Tropical Storm ONE Advisory dom, 06-01

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (ONE) WARNING
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 01W (ONE), LOCATED APPROXIMATELY 84 NM
EAST OF MILI, HAS TRACKED NORTHWESTWARD AT 08 KNOTS (KTS) OVER THE
PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS
FLARING CONVECTION AROUND AN ILL-DEFINED, OBSCURED LOW LEVEL
CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH LOW
CONFIDENCE BY EXTRAPOLATING FROM A 050536Z SSMIS 37 GHZ MICROWAVE
IMAGE WHICH SHOWS A HINT OF FORMATIVE BANDING WRAPPING TOWARDS THE
LLC. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON 6-HOUR OLD PGTW
DVORAK CURRENT INTENSITY ESTIMATES OF T1.5/25KTS. HOWEVER, THE MOST
RECENT PGTW DVORAK FIX WAS TOO WEAK FOR DVORAK. THE ENVIRONMENT IS
MARGINALLY FAVORABLE WITH LOW (10-15 KT) VERTICAL WIND SHEAR, POOR
OUTFLOW, AND WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE. THE
CYCLONE IS TRACKING SLOWLY NORTHWESTWARD TOWARD A BREAK IN A
SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TD 01W WILL CONTINUE TRACKING SLOWLY NORTHWESTWARD TOWARD THE
BREAK IN THE STR UNTIL TAU 48 WHEN THE STR WILL BUILD TO THE NORTH
AND TURN TD 01W WEST-NORTHWESTWARD. SLIGHTLY IMPROVED OUTFLOW WILL
ENABLE SLOW INTENSIFICATION TO 35 KNOTS BY TAU 36 AND STEADY
INTENSITY THROUGH TAU 72. TD 01W WILL PASS NEAR KWAJALEIN PRIOR TO
TAU 72.
   C. AFTER TAU 72, TD 01W WILL CONTINUE ON A WEST-NORTHWESTWARD
TRACK TOWARD GUAM. MARGINALLY FAVORABLE ENVIRONMENTAL CONDITIONS
WILL PERSIST AND PROMOTE SOME ADDITIONAL INTENSIFICATION TO 40 KNOTS
(POSSIBLY HIGHER) BY TAU 120. NUMERICAL GUIDANCE IS IN POOR
AGREEMENT BUT ALL MEMBERS SHOW A GENERALLY WESTWARD TO WEST-
NORTHWESTWARD TRACK. THE MOST RECENT MODEL DATA SHOWED A SIGNIFICANT
SOUTHWARD SHIFT IN THE CONSENSUS TRACK. THIS SHIFT IS LARGELY DUE TO
THE ECMWF TRACKER, A NOTABLE SOUTHERN OUTLIER. THE JTWC FORECAST
TRACK CLOSELY FOLLOWS THE PREVIOUS TRACK. IF THE CONSENSUS TRACK
REMAINS FURTHER SOUTH, IT IS VERY LIKELY THE JTWC TRACK FORECAST
WILL SHIFT. BASED ON HIGH UNCERTAINTY IN THE INITIAL POSITION AND
MODEL GUIDANCE, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.//
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