WDPN32 PGTW 070300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W (SIXTEEN) 
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.4N 147.8E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 224 NM NORTH-NORTHEAST OF SAIPAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
DEPRESSION (TD) 16W WITH A HIGHLY COMPACT, OBSCURED LOW-LEVEL
CIRCULATION CENTER (LLCC) AND VIGOROUS BURSTS OF CONVECTION OVER
THE CENTER. A 062350Z METOP-B ASCAT PASS SHOWS THE COMPACT WIND
FIELD WITH 25 KTS WITHIN THE SOUTHERN SEMICIRCLE AND SOME 30 KNOT
BARBS THAT ARE RAIN FLAGGED. ENVIRONMENTAL ANALYSIS INDICATES THAT
16W IS IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY MODERATE
POLEWARD OUTFLOW ALOFT, LOW (10-15 KTS) NORTHEASTERLY VERTICAL
WINDS SHEAR, AND WARM (29-30 C) SEA SURFACE TEMPERATURES. THE
INITIAL POSITION AND INTENSITY ARE BOTH PLACED WITH HIGH CONFIDENCE
BASED ON THE MENTIONED ASCAT IMAGE.

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

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF RIDGING TO THE
NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS
   CIMSS D-PRINT: 26 KTS AT 070000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TD 16W IS FORECAST TO TRACK RATHER SLOWLY
WEST-NORTHWESTWARD THROUGH TAU 48. AFTER TAU 48, THE STEERING
PATTERN BECOMES MORE DEFINED AS AN EXTENSION OF THE SUBTROPICAL
RIDGE EXTENDS OVER TO THE NORTH OF THE SYSTEM. TRACK SPEEDS WILL
THEN INCREASE AND THE TRAJECTORY WILL BE MORE WESTWARD THROUGH THE
REMAINDER OF THE FORECAST PERIOD. REGARDING INTENSITY, 16W IS
FORECAST TO STEADILY INTENSIFY THROUGHOUT THE ENTIRETY OF THE
FORECAST PERIOD. THE ENVIRONMENT IS EXPECTED TO REMAIN FAVORABLE
WITH LOW VERTICAL WIND SHEAR, PLENTY OF MOISTURE, AND WARM SEA
SURFACE TEMPERATURES. ACTUAL INTENSIFICATION RATE IS UNCERTAIN DUE
TO THE MASSIVE DISPARITY BETWEEN MODEL GUIDANCE. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT WITH A 110 NM CROSS TRACK SPREAD AT TAU 72, WHICH
PERSISTS THROUGH TAU 120. THE JTWC TRACK FORECAST IS PLACED WITH
MEDIUM CONFIDENCE, CLOSE TO THE MULTI-MODEL CONSENSUS. INTENSITY
GUIDANCE IS IN EXTREMELY POOR AGREEMENT. GLOBAL MODELS ARE BARELY
INTENSIFYING THE SYSTEM AT ALL (AND NOT INITIALIZING WELL) WHILE THE
MESOSCALE MODELS (COAMPS-TC AND HAFS-A) INTENSIFY THE SYSTEM MUCH
MORE. COAMPS-TC (GFS BASED) IN PARTICULAR HAS THE SYSTEM REACH 135
KTS AT TAU 120. HAFS-A HAS A STEADIER INTENSIFICATION TREND TO
AROUND 95 KTS AT TAU 120. THE JTWC INTENSITY FORECAST IS PLACED
MORE IN LINE WITH THE HAFS-A DEPICTION AND IS MUCH HIGHER THAN
DETERMINISTIC MODELS DUE TO THE EXPECTED FAVORABLE ENVIRONMENT.
OVERALL, THERE IS VERY LOW CONFIDENCE IN THE JTWC INTENSITY
FORECAST THROUGHOUT THE FORECAST PERIOD.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: LOW
   INTENSITY 72-120 HR: LOW//
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