05W(DOKSURI) likely to rapidly intensify next 48h up to powerful CAT 4 US//05L(DON) peaked at CAT 1 US//Invest 91W/Invest 95L//2309utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TY 05W(DOKSURI).

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANALYSIS OF ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES THAT TYPHOON (TY) 05W (DOKSURI) HAS BEGUN TO RAPIDLY INTENSIFY. THE ANIMATED MSI SUGGESTS THAT THE VORTEX REMAINS SLIGHTLY TILTED, AS THE LOW LEVEL CIRCULATION CENTER (LLCC) CAN BE SEEN WITHIN THE BROAD, RAGGED EYE, DISPLACED SLIGHTLY WEST OF THE UPPER-LEVEL VORTEX CENTER. BUT THE INNER CORE IS RAPIDLY CONSOLIDATING AND UNDERGOING AXISYMMETRIZATION, TAKING ADVANTAGE OF A PERIOD OF LOW VERTICAL WIND SHEAR (VWS) AND STEADILY IMPROVING UPPER-LEVEL OUTFLOW. THE MSI SHOWS DEEP CONVECTION IS STILL SPOTTY AROUND THE NASCENT EYE FEATURE AND HAS AS OF THE 230700Z HOUR NOT YET FORMED A COHERENT EYEWALL, BUT ITS ALMOST THERE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE VISIBLE LOW-LEVEL STRUCTURE IN THE ANIMATED MSI. THE INITIAL INTENSITY AT 230600Z WAS ASSESSED WITH HIGH CONFIDENCE BASED ON T4.0 DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW, KNES AND RCTP, WITH ADDITIONAL SUPPORT FROM THE ADT ESTIMATE OF 65 KNOTS AND A DPRINT ESTIMATE OF 70 KNOTS. A HINT OF WHAT IS TO COME IS PROVIDED BY THE ADT RAW, WHICH AS OF 230700Z IS ALREADY UP TO T5.7. ANIMATED WATER VAPOR IMAGERY AND MESOSCALE ATMOSPHERIC MOTION VECTORS (AMVS) DEPICT DRAMATICALLY IMPROVED UPPER-LEVEL OUTFLOW, PARTICULARLY TO POLEWARD AS THE SYSTEM HAS DEVELOPED A POINT SOURCE OVER TOP OF THE SYSTEM, ENHANCED BY CONTINUED FLOW INTO THE TUTT-CELL THAT REMAINS NORTHEAST. OF NOTE, ANOTHER CUTOFF UPPER-LEVEL LOW IS SLIDING SOUTH OF 30N TO THE EAST OF JAPAN AT PRESENT. THE OUTFLOW OF TY 05W HAS NOT YET REACHED THAT FAR NORTH, BUT SOON WILL AND THEN THINGS WILL GET REALLY EXCITING. IN ADDITION TO THE ROBUST OUTFLOW ENVIRONMENT, THE SYSTEM SITS IN A POCKET OF LITTLE TO NO SHEAR AND IS MOVING OVER ZESTY 30C WATERS WITH HIGH OHC EXCEEDING 90 KJ PER CM2 AND GETTING HIGHER. TO SUM IT UP, CONDITIONS COULD NOT BE BETTER FOR NEAR-TERM RAPID INTENSIFICATION (RI).

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE ONSET OF RI HAS BEEN MOVED EARLIER IN THE FORECAST, THE PEAK INTENSITY HAS BEEN RAISED BY 10 KNOTS AND SHIFTED EARLIER IN THE FORECAST, WHILE THE TRACK CONTINUES TO WALK SOUTHWESTWARD. FORECAST DISCUSSION: TY 05W CONTINUES TO TRACK SLOWLY WESTWARD ALONG THE SOUTHERN SIDE OF THE STR TO THE NORTH. CONTRARY TO EARLIER FORECASTS, THE STR HAS NOT WEAKENED SIGNIFICANTLY, IN FACT IT REMAINS VERY FIRMLY ENTRENCHED FROM THE EAST COAST OF HONSHU ALL THE WAY TO SOUTHERN CHINA. HENCE, A GENERAL WESTWARD TRACK IS EXPECTED FOR THE NEXT 24 HOURS. A DEEP UPPER-LEVEL LOW IS MOVING ACROSS NORTHERN MANCHURIA AND DRAGGING A TROUGH ACROSS EASTERN CHINA. THE GLOBAL MODELS CONTINUE TO INSIST THIS TROUGH WILL ERODE THE STR ENOUGH TO GENERATE A BREAK IN THE RIDGE AFTER TAU 24, WHICH WILL INDUCE TY 05W NORTHWARD. HOWEVER, THERE REMAINS A LARGE DEGREE OF UNCERTAINTY INTO THE EXACT TIMING AND STRENGTH OF THE BREAK IN THE RIDGE AND THE SUBSEQUENT TRACK OF TY 05W. THE FORECAST CALLS FOR THE SYSTEM TO TURN NORTHWESTWARD BY TAU 36, CONTINUING ON THIS TRACK THROUGH THE REMAINDER OF THE FORECAST. ON THE CURRENT TRACK, LANDFALL ALONG THE SOUTHERN TIP OF TAIWAN IS ANTICIPATED BETWEEN TAU 72 AND TAU 96 FOLLOWED BY A TRACKING INTO EASTERN CHINA BY TAU 120. IN TERMS OF INTENSITY, THE REAL SHOW IS ABOUT TO BEGIN. ONCE THE OUTFLOW REACHES FAR ENOUGH NORTH TO ESTABLISH A CHANNEL INTO THE UPPER-LEVEL LOW CURRENTLY DIVING SOUTH OF 30N, THE SYSTEM WILL EMBARK UPON A PERIOD OF EXTREMELY RAPID INTENSIFICATION (ERI), FUELED BY THE ROBUST OUTFLOW, LOW SHEAR AND VERY WARM, HIGH OHC WATERS. THE CURRENT FORECAST CALLS FOR 60 KNOTS OF INTENSIFICATION IN THE NEXT 48 HOURS, PEAKING AT LEAST AS HIGH AS 125 KNOTS BY TAU 48. A HIGHER PEAK AND HIGHER RATE OF INTENSIFICATION IS A DISTINCT POSSIBILITY, DEPENDING ON HOW HIGH THE INTENSITY GETS BEFORE MOVING INTO AN AREA OF SLIGHTLY COOLER, LOWER OHC WATERS JUST AFTER TAU 48. THE SYSTEM IS EXPECTED TO WEAKEN SLIGHTLY PRIOR TO LANDFALL DUE TO REDUCTION IN THE OUTFLOW ALOFT AND SLIGHTLY INCREASED NORTHEASTERLY SHEAR BUT WILL STILL BE A VERY POWERFUL TYPHOON UPON LANDFALL.

MODEL DISCUSSION: WHILE THE MODEL ENVELOPE ITSELF HAS SHRUNK IN TERMS OF CROSS-TRACK SPREAD, WITH ABOUT 215NM SPREAD AT TAU 72, BOTH THE DETERMINISTIC TRACKERS AND THE ENSEMBLE MEANS CONTINUE THEIR STEADY WALK TO THE WEST WITH THIS MODEL RUN. THE MULTI-MODEL CONSENSUS MEAN NOW LIES OFF THE SOUTHWEST COAST OF TAIWAN, VERY CLOSE TO THE ECMWF DETERMINISTIC TRACKER WHILE THE GFS AND GEFS MEAN HAVE ALSO MOVED WEST BUT STILL LIE ON THE EASTERN SIDE OF THE CONSENSUS ENVELOPE. OF NOTE, THE ECMWF DETERMINISTIC TRACK NOW CLIPS THE NORTHEAST TIP OF LUZON AT TAU 60 BEFORE TURNING NORTH TOWARDS TAIWAN AND THE NAVGEM TRACKER PERSISTS IN TAKING THE SYSTEM INTO NORTH-CENTRAL LUZON. THE JTWC FORECAST SHIFTS WEST FROM THE PREVIOUS FORECAST BUT REMAINS ON THE EAST SIDE OF THE CONSENSUS MEAN THROUGH THE BULK OF THE FORECAST PERIOD. HOWEVER, IN LIGHT OF THE PERSISTENT WESTWARD DRIFT AND WIDE SPREAD IN THE ENSEMBLE MEMBERS, CONFIDENCE IN THE FORECAST TRACK REMAINS LOW, PARTICULARLY AFTER TAU 72. THE BULK OF THE INTENSITY GUIDANCE IS IN GOOD AGREEMENT ON A RI SCENARIO, WITH EVEN THE NORMALLY SLUGGISH DECAY-SHIPS JUMPING ON BOARD. ADDITIONAL CONFIDENCE IS PROVIDED BY THE 85 PERCENT RI PROBABILITY IN THE 230000Z COAMPS-TC ENSEMBLE RUN AND THE FACT THAT EVERY ONE OF THE AVAILABLE RI AIDS IS SHOWING EXTREMELY HIGH PROBABILITIES, BEYOND THAT SEEN IN ANY OTHER STORM TO DATE. THUS, THE JTWC INTENSITY FORECAST OF RI IS MADE WITH HIGH CONFIDENCE, THOUGH THE PEAK COULD BE EVEN HIGHER THAN CURRENTLY ANTICIPATED. CONFIDENCE IN THE INTENSITY FORECAST BEYOND TAU 72 IS MEDIUM DUE TO UNCERTAINTIES ASSOCIATED WITH VERY INTENSE TYPHOONS INCLUDING POTENTIAL EYEWALL REPLACEMENT CYCLES (EWRC).