Tropical Storm GAEMI Advisory Çar, 03.10.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 21W (GAEMI) WARNING NR
06//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 21W (GAEMI), LOCATED APPROXIMATELY 550 NM
EAST OF HUE, VIETNAM, HAS TRACKED SOUTHEASTWARD AT 04 KNOTS OVER
THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS A
CONSOLIDATING SYSTEM WITH A CENTRAL DENSE OVERCAST CONCEALING THE
LOW-LEVEL CIRCULATION CENTER (LLCC). A 021718Z AMSU IMAGE SHOWS
IMPROVED CONVECTIVE BANDING WRAPPING INTO THE CENTER; HOWEVER, THE
EXACT CENTER IS DIFFICULT TO ASCERTAIN DUE TO THE LOW RESOLUTION OF
THE SENSOR. THEREFORE, THERE IS FAIR CONFIDENCE IN THE INITIAL
POSITION AND RECENT MOTION. ANIMATED WATER VAPOR IMAGERY INDICATES
IMPROVING POLEWARD OUTFLOW AS THE DEEP MIDLATITUDE SHORTWAVE TROUGH
TRACKS EASTWARD INTO WESTERN JAPAN. THE 02/12Z 500MB ANALYSIS SHOWS
THAT THIS DEEP TROUGH IS MOVING EASTWARD SLOWLY AND ALSO PROVIDES
EVIDENCE THAT THE SUBTROPICAL RIDGE (STR) IS BUILDING EASTWARD INTO
SOUTHEAST CHINA.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE. PEAK INTENSITY HAS BEEN
INCREASED TO 65 KNOTS AT TAU 48 AND 72.
   B. TS 21W IS FORECAST TO SLOW DOWN AND BECOME QUASI-STATIONARY
OVER THE NEXT 12 TO 24 HOURS AS THE SYSTEM BEGINS TO TRANSITION TO
THE STEERING INFLUENCE OF THE STR BUILDING TO THE NORTH. AS
MENTIONED ABOVE, THE STR IS BUILDING INTO SOUTHEAST CHINA BUT
RELATIVELY SLOWLY DUE TO THE DEEP, BROAD TROUGH, WHICH HAS DOMINATED
EAST CHINA AND THE EAST CHINA SEA. AFTER TAU 24, THE STR IS FORECAST
TO BUILD EASTWARD AND WILL PROVIDE A STRONGER WESTWARD STEERING
INFLUENCE, WHICH WILL RESULT IN A SHARP WESTWARD TURN AND A MARKED
ACCELERATION. DESPITE THE COMPLEX SCENARIO, DYNAMIC MODEL GUIDANCE
HAS BEEN CONSISTENT OVER THE PAST 2 DAYS AND IS IN GOOD AGREEMENT.
THERE IS SOME UNCERTAINTY, HOWEVER, IN THE TIMING OF THIS WESTWARD
TURN AND THE EXACT TRACK MOTION THROUGH TAU 36, THEREFORE, THERE IS
LOW CONFIDENCE IN THE FORECAST TRACK THROUGH TAU 48. AFTER TAU 48,
THERE IS INCREASING CONFIDENCE DUE TO THE TIGHT GROUPING OF DYNAMIC
MODELS, WHICH TRACK THE SYSTEM WESTWARD. TS 21W IS FORECAST TO
INTENSIFY THROUGH TAU 72 UNDER GENERALLY FAVORABLE CONDITIONS.
    C. IN THE EXTENDED TAUS, TS 21W IS FORECAST TO ACCELERATE
WESTWARD AND MAKE LANDFALL ALONG THE EAST COAST OF VIETNAM AFTER TAU
72. THE SYSTEM WILL DISSIPATE BY TAU 120 AS IT INTERACTS WITH THE
RUGGED TERRAIN OF THIS REGION. DYNAMIC MODEL GUIDANCE IS IN GOOD
AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THIS PORTION OF
THE TRACK FORECAST.//
NNNN
NNNN