Western Pacific: Warnings re-issued on TD 16W, 19/15utc updates

TD 16W. JTWC HAVE ARE RE-ISSUING 6HOURLY WARNINGS ON 16W. 3HOURLY SATELLITE BULLETINS ARE STILL ISSUED ON THIS SYSTEM.

TD 16W. WARNING 29 ISSUED AT 19/15UTC. THIS IS THE INITIAL PROGNOSTIC REASONING MESSAGE AFTER REGENERATION AND ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TD 16W WILL CONTINUE TO TRACK NORTHWEST ALONG THE SOUTHWEST PERIPHERY OF THE DEEP SUBTROPICAL RIDGE(STR) THROUGH 48H, THEN TURN NORTH BY 72H AS IT APPROACHES A BREAK IN THE STR, THEN ACCELERATE NORTH-NORTHEASTWARD THROUGH THE REMAINDER OF THE FORECAST ALONG THE GRADIENT BETWEEN THE STR AND A MID-LATITUDE TROUGH APPROACHING FROM THE WEST. AS THE UPPER-LEVEL ANTI-CYCLONE ALOFT TRACKS ALONG WITH THE LOW LEVEL CIRCULATION CENTER, PROVIDING A SOURCE OF WEAK RADIAL OUTFLOW ALOFT AND RELATIVELY LOW VERTICAL WIND SHEAR(VWS), THE SYSTEM IS FORECAST TO STEADILY INTENSIFY AT THE CLIMATOLOGICAL RATE OF ROUGHLY ONE T-NUMBER PER DAY, PEAKING AT 40 KNOTS BY 48H. WHILE OVERALL INTENSITY IS EXPECTED TO STEADILY INCREASE, THE LOW-LEVEL WIND FIELD IS FORECAST TO REMAIN ASYMMETRIC, WITH THE HIGHEST WINDS CONFINED TO THE EASTERN HEMISPHERE OF THE SYSTEM. THE SHARP TROUGH CURRENTLY NEAR THE RYUKUS IS NOT EXPECTED TO MOVE MUCH FURTHER TO THE SOUTH OR EAST BUT THE STRONG NORTHEASTERLY FLOW BEHIND IT WILL SERVE AS A WALL UPON WHICH TD 16W WILL ULTIMATELY MEET ITS DEMISE. BETWEEN 48H AND 72H, TD 16W WILL MOVE UNDER THESE STRONG NORTHEASTERLY WINDS ALOFT, EXPERIENCE DRAMATICALLY INCREASED VWS AND CONVERGENCE ALOFT, LEADING TO FAIRLY RAPID DISSIPATION NO LATER THAN 96H.

TD 16W. SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TD 16W (SIXTEEN) HAS REGENERATED AS A TROPICAL DEPRESSION IN THE PHILIPPINE SEA. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT DEEP CONVECTION BEGAN DEVELOPING ONCE MORE OVER THE LOW LEVEL CIRCULATION CENTER (LLCC) AT APPROXIMATELY 190600UTC, AND HAS PERSISTED THROUGH THE 191200UTC HOUR. CLOUD TOP TEMPS HAVE COOLED SIGNIFICANTLY, AND HIGH RESOLUTION IMAGERY DEPICTS THE DEVELOPMENT OF SOME OVERSHOOTING TOPS, INDICATING THE SYSTEM IS UNDERGOING INTENSIFICATION. WHILE THE CONVECTION SIGNATURE IS VERY SYMMETRICAL, THE OVERALL SURFACE WIND FIELD IS HIGHLY ASYMMETRICAL, AS CONFIRMED BY A PARTIAL 191218UTC ASCAT-B PASS, WHICH SHOWED 15-20 KNOT WINDS ON THE NORTH-NORTHWEST SIDE OF THE SYSTEM. EARLIER SCATTEROMETER DATA SHOWED 25-30 KNOT WINDS CONFINED TO AN AREA EXTENDING FROM THE NORTHEAST-SOUTH OF THE LLCC. THE INITIAL POSITION IS ASSESSED WITH LOW CONFIDENCE DUE TO AN OBSCURED LLCC AND THE LACK OF RECENT MICROWAVE IMAGERY AND SCATTEROMETER DATA. THE INITIAL INTENSITY IS HEDGED SLIGHTLY HIGHER THAN THE MULTI-AGENCY INTENSITY ESTIMATES OF T1.0 IN LIGHT OF THE IMPROVED STRUCTURE AND CONVECTIVE DEVELOPMENT. EARLIER IN THE DAY, MODERATE TO STRONG WESTERLY SHEAR WAS INHIBITING THE DEVELOPMENT OF THE CONVECTIVE CORE, HOWEVER OVER THE PAST 12 HOURS THE UPPER-LEVEL PATTERN HAS MODIFIED, WITH A ANTICYCLONE DEVELOPING OVER TOP OF TD 16W, LEADING TO MUCH LOWER SHEAR AND WEAK RADIAL OUTFLOW, WITH THE REMNANTS OF A WEAK TUTT CELL TO THE NORTH PROVIDING A VERY WEAK TAP INTO SOME POLEWARD OUTFLOW AS WELL. A DEEP, SHARP, MID-LATITUDE TROUGH EXTENDS SOUTHWARD FROM THE KOREAN PENINSULA, ALONG THE RYUKU CHAIN, TO THE LUZON STRAIT.

