WDXS32 PGTW 012100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 22S (GARANCE) WARNING 
NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 31.0S 55.5E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 630 NM SOUTH OF ST DENIS
   MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 22S (GARANCE) WITH FLARING CONVECTION ALONG THE
SOUTHEASTERN PERIPHERY OF AN INCREASINGLY DISORGANIZED LOW-LEVEL
CIRCULATION CENTER (LLCC). EASTERLY SHEAR HAS PICKED UP QUITE A BIT
AS THE SYSTEM STARTS TO INTERACT WITH THE UPPER-LEVEL JET.
ENVIRONMENTAL ANALYSIS INDICATES THAT 22S IS IN AN UNFAVORABLE
ENVIRONMENT CHARACTERIZED BY STRONG POLEWARD OUTFLOW, HIGH (30-35
KTS) VERTICAL WIND SHEAR, AND COOL (25-26 C) SEA SURFACE
TEMPERATURES. THE INITIAL POSITION AND INTENSITY ARE BOTH PLACED
WITH HIGH CONFIDENCE BASED ON THE 011718Z METOP-B ASCAT IMAGE
REVEALING A SWATH OF 45 KNOT WINDS WITHIN THE EASTERN PERIPHERY.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) CENTERED TO THE EAST-NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   FIMP: T3.0 - 45 KTS
   CIMSS SATCON: 48 KTS AT 011610Z
   CIMSS ADT: 35 KTS AT 011800Z
   CIMSS AIDT: 40 KTS AT 011800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE
   VWS: 30-35 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 22S IS FORECAST TO TRACK SOUTHEASTWARD
THROUGH TAU 24 AS IT CONTINUES TO ROUND THE RIDGE AXIS.
EXTRATROPICAL TRANSITION IS FORECAST TO OCCUR AROUND NEAR TAU 24 AS
THE SYSTEM ENTERS THE BAROCLINIC ZONE AND TRANSITIONS INTO A
COLD-CORE LOW. REGARDING INTENSITY, 22S IS FORECAST TO GRADUALLY
WEAKEN THROUGH TAU 24 AS VERTICAL WIND SHEAR CONTINUES TO INCREASE
AND SEA SURFACE TEMPERATURES CONTINUE TO DROP.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
REGARDING THE TRACK OF 22S. THE JTWC TRACK FORECAST IS PLACED WITH
HIGH CONFIDENCE AS A RESULT. INTENSITY GUIDANCE IS ALSO IN GOOD
AGREEMENT ON A GRADUAL WEAKENING TREND THROUGH THE FORECAST PERIOD.
THE JTWC INTENSITY FORECAST IS ALSO PLACED WITH HIGH CONFIDENCE. 

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