MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 10W (TEN) WARNING NR 01// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 10W (TEN), LOCATED APPROXIMATELY 659 NM SOUTH-SOUTHEAST OF KADENA AB, HAS TRACKED EAST-NORTHEASTWARD AT 06 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS AN AREA EMBEDDED IN A BROAD CIRCULATION WHERE SUSTAINED CONVECTION APPEARS TO BE CAUSING CONSOLIDATION. THERE IS VERY LOW CONFIDENCE IN THE INITIAL POSITION, PLACED NEAR THE APPARENT CONSOLIDATION IN THE MSI IMAGERY AND CONSISTENT WITH A 032009 AMSU 89 GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY OF 25 KTS IS BASED ON RJTD AND KNES DVORAK CURRENT INTENSITY ESTIMATES OF T1.5 (25 KTS) BUT THERE HAS BEEN A LARGE AREA OF APPROXIMATELY 30 KT WESTERLY WINDS OVER 100 NM TO THE SOUTH OF THE CURRENT POSITION. THE ENVIRONMENT IS MARGINAL WITH EXCELLENT EQUATORWARD OUTFLOW AND WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURE OFFSETTING MODERATE (10-20 KT) VERTICAL WIND SHEAR (VWS). NOTABLY, THERE IS AN ADJACENT AREA OF FAVORABLE WIND SHEAR JUST NORTH OF THE CURRENT POSITION AND IN THE PATH OF THE SYSTEM. TD 10W IS DRIFTING GENERALLY POLEWARD UNDER WEAK STEERING INFLUENCE FROM A SUBTROPICAL RIDGE (STR) THAT EXTENDS FROM THE NORTH TO THE EAST. 3. FORECAST REASONING. A. THIS IS THE INITIAL PROGNOSTIC REASONING AND SETS THE FORECAST PHILOSOPHY. TD 10W IS STILL CONSOLIDATING SO INITIAL UNCERTAINTY IS HIGH. INTENSITY IS ANTICIPATED TO REACH 35 KTS IN ABOUT 24 HOURS, NECESSITATING A WARNING. B. THROUGH TAU 48, TD 10W IS EXPECTED TO DRIFT SLOWLY POLEWARD BY THE EASTERN EXTENSION OF THE STR. BETWEEN TAU 48 AND 72, THE STR EXTENSION TO THE NORTH WILL TAKE OVER AS THE PRIMARY STEERING INFLUENCE AND THE TRACK SHOULD SHIFT MORE NORTHWESTWARD. AS TD 10W MOVES INTO A MORE FAVORABLE VWS REGION, THE CYCLONE IS EXPECTED TO STEADILY INTENSIFY, REACHING 55 KTS BY TAU 72. MOST OF THE UNCERTAINTY IN THE MODEL GUIDANCE FOR THIS PORTION OF THE FORECAST IS IN THE EARLY TAUS AS THE MODEL TRACKERS ARE LIKELY HAVING DIFFICULTY IDENTIFYING THE LLCC IN THE BROADER CIRCULATION. BY TAU 36, NAVGEM STARTS TO APPEAR AS A SOUTHERN OUTLIER RELATIVE TO THE OTHER MEMBERS. OVERALL, THERE IS VERY LOW CONFIDENCE IN THE EARLY PORTION OF THE FORECAST, LARGELY OWING TO HIGH UNCERTAINTY IN THE INITIAL POSITION AND SUBSEQUENT UNCERTAINTY IN THE MODEL TRACK GUIDANCE. C. BEYOND TAU 72, TD 10W IS EXPECTED TO CONTINUE ON A NORTHWESTWARD TRACK ALONG THE SOUTHWEST PERIPHERY OF THE STR AND TO STEADILY INCREASE INTENSITY TO 70 KTS BY TAU 120. FOR THE MOST PART, ALL THE INTENSITY GUIDANCE SHOWS A SIMILAR TREND TO THE FORECAST INTENSITY; HOWEVER, THE ENVELOPE OF POSSIBILITIES IS QUITE LARGE (50- 85 KTS) BY THE END OF THE FORECAST. THE JTWC INTENSITY FORECAST IS HEDGED JUST ABOVE THE INTENSITY CONSENSUS ONLY DUE TO THE ENVIRONMENT APPEARING TO REMAIN FAVORABLE FOR THE DURATION OF THE FORECAST. TRACK GUIDANCE, WITH THE EXCEPTION OF NAVGEM, IS IN FAIR AGREEMENT BUT CONFIDENCE IN THE EXTENDED FORECAST IS VERY LOW PRIMARILY DUE TO HIGH UNCERTAINTY IN THE INITIAL POSITION.// NNNN NNNN