Tropical Storm IN-FA Advisory Qui, 19-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (IN-FA)
WARNING NR 10//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 27W (IN-FA), LOCATED APPROXIMATELY 481 NM
SOUTHEAST OF ANDERSEN AFB, HAS TRACKED WEST-NORTHWESTWARD AT 16
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) INDICATES A CONSOLIDATING, COMPACT LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH IMPROVED CONVECTIVE BANDING. A
190442Z SSMI 85GHZ IMAGE AND A 190548Z SSMIS 91GHZ IMAGE ALSO SHOW A
CONSOLIDATING LLCC WITH A WEAK MICROWAVE EYE FEATURE, WHICH SUPPORT
THE CURRENT POSITION WITH HIGH CONFIDENCE. DESPITE THE SLIGHTLY
IMPROVED ORGANIZATION, THE CURRENT INTENSITY REMAINS ASSESSED AT 55
KNOTS BASED ON DVORAK INTENSITY ESTIMATES OF 55 KNOTS FROM PGTW AND
KNES, WHICH IS CONSISTENT WITH THE MICROWAVE EYE FEATURE. UPPER-
LEVEL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT WITH LOW VERTICAL
WIND SHEAR AND GOOD POLEWARD AND EQUATORWARD OUTFLOW. TS 27W IS
TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL
RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE. CPA DISTANCE AND TIMING TO
ANDERSEN AFB HAVE CHANGED SLIGHTLY DUE TO A NORTHWARD ADJUSTMENT TO
THE ANALYSIS POSITIONS AND THE RECENT ACCELERATED TRACK SPEEDS.
   B. TS 27W IS FORECAST TO CONTINUE TRACKING WEST-NORTHWESTWARD
THROUGH TAU 72 UNDER THE DOMINANT STR, WHICH IS EXPECTED TO REMAIN
ENTRENCHED TO THE NORTH. TS 27W HAS ACCELERATED TO 16 KNOTS AS IT
TRACKS UNDER THE STRONG STR AND IS EXPECTED TO MAINTAIN RELATIVELY
FAST TRACK SPEEDS THROUGH TAU 72. DYNAMIC MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT THROUGH TAU 72. MODEL SPREAD AT CPA (TAU 36) WITH
GUAM IS ABOUT 110 NM, THEREFORE, THERE IS SOME UNCERTAINTY IN THE
EXACT CPA DISTANCE AND TIMING. TS 27W IS EXPECTED TO INTENSIFY AT A
CLIMATOLOGICAL RATE THROUGH TAU 72 TO A PEAK OF NEAR 105 KNOTS.
   C. IN THE EXTENDED TAUS, TS 27W WILL BEGIN SLOWING AS IT BEGINS
TO RE-CURVE POLEWARD IN RESPONSE TO AN APPROACHING MIDLATITUDE
TROUGH. EXTRA-TROPICAL TRANSITION IS EXPECTED TO COMMENCE NEAR TAU
108 AS THE SYSTEM BEGINS TO INTERACT WITH THE BAROCLINIC ZONE AND
MIDLATITUDE WESTERLIES. THIS INTERACTION SHOULD RESULT IN INCREASING
VERTICAL WIND SHEAR, WHICH WILL SERVE TO WEAKEN THE SYSTEM. DYNAMIC
MODEL GUIDANCE DIVERGES AFTER TAU 72 DUE TO DIFFERENCES BETWEEN THE
MODELS IN THE TIMING AND DEGREE OF THE RE-CURVE, WHICH IS TYPICAL IN
THIS SCENARIO, THEREFORE, THERE IS LOW OVERALL CONFIDENCE IN THE
JTWC FORECAST TRACK, WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL
CONSENSUS.//
NNNN
NNNN