WDIO31 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05A (FIVE)
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 9.3N 61.0E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 613 NM SOUTHEAST OF SALALAH, OMAN
   MOVEMENT PAST 6 HOURS: WESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE (TC) 05A (FIVE) HAVING GREATLY CONSOLIDATED OVER THE PAST
SIX HOURS. FORMATIVE BANDS OF DEEP CONVECTION ARE OBSERVED
SPIRALING RADIALLY FROM THE LOW LEVEL CIRCULATION CENTER (LLCC). 
SINCE APPROXIMATELY 201000Z, FLARING CONVECTION WITH OVERSHOOTING 
TOPS HAS PERSISTED DIRECTLY OVER THE LLCC, EVIDENCING THE SYSTEMS 
CORE HAS ALIGNED AND FOUND A PROMINENT EXHAUST FOR CONVERGENCE AT THE 
SURFACE. ENVIRONMENTAL CONDITIONS ARE VERY FAVORABLE FOR DEVELOPMENT, 
WITH VERY WARM SST (30-31 C) AND VERY LOW VERTICAL WIND SHEAR (5-10 
KTS). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON 
A 201201Z G13 GVIRI ENHANCED INFRARED (EIR) IMAGE. THE INITIAL 
INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A 
200901Z AMSR2 DERIVED WIND SPEED IMAGE, AS WELL AS THE SUBJECTIVE AND 
OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: AMSR2 DERIVED WIND SPEED

CURRENT STEERING MECHANISM: STR TO THE NORTH-NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TC 05A IS FORECAST TO TRACK WEST-NORTHWESTWARD
THROUGH TAU 36 AND THEN GRADUALLY TURN TO A NORTHWESTWARD TRACK BY 
TAU 48 AND MAINTAIN THROUGH TAU 120.  RAPID INTENSIFICATION IS 
IMMINENT, AS THE AFOREMENTIONED VERY FAVORABLE ENVIRONMENTAL 
CONDITIONS ALLUDE TO. AS SUGGESTED IN THE MODEL DISCUSSION, THE PEAK 
INTENSITY WILL LIKELY BE REALIZED NEAR TAU 60. THEREAFTER (TAU 60 TO 
72), DRY AIR ENTRAINMENT IS EXPECTED TO BEGIN IMPEDING THE MOIST CORE 
NECESSARY FOR INTENSIFICATION AND SUSTAINMENT. A RAPID WEAKENING 
TREND, AS INCREASING AMOUNTS OF VERY DRY AIR ADVECT INTO STRUCTURE, 
IS EXPECTED FROM TAU 72 TO TAU 120.

MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE IS IN EXCEPTIONAL
AGREEMENT THROUGH TAU 72 AND GOOD AGREEMENT THEREAFTER. THE JTWC
CONSENSUS MEMBERS REFLECT A TIGHT CROSS-TRACK SPREAD OF 73NM AND AN
ALONG-TRACK SPREAD OF 108 NM AT TAU 72.  THROUGH THIS INTERVAL,
CONSENSUS INTENSITY GUIDANCE TRIGGERED MULTIPLE INDICATIONS THAT
RAPID INTENSIFICATION MAY OCCUR. COAMPS-TC ENSEMBLE GUIDANCE
(200000Z) SHOWED ASTOUNDING 90 PERCENT OR HIGH PROBABILITIES FOR
RAPID INTENSIFICATION TO OCCUR BETWEEN TAU 18 AND TAU 60. THE BULK
OF JTWC INTENSITY CONSENSUS MEMBERS SHOW PEAK INTENSITY OCCURRING
NEAR TAU 60, SUGGESTING A RAPID RUN UP OF INTENSITY IN AN UNHINGED
ENVIRONMENT.  AFTER TAU 72, THE CONSENSUS MEMBERS SPREAD LEFT AND
RIGHT OF THE JTWC FORECAST TRACK, TO REFLECT AN EVENTUAL (TAU 120)
CROSS-TRACK SPREAD OF 282NM AND ALONG-TRACK SPREAD OF 200NM. THE
TRACK FORECAST CONFIDENCE IS HIGH THROUGH TAU 72 AND MEDIUM
THEREAFTER. THE INTENSITY FORECAST CONFIDENCE IS MEDIUM THROUGH TAU
72 AND LOW THEREAFTER.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
NNNN