MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 19W (NINETEEN) WARNING NR 01// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 19W (NINETEEN), LOCATED APPROXIMATELY 906 NM SOUTHEAST OF KADENA AB, JAPAN, HAS TRACKED WESTWARD AT 21 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THAT TD 19W CONTINUES TO CONSOLIDATE AND IMPROVE IN STRUCTURE WITH BANDS OF DEEP CONVECTION WRAPPING IN FROM THE NORTH AND THE SOUTH. THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE AND IS BASED ON A 270603Z 85GHZ SSMI MICROWAVE IMAGE SHOWING DEEP CONVECTION AROUND THE LOW LEVEL CIRCULATION CENTER (LLCC) WITH GOOD CONVECTIVE BANDING TO THE NORTH AND SOUTH. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON DVORAK CURRENT INTENSITY (CI) ESTIMATES OF T1.5 FROM PGTW AND RJTD. ENVIRONMENTAL ANALYSIS SHOWS THAT TD 19W IS EXPERIENCING FAVORABLE VERTICAL WIND SHEAR (5 TO 15 KNOTS). TD 19W HAS EXCELLENT EQUATORWARD OUTFLOW BUT LIMITED POLEWARD OUTFLOW. SEA SURFACE TEMPERATURES REMAIN FAVORABLE FOR DEVELOPMENT, BETWEEN 28 AND 30 DEGREES CELSIUS. TD 19W IS QUICKLY TRACKING WEST-NORTHWESTWARD WHILE UNDER THE INFLUENCE OF A SUBTROPICAL RIDGE (STR) WHICH IS POSITIONED TO THE NORTH. 3. FORECAST REASONING. A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE AND SETS THE FORECAST PHILOSOPHY. B. IN THE SHORT TERM, TD 19W WILL CONTINUE TO RAPIDLY TRACK WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE AFOREMENTIONED STR. FORWARD TRACK SPEED HAS BEEN ABNORMALLY FAST OVER THE PAST 12 HOURS. DURING THIS PERIOD DYNAMIC MODEL GUIDANCE HAS NOT ACCURATELY CAPTURED THE FORWARD SPEED OF THE SYSTEM. FAVORABLE VERTICAL WIND SHEAR, UPPER LEVEL OUTFLOW, AND SEA SURFACE TEMPERATURES WILL ALLOW TD 19W TO STAIDLY INTENSIFY. AFTER TAU 48, TD 19W WILL BEGIN TO ROUND THE WESTERN EDGE OF THE STR AND BEGIN TO TRACK NORTH-NORTHWESTWARD. DYNAMIC MODEL GUIDANCE INDICATES A BIFURCATION WITH NAVGEM AND JGSM OUTLIERS TO THE EAST WITH THE REMAINING CONSENSUS MEMBERS TIGHTLY GROUPED JUST TO THE WEST OF THE MULTI-MODEL CONSENSUS. DYNAMIC MODEL GUIDANCE HAS A SPREAD OF 265 NM BY TAU 72 WITH ECMWF ON THE WESTERN EDGE OF THE MODELS AND JGSM ON THE EASTERN EDGE. THE JTWC FORECAST TRACK IS PLACED SLIGHTLY TO THE WEST OF THE MULTI-MODEL CONSENSUS. DUE TO THE ABNORMALLY FAST TRACK SPEED AND THE SPREAD IN MODEL GUIDANCE THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK. C. BEYOND TAU 72, TD 19W WILL BEGIN TO ROUND THE WESTERN EDGE OF THE STR AND BEGIN TO TRACK NORTH-NORTHEASTWARD. UPPER LEVER OUTFLOW WILL CONTINUE TO IMPROVE AND ALLOW TD 19W TO REACH 90 KNOTS BY TAU 96. AN APPROACHING WEST TO EAST MOVING SHORTWAVE THROUGH WILL HELP TO ACCELERATE TD 19W NORTHEASTWARD AFTER TAU 96. DYNAMIC MODEL GUIDANCE REMAINS IN POOR AGREEMENT THROUGH TAU 120 WITH A SPREAD OF 480 NM. ECMWF CONTINUES TO BE ON THE WESTERN EDGE OF THE MODELS WITH JGSM AND NAVGEM STILL OUTLIERS TO THE EAST. THE JTWC FORECAST TRACK REMAINS SLIGHTLY TO THE WEST OF THE MULTI-MODEL CONSENSUS. BASED ON THE WIDE SPREAD IN MODEL GUIDANCE THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.// NNNN NNNN