Tropical Storm SAOLA Advisory Mon Oct 23

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 27W (TWENTYSEVEN)
WARNING NR 11//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 27W (TWENTYSEVEN), LOCATED APPROXIMATELY 342
NM SOUTHEAST OF ANDERSEN AFB, HAS TRACKED SOUTH-SOUTHEASTWARD AT
15 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS WELL DEFINED AND FULLY EXPOSED LOW LEVEL CIRCULATION
CENTER (LLCC) LENDING HIGH CONFIDENCE TO THE INITIAL POSITION, AND
FLARING CENTRAL CONVECTION BEING SHEARED TO THE WEST. THE INITIAL
INTENSITY IS ASSESSED AT 30 KNOTS WHICH IS BASED ON AGENCY CURRENT
INTENSITY DVORAK ESTIMATES OF T2.0 (30 KNOTS) AND ALSO SUPPORTED BY
A 220018Z METOP-A ASCAT IMAGE SHOWING A SOLID REGION OF 30 KNOT
WINDS ON THE SOUTHERN PERIPHERY. UPPER-LEVEL ANALYSIS SHOWS STRONG
EASTERLIES FROM THE NORTHEAST RIDGE INDUCING A VERY UNFAVORABLE
SHEAR ENVIRONMENT, BEING OFFSET BY MODERATE DIFFLUENCE. SSTS IN THE
REGION ARE ALSO VERY FAVORABLE NEAR 30 CELSIUS, HOWEVER DUE TO THE
HOSTILE UPPER-LVEL CONDITIONS TD 27W HAS NOT SHOWN SIGNS OF FURTHER
CONSOLIDATION. CURRENTLY TD 27W IS TRACKING ERRATICALLY WITHIN A
COMPETING STEERING ENVIRONMENT POSITIONED BETWEEN A NEAR-EQUATORIAL
RIDGE (NER) TO THE SOUTHWEST AND A SUBTROPICAL RIDGE (STR) TO THE
NORTHEAST.
3. FORECAST REASONING.
   A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. THE COMPETING STEERING ENVIRONMENT IS FORECAST TO PERSIST OVER
THE NEXT 24 HOURS AS THE NER WEAKENS RETREATING TO THE SOUTHWEST AND
THE STR STRENGTHENS DRIVING TD 27W TO THE NORTHWEST. RECENT UPPER
AIR SOUNDINGS FROM GUAM SHOW THE MID-TO LOW LEVEL WINDS SHIFTING TO
A EASTERLY PATTERN, INDICATING THE SUBTROPICAL RIDGE IS
STRENGTHENING. HOWEVER, THE STRONG STR WILL KEEP EASTERLY FLOW ALOFT
FAIRLY STRONG AND CONSEQUENTLY HIGH VERTICAL WIND SHEAR OVER THE
NEXT 48 HOURS. THE SYSTEM WILL REMAIN A TROPICAL DEPRESSION TO WEAK
TROPICAL STORM BEFORE UPPER-LEVEL CONDITIONS BEGIN TO IMPROVE
SHORTLY AFTER TAU 48.
   C. IN THE EXTENDED PERIOD, TD 27W IS FORECAST TO CONTINUE
NORTHWESTWARD SHIFTING TO A POLEWARD TRACK AROUND TAU 96. AS OUTFLOW
IMPROVES TD 27W WILL GRADUALLY INTENSIFY REACHING A PEAK INTENSITY
OF 65 KNOTS BY TAU 120. DYNAMIC MODEL GUIDANCE SHOWS GENERAL
AGREEMENT ON THE SYSTEM ACCELERATING TO THE NORTHWEST SOMETIME IN
THE NEXT 24 TO 36 HOURS, HOWEVER THERE IS A LARGE DEGREE OF
UNCERTAINTY IN THE EXACT POSITION AND TIMING OF THE TURN.
FURTHERMORE, THERE IS ALSO UNCERTAINTY IN THE EXTENDED TRACK LARGELY
DEPENDENT ON THE SCALE OF INTENSIFICATION WHICH MODELS ARE MIXED.
DUE TO THESE UNCERTAINTIES, THERE IS LOW CONFIDENCE IN THE FORECAST
TRACK.//
NNNN
NNNN