MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 27W (KALMAEGI) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 27W (KALMAEGI), LOCATED APPROXIMATELY 421 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON RECENT MICROWAVE SATELLITE IMAGERY, INCLUDING 131653Z AMSR2 IMAGERY, WHICH SHOWS A BROAD AND ILL-DEFINED CIRCULATION CENTER. THE INTENSITY OF 30 KNOTS IS CONSISTENT WITH A CONSENSUS OF AVAILABLE AGENCY SUBJECTIVE DVORAK AND AUTOMATED INTENSITY ESTIMATES. TD 27W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL STEERING RIDGE SITUATED TO THE NORTHEAST. THE CENTER IS DEVOID OF DEEP CONVECTION, WHICH IS CONFINED TO THE WESTERN AND NORTHWESTERN PERIPHERIES OF THE CIRCULATION CONSISTENT WITH STRONG (20-25 KNOTS) EASTERLY VERTICAL WIND SHEAR. 3. FORECAST REASONING. A. THE FORECAST TRACK HAS BEEN SHIFTED TO THE MORE WEST- NORTHWESTERLY TRACK WITH AN EXPECTED PASSAGE OVER LUZON. B. TD 27W WILL CONTINUE TO TRACK NORTHWESTARD FOLLOWING THE SUBTROPICAL STEERING RIDGE FLOW TOWARD A BREAK IN THE RIDGE THROUGH TAU 72. FORWARD TRACK SPEED IS EXPECTED TO SLOW AFTER TAU 24 AS THE SYSTEM APPROACHES THE DEVELOPING BREAK IN THE RIDGE AND THE STEERING FLOW WEAKENS. SLOW INTENSIFICATION IS EXPECTED AS UPPER-LEVEL DIFFLUENCE REMAINS FAVORABLE, VERTICAL WIND SHEAR RELAXES SLIGHTLY AND ALONG-TRACK SEA SURFACE TEMPERATURES REMAIN HIGH (29-30C). CONSOLIDATION OF THE BROAD LOW-LEVEL CIRCULATION WILL REQUIRE SOME TIME, AND WILL LIKELY LIMIT NEAR-TERM INTENSIFICATION. NUMERICAL MODEL GUIDANCE IS IN AGREEMENT REGARDING THE OVERALL FORECAST SCENARIO THROUGH TAU 72. HOWEVER, THERE IS SIGNIFICANT SPREAD BETWEEN THE WESTERN AND EASTERNMOST OUTLIERS, LENDING LOW CONFIDENCE TO THE CURRENT JTWC TRACK FORECAST FOR THIS TIME PERIOD. C. AFTER TAU 72, RIDGING IS EXPECTED TO REBUILD TO THE NORTH OF TD 27W, STEERING THE SYSTEM WESTWARD INTO AND ACROSS THE ISLAND OF LUZON. PASSAGE OVER LAND WILL RESULT IN STEADY WEAKENING. THE GALWEM AND UKMET MODELS INDICATE THAT THE SYSTEM MAY TRACK POLEWARD TO THE EAST OF LUZON, FARTHER INTO THE DEVELOPING BREAK IN THE STEERING RIDGE TO THE NORTH, DURING THE EXTENDED FORECAST PERIOD. HOWEVER, ALL OTHER CONSENSUS GUIDANCE SUPPORTS THE BUILDING RIDGE AND WESTWARD MOTION SCENARIO, CONSISTENT WITH THE CURRENT FORECAST. BASED ON NOTED MODEL SPREAD AND DISAGREEMENT REGARDING THE OVERALL SCENARIO, THERE IS LOW CONFIDENCE IN THE EXTENDED FORECAST TRACK.// NNNN NNNN