WDPN32 PGTW 221500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (TEN) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.6N 131.6E
   INITIAL INTENSITY: 25 KTS
   GEOGRAPHIC REFERENCE: 464 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 19 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
DEPRESSION (TD) 10W SLOWLY CONSOLIDATING AS DEEP CONVECTIVE BANDS
WRAP INWARD FROM THE SOUTHWEST AND SOUTHEAST. AN UPPER-LEVEL TROUGH
TO THE NORTHWEST BOTH APPLIES PRESSURE TO THE NORTHWEST QUADRANT
AND POLEWARD UPPER LEVEL DIFFLUENCE. THE POLEWARD OUTFLOW IS
COMPLEMENTED BY EQUATORWARD DIFFLUENCE, ALLOWING FOR FAVORABLE
DUAL-CHANNEL OUTFLOW. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED MSI AND A 221130Z
METOP-B ASCAT IMAGE WHICH PARTIALLY REVEALS THE LOW-LEVEL
CIRCULATION CENTER BOUNDED BY 25KT WINDS TO THE EAST. THE INITIAL
INTENSITY OF 25 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE
SAME IMAGE WHILE SUPPLEMENTED BY THE AGENCY AND OBJECTIVE FIXES
LISTED BELOW.

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

CURRENT STEERING MECHANISM: A DEEP-LAYER RIDGE TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   CIMSS ADT: 25 KTS AT 220840Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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: A DEEP-LAYER RIDGE TO THE EAST WILL STEER TD
10W NORTH-NORTHWESTWARD ALONG THE NORTHERN EDGE OF THE MONSOONAL
FLOW FOR THE NEXT 36 HOURS. BETWEEN TAU 36-48, THE PRIMARY STEERING
MECHANISM WILL TRANSFER TO THE SUBTROPICAL RIDGE CENTERED OVER
JAPAN, CURVING NORTHWESTWARD. BETWEEN TAU 48-72, AN APPROACHING
UPPER-LEVEL TROUGH WILL CAUSE TD 10W TO BECOME SHALLOW AND THE WIND
FIELD WILL BECOME BROAD. THE MONSOONAL FLOW WILL CLOSE OFF,
DEVELOPING INTO A MONSOON DEPRESSION OVER THE EAST CHINA SEA, AND
ULTIMATELY CAUSING TD 10W TO WEAKEN AND DISSIPATE INTO THE LARGER
MONSOONAL FLOW. THE SYSTEM WILL INTENSIFY DURING THE FIRST 36 HOURS
OF THE FORECAST WHILE IN A FAVORABLE ENVIRONMENT OF UPPER-LEVEL
DIVERGENCE, LOW VERTICAL WIND SHEAR, AND WARM SEA SURFACE
TEMPERATURES. DRY AIR WILL ENTRAIN INTO THE CIRCULATION AFTER TAU
36 AND AN APPROACHING UPPER-LEVEL TROUGH WILL INTRODUCE UNFAVORABLY
HIGH VERTICAL WIND SHEAR, INITIATING A WEAKENING PERIOD. THE SYSTEM
WILL DISSIPATE INTO THE STRONG MONSOONAL FLOW, ENDING THE FORECAST
AT 30KTS. 

MODEL DISCUSSION: THE JTWC MULTI-MODEL CONSENSUS IS IN GOOD
AGREEMENT, BUT NOT REPRESENTATIVE OF THE CURRENT FORECAST AS THE
VORTEX TRACKERS APPEAR TO TRACK THE CENTER OF VORTICITY OF THE
DEVELOPING MONSOON DEPRESSION RATHER THAN TD 10W. DETERMINISTIC
MODEL GUIDANCE OVER THE LAST FEW DAYS HAS NOT REPRESENTED THE
DEVELOPMENT OF THE TROPICAL DEPRESSION, INSTEAD FAVORING THE
DEVELOPMENT OF A LARGE MONSOON DEPRESSION. THE 850MB VORTICITY
FIELDS OF ECMWF AND EC-AIFS BETTER PORTRAY TD 10W RATHER THAN THE
WIND FIELDS, AND THE JTWC FORECAST CLOSELY RESEMBLES THE EC-AIFS
AND ECMWF VORTICITY TRACKS. THE INTENSITY GUIDANCE IS LARGELY
SPREAD AS A RESULT OF THE UNCERTAINTY IN THE JTWC MULTI-MODEL
CONSENSUS, REVEALING A LARGE SPREAD OF PEAK INTENSITIES. THE PEAK
AND LENGTH OF THE FORECAST MAY VARY BASED ON HOW STRONGLY THE
UPPER-LEVEL TROUGH CAUSES THE SYSTEM TO SHALLOW AND HOW QUICKLY,
AND LONGER OR SHORTER FORECAST PERIODS MAY RESULT.

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