MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 30W (THIRTY) WARNING NR 02// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 30W (THIRTY), LOCATED APPROXIMATELY 413 NM SOUTHEAST OF ANDERSEN AFB, GUAM, HAS TRACKED NORTHWESTWARD AT 20 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS A BROAD AREA OF CONVECTION LOCATED MAINLY TO THE WEST OF THE PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON A PARTIAL 280519Z 91GHZ SSMIS MICROWAVE IMAGE WHICH SHOWS THE IMPROVING BANDING STRUCTURE OF TD 30W. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON A PGTW DVORAK INTENSITY ESTIMATE OF 1.5 (25 KNOTS). ENVIRONMENTAL ANALYSIS SHOWS TD 30W IS EXPERIENCING FAVORABLE VERTICAL WIND SHEAR (5 TO 10 KNOTS). UPPER LEVEL OUTFLOW CONTINUES TO IMPROVE WITH MODERATE EQUATORWARD AND POLEWARD OUTFLOW CHANNELS. SEA SURFACE TEMPERATURES ARE FAVORABLE, BETWEEN 30 AND 31 DEGREES CELSIUS. TD 30W IS TRACKING NORTHWESTWARD ALONG THE SOUTHWESTERN EDGE OF THE SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 30W WILL CONTINUE TO TRACK NORTHWESTWARD UNDER THE INFLUENCE OF THE AFOREMENTIONED STR. AS IT TRACKS NORTHWESTWARD IT WILL CONTINUE TO CONSOLIDATE AS IT ENCOUNTERS FAVORABLE SEA SURFACE TEMPERATURES AND FAVORABLE VERTICAL WIND SHEAR. BY TAU 72, TD 30W WILL REACH AN INTENSITY OF 90 KNOTS AS IT CONTINUES TO TRACK NORTHWESTWARD. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 72 WITH A SPREAD OF 170 NM AT TAU 72. THEREFORE, THERE IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. C. AFTER TAU 72, TD 30W WILL CONTINUE TO TRACK ALONG THE SOUTHWESTERN EDGE OF THE STR. FAVORABLE ENVIRONMENTAL CONDITIONS WILL CONTINUE AND ALLOW TD 30W TO REACH A PEAK INTENSITY OF 115 KNOTS BY TAU 120. BY TAU 120, TD 30W WILL BEGIN TO APPROACH THE STR AXIS AND TURN SLIGHTLY NORTHWARD. DYNAMIC MODEL GUIDANCE IS IN POOR AGREEMENT WITH A SPREAD OF NEARLY 800 NM BY TAU 120. ECMWF IS THE WESTERN OUTLIER WITH CTCX THE EASTERN OUTLIER. THE JTWC FORECAST IS PLACED NEAR, BUT SLIGHTLY SOUTHWEST OF THE MULTI-MODEL CONSENSUS. DUE TO THE WIDE SPREAD IN MODEL GUIDANCE THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN