Tropical Storm MALAKAS Advisory Thu Sep 15

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (MALAKAS) WARNING NR 16//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 18W (MALAKAS), LOCATED APPROXIMATELY 489 NM SOUTH OF
KADENA AB, HAS TRACKED NORTHWESTWARD AT 12 KNOTS OVER THE PAST
SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A
WARMING PINHOLE EYE FEATURE THAT HAS RECENTLY EMERGED. THE
INITIAL POSITION IS BASED ON SATELLITE FIXES FROM PGTW AND RJTD AS
WELL AS A 151028Z SSMIS 91GHZ IMAGE WITH GOOD CONFIDENCE. THE
INITIAL INTENSITY IS ASSESSED AT 90 KNOTS AND IS BASED ON SUBJECTIVE
DVORAK ESTIMATE FROM PGTW AND RJTD NOW REPORTING THE CURRENT
INTENSITY AT T4.5 (90 KNOTS). UPPER-LEVEL ANALYSIS SHOWS IMPROVING
POLEWARD OUTFLOW AND VERTICAL WIND SHEAR, HOWEVER THERE IS A
DEEPENING UPPER-LEVEL LOW OFF TO THE EAST CREATING A REGION OF
SUBSIDENCE AND CURRENTLY HAVING MINIMAL AFFECT ON THE SYSTEM. SEA
SURFACE TEMPERATURES ARE VERY FAVORABLE NEAR 30 CELSIUS. CURRENTLY
TY MALAKAS IS TRACKING WEST-NORTHWEST ALONG THE PERIPHERY OF A DEEP-
LAYERED SUBTROPICAL RIDGE.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. IN THE NEAR TERM FORECAST TY MALAKAS WILL CONTINUE TO
TRACK NORTHWEST ALONG THE STEERING RIDGE UNDER FAVORABLE CONDITIONS.
THE UPPER-LEVEL LOW IS EXPECTED TO PERSIST AND MITIGATE OUTFLOW ON
THE EASTERN PERIPHERY, HOWEVER ENHANCED POLEWARD FLOW IS ALSO
EXPECTED TO IMPROVE PROVIDING A WINDOW FOR INTENSIFICATION
THROUGH TAU 36 REACHING A PEAK INTENSITY OF 115 KNOTS. FROM TAU 36
TO 72, TY MALAKAS WILL BEGIN TO SLOW DOWN AS IT ROUNDS THE RIDGE
AXIS NEAR NORTHEASTERN TAIWAN. SLIGHT LAND INTERACTION IS EXPECTED
DURING THIS TIME LEADING TO A GRADUAL WEAKENING TREND.
   C. IN THE EXTENDED TAUS BEYOND TAU 72, TY MALAKAS WILL TRACK
NORTHEASTWARD ALONG THE NORTHERN PERIPHERY OF THE SUBTROPICAL RIDGE
INTO THE WESTERLY JET. VERTICAL WIND SHEAR WILL INCREASE
SIGNIFICANTLY LEADING TO RAPID WEAKENING OF THE SYSTEM BY TAU 120.
DYNAMIC MODEL GUIDANCE IS STILL SHOWING SOME UNCERTAINTY AS TY
MALAKAS ROUNDS THE RIDGE AXIS, BUT OVERALL NUMERICAL SOLUTIONS ARE
SHOWING TIGHTER GROUPING. THE DECREASED UNCERTAINTY LENDS HIGH
CONFIDENCE TO THE FORECAST TRACK.//
NNNN
NNNN