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