Tropical Storm SAOLA Advisory Sat Oct 28

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (SAOLA)
WARNING NR 31//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 27W (SAOLA), LOCATED APPROXIMATELY 253 NM SOUTH-
SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWESTWARD AT 12 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS
SOME STRUCTURAL IMPROVEMENT OVER THE LAST SIX HOURS WITH CONVECTIVE
BANDING WRAPPING INTO A PARTIALLY EXPOSED LOW LEVEL CIRCULATION
CENTER (LLCC) FROM THE SOUTHERN PERIPHERY. A 270457Z 89GHZ AMSR2
IMAGE SHOWS THE LLCC STILL RELATIVELY BROAD WITH THE BULK OF
CONVECTION WEAK AND CONFINED TO THE SOUTHERN PORTION OF THE SYSTEM.
THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION BASED ON THE
MICROWAVE IMAGE AND SATELLITE FIXES. THE INITIAL INTENSITY IS
ASSESSED AT 50 KNOTS AND IS BASED ON PERSISTENCE, COMBINED WITH
AGENCY DVORAK ESTIMATES OF T3.0 (45 KNOTS) AND A 270104 SATCON
ESTIMATE OF 49 KNOTS. UPPER-LEVEL ANALYSIS SHOWS LOW VERTICAL WIND
SHEAR AS THE NORTHEASTERN ANTICYCLONE RETREATS TO THE EAST ALLOWING
THE ESTABLISHMENT OF A POLEWARD OUTFLOW CHANNEL. EQUATORWARD OUTFLOW
REMAINS FAIRLY ROBUST WITH A POINT SOURCE NOW DEVELOPED OVER THE
SYSTEM. HOWEVER, THE UPPER-LEVEL RIDGE WITH ACCOMPANYING EASTERLIES
ARE STILL EXERTING INFLUENCE ON THE SOUTHEASTERN EDGE, CREATING A
RECEDING OUTFLOW BOUNDARY. SSTS ARE RELATIVELY WARM NEAR 28 CELSIUS
AND CONDUCIVE FOR CYCLOGENESIS. CURRENTLY TS 27W IS TRACKING
NORTHWESTWARD ALONG THE WESTERN BOUNDARY OF DEEP-LAYERED SUBTROPICAL
RIDGE (STR) TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 27W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD OVER THE
NEXT 12 HOURS GUIDED BY THE STR, THEN TURNING POLEWARD AS IT ROUNDS
THE RIDGE AXIS TAKING A TRACK OVER THE ISLAND OF OKINAWA. THE
POLEWARD OUTFLOW IS FORECAST TO PERSIST AND GRADUALLY STRENGTHEN
OVER THE NEXT 24 HOURS AS IT TAPS INTO THE WESTERLY JET. BEYOND TAU
24 TS 27W WILL ACCELERATE EAST-NORTHEASTWARD WITH INCREASING WIND
SHEAR AND BAROCLINIC INSTABILITY AS IT BEGINS TRANSITION INTO A COLD
CORE LOW SOMETIME BETWEEN TAU 36 AND 48. AROUND TAU 48 A COLD SURGE
OVER THE SEA OF JAPAN WILL EXTEND OVER THE SOUTHERN JAPANESE ISLANDS
ENHANCING THE DISTRIBUTION OF GALE FORCE WINDS. THE COOL DRY AIR
ENTRAINMENT INTO TS 27W WILL AID IN THE RAPID DETERIORATION OF THE
SYSTEM AS IT GETS EMBEDDED INTO THE MID-LATITUDE WESTERLIES AND
COMPLETES ETT SHORTLY AFTER TAU 48 SOUTH OF HONSHU. DYNAMIC MODEL
GUIDANCE IS COMING INTO BETTER AGREEMENT WHICH IS IMPROVING
CONFIDENCE IN THE FORECAST TRACK, ESPECIALLY IN THE NEXT 24 HOURS.
HOWEVER, BEGINNING AROUND TAU 36 THE SPEED IN WHICH TS 27W
ACCELERATES NORTHEASTWARD IS SOMEWHAT VARIABLE. BECAUSE OF THIS
UNCERTAINTY, THERE IS OVERALL FAIR CONFIDENCE IN THE FORECAST
TRACK.//
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