WPAC: LAN - Post-Tropical

[cycloneye]

WDPN31 PGTW 090900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (LAN) WARNING NR
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 24.5N 146.0E
INITIAL INTENSITY: 55 KTS
GEOGRAPHIC REFERENCE: 257 NM EAST OF IWO TO
MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDS
OF DEEP CONVECTION WRAPPING INTO AND OBSCURING THE LOW-LEVEL
CIRCULATION CENTER (LLCC). MSI ALSO SHOWS EXTENSIVE WELL-DEFINED
LOW-LEVEL CLOUD LINES WRAPPING IN ON THE SOUTHERN SEMICIRCLE. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE
GROUPING OF AGENCY POSITION FIXES. ENVIRONMENTAL CONDITIONS REMAIN
FAVORABLE FOR INTENSIFICATION DUE TO WARM (30-31C) SEA SURFACE
TEMPERATURES (SSTS), LOW (0-5 KNOTS) VERTICAL WIND SHEAR (VWS), AND
GOOD DUAL OUTFLOW ALOFT. THE INITIAL INTENSITY OF 55 KNOTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK
ESTIMATES FROM PGTW AND KNES AND AUTOMATED DVORAK ESTIMATES.

INITIAL WIND RADII BASIS: PERSISTENCE

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTHEAST.


AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.5 - 55 KTS
RJTD: T3.0 - 45 KTS
KNES: T3.5 - 55 KTS
CIMSS ADT: 45 KTS AT 090540Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 0-5 KTS
SST: 30-31 CELSIUS
OUTFLOW: STRONG EQUATORWARD
OTHER FACTORS: STRONG EASTWARD OUTFLOW INTO A TUTT CELL.

ANALYSIS CONFIDENCE:
INITIAL POSITION: MEDIUM
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: OVER THE NEXT 24 HOURS, TS 07W IS FORECAST TO
TRACK NORTHWESTWARD ON THE SOUTHWESTERN PERIPHERY OF THE
DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST.
BY TAU 36, TS 07W WILL SLOW AND TURN NORTH-NORTHWESTWARD AS A
MID-LATITUDE TROUGH TO THE NORTH WILL WEAKEN AND REORIENT THE
DEEP-LAYERED STR. BY TAU 48, THE STR IS EXPECTED TO EXTEND WESTWARD
WHICH WILL ACCELERATE AND STEER 07W NORTHWESTWARD TOWARD YOKOSUKA,
JAPAN. IN TERMS OF INTENSITY, THE FAVORABLE ENVIRONMENT WILL FUEL A
STEADY INTENSIFICATION TO A PEAK OF 90KTS BETWEEN TAUS 36-48.
AFTERWARD, COOLING SSTS DUE TO UPWELLING IN RELATIVELY SHALLOW
WATERS NEAR THE COAST OF HONSHU WILL GRADUALLY WEAKEN THE SYSTEM,
DOWN TO 75 KNOTS BY TAU 120.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE ARE IN OVERALL GOOD
AGREEMENT THROUGH TAU 72, WITH ONLY A 103 NM SPREAD IN MODEL TRACK
SOLUTIONS. BY TAU 120 THE MODEL TRACK SPREAD INCREASES SLIGHTLY TO
200 NM. THIS LENDS OVERALL HIGH CONFIDENCE TO THE JTWC TRACK
FORECAST THROUGH TAU 72, WITH MEDIUM CONFIDENCE BY TAU 120.
INTENSITY GUIDANCE REMAINS IN FAIR AGREEMENT WITH A STEADY
INTENSIFICATION TO A PEAK OF 90 KNOTS. OVERALL, THE JTWC INTENSITY
FORECAST IS ASSESSED WITH MEDIUM CONFIDENCE AND FOLLOWS CLOSELY TO
THE MULTI-MODEL CONSENSUS.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: HIGH
TRACK 72-120 HR: MEDIUM
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//

[Sciencerocks]

[cycloneye]

WDPN31 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (LAN) WARNING NR
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 24.7N 145.3E
INITIAL INTENSITY: 55 KTS
GEOGRAPHIC REFERENCE: 218 NM EAST OF IWO TO
MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 07 KTS
SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS MULTIPLE
DEEP CONVECTIVE BANDS SURROUNDING THE CENTER AND OBSCURING THE
LOW-LEVEL CIRCULATION CENTER (LLCC). WATER VAPOR IMAGERY ALSO
INDICATES EQUATORWARD OUTFLOW AND EASTWARD OUTFLOW INTO A TUTT CELL
TO THE EAST. THUS, ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE
GROUPING OF AGENCY POSITION FIXES. THE INITIAL INTENSITY OF 55 KTS
IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A CONSENSUS OF
SUBJECTIVE DVORAK AND AUTOMATED SATELLITE INTENSITY DATA AS WELL AS
A 090817Z SAR WIND SPEED IMAGE. ENVIRONMENTAL CONDITIONS REMAIN
FAVORABLE FOR INTENSIFICATION DUE TO WARM (30-31C) SEA SURFACE
TEMPERATURES (SST), LOW (0-5 KNOTS) VERTICAL WIND SHEAR (VWS), AND
GOOD OUTFLOW ALOFT.

