WDPN31 PGTW 170300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W (SIXTEEN) 
WARNING NR 027//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.3N 145.1E
   INITIAL INTENSITY: 20 KTS
   GEOGRAPHIC REFERENCE: 30 NM EAST-SOUTHEAST OF NAVSTA GUAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A
DISORGANIZED SYSTEM WITH WEAK CONVECTION AND GIVING NO INDICATION
OF A LOW LEVEL CIRCULATION UNDERNEATH. RADAR IMAGERY FROM GUAM
SIMILARLY DEPICTS AN ILL-DEFINED SYSTEM CURRENTLY CROSSING OVER
THE NORTHERN MARIANAS ISLANDS. THE INITIAL POSITION AND INTENSITY IS
BASED ON A 162254Z ASCAT-A IMAGE SHOWING ELONGATED TROUGHING WITH A
PATCHY WIND FIELD OF 15-20 KT WINDS TO THE NORTH OF GUAM. THIS IS
SUPPORTED BY SURFACE OBSERVATIONS FROM ROTA SHOWING 12-15 KT WINDS
NORTHERLY WINDS TURNING EASTERLY OVER THE PAST COUPLE HOURS.

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

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   CIMSS ADT: 37 KTS AT 162350Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE RADIAL

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: TROPICAL DEPRESSION 16W IS CURRENTLY TRACKING
WESTWARD OVER THE NORTHERN MARIANAS ISLANDS AND CONTINUES TO
STRUGGLE TO DEVELOP DESPITE A MARGINALLY FAVORABLE ENVIRONMENT. IF
THE SYSTEM IS ABLE TO MAINTAIN ITSELF OVER THE NEXT 24 HOURS, IT
WILL EVENTUALLY BEGIN A WEST-NORTHWESTWARD TRACK AROUND THE
SUBTROPICAL RIDGE TO THE NORTH. BY TAU 24, WARM SEA SURFACE
TEMPERATURES AND A MOISTENING ENVIRONMENT SHOULD BEGIN TO GRADUALLY
INTENSIFY THE SYSTEM. TD 16W WILL CONTINUE A WEST-NORTHWESTWARD
TRACK, EVENTUALLY TURNING SLIGHTLY NORTHWESTWARD AND REACHING AN
INTENSITY OF 70 KTS BY TAU 120. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN FAIR 
AGREEMENT UP TO TAU 48, BUT AFTERWARDS MODELS BEGIN TO DIVERGE 
REACHING A 500NM CROSS-TRACK SPREAD AT TAU 120. INTENSITY GUIDANCE 
IS ALSO WIDELY SPREAD WITH HWRF RAPIDLY INTENSIFYING THE SYSTEM 
WHILE GFS FLAT LINES THE SYSTEM UNTIL EVENTUAL DISSIPATION AROUND 
TAU 120. THEREFORE, THERE IS OVERALL LOW CONFIDENCE IN THE INTENSITY 
OF THE JTWC FORECAST.

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