Tropical Storm KALMAEGI Advisory dom, 17-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (KALMAEGI)
WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 27W (KALMAEGI), LOCATED APPROXIMATELY 296 NM
EAST-NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED SOUTHWESTWARD AT
01 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A BROAD, PARTIALLY-EXPOSED LOW-LEVEL
CIRCULATION WITH PERSISTENT DEEP CONVECTION OVER THE NORTHERN AND
EASTERN SEMICIRCLES. A 160510Z AMSR2 36GHZ IMAGE INDICATES FORMATIVE
BANDING WRAPPING AROUND AN ELONGATED, ILL-DEFINED LOW-LEVEL
CIRCULATION CENTER. MSI AND RECENT ASCAT IMAGERY INDICATE A QUASI-
STATIONARY (QS) MOTION. THE INITIAL INTENSITY REMAINS ASSESSED AT 35
KNOTS BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T2.5 (35 KNOTS)
AND RECENT ASCAT DATA SHOWING 30-35 KNOT WINDS OVER THE EAST
QUADRANT. UPPER-LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH
A VIGOROUS POLEWARD OUTFLOW OFFSET BY MODERATE TO STRONG (15-25KT)
VERTICAL WIND SHEAR (VWS). TS 27W REMAINS IN A WEAK STEERING
ENVIRONMENT BETWEEN THE SUBTROPICAL RIDGE (STR) TO THE WEST AND THE
STR TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 27W WILL REMAIN QS OVER THE NEXT 12 HOURS. AFTERWARD, THE
STR TO THE EAST WILL SLOWLY DRIVE THE SYSTEM NORTHWESTWARD. BETWEEN
TAUS 48 AND 72, THE STR TO THE WEST WILL BUILD, REORIENT NORTHWARD,
AND GRADUALLY STEER THE CYCLONE WESTWARD INTO NORTHERN LUZON. THE
MARGINALLY FAVORABLE ENVIRONMENT WILL FUEL SLOW INTENSIFICATION TO A
PEAK OF 55 KNOTS BY TAU 48. AFTERWARD, INCREASING VWS AND LAND
INTERACTION WILL ERODE THE SYSTEM AFTER LANDFALL. THERE IS A
DISTINCT POSSIBILITY THAT THE STRONG VWS, COLD/DRY SURGE,
AND LAND INTERACTION WILL GREATLY OFFSET THE STRONG OUTFLOW AND
ERODE THE SYSTEM MORE RAPIDLY AND INTO DISSIPATION BY TAU 72.
   C. AFTER TAU 72, TS KALMAEGI IS EXPECTED TO TRACK SOUTHWESTWARD
UNDER THE STEERING INFLUENCE OF THE WESTERN STR. TS 27W IS FORECAST
TO DISSIPATE DUE TO STRONG VWS BY TAU 120. THE NUMERICAL MODELS ARE
IN GOOD AGREEMENT WITH THE OVERALL SCENARIO, HOWEVER, THERE IS A
LARGE DEGREE OF UNCERTAINTY IN THE TRACK MOTION IN THE EARLY TAUS.
THEREFORE, THERE IS LOW OVERALL CONFIDENCE IN THE JTWC TRACK
FORECAST.//
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