WDXS32 PGTW 301500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 22S (HALIMA) WARNING 
NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.7S 82.3E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 947 NM SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 21 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND A 301119Z
SSMIS 91GHZ MICROWAVE IMAGE DEPICT A PARTIALLY-EXPOSED,
WELL-DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC) POSITIONED ON THE
NORTHERN EDGE OF A CURVED DEEP CONVECTIVE BAND WITH EXTENSIVE
EXPOSED SHALLOW BANDING WRAPPING TIGHTLY INTO THE LLCC. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED
IMAGERY. UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY UNFAVORABLE 
ENVIRONMENT WITH HIGH (25 KNOTS) MID-LEVEL VERTICAL WIND SHEAR AND 
SIGNIFICANT DRY AIR ENTRAINMENT OFFSET SLIGHTLY BY STRONG EASTWARD 
OUTFLOW. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH HIGH 
CONFIDENCE BASED ON AN AVERAGE OF THE DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT WITH A
STRONG STEERING RIDGE TO THE WEST AND SOUTHWEST AND AN EXTENSION OF
THE NEAR-EQUATORIAL RIDGE TO THE NORTHEAST AND EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   FMEE: T3.0 - 45 KTS
   FIMP: T3.0 - 45 KTS
   CIMSS ADT: 39 KTS AT 300915Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 10-15 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG EASTWARD
   OTHER FACTORS: HIGH MID-LEVEL VERTICAL WIND SHEAR AND A VERY DRY 
ENVIRONMENT

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 22S IS ESSENTIALLY BOXED IN WITH RIDGING
OVER THE WESTERN AND EASTERN SEMICIRCLES AS WELL AS A STRONG
LOW-LEVEL HIGH POSITIONED TO THE SOUTH. THERE IS NO CLEAR, DOMINANT
STEERING FEATURE THUS THE SYSTEM IS DRIFTING SLOWLY NORTH-
NORTHEASTWARD TO NORTHEASTWARD IN AN ERRATIC FASHION. THIS TRACK 
MOTION IS EXPECTED TO PERSIST THROUGH TAU 36 UNTIL A STRONG EAST-
WEST ORIENTED RIDGE BUILDS IN TO THE SOUTH AND INDUCES A WESTWARD 
TRACK TURN AND EVENTUAL ACCELERATION WESTWARD AFTER THE FORECAST 
PERIOD. TC 22S SHOULD GRADUALLY WEAKEN THROUGH THE FORECAST PERIOD 
DUE TO CONTINUED DRY AIR ENTRAINMENT AND WILL DISSIPATE BY TAU 
48.    

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT
WITH THE GENERALLY NORTHEASTWARD, SLOW TRACK THROUGH TAU 24 BUT
DIVERGES AFTER TAU 24 WITH SIGNIFICANT DIFFERENCES IN THE TIMING OF
THE WESTWARD TURN THUS CONFIDENCE IN THE JTWC FORECAST TRACK IS
MEDIUM. THE JTWC INTENSITY GUIDANCE IS ALSO IN FAIR AGREEMENT WITH
COAMPS-TC (BOTH GFS AND NAVGEM VERSIONS) INDICATING A SLIGHT
INTENSIFICATION TREND WITH A PEAK INTENSITY OF 43-48 KNOTS AT TAU 12 
BEFORE STEADILY WEAKENING. THE JTWC INTENSITY CONSENSUS (ICNW) SHOWS 
A STEADY DECLINE THROUGH THE FORECAST PERIOD.

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