TD 16W. MODEL DISCUSSION: TRACK GUIDANCE IS IN MODEST AGREEMENT ON THE RECURVE SCENARIO, WITH CROSS-TRACK SPREAD BEING THE MAJOR CONTRIBUTOR TO UNCERTAINTY THROUGH 72H, AND ALONG-TRACK SPREAD THEREAFTER AS THE SYSTEM ACCELERATES NORTHEASTWARD AFTER RECURVING. THE UKMET ENSEMBLE IS THE LEFT OUTLIER WHILE ECMWF IS THE RIGHT OUTLIER, WITH A CROSS-TRACK SPREAD OF 300 KM AT 48H. AFTER CROSSING THE RIDGE AXIS, GFS AND THE GFS ENSEMBLE ACCELERATE THE SYSTEM EXCESSIVELY FAST, WHILE THE UKMET ENSEMBLE DOES NOT SHOW A RECURVE, LEADING TO A SPREAD OF 1170 KM AT 96H. THE JTWC TRACK LIES ON THE LEFT EDGE OF GUIDANCE ENVELOPE THROUGH 72H, THEN JUST AHEAD OF THE MULTI-MODEL CONSENSUS MEAN BY 96H. INTENSITY GUIDANCE HAS COME INTO MUCH BETTER AGREEMENT WITH THIS RUN, WITH THE MAJORITY OF MESOSCALE MODELS SUPPORTING THE JTWC FORECAST, WHICH LIES CLOSE TO THE CONSENSUS MEAN THROUGH 48H, THEN WEAKENS THE SYSTEM FASTER THAN THE MEAN THROUGH 96H. OVERALL CONFIDENCE IN THE TRACK IS MEDIUM TRENDING TO LOW AFTER 72H. CONFIDENCE IN THE INTENSITY IS MEDIUM IN THE NEAR-TERM, TRENDING TO HIGH THEREAFTER.

19/00UTC.

HU 12E(LINDA). WARNING 36 ISSUED AT 19/04UTC. CURRENT INTENSITY IS 80KNOTS/CAT 1 AND IS FORECAST TO FALL BELOW 65KNOTS BY 18/24H.

HU 12E(LINDA). GUIDANCE.

19/00UTC.

ATLANTIC. HU 07L(GRACE). WARNING 23 ISSUED AT 19/03UTC. CURRENT INTENSITY IS 70KNOTS/CAT 1. THE CYCLONE IS FORECAST TO MAKE LANDFALL OVER THE YUCATAN PENINSULA WITHIN 12HOURS. FORECAST TO PEAK AT 75KNOTS/CAT 1 BY 21/00UTC.

HU 07L(GRACE). GUIDANCE.

TS 08L(HENRI). WARNING 13 ISSUED AT 19/03UTC. CURRENT INTENSITY IS 60KNOTS AND IS FORECAST TO PEAK AT 80KNOTS/CAT 1 BY 22/00UTC.

TS 08L(HENRI). GUIDANCE.