Tropical Storm CHAN-HOM Advisory Tue Jul 07

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (CHAN-HOM) WARNING NR 29//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 09W (CHAN-HOM), LOCATED APPROXIMATELY 506 NM
SOUTHWEST OF IWO TO, HAS TRACKED WESTWARD AT 10 KNOTS OVER THE PAST
SIX HOURS. ANIMATED ENHANCED IR IMAGERY SHOWS A NEAR CLOUD FILLED
LLCC AS THE APPARENT EYE HAS SEEMINGLY COLLAPSE ALONG WITH THE DEEP
CONVECTION IN THE NORTHWESTERN QUADRANT. A 071205Z AMSU-B IMAGE
CONTINUES TO SHOW A MICROWAVE EYE AND THE LACK OF DEEP CONVECTION ON
THE NORTHERN SIDE OF THE LLCC. THE POSITION IS BASED ON THE
AFOREMENTIONED IMAGERY WITH GOOD CONFIDENCE. THE INTENSITY IS HELD
AT 80 KNOTS IN KEEPING WITH DVORAK CURRENT INTENSITY ESTIMATES FROM
ALL AGENCIES. UPPER-LEVEL ANALYSIS DEPICTS A FAVORABLE ENVIRONMENT
WITH MODERATE (15 TO 20 KNOTS) VWS AND NEAR-RADIAL OUTFLOW. TY 09W
IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A STR EXTENSION.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 09W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD UNDER
THE STEERING INFLUENCE OF THE STR THROUGH TAU 72. IT IS EXPECTED TO
INTENSIFY STEADILY PEAKING AT 125 KNOTS BY TAU 48 DUE TO CONTINUED
FAVORABLE ENVIRONMENTAL CONDITIONS. DYNAMIC GUIDANCE IS IN TIGHT
AGREEMENT THROUGH TAU 72, LENDING HIGH CONFIDENCE TO THIS PORTION OF
THE TRACK FORECAST.
   C. AFTER TAU 72, TY CHAN-HOM WILL BEGIN TO TRACK MORE TO THE
NORTH AS THE STR EXTENSION RETREATS TO THE EAST AND BREAKS DOWN DUE
TO AN INBOUND MID-LATITUDE TROUGH. EXPECT SOME DECREASE IN INTENSITY
DUE TO LIMITED OHC AND LAND INTERACTION SOUTH OF SHANGHAI, DESPITE
GOOD POLEWARD OUTFLOW. NUMERICAL GUIDANCE HAS BEGUN TO SPREAD FROM
THE 00Z RUN DUE TO SOME UNCERTAINTY IN THE TIMING AND POSITION OF
THE MID-LATITUDE TROUGHS EFFECTS ON THE STEERING STR. AS SUCH, THERE
IS A LOW CONFIDENCE IN THE JTWC FORECAST TRACK, WHICH IS LAID CLOSE
TO THE MULTI-MODEL CONSENSUS.//
NNNN
NNNN