Tropical Storm WUTIP Advisory Ter, 19-02

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 02W (TWO)
WARNING NR 02//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 02W (TWO), LOCATED APPROXIMATELY 908 NM
SOUTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED WESTWARD AT 13 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY DEPICTS A CONSOLIDATING SYSTEM WITH IMPROVED DEEP CONVECTIVE
BANDING OVER THE NORTHERN AND WESTERN SEMICIRCLES OF A BROAD LOW-
LEVEL CIRCULATION. A 191030Z MHS 89GHZ MICROWAVE IMAGE (MI) DEPICTS
SHALLOW BANDING WRAPPING INTO A DEFINED LOW-LEVEL CIRCULATION CENTER
POSITIONED UNDER THE EASTERN EDGE OF AN AREA OF PERSISTENT CORE
CONVECTION AND FORMATIVE BANDING. BASED ON THE MI, THERE IS FAIR
CONFIDENCE IN THE INITIAL POSITION. THE INITIAL INTENSITY IS
ASSESSED AT 30 KNOTS BASED ON DVORAK INTENSITY ESTIMATES RANGING
FROM T1.5 TO T2.0 (25 TO 30 KNOTS). ENVIRONMENTAL CONDITIONS ARE
VERY FAVORABLE WITH LOW TO MODERATE VERTICAL WIND SHEAR OFFSET BY
GOOD EQUATORWARD AND POLEWARD OUTFLOW, WARM SST (29 TO 30C) AND HIGH
OCEAN HEAT CONTENT VALUES. TD 02W IS CURRENTLY TRACKING WESTWARD
ALONG THE SOUTHEASTERN PERIPHERY OF A LOW- TO MID-LEVEL SUBTROPICAL
RIDGE (STR) POSITIONED TO THE NORTH AND NORTHWEST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. THROUGH TAU 72, TD 02W IS EXPECTED TO TRACK WESTWARD TO WEST-
NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED STR
ENTRENCHED TO THE NORTH. DUE TO THE VERY FAVORABLE ENVIRONMENTAL
CONDITIONS, THE SYSTEM IS FORECAST TO INTENSIFY RAPIDLY TO 100 KNOTS
BY TAU 72. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH A
SPREAD OF 175NM AT TAU 72.
   C. IN THE EXTENDED PERIOD, UNCERTAINTY INCREASES SIGNIFICANTLY
WITH A BIFURCATION IN THE MODEL GUIDANCE. GFS, GFS ENSEMBLE, AFUM,
EGRR, JGSM AND NAVGEM INDICATE A RECURVE SCENARIO NEAR GUAM, WHICH
APPEARS UNLIKELY. GFS AND NAVGEM ERRONEOUSLY DRIVE THE SYSTEM
DIRECTLY INTO AND THROUGH A STRONG STR POSITIONED OVER GUAM WITH NO
MIDLATITUDE SHORTWAVE TROUGH PRESENT. ADDITIONALLY, GFS AND NAVGEM
SHOW A BROAD STR TO THE EAST OF JAPAN, WHICH SHOULD REINFORCE THE
EXISTING STR. THE REMAINDER OF THE DYNAMIC MODEL GUIDANCE (ECMF,
EEMN) INDICATES A FLATTER TRACK MUCH FURTHER TO THE SOUTHWEST WITH A
WEST-NORTHWESTWARD TO NORTHWESTWARD TRAJECTORY. THE JTWC OFFICIAL
FORECAST FAVORS A NON-RECURVE SCENARIO CLOSER TO THE ECMWF SOLUTION
DUE TO THE LACK OF A MIDLATITUDE RECURVE MECHANISM (DEEP SHORTWAVE
TROUGH AND ASSOCIATED FRONTAL SYSTEM), AND PRESENCE OF A STRONG STR.
TD 02W IS FORECAST, HOWEVER, TO INTENSIFY TO 105 KNOTS AS IT SKIRTS
SOUTH OF GUAM, AND MAY STILL PRODUCE GALE-FORCE SUSTAINED WINDS AND
ISOLATED GUSTS NEAR 50 KNOTS OVER GUAM. OVERALL, CONFIDENCE REMAINS
LOW DUE TO THE BIFURCATION IN THE NUMERICAL GUIDANCE.//
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