Tropical Storm WUTIP Advisory 21.02.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 02W (WUTIP)
WARNING NR 08//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
  TYPHOON (TY) 02W (WUTIP), LOCATED APPROXIMATELY 558 NM SOUTHEAST OF
ANDERSEN AFB, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED MULTI-SPECTRAL SATELLITE IMAGERY (MSI) SHOWS
A STEADILY INTENSIFYING SYSTEM WITH DEEP CONVECTION FLARING OVER THE
OBSCURED LLCC. A 202355Z AMSU-B 89GHZ MICROWAVE IMAGE INDICATES DEEP
CONVECTIVE BANDING IS NOW COMPLETELY SURROUNDING THE LLCC AND
WRAPPING INTO A WELL DEFINED CENTER WITH A DEVELOPING MICROWAVE EYE
FEATURE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON
THE MICROWAVE IMAGERY AND ACCOMPANYING ASCAT AMBIGUITY DATA. THE
INITIAL INTENSITY IS ASSESSED AT 65 KNOTS BASED ON A DVORAK INTENSITY
ESTIMATE OF T4.0 (65 KNOTS) FROM PGTW AND KNES, A SATELLITE CONSENSUS
ESTIMATE OF 58 KNOTS AND AN ADVANCED DVORAK TECHNIQUE ESTIMATE OF
T3.9 (63 KNOTS). TY 02W LIES IN A FAVORABLE UPPER-LEVEL ENVIRONMENT
WITH EASTERLY DIFFLUENT FLOW ALOFT AND LOW TO MODERATE (15-20 KNOTS)
EASTERLY VWS. HOWEVER, THE RELATIVE SHEAR VALUES ARE MUCH LOWER, AS
THE STORM MOTION IS IN PHASE WITH THE SHEAR VECTOR, WHICH IS ALSO
SUPPORTED BY THE OVERALL IMPROVING CONVECTIVE ORGANIZATION APPARENT
OVER THE PAST FEW HOURS. WARM, SSTS NEAR 29 CELSIUS AS WELL AS
MODERATE TO HIGH OCEAN HEAT CONTENT VALUES ARE CONDUCIVE FOR FURTHER
DEVELOPMENT. TY 02W IS TRACKING WEST-NORTHWESTWARD UNDER THE STEERING
INFLUENCE OF DEEP-LAYER SUBTROPICAL RIDGE (STR) POSITIONED TO THE
NORTH.
3. FORECAST REASONING.
   A. THIS FORECAST REPRESENTS A CHANGE IN THE OVERALL FORECAST
PHILOSOPHY, WITH THE RECURVE SCENARIO NOW BEING THE FAVORED SOLUTION
BEYOND TAU 72. ADDITIONALLY, THE ASCAT BULLSEYE AT 202307Z PROVIDED
EXCELLENT DATA TO SUPPORT ADJUSTING THE WIND RADII, WHICH ARE MUCH
SMALLER TO THE NORTHEAST AND NORTHWEST THAN PREVIOUSLY ANALYZED.
   B. TY 02W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD
ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED STR ENTRENCHED TO THE
NORTH THROUGH TAU 72. THE SYSTEM IS FORECAST TO QUICKLY INTENSITY
UNDER FAVORABLE ENVIRONMENTAL CONDITIONS, REACHING A PEAK OF 105
KNOTS AT TAU 48. BEYOND TAU 48 TO TAU 72, THE SYSTEM WILL BEGIN A
SLOW WEAKENING TREND AS VWS INCREASES AND SSTS COOL. NUMERICAL MODEL
GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH TAU 48 WITH A SPREAD OF
ONLY 65NM AT TAU 48. THEREAFTER THE MODELS DIVERGE QUICKLY, WITH
SPREAD INCREASING TO 155NM BY TAU 72 REFLECTING A VARIANCE IN THE
MODEL INTERACTION WITH THE MID-LATITUDE WESTERLIES AND PASSING
SHORTWAVE TROUGH WELL TO THE NORTH.
   C. BEYOND TAU 72, THE STEERING RIDGE CURRENTLY TO THE NORTH OF THE
SYSTEM BREAKS DOWN IN RESPONSE TO THE APPROACH OF A MAJOR SHORTWAVE
TROUGH FROM THE WEST AND REFORMS TO THE EAST OF TY 02W, ALLOWING FOR
A CURVE TO THE NORTH BEYOND TAU 72. TY 02W IS EXPECTED TO STEADILY
WEAKEN AFTER TAU 72 AS VWS CONTINUES TO INCREASE AND SSTS HOVER NEAR
26 CELSIUS, OFFSETTING THE IMPROVED POLEWARD OUTFLOW AS THE SYSTEM
TAPS INTO THE MID-LATITUDE WESTERLY FLOW. NUMERICAL GUIDANCE HAS COME
INTO BETTER AGREEMENT ON THIS SCENARIO, WITH ALL MEMBERS OF THE
CONSENSUS AGREEING ON THE OVERALL SCENARIO, BUT WITH CONTINUED
UNCERTAINTY IN THE MAGNITUDE OF THE CURVE. THE ECMWF REPRESENTS THE
SLOWEST TURN AND LIES ON THE WESTERN EDGE OF THE ENVELOPE, WHILE THE
GFS ENSEMBLE REPRESENTS THE QUICKEST TURN AND IS THE EASTERN OUTLIER.
THE OFFICIAL TRACK LIES WEST OF THE CONSENSUS TRACK AND CLOSER TO THE
ECMWF SOLUTION. WITH A 355NM SPREAD BETWEEN OUTLIERS AT TAU 120,
THERE IS LOW CONFIDENCE IN THE JTWC FORECAST BEYOND TAU 72.//
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