Advisories

WDPN32 PGTW 112100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W (PEILOU) 
WARNING NR 020//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 28.4N 160.2E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 418 NM NORTHEAST OF MINAMI TORI SHIMA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 21 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
DEPRESSION 13W (PEILOU) WITH AN OBSCURED LOW-LEVEL CIRCULATION
CENTER (LLCC) ASSOCIATED WITH PERIODIC BURSTS OF DEEP CONVECTION
CONFINED TO THE SOUTHEAST QUADRANT. THE CURRENT POSITION IS PLACED
WITH LOWER THAN AVERAGE CONFIDENCE DUE TO THE OBSCURED SCENE, BUT
IS ASSESSED TO BE BENEATH THE NORTHWESTERN EDGE OF THE CONVECTIVE
MASS. WEAK UPPER-LEVEL OUTFLOW IS OBSERVED EASTWARD AND
EQUATORWARD. EARLIER 111319Z SCATTEROMETER DATA SHOWED AN
ASYMMETRIC WIND FIELD WITH MAXIMUM WINDS OF 30 TO 35 KT IN THE
SOUTHEAST QUADRANT. THE INITIAL INTENSITY IS SET AT 30 KT BASED ON
THIS DATA AND DECLINING AGENCY DVORAK INTENSITY ESTIMATES WITHIN A
GENERAL TREND OF DEGRADING SATELLITE PRESENTATION. THE REMNANTS OF
TROPICAL DEPRESSION 15W CAN BE OBSERVED IN SHORTWAVE IR IMAGERY
ROTATING WESTWARD WITHIN THE NORTHWEST QUADRANT OF 13W, MANIFESTING
AS A TROUGH EXTENSION TOWARDS THE NORTHWEST FROM 13W'S LLCC.

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

CURRENT STEERING MECHANISM: MONSOONAL SOUTHWESTERLY FLOW BELT
RIMMING A NEAR-EQUATORIAL RIDGE TO THE SOUTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   PHFO: T1.5 - 25 KTS
   CIMSS D-MINT: 40 KTS AT 111528Z
   CIMSS D-PRINT: 34 KTS AT 111730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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 13W (PEILOU) CONTINUES TO
TRACK NORTHEASTWARD ALONG THE MONSOONAL SOUTHWESTERLY FLOW BELT,
BENDING SLIGHTLY MORE NORTHWARD IN RECENT HOURS DUE TO WEAK BINARY
INTERACTION WITH THE REMNANTS OF 15W TO ITS NORTHWEST. WHILE THE
CURRENT ENVIRONMENT IS NOT OVERTLY HOSTILE, THE STORM WILL MOVE
INTO COOLER SEA SURFACE TEMPERATURES OF 26C TO 27C DURING THE NEXT
24 HOURS, AND VERTICAL SHEAR IS EXPECTED TO MARKEDLY INCREASE AS
THE SUBTROPICAL JET EXTENDS EASTWARD AND STRENGTHENS OVER TOP OF
13W. THE STORM WILL INTERACT WITH AND ULTIMATELY BECOME ABSORBED
INTO A BAROCLINIC LOW TO ITS NORTHEAST OVER THE NEXT 24 TO 48
HOURS. THE JTWC FORECAST EXPECTS 13W TO GRADUALLY WEAKEN, WITH ITS
CORE WIND FIELD DISSIPATING BELOW WARNING THRESHOLD IN AROUND 24
HOURS AS IT BEGINS TO WASH OUT INTO THE BROADER WIND FIELD OF THE
AFOREMENTIONED BAROCLINIC LOW.

MODEL DISCUSSION: THE JTWC TRACK FORECAST IS CLOSE TO THE
MULTI-MODEL CONSENSUS, WITH THE GUIDANCE SUITE IN TIGHT AGREEMENT O
THE NORTHEAST WARD TRACK OVER THE NEXT 24 HOURS. THE JTWC INTENSITY
FORECAST IS CLOSE TO A BLEND OF THE GFS, ECMWF, AND HAFS-A
INTENSITIES DERIVED FROM THEIR RESPECTIVE MODEL FIELDS, AS MOST
INTENSITY TRACKERS ARE ERRONEOUSLY CONTAMINATED WITH THE BROADER
WIND FIELD OF THE BAROCLINIC LOW TO THE NORTHEAST OF 13W.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   INTENSITY 00-72 HR: MEDIUM//
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