INITIAL WIND RADII BASIS: PERSISTENCE

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTHEAST.


AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T3.5 - 55 KTS
RCTP: T3.5 - 55 KTS
KNES: T3.5 - 55 KTS
CIMSS ADT: 49 KTS AT 091140Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 0-5 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE EQUATORWARD
OTHER FACTORS: MODERATE EASTWARD OUTFLOW INTO A TUTT CELL.

ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: HIGH
INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS 07W (LAN) WILL TRACK NORTHWESTWARD ALONG
THE SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE
(STR) POSITIONED TO THE NORTHEAST THROUGH TAU 24. BY TAU 36, THE
STR WILL SHIFT EAST AND ERODE SLIGHTLY AS A MID-LATITUDE TROUGH
PROPAGATES EASTWARD NORTH OF HOKKAIDO. BY TAU 48, THE STR WILL
REORIENT WHICH WILL GENERALLY ACCELERATE THE SYSTEM
NORTH-NORTHWESTWARD WITHIN THE ENHANCED FLOW ON THE WESTERN
PERIPHERY OF THE RIDGE. BY TAU 72, THE STR IS EXPECTED TO EXTEND
WESTWARD WHICH WILL THEN STEER 07W NORTHWESTWARD TOWARD YOKOSUKA,
JAPAN THROUGH THE END OF THE FORECAST. IN TERMS OF INTENSITY, THE
FAVORABLE ENVIRONMENT WILL FUEL A STEADY INTENSIFICATION TO A PEAK
OF 85KTS BETWEEN TAUS 48-72. AFTERWARD, COOLING SSTS DUE TO
UPWELLING IN RELATIVELY SHALLOW WATERS NEAR THE COAST OF HONSHU
WILL GRADUALLY WEAKEN THE SYSTEM, DOWN TO 65 KNOTS BY TAU 120.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT WITH A 135NM SPREAD IN SOLUTIONS AT TAU 72. AFTER TAU 72,
GUIDANCE GRADUALLY DIVERGES WITH A 233 NM SPREAD IN SOLUTIONS AND
RESULTS IN SOME CROSS-TRACK UNCERTAINTY BY TAU 120. BOTH THE
090600Z ECMWF (EPS) AND GFS (GEFS) ENSEMBLES DEPICT A SIMILAR
SPREAD WITH MODERATE UNCERTAINTY (MEDIUM CONFIDENCE IN THE JTWC
FORECAST TRACK) IN THE EXACT TRACK NEAR HONSHU. THIS LENDS OVERALL
HIGH CONFIDENCE TO THE JTWC TRACK FORECAST THROUGH TAU 72, WITH
MEDIUM CONFIDENCE BY TAU 120. THE INTENSITY GUIDANCE REMAINS IN
FAIR AGREEMENT WITH A STEADY INTENSIFICATION TO A PEAK OF 85 KNOTS.
ADDITIONALLY, AS INDICATED IN THE 091200Z COAMPS-TC ENSEMBLE, RAPID
INTENSIFICATION (RI) IS POSSIBLE WITHIN THE NEXT 36-48 HOURS WITH
PEAK PROBABILITIES OF 60 TO 80 PERCENT. OVERALL, THE JTWC INTENSITY
FORECAST IS ASSESSED WITH MEDIUM CONFIDENCE AND FOLLOWS CLOSELY TO
THE MULTI-MODEL CONSENSUS.


FORECAST CONFIDENCE:
TRACK 0 - 72 HR: HIGH
TRACK 72-120 HR: MEDIUM
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN

[cycloneye]

WDPN31 PGTW 092100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (LAN) WARNING NR
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 25.1N 144.6E
INITIAL INTENSITY: 60 KTS
GEOGRAPHIC REFERENCE: 123 NM NORTHEAST OF IWO TO
MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 06 KTS
SIGNIFICANT WAVE HEIGHT: 28 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM LAN HAS NOT INTENSIFIED VERY MUCH DURING THE PAST
TWELVE HOURS DESPITE GOING THROUGH THE DIRUNAL MAXIMUM PERIOD.
ANIMATED PROXY VIS IMAGERY SHOWS AND OPEN CENTER WITH A
DISCONTINUOUS BUT DEVELOPING EYEWALL. THERE IS A DEARTH OF DEEP
CONVECTION OVER THE NORTHERN SEMICIRCLE BUT THE ABUNDANT DEEP
CONVECTION OVER THE SOUTHWEST QUADRANT IS SHOWING THE EARLY SIGNS
OF WRAPPING INTO THE NORTHERN SEMICIRCLE AND ENCIRCLING THE CORE.
THERE IS SIGNIFICANT DRY AIR ENTRAINMENT WRAPPING IN FROM THE
NORTHWEST EVIDENT IN TOTAL PRECIPITABLE WATER LOOPS AND 700-300MB
MOISTURE ANALYSES. SATELLITE ANIMATION VERIFIES AN ASYMMETRIC
CIRCULATION WITH THE BULK OF THE DEEP CONVECTION OCCURRING OVER THE
SOUTHWEST QUADRANT. TS 07W IS TRACKING THROUGH A LOW SHEAR
ENVIRONMENT WITH 30-31C SEA SURFACE TEMPERATURES. ANIMATED WATER
VAPOR IMAGERY SHOWS THE LOW LEVEL CIRCULATION PULLING AWAY FROM
WHAT WAS AN EXCELLENT POLEWARD OUTFLOW CHANNEL, BUT A WEAK
EQUATORWARD CHANNEL PERSISTS. THE SYSTEM IS BEING DRIVEN POLEWARD
BY THE SOUTHWESTERN FLANK OF THE SUBTROPICAL RIDGE. THE RIDGE IS
ANCHORED IN A 595DM 500MB HEIGHT CENTER NEAR 25N 170W, WITH A LONG
EXTENSION THAT CROSSES NORTHERN HONSHU. THAT LONG AND STRONG RIDGE
IS PREVENTING RECURVATURE AND FORCING THE SYSTEM TOWARDS MAINLAND
JAPAN.

INITIAL WIND RADII BASIS: PERSISTENCE FROM A 090817Z SAR PASS.

CURRENT STEERING MECHANISM: THE WESTERN FLANK OF THE SUBTROPICAL
RIDGE.

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T4.0 - 65 KTS
RJTD: T3.5 - 55 KTS
RCTP: T4.0 - 65 KTS
KNES: T4.0 - 65 KTS
CIMSS ADT: 53 KTS AT 091740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 5-10 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: HIGH
INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: A BALANCE OF FAVORABLE AND UNFAVORABLE
ENVIRONMENTAL CONDITIONS WILL KEEP TS 07W INTENSIFYING NEAR A
CLIMATOLOGICAL RATE. THE DEEP LAYER STEERING RIDGE TO THE WEST OF
THE SYSTEM WILL FORCE THE SYSTEM TO REMAIN ON A POLEWARD TRACK.
SUBSTANTIAL DRY AIR UPSTREAM WILL IMPEDE THE SYSTEM FROM SHARP
INTENSIFICATION, BUT SEA SURFACE TEMPERATURES AVERAGING 29C WILL
SUPPORT THE SYSTEM ALMOST TO LANDFALL. THE KUROSHIO CURRENT IS VERY
NEAR THE COAST WITH ONLY A SHORT ZONE OF COOL WATERS PRIOR TO
LANDFALL. VERTICAL WINDSHEAR WILL ALSO REMAIN BELOW 20 KNOTS
THROUGH THE ENTIRE TRACK. DRY AIR AND SUBSIDENCE UNDERNEATH AN
UPPER LEVEL ANTICYCLONE OVER NORTHERN HONSHU WILL RESTRICT OUTFLOW.
TRACK GUIDANCE THUS FAR HAS BEEN IN GOOD AGREEMENT REGARDING
LANDFALL BETWEEN WAKAYAMA AND CHIBA PREFECTURES, WITH IZU NOW IN
THE CENTER OF THE TRACK. THERE IS GOOD CONFIDENCE THAT THE SYSTEM
WILL MAKE LANDFALL WELL ABOVE TYPHOON STRENGTH BUT BELOW 100 KNOTS
AND IMPACT THE KANTO PLAIN AND YOKOSUKA AREA.

MODEL DISCUSSION: ALONG TRACK SPREAD INCREASED OVER THE PAST RUN
BUT CROSS TRACK SPREAD IS MINIMAL. THE TRACK IS EXPECTED TO
INCREASINGLY FOCUS IN ON A LAND STRIKE THAT WILL IMPACT THE KANTO
PLAIN. INTENSITY GUIDANCE IS TIGHTER AGREEMENT THAN NORMAL. THE
JTWC TRACK FORECAST STAYS CLOSE TO THE MULTI MODