WDPN31 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W (SIXTEEN) 
WARNING NR 014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.5N 164.9E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 147 NM EAST-NORTHEAST OF ENEWETAK ISLAND
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: 
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A STRUGGLING
SYSTEM UNDERNEATH PATCHY AND RAGGED CONVECTION. THE INITIAL POSITION
IS BASED ON A 131710Z SSMIS 91GHZ IMAGE DEPICTING WEAK LOW LEVEL
BANDING. THE INITIAL INTENSITY IS BASED ON A 131329Z AMSR2 WIND 
SPEED PRODUCT SHOWING 25-29 KT WINDS TO THE NORTH OF THE SYSTEM 
CENTER AND THE PGTW DVORAK INTENSITY ESTIMATE. 

INITIAL WIND RADII BASIS: NO WIND RADII. 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: N/A

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 IN A MARGINALLY FAVORABLE ENVIRONMENT CREATED BY LOW
VERTICAL WIND SHEAR AND WARM SEA SURFACE TEMPERATURES. HOWEVER, DUE
TO A MODERATELY DRY ENVIRONMENT SURROUNDING THE SYSTEM, 16W IS
EXPECTED TO REMAIN AT ITS CURRENT INTENSITY OF 30 KTS UNTIL ABOUT 
TAU 36 AS IT CONTINUES ITS WESTWARD TRACK. AROUND TAU 48, DESPITE 
INCREASING VERTICAL WIND SHEAR, 16W WILL BEGIN TO INCREASE IN 
INTENSITY DUE TO A MOISTENING ENVIRONMENT AND WARMING SEA SURFACE 
TEMPERATURES. BY TAU 120, THE INTENSITY WILL REACH 65 KTS AS THE 
SYSTEM BEGINS A NORTHWESTWARD TRACK.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT EARLY IN 
THE FORECAST BUT GRADUALLY INCREASE TO A 200 NM CROSS-TRACK SPREAD 
BY TAU 72, WITH NVGM AS THE NOTABLE OUTLIER TO THE NORTH. THE JTWC 
FORECAST TRACK UP TO TAU 72 IS LAID WITH HIGH CONFIDENCE JUST TO THE 
SOUTH OF THE MODEL CONSENSUS TO OFFSET NVGM. THERE IS MORE 
UNCERTAINTY IN THE FORECAST INTENSITY DUE TO THE UNCERTAINTY IN THE 
CONVECTIVE STRUCTURE OF THE CYCLONE AND COMPETING ENVIRONMENTAL 
FACTORS.

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