TY 20W(MINDULLE) CAT 2 likely to re-intensify next 48h// Altantic:Hurricane 18L(SAM) CAT 3 forecast to remain strong next 96h,27/15utc

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: THE DEVELOPMENT OF A FAIRLY STRONG UPPER-LEVEL CYCLONE EAST OF JAPAN AND THE PASSAGE OF THE ASSOCIATED UPPER-LEVEL TROUGH CONTINUES TO ERODE THE EXTENSION OF THE SUBTROPICAL RIDGE(STR) LYING ALONG THE 30TH PARALLEL. NOW THAT THE RIDGE TO THE NORTH IS RETREATING, THE BUILDING STR CENTERED NEAR GUAM IS QUICKLY ESTABLISHING DOMINANCE OVER THE STEERING OF TY 20W. IN RESPONSE, TY 20W IS SLOWLY BUT STEADILY STARTING TO TRACK TOWARDS THE NORTHWEST. OVER THE NEXT 48 HOURS THE TRACK WILL SLOWLY TURN TO THE NORTH AS THE RIDGE TAKES ON A MORE NORTH-SOUTH AXIS AND MOVES NORTH ALONG WITH TY 20W. AFTER 48H TY 20W WILL ACCELERATE TO THE NORTHEAST AHEAD OF AN APPROACHING MID-LATITUDE TROUGH MOVING IN FROM THE WEST. TY 20W HAS BOTTOMED OUT FROM AN INTENSITY PERSPECTIVE AND NOW THAT ITS MOVING AWAY FROM THE UPWELLING INDUCED COLD POOL, WILL HAVE ENOUGH OF AN ENERGY SOURCE THAT, WHEN COMBINED WITH LOW SHEAR AND STRONG OUTFLOW, WILL FUEL A PERIOD OF INTENSIFICATION THROUGH 48H. THEREAFTER, SHEAR AND DRY AIR IN THE MID-LEVELS WILL LEAD TO SLOW WEAKENING THROUGH 72H. SHEAR DRAMATICALLY INCREASES AFTER 72H, AND COMBINED WITH COOLER WATERS, WILL LEAD TO MORE RAPID WEAKENING THROUGH THE REMAINDER OF THE FORECAST. THE SYSTEM IS EXPECTED TO BEGIN EXTRATROPICAL TRANSITION (ETT) AROUND 84H AND SHOULD BE COMPLETE ETT AS A STORM FORCE LOW PRESSURE AREA NO LATER THAN 120H, BUT LIKELY BY 108H AS IT MOVES UNDER A 500 MB SHORTWAVE, AND DEVELOPS THERMAL ADVECTION AND FRONTAL CHARACTERISTICS.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TY 20W HAS COMPLETED OR NEARLY COMPLETED AN EYEWALL REPLACEMENT CYCLE, WITH A 270700Z SSMIS 89GHZ MICROWAVE IMAGE CONFIRMING THE DISSIPATION OF THE INNER EYEWALL AND THE DEVELOPMENT OF A MUCH LARGER, BUT FRAGMENTED EYEWALL ABOUT 140 KM FROM THE CENTER. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AT THE 1200Z DEPICTS DEEP CONVECTION DEVELOPING IN THE WESTERN PORTION OF THE OUTER EYEWALL, AND THE EYEWALL DIAMETER BEGINNING TO CONSTRICT ONCE MORE. THE PRESENCE OF DEEP CONVECTION IN THE EYEWALL FOR THE FIRST TIME IN ABOUT 36 HOURS LIKELY MEANS THAT THE SYSTEM IS MOVING OUT OF THE COLD POOL OF UPWELLED WATER AND INTO MORE FAVORABLE OCEANOGRAPHIC CONDITIONS. NOW THAT THE ERC HAS EVIDENTLY FINISHED, THE SYSTEM HAS LIKELY REACHED THE BOTTOM OF THE INTENSITY BARREL. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE BROAD EYE FEATURE IN THE EIR AND AMONGST THE TIGHTLY CLUSTERED AGENCY FIX POSITIONS. THE INITIAL INTENSITY IS ASSESSED AT 90 KNOTS/CAT 2 WITH HIGH CONFIDENCE BASED ON THE CONGRUENCE OF AGENCY CURRENT INTENSITY ESTIMATES WHICH ALIGN NICELY WITH THE ADT AND SATCON ESTIMATES. ENVIRONMENTAL CONDITIONS ARE IMPROVING NOW THAT THE SYSTEM IS MOVING AWAY FROM THE COLD POOL. WHILE OHC VALUES ON THE ROAD AHEAD ARE NOTHING TO WRITE HOME ABOUT, THEY ARE FAVORABLE, ESPECIALLY FOR A SYSTEM THAT IS MOVING STEADILY DOWN TRACK. OTHERWISE THE ENVIRONMENT REMAINS FAVORABLE FOR DEVELOPMENT.

ERC HAS COMPLETED. SATELLITE SIGNATURE IS GRADUALLY IMPROVING WITH CONVECTION INTENSIFYING AROUND THE EYE FEATURE.

MODEL DISCUSSION: TRACK GUIDANCE IS IN REMARKABLY GOOD AGREEMENT WITH A SPREAD OF ONLY 185 KM AT 72H, INCREASING TO A MODEST 370 KM AT 120H. ALONG-TRACK SPREAD DOES INCREASE A FAIR AMOUNT AFTER 96H, REACHING 880 KM BY 120H. BUT THE MAJORITY OF THIS SPREAD IS ACCOUNTED FOR BY THE UNREALISTICALLY PROGRESSION OF THE SYSTEM AFTER 72H AS DEPICTED BY THE NAVGEM. IF ONE DISCOUNTS NAVGEM, THE ALONG TRACK SPREAD DECREASES TO ABOUT 610 KM. THE JTWC FORECAST REMAINS CONSISTENT WITH THE PREVIOUS FORECAST, JUST INSIDE AND SLIGHTLY SLOWER THAN THE CONSENSUS MEAN, WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT ON THE OVERALL SCENARIO, WITH ALL MEMBERS EXCEPT COAMPS-TC TIGHTLY CLUSTERED IN A 30 KM/H ENVELOPE. THE JTWC FORECAST LIES ROUGHLY FIVE KNOTS ABOVE THE MEAN THROUGHOUT THE FORECAST WITH MEDIUM CONFIDENCE.

CURRENT INTENSITY IS 110KNOTS/CAT 3 AND IS FORECAST TO REMAIN STEADY NEXT 96H.

HU 18L(SAM). TRACK AND INTENSITY GUIDANCE.

27/15UTC.