMENT ARE HINDERING SUSTAINED 
CONVECTION AND LIMITING DEVELOPMENT.

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
ENTRENCHED TO THE NORTH.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.5 - 35 KTS
   CIMSS SATCON: 42 KTS AT 142308Z
   CIMSS ADT: 43 KTS AT 142340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TD 16W IS EXPECTED TO TRACK WESTWARD ALONG THE
SOUTHERN PERIPHERY OF THE STR THROUGH TAU 48 THEN TURN WEST-
NORTHWESTWARD THROUGH TAU 120 AS IT TRACKS ALONG THE SOUTHWEST
PERIPHERY OF THE STR. TD 16W SHOULD BEGIN STRENGTHENING AFTER 24 TO
36 HOURS AS INDICATED IN THE BULK OF THE INTENSITY GUIDANCE WITH A
STEADY INTENSIFICATION TREND AFTER TAU 72 WITH A PEAK INTENSITY OF
75 KNOTS ANTICIPATED BY TAU 120. 


MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS NOW IN BETTER
AGREEMENT THROUGH TAU 48 WITH A SPREAD OF 85NM AT TAU 48 NEAR GUAM.
DUE TO THE BROAD NATURE OF THE LLC, THERE IS ADDITIONAL UNCERTAINTY
IN THE INITIAL POSITION OF THIS BROAD LLC, WHICH COULD LEAD TO
MINOR SHIFTS IN THE TRACK AND CPA TIMING AS THE SYSTEM SLOWLY
CONSOLIDATES OVER THE NEXT TWO DAYS. INTENSITY GUIDANCE IS IN FAIR
AGREEMENT THROUGH TAU 48 THEN DIVERGES WITH HWRF INDICATING AN
OVERLY AGRESSIVE PEAK INTENSITY OF 125 KNOTS AT TAU 120, WHICH IS  
CONSIDERED UNLIKELY DUE TO THE MARGINALLY FAVORABLE ENVIRONMENT 
THROUGH THE FORECAST PERIOD. THE JTWC INTENSITY FORECAST REMAINS 
CONSERVATIVE BUT IS SUPPORTED BY THE JTWC INTENSITY CONSENSUS, SHIPS 
AND GFS SOLUTIONS. OVERALL, THERE IS LOW CONFIDENCE IN THE INTENSITY 
FORECAST.    


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