MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (DANAS) WARNING NR 05// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 06W (DANAS), LOCATED APPROXIMATELY 504 NM SOUTH- SOUTHWEST OF KADENA AB, HAS TRACKED NORTH-NORTHEASTWARD AT 09 KNOTS (KTS) OVER THE PAST SIX HOURS. THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION BASED ON A FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) EVIDENT IN ANIMATED MULTISPECTRAL SATELLITE IMAGERY. THERE IS LITTLE TO NO CONVECTION NEAR THE LLCC BUT THERE ARE TWO AREAS OF DEEP CONVECTION (90W TO THE EAST, 91W WEST OF THE PHILIPPINES) ALONG THE PERIPHERY OF THE CIRCULATION. PREVIOUS ASCAT PASSES AND MICROWAVE IMAGERY REVEAL THAT NEITHER INVEST HAS A DEFINED LLCC ALTHOUGH BOTH BEAR MONITORING. THE INITIAL INTENSITY OF 35 KTS IS HEDGED SLIGHTLY ABOVE MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES FROM T1.5-T2.0 (25-30 KTS) BASED ON THE STRONG WINDS MEASURED BY PREVIOUS ASCAT PASSES AND THE FACT THAT THE DVORAK TECHNIQUE IS NOT WELL-SUITED TO ESTIMATE INTENSITY FOR MONSOON DEPRESSIONS. THE ENVIRONMENT IS MARGINAL OVERALL WITH GOOD EQUATORWARD OUTFLOW, IMPROVING POLEWARD OUTFLOW, AND WARM (30-31 CELSIUS) SEA SURFACE TEMPERATURE BEING PARTIALLY OFFSET BY MODERATE (15-25 KTS) VERTICAL WIND SHEAR (VWS). TS 06W IS TRACKING ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THE FORECAST TRACK HAS SHIFTED TO THE EAST ABOUT 115 NM CLOSER TO KADENA AB AT TAU 36, HOWEVER, THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 06W WILL CONTINUE TRACKING GENERALLY POLEWARD THROUGH THE NEXT 72 HOURS AS IT FOLLOWS THE PERIPHERY OF THE STR. SLOW INTENSIFICATION IS EXPECTED AS THE SYSTEM ENTERS AN AREA OF MORE FAVORABLE VWS. THE PEAK INTENSITY OF 50 KTS IS EXPECTED AROUND TAU 48. NUMERICAL MODEL TRACK GUIDANCE HAS HIGH SPREAD AFTER TAU 36, PRIMARILY DUE TO TWO MEMBERS THAT REPRESENT THE WESTERN (ECMWF ENSEMBLE MEAN) AND EASTERN (GFS) OUTLIERS. THE BULK OF THE GUIDANCE ALIGNS WELL WITH THE CONSENSUS TRACK. THE JTWC TRACK FORECAST CLOSELY FOLLOWS THE CONSENSUS TRACK BUT CONFIDENCE IS LOW DUE TO THE HIGH SPREAD IN THE MODEL GUIDANCE, A RELATIVELY WEAK AND RE- ORIENTING SUBTROPICAL STEERING RIDGE, AND HIGH UNCERTAINTY IN THE POSITION OF THE LLCC AS THE MONSOON DEPRESSION CONSOLIDATES. C. IN THE EXTENDED RANGE, TS 06W IS EXPECTED TO TURN NORTHEASTWARD AND SLOWLY UNDERGO EXTRATROPICAL TRANSITION AS IT ENCOUNTERS A MID- LATITUDE TROUGH. SLIGHT WEAKENING IS ANTICIPATED, ALTHOUGH BAROCLINIC INTERACTION WITH THE TROUGH SHOULD ALLOW THE SYSTEM TO MAINTAIN GALE FORCE OR STRONGER WINDS THROUGHOUT THE TRANSITION. THE MODEL TRACKERS DEPICT A HIGHLY UNCERTAIN STORM TRACK IN THE EXTENDED PERIOD, SO CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC FORECAST TRACK IS LOW.// NNNN NNNN