07L(LAN) to landfall over HONSHU near 48h at Typhoon intensity//Long-lived TS 05E(DORA)//TS 07E(FERNANDA)//Invest 99E//1303utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON 07W(LAN) AND ON 05E(DORA).

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN 80 NM WIDE EYE WITH MULTIPLE MESOVORTICES ROTATING ABOUT A COMMON CENTER. THE COLD RING OF -60 TO -70 CELSIUS CLOUD TOPS HAS STRUGGLED TO FULLY CLOSE OFF AROUND THE EYE, BUT THE OVERALL CLOUD PATTERN HAS NOT DECAYED OVER THE PAST SIX HOURS AND HAS REMAINED STEADY IN PRESENTATION. UPPER-LEVEL OUTFLOW HAS BECOME MORE RADIAL, AS SOME EXPANSION POLEWARD IS NOW NOTED. THE INITIAL INTENSITY IS SET AT 70 KT BASED ON TWO COINCIDENT SAR PASSES THAT CAME IN AROUND 122030Z, BOTH OF WHICH SHOWED REPRESENTATIVE MAX WINDS OF ABOUT 70 KT IN THE NORTHEAST AND SOUTHWEST QUADRANTS.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TYPHOON 07W (LAN) CONTINUES TO EXHIBIT A VERY BROAD CORE RING OF MAXIMUM WINDS WITH A RADIUS OF 40 NM, OWING TO THE DEMOLITION OF THE INNER CORE BY REDUCED OCEAN HEAT FLUXES DURING THE PAST 24HOURS. LAN IS NOW MOVING INTO AN AREA OF SLIGHTLY HIGHER OCEAN HEAT CONTENT AS IT TRACKS NORTHWESTWARD NEAR THE EASTERN SIDE OF A DEEP WARM EDDY. THIS WILL LIKELY PREVENT FURTHER WEAKENING, AND MAY EVEN RESULT IN SLIGHT REINTENSIFICATION OF THE VORTEX AS IT TRACKS AROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE TOWARDS CENTRAL HONSHU. HOWEVER, THE BROAD NATURE OF THE VORTEX WILL LIKELY LIMIT THE PACE OF STRENGTHENING, IF ANY. DYNAMICAL MODELS ARE IN GOOD AGREEMENT ON THE LANDFALL LOCATION, BUT HAVE SHIFTED WESTWARD SLIGHTLY SINCE THE LAST CYCLE, AND THE JTWC TRACK FORECAST HAS FOLLOWED SUIT WITH A SLIGHT WESTWARD SHIFT. MODELS ARE IN GOOD AGREEMENT THAT LAN WILL CROSS HONSHU BETWEEN 48 AND 72 HOURS, EMERGING OVER THE SEA OF JAPAN AND TURNING NORTHEASTWARD. INTERACTION WITH UPPER-LEVEL TROUGHING OVER NORTHEASTERN CHINA AND A COOLER AIR MASS IS EXPECTED TO INITIATE EXTRATROPICAL TRANSITION DURING THE 96-120 HOUR PERIOD, COMPLETING BY 120 HOURS AS THE WARM CORE STRUCTURE OF THE STORM DISSOLVES.

MODEL DISCUSSION: THE JTWC TRACK FORECAST IS SLIGHTLY TO THE RIGHT OF THE MULTI-MODEL CONSENSUS, AND A LITTLE WEST OF THE PREVIOUS FORECAST. THE JTWC INTENSITY FORECAST IS CLOSE TO THE MULTI-MODEL CONSENSUS AND IS SIMILAR TO THE PREVIOUS FORECAST.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT DORA CONTINUES TO DECAY, WITH SOUTHWESTERLY VERTICAL SHEAR OF AROUND 20 KT PERIODICALLY CAUSING THE LOW-LEVEL CIRCULATION CENTER (LLCC) TO BECOME EXPOSED SOUTHWEST OF THE DEEP CONVECTION. CONVECTION IS NOW BURSTING PERIODICALLY OVER THE COMPACT LLCC, A TYPICAL PATTERN OF SHEARED TROPICAL CYCLONES. THE INITIAL INTENSITY IS LOWERED TO 55 KT BASED ON AGENCY DVORAK ESTIMATES. NO RECENT SCATTEROMETER OR SAR DATA IS AVAILABLE.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL STORM DORA (05E) CONTINUES TO DECAY IN THE FACE OF 20 KT SOUTHWESTERLY VERTICAL SHEAR. WEAKENING IS EXPECTED TO CONTINUE FOR THE NEXT 36 HOURS OR SO AS THIS SHEAR PERSISTS AHEAD OF AN UPPER-LEVEL LOW THAT HAS CUT OFF 680 NM TO THE NORTHWEST OF DORA. THE SUBTROPICAL RIDGE TO THE NORTHEAST WILL CONTINUE TO GUIDE DORA WEST-NORTHWESTWARD TO NORTHWESTWARD DURING THAT TIME. AFTER 36-48 HOURS, A TURN NORTHWARD IS EXPECTED AS DORA NEARS THE AFOREMENTIONED UPPER-LEVEL LOW AND ROUNDS THE WESTERN FLANK OF THE SUBTROPICAL RIDGE. BY THIS POINT, DORA'S TRACK AND INTENSITY WILL BE STRONGLY LINKED, AS A STRONGER STORM WOULD TRACK FARTHER EAST AND REMAIN EAST OF THE UPPER-LEVEL LOW, SUCH AS IN THE GFS MODEL. THIS WOULD BRING DORA INTO A REGION OF LOWER VERTICAL SHEAR AS THE UPPER-LEVEL FLOW BACKS TO SOUTHERLY OR SOUTHEASTERLY, AND THE UPSHEAR ENVIRONMENT WOULD MOISTEN, FACILITATING A PERIOD OF REINTENSIFICATION. ON THE OTHER HAND, THERE REMAINS A CHANCE THAT DORA DISSIPATES BEFORE THIS OPPORTUNITY TO REINTENSIFY, AS SHOWN BY THE ECMWF MODEL. THE JTWC FORECAST CONTINUES TO LEAN TOWARDS A MORE RIGHTWARD TRACK WITH SOME REINTENSIFICATION DURING THE 48-96 HOUR PERIOD, AS THE ECMWF INITIALIZES DORA WEAKER THAN IT ACTUALLY IS, LEADING TO EARLY DISSIPATION. THE TRACK AND INTENSITY FORECASTS ARE OF LOW CONFIDENCE IN THE 72-120 HOUR PERIOD DUE TO UNCERTAINTY IN WHETHER DORA WILL SURVIVE THAT LONG, AS WELL AS HOW QUICKLY IT WILL BE PULLED NORTHEASTWARD ALONG A FRONTAL BOUNDARY THAT IS FORECAST TO BE DRAPED ACROSS THE NORTHERN PACIFIC BETWEEN 30N AND 40N DURING THAT PERIOD. THIS FORECAST IS SLOWER THAN THE PREVIOUS ONE AT 96-120 HOURS. EXTRATROPICAL TRANSITION IS FORECAST TO BEGIN BY 120 HOURS DUE TO THE INTERACTION WITH THIS FRONT.

MODEL DISCUSSION: THE JTWC FORECAST TRACK IS A BIT EAST OF THE MULTI-MODEL CONSENSUS, LEANING TOWARDS THE GFS AND GFS ENSEMBLE DUE TO THEIR BETTER REPRESENTATION OF DORA'S INTENSITY. THE JTWC INTENSITY FORECAST IS CLOSE TO THE MEAN OF THE GFS, HAFS, AND COAMPS-TC SOLUTIONS.

1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 160 NM EITHER SIDE OF A LINE FROM 11.5N 140.7W TO 9.3N 133.2W WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO BE 18 TO 23 KNOTS. METSAT IMAGERY AT 121200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 9.3N 133.5W. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 10 KNOTS. 2. REMARKS: AN AREA OF CONVECTION HAS PERSISTED NEAR 9.6N 133.3W, 1629 NM SOUTHWEST OF SAN DIEGO, CA. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY AND A 121536Z SSMIS 91GHZ IMAGE REVEAL AN ELONGATED LOW LEVEL CIRCULATION (LLC) WITH DISORGANIZED SCATTERED CONVECTION. ANALYSIS INDICATES A FAVORABLE ENVIRONMENT FOR DEVELOPMENT DEFINED BY GOOD POLEWARD OUTFLOW, WEAK VERTICAL WIND SHEAR (10-15 KTS), AND WARM (28C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 99E WILL TRACK NORTHWESTWARD OVER THE NEXT 48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.