MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01C (HALOLA) WARNING NR 32// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 01C (HALOLA), LOCATED APPROXIMATELY 920 NM EAST-SOUTHEAST OF IWO TO, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS ELONGATED, EXPOSED LOW-LEVEL CLOUD LINES WRAPPING INTO AN ILL-DEFINED CENTER WITH FORMATIVE BANDING DISPLACED NORTH AND SOUTH OF THE CENTER. MSI ALSO SHOWS A WELL-DEFINED MID-LEVEL CIRCULATION CENTER NEAR 17.6N 157.3E, WHICH IS DISPLACED OVER THE EASTERN PERIPHERY OF THE SYSTEM. IR IMAGERY INDICATES CLOUD TOP TEMPERATURES RANGING FROM -12C TO -15C ASSOCIATED WITH THE MID-LEVEL CIRCULATION CENTER. A 172341Z METOP-B 89 GHZ IMAGE REVEALS A BROAD LOW-LEVEL CIRCULATION CENTER WITH CONVECTIVE BANDING OVER THE SOUTHERN SEMI- CIRCLE WITH SIGNIFICANT DRY AIR WEST OF THE SYSTEM. A 172343Z ASCAT IMAGE SHOWS AN ELONGATED CIRCULATION WITH 25 TO 30 KNOT WINDS, WHICH SUPPORTS THE CURRENT INTENSITY ASSESSMENT OF 30 KNOTS. BASED ON THE WEAK OVERALL STRUCTURE, THERE IS FAIR CONFIDENCE IN THE CURRENT POSITION. UPPER-LEVEL ANALYSIS INDICATES A MARGINAL ENVIRONMENT DUE TO THE CLOSE PROXIMITY OF A TUTT CELL NEAR 22N 160E, WHICH IS PRODUCING CONVERGENT FLOW OVER THE NORTHERN SEMI-CIRCLE AND WESTERLY VERTICAL WIND SHEAR. TD 01C IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE DEEP-LAYERED STR. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 01C WILL CONTINUE TRACKING WESTWARD TO WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR THROUGH TAU 72. AVAILABLE DYNAMIC GUIDANCE IS IN TIGHT AGREEMENT WITH A SPREAD OF 60 NM AT TAU 72, THEREFORE HIGH CONFIDENCE IN THE JTWC FORECAST TRACK THROUGH TAU 72. TD 01C IS STRUGGLING DUE TO THE MARGINAL UPPER-LEVEL ENVIRONMENT AND POSSIBLE DRY AIR ENTRAINMENT, THEREFORE, THE SYSTEM IS FORECAST TO MAINTAIN INTENSITY THROUGH TAU 12 WITH A SLOW RATE OF INTENSIFICATION FROM TAU 12 TO 48. DUE TO THE WEAK NATURE OF THE SYSTEM AND THE STRONG LOW-LEVEL STR, THE SYSTEM IS EXPECTED TO MAINTAIN A GENERALLY WESTWARD TRACK THROUGH TAU 24. THEREAFTER, THE SYSTEM SHOULD TURN MORE WEST-NORTHWESTWARD AS IT INTENSIFIES AND BECOMES BETTER ORGANIZED. FORECAST GUIDANCE INDICATES MARGINAL CONDITIONS THROUGH, AT LEAST, TAU 48; HOWEVER, THERE IS UNCERTAINTY IN THE INTENSITY FORECAST DUE TO THE COMPLEX INTERACTION WITH THE TUTT. C. IN THE EXTENDED FORECAST PERIOD, EXPECT A MORE WEST- NORTHWESTWARD TO NORTHWESTWARD TRACK AS THE SYSTEM BEGINS TO APPROACH THE WESTERN PERIPHERY OF THE STR. DYNAMIC MODEL GUIDANCE DIVERGES SIGNIFICANTLY WITH THE MESO-SCALE MODELS SHOWING A SHARPER NORTHWESTWARD TURN THAN THE GLOBAL MODELS, WHICH SHOW A MORE WEST- NORTHWESTWARD TRACK. THERE IS A 320-NM SPREAD IN SOLUTIONS AT TAU 120, THEREFORE, UNCERTAINTY IS HIGH AND CONFIDENCE IN THE JTWC FORECAST TRACK IS LOW. INTENSIFICATION IS MORE LIKELY DUE TO IMPROVED POLEWARD OUTFLOW WITH A PEAK INTENSITY OF 80 KNOTS FORECAST AT TAU 96.// NNNN NNNN