WDPN32 PGTW 060900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 19W (NINETEEN) 
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.0N 138.3E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 270 NM NORTH OF YAP
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 10 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A SYSTEM
WHICH IS STEADILY CONSOLIDATING WITH SUSTAINED DEEP CONVECTION OVER
THE CENTER AND LOW LEVEL BANDING BEGINNING TO WRAP INTO THE
CIRCULATION. THE INITIAL POSITION IS BASED ON THE PGTW POSITION FIX.
THE INITIAL INTENSITY IS BASED ON MULTI-AGENCY DVORAK INTENSITY
ESTIMATES AND AN EXTRAPOLATION OF A 2357Z ASCAT-B IMAGE SHOWING A
BROAD FIELD OF 25 KNOT WINDS IN THE NORTHERN HALF OF THE
CIRCULATION.

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

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T1.5 - 25 KTS
   KNES: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TD 19W IS FORECAST TO TRACK GENERALLY
NORTHWESTWARD ALONG THE PERIPHERY OF THE SUBTROPICAL RIDGE FOR THE
ENTIRETY OF THE FORECAST. THE SYSTEM IS CURRENTLY IN A MARGINALLY
FAVORABLE ENVIRONMENT WITH WARM SEA SURFACE TEMPERATURES AND LOW
VERTICAL WIND SHEAR OFFSET BY AN UPPER-LEVEL LOW TO THE NORTHWEST
WHICH SEEMS TO BE INHIBITING OUTFLOW. THIS MARGINALLY FAVORABLE
ENVIRONMENT IS EXPECTED TO PERSIST FOR THE MAJORITY OF THE
FORECAST, ALLOWING STEADY INTENSIFICATION TO 95 KTS BY TAU 120.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT IN REGARDS
TO FORECAST UP TO TAU 72, AT WHICH POINT THEY BEGIN TO DIVERGE BUT
REACH OF CROSS-TRACK SPREAD OF ONLY 260 NM BY TAU 120, IGNORING GFS
WHICH IS AN OUTLIER, TRACKING THE SYSTEM STRAIGHT WEST AFTER TAU
72. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT WITH ALL MODELS
SHOWING STEADY INTENSIFICATION THROUGHOUT THE FORECAST PERIOD WITH
A SPREAD RANGING FROM 75 KTS TO 115 KTS AT TAU 120. AGAIN, THE 
EXCEPTION IS GFS, WHICH FAVORED STEADY INTENSIFICATION UNTIL THE 00Z 
MODEL RUN, AND IS NOW CURRENTLY SHOWING THE SYSTEM NOT GOING ABOVE 
25 KTS. TO OFFSET THIS, THE FORECAST INTENSITY IS PLACED SLIGHTLY 
HIGHER THAN
CONSENSUS.

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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