Tropical Storm DAMREY Advisory lun, 30-07

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 11W (DAMREY) WARNING NR
06//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 11W (DAMREY), LOCATED APPROXIMATELY 200 NM EAST-
NORTHEAST OF IWO TO, JAPAN, HAS TRACKED WEST-SOUTHWESTWARD AT 04
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) CONTINUES TO SHOW A WELL DEFINED, EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC) WITH SOME WEAK CONVECTIVE BANDING AROUND
THE SOUTHERN SEMI-CIRCLE AND DISPLACED CONVECTION OVER THE EASTERN
SEMI-CIRCLE. THE CURRENT INTENSITY IS BEING HELD HIGHER THAN THE
DVORAK ESTIMATES OF 35 KNOTS BASED ON A 300032Z ASCAT IMAGE SHOWING
NUMEROUS 35-40 KNOT WIND BARBS AROUND STORM. UPPER LEVEL ANALYSIS
REVEALS THE TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL EAST OF
TS 11W CONTINUES TO PROVIDE OUTFLOW FOR THE STORM AND THE TUTT CELL
TO THE SOUTH THAT HAD BEEN PROVIDING CONVERGENCE ALOFT HAS FILLED
CONSIDERABLY IN THE PAST SIX HOURS. THERE IS ALSO MODERATE (15-20
KNOT) NORTHERLY VERTICAL WIND SHEAR ACTING UPON THE STORM AND RECENT
ANIMATED TOTAL PRECIPITABLE WATER LOOP IS STARTING TO SHOW DRY AIR
SURROUNDING THE WESTERN SEMI CIRCLE. TRACK SPEEDS WILL CONTINUE TO
REMAIN SLOW UNTIL THE DOMINANT SUBTROPICAL RIDGE (STR) BUILDS IN.
THE CURRENT POSITION CONFIDENCE IS HIGH BASED UPON MSI.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING.
   B. TS 11W IS FORECAST TO TRACK WEST-NORTHWESTWARD THROUGH TAU 72,
SLOWLY INTENSIFYING UNDER A COMPLEX UPPER LEVEL ENVIRONMENT. TS 11W
SHOULD REACH ITS PEAK INTENSITY OF 55 KNOTS NEAR TAU 48, SOUTH OF
KYUSHU. TRACK SPEEDS WILL INCREASE AFTER TAU 24 AS THE SUBTROPICAL
RIDGE (STR) BECOMES THE DOMINANT STEERING MECHANISM. DYNAMIC MODEL
GUIDANCE CONTINUES TO REMAIN CONSISTENT WITH A TIGHT GROUPING
THROUGH TAU 72. AT TAU 72, TS 11W SHOULD START TO WEAKEN AND
DISSIPATE CONSIDERABLY AS THE OUTFLOW FROM TS 10W, FORECASTED TO BE
ONLY 400NM FROM TS 11W AT THAT TIME, SEVERELY DEGRADES THE UPPER-
LEVEL ENVIRONMENT. THE CURRENT TRACK IS BASED ON THE CONSENSUS OF
AVAILABLE DYNAMIC MODEL GUIDANCE.
   C. TS 11W WILL RAPIDLY WEAKEN DUE TO INCREASING VERTICAL WIND
SHEAR AND FRICTIONAL EFFECTS. DYNAMICAL MODELS ARE IN TIGHT
AGREEMENT UNTIL TAU 96 WHERE MODELS SPREAD DUE TO SLIGHT INTERACTION
WITH TS 1OW OVER LAND. THIS INTERACTION, IF ANY, SHOULD MOVE THE
TRACK TO THE SOUTH AND FASTER. TS 11W WILL BECOME ABSORBED INTO THE
OUTER PERIPHERY OF TS 10W BY TAU 96. THERE IS HIGH CONFIDENCE IN THE
FORECAST TRACK.//
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