WDPN31 PGTW 050900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15E (NOLO) WARNING NR 059//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 25.3N 177.7E
   INITIAL INTENSITY: 105 KTS
   GEOGRAPHIC REFERENCE: 882 NM NORTHWEST OF JOHNSTON ISLAND
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 46 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
SYMMETRICAL EYE FEATURE OF TYPHOON (TY) 15E (NOLO) SURROUNDED BY
WELL-ORGANIZED SPIRAL BANDS OF DEEP CONVECTION FORMING A CENTRAL
DENSE OVERCAST (CDO). AN EARLIER (050017Z) GOSAT AMSR3 37 GHZ
REVEALED A SLIGHT TILT PLACING THE LOW-LEVEL CIRCULATION CENTER
(LLCC) WITHIN THE SOUTHWESTERN PORTION OF THE EYE. THE SYSTEM
MAINTAINED INTENSITY OVER THE LAST 6 HOURS, AS WITNESSED BY
SUSTAINED, WARM (18 C) EYE AND SLIGHTLY COOLING (-72 C) CLOUD TOPS.
ENVIRONMENTAL ANALYSIS REVEALS MARGINALLY FAVORABLE CONDITIONS
CHARACTERIZED BY WARM (28-29 C) SEA SURFACE TEMPERATURES (SST),
SLIGHTLY INCREASED, BUT STILL LOW (10-15 KTS) VERTICAL WIND SHEAR
(VWS) AND MODERATE RADIAL OUTFLOW ALOFT, OFFSET BY SURROUNDING DRY
AIR SIGNIFICANTLY LIMITING THE RANGE OF THE DEEP CONVECTIVE
BANDING. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED
ON THE CLEAR EYE FEATURE IN THE ENHANCED INFRARED IMAGERY, WHILE
THE INITIAL INTENSITY OF 105 KTS IS ASSESSED WITH HIGH CONFIDENCE
BASED ON THE HIGH AGREEMENT BETWEEN THE AGENCY DVORAK ESTIMATES AND
OBJECTIVE ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) CENTERED TO THE
NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T5.5 - 102 KTS
   RJTD: T6.0 - 115 KTS
   RCTP: T5.0 - 90 KTS
   CIMSS ADT: 104 KTS AT 050540Z
   CIMSS AIDT: 107 KTS AT 050510Z
   CIMSS D-PRINT: 113 KTS AT 050510Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: UNDER THE STEERING INFLUENCE OF THE DEEP-LAYER
STR CENTERED TO THE NORTHEAST, TY 15E IS PROJECTED TO MAINTAIN ITS
WEST-NORTHWESTWARD TRAJECTORY FOR THE NEXT 5 TO 12 HOURS. SHORTLY
AFTER, A HANDOFF IS EXPECTED IN REGARD TO THE PRIMARY STEERING
MECHANISM - AS TY NOLO ENCOUNTERS A CONSOLIDATING AND BUILDING STR
TO NORTHWEST. WITH THAT, TY 15E IS EXPECTED TO TRACK GENERALLY
WESTWARD UNTIL TAU 72. BETWEEN TAUS 72 AND 96, TY NOLO IS PROJECTED
TO BEGIN TURNING NORTHWESTWARD AS IT STARTS TO ROUND THE RIDGE
AXIS. REGARDING INTENSITY, TY 15E IS FORECAST TO SUSTAIN A PEAK
INTENSITY OF APPROXIMATELY 105 KTS THROUGH THE NEXT 12 HOURS,
PROPAGATING THROUGH MARGINALLY FAVORABLE ENVIRONMENT. AROUND TAU
24, THE SYSTEM WILL APPROACH AN AREA OF INCREASINGLY HOSTILE VERTICAL
WIND SHEAR, DEGRADED OUTFLOW, AND ENTRAINMENT OF DRY MID-LEVEL AIR
INTO THE CYCLONE CORE. A BRIEF PERIOD OF IMPROVED CONDITIONS IS
EXPECTED AROUND TAU 96, AS THE OUTFLOW IMPROVES AND DRY AIR
ENTRAINMENT TEMPORARILY DECREASES. SOON AFTER HOWEVER, THE VERTICAL
WIND SHEAR WILL DRAMATICALLY INCREASE YET AGAIN, AS THE SYSTEM
TRANSITS ALONG THE WESTERN PERIPHERY OF THE STR.

MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE IS IN GOOD
AGREEMENT INITIALLY, AS WITNESSED BY A 130 NM MULTI-MODEL CONSENSUS
CROSS-TRACK SPREAD AT TAU 72, FURTHER SUPPORTED BY A 115 NM
ALONG-TRACK GUIDANCE ENVELOPE. BEYOND THAT POINT, GUIDANCE
CONFIDENCE DRAMATICALLY DECREASES, DRIVEN BY A DIFFERENT DEPICTION
OF THE TIMELINE OF THE RECURVATURE MOTION. NAVGEM AND JGSM ARE
CURRENTLY THE MOST AGGRESSIVE IN PROJECTING THE FASTEST AND SHARPEST
RECURVATURE, WHEREAS THE DETERMINISTIC GFS AND ECMWF, AS WELL AS
BOTH GLOBAL MODEL ENSEMBLES CONTINUE TO PROJECT A WIDER AND SLOWER
POLEWARD TURN. ACCORDINGLY, THE OFFICIAL JTWC TRACK IS COMPILED
WITH HIGH CONFIDENCE THROUGH TAU 72, MODERATING TO LOW CONFIDENCE
THEREAFTER OWING TO ASSOCIATED HIGH UNCERTAINTY. THE JTWC
PREDICTION ALIGNS CLOSELY WITH THE MULTI-MODEL AND AI GUIDANCE
CONSENSUS TRACKS. INTENSITY MODELING AIDS SHARE FAIR AGREEMENT ON A
STEADY WEAKENING TREND INITIATING AROUND TAU 12. REGARDLESS, AN
INTENSITY SPREAD OF 35-40 KTS PERSISTS THROUGHOUT THE FORECAST
PERIOD, BOUNDED BY THE ROBUSTLY INTENSE HAFS-A RUN AND PERSISTENTLY
MORE AGGRESSIVE SOLUTIONS FROM GFS, COAMPS-TC AND GDMI. THE 
ACCENTUATED HAFS-A SOLUTION IS ATTRIBUTED TO THE APPARENT LACK OF 
DEPICTED RECURVATURE ALONG ITS RUN TRACK. THE DEPICTED JTWC INTENSITY 
PROGNOSIS IS ASSESSED WITH MEDIUM CONFIDENCE THROUGH TAU 72 AND LOW 
CONFIDENCE SUBSEQUENTLY DUE TO DETRIMENTAL SPREAD IN THE CURRENT 
DYNAMIC SUITE, CLOSELY MATCHING THE MULTI-MODEL CONSENSUS ESTIMATE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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