Tropical Storm MERANTI Advisory Fr, 09.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 16W (SIXTEEN)
WARNING NR 02//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 16W (SIXTEEN), LOCATED APPROXIMATELY 135
NM WEST-SOUTHWEST OF ANDERSEN AFB, GUAM, HAS TRACKED SOUTHEASTWARD
AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY INDICATES THE LOW LEVEL CIRCULATION CENTER (LLCC)
IS LOOPING TO THE SOUTHEAST AS IT TRIES TO CONSOLIDATE. A GROUPING
OF RECENT MICROWAVE FIXES PROVIDES BETTER CONFIDENCE IN THE 0900Z
POSITION. THE INITIAL INTENSITY IS BASED ON DVORAK ESTIMATES FROM
PGTW, KNES, AND RJTD, AND CONSISTENT WITH THE CURRENT POOR
ORGANIZATION. THE SYSTEM IS CURRENTLY WITHIN A WEAKNESS IN THE LOW
LEVEL SUB-TROPICAL RIDGE (STR), LEADING TO THE ERRATIC MOTION. UPPER
LEVEL ANALYSIS INDICATES VERTICAL WIND SHEAR (VWS) IS LOW (05-10
KNOTS), HOWEVER, THERE IS NO WELL DEFINED OUTFLOW CHANNEL AT THIS
TIME DUE TO THE PROXIMITY OF A TUTT CELL TO THE NORTH. SEA SURFACE
TEMPERATURES ARE FAVORABLE.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. AS THE STR REBUILDS OVER THE NEXT 6-12 HOURS, TD 16W WILL
RETURN TO A NORTHWESTWARD TRACK. THIS STEERING MECHANISM IS EXPECTED
TO REMAIN IN PLACE THROUGHOUT THE FORECAST PERIOD, LEADING TO
PERSISTENT NORTHWESTWARD MOTION. INTENSIFICATION IS EXPECTED TO BE
SLOW IN THE SHORT TERM, AS THE CONVECTION CONTINUES TO ORGANIZE AND
MOVES AWAY FROM THE NEGATIVE EFFECTS OF THE TUTT CELL, AFTER WHICH,
INTENSIFICATION WILL BE NEAR THE CLIMATOLOGICAL AVERAGE. MODELS ARE
GENERALLY IN GOOD AGREEMENT ON THE TRACK SOLUTION ONCE THE STEERING
FLOW RE-ESTABLISHES, WITH THE GFS SERVING AS A NOTABLE OUTLIER GIVEN
THAT MODEL NEVER DEVELOPS BEYOND A TROPICAL DISTURBANCE IN THE
SURFACE FIELDS.
   C. IN THE EXTENDED PERIOD, TD 16W WILL REMAIN UNDER THE STEERING
INFLUENCE OF THE STR. BEYOND TAU 72, VWS AND OUTFLOW CONDITIONS ARE
EXPECTED TO IMPROVE SIGNIFICANTLY AND SSTS WILL INCREASE, LEADING TO
THE POSSIBILITY OF RAPID INTENSIFICATION. DYNAMICAL AID SPREAD IS
HIGHER IN THE EXTENDED TAUS. DUE TO THE INITIAL MOTION UNCERTAINTY
AND LONG TERM MODEL SPREAD, THERE IS LOW CONFIDENCE IN THE JTWC
WARNING TRACK.//
NNNN
NNNN