Tropical Storm CHAN-HOM Advisory Tue Jun 30

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 09W (CHAN-HOM)
WARNING NR 01//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 09W (CHAN-HOM), LOCATED APPROXIMATELY
204 NM NORTHEAST OF POHNPEI, HAS TRACKED WESTWARD AT 03 KNOTS OVER
THE PAST SIX HOURS. ANIMATED EIR DEPICTS DEEPENED CENTRAL CONVECTION
WITH FORMATIVE BANDS WRAPPING INTO AN OBSCURED LLCC. A 301021Z ASCAT
PASS SHOWS 15 TO 20 KNOT CORE WINDS WITH STRONGER (25 TO 30 KNOT)
WINDS SURROUNDING CIRCULATION. THE CURRENT POSITION IS BASED ON THE
EIR LOOP AND THE AFOREMENTIONED ASCAT PASS WITH GOOD CONFIDENCE. THE
INITIAL INTENSITY OF 30 KNOTS IS BASED ON MATCHING DVORAK INTENSITY
ESTIMATES OF T2.0 FROM BOTH PGTW AND RJTD. UPPER-LEVEL ANALYSIS
INDICATES 09W IS LOCATED IN A MODERATE (20 KNOT) VWS BEING OFFSET BY
THE EXCELLENT OUTFLOW, NAMELY THE POLEWARD CHANNEL ENHANCED BY THE
TUTT CELL LOCATED TO THE NORTH. TD 09W IS CURRENTLY TRACKING
GENERALLY WESTWARD ALONG THE SOUTHERN PERIPHERY OF A STR TO THE
NORTH.
3. FORECAST REASONING.
   A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST
PHILOSOPHY.
   B. TD 09W WILL MAINTAIN A WESTWARD TRAJECTORY THROUGH TAU 72.
MODERATE VWS WILL PERSIST, BUT FAVORABLE SST AND HIGH OHC CONTENT
VALUES WILL ALLOW THE SYSTEM TO GRADUALLY INTENSIFY. AVAILABLE MODEL
GUIDANCE IS OVERALL IN GOOD AGREEMENT, LENDING HIGH CONFIDENCE
DURING THIS PERIOD. FURTHERMORE, AS TD 09W CONTINUES TO TRACK
WESTWARD, THERE IS A POSSIBILITY THAT THE SYSTEM WILL CONSUME AND/OR
SUFFOCATE 94W, THE DISTURBANCE THAT IS LOCATED NEAR 8.5N 148.8E (SEE
ABPW BULLETIN FOR FURTHER DETAILS ON THIS DISTURBANCE).
   C. AFTER TAU 72, AN APPROACHING UPPER-LEVEL TROUGH PASSING TO THE
NORTH WILL WEAKEN THE STR, CAUSING TD 09W TO SHIFT NORTHWESTWARD.
DUE TO DIFFERENCES IN TRACK SPEEDS AMONG AVAILABLE TRACKERS, THERE
IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST FOR THIS PERIOD.//
NNNN
NNNN