WDXS32 PGTW 310300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 22S (HALIMA) 
WARNING NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.3S 83.3E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 965 NM SOUTHEAST OF DIEGO GARCIA
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION, AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND A PARTIAL 
310027Z GMI 37GHZ MICROWAVE EYE DEPICTS DEEP CONVECTION REMAINING ON 
THE SOUTHERN SECTOR OF THE LLC. THE INITIAL POSITION IS PLACED WITH 
MEDIUM CONFIDENCE BASED ON THE PREVIOUSLY MENTIONED IMAGERY. UPPER-
LEVEL ANALYSIS INDICATES A MARGINALLY UNFAVORABLE ENVIRONMENT WITH 
MODERATE (15-20 KNOTS) MID-LEVEL VERTICAL WIND SHEAR AND SIGNIFICANT 
DRY AIR ENTRAINMENT OFFSET SLIGHTLY BY STRONG POLEWARD OUTFLOW. THE 
INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED 
UPON AN AVERAGE OF THE DVORAK ESTIMATES LISTED BELOW.

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: 32 KTS AT 310015Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY UNFAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 22S IS MOVING SLOWLY TO THE EAST DUE TO THE 
COMPLEX STEERING ENVIRONMENT WITH THE RIDGING BLOCKING THE SYSTEM TO 
THE EASTERN SEMICIRCLES AND A DEEP TROUGH APPROACHING FROM THE 
SOUTH. THERE IS NO CLEAR DOMINANT STEERING FEATURE CURRENTLY, 
THEREFORE TC 22S WILL DRIFT SLOWLY TO THE EAST-NORTHEAST IN AN 
ERRATIC MOTION. A STRONG LOW-LEVEL HIGH POSITIONED TO THE SOUTHWEST 
WILL PUSH IN AND CREATE A BLOCK, PREVENTING THE SYSTEM FROM MOVING 
ANY FURTHER SOUTH OVER THE NEXT 12 TO 24 HOURS. THIS TRACK MOTION IS 
EXPECTED TO PERSIST THROUGH TAU 24 UNTIL THE STRONG EAST-WEST 
ORIENTED RIDGE BUILDS IN TURNING THE SYSTEM BACK TOWARDS THE WEST. 
AS THE SYSTEM TURNS BACK, IT WILL ENCOUNTER A MUCH DRIER AIR REGION 
IN THE LOW-MID LEVELS. TC HALIMA WILL CONTINUALLY WEAKEN BELOW 
WARNING CRITERIA AS THE DRY AIR ENTRAINMENT AND POLEWARD OUTFLOW 
WILL EXHAUST THE REST OF THE MOISTURE OUT OF THE SYSTEM BY TAU 36. 
  
MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT WITH 
THE GENERALLY SLOW NORTHEASTWARD TRACK, NEARING THE EXPECTED TURN 
TOWARD THE WEST AT TAU 24. THERE ARE DIFFERENCES IN THE TIMING AND 
THE DIRECTION OF THE TURN. AFUM, ECMF, AND THE ECMF ENSEMBLE TURN 
THE SYSTEM POLEWARD, WHILE GFS, NVGM, AND UKMET TURN IT EQUATORWARD. 
HOWEVER, THE MODELS ARE IN TIGHT AGREEMENT IN TIMING THROUGH TAU 24. 
THEREAFTER THE SYSTEM WILL TURN BACK TOWARDS THE WEST WITH ONLY A 
60NM DIFFERENCE IN THE OVERALL SPREAD. DUE TO THIS SMALL SPREAD, 
THERE IS HIGH CONFIDENCE IN THE OVERALL JTWC FORECAST TRACK AND 
INTENSITY GUIDANCE FOR THE REMAINDER OF THE FORECAST PERIOD. 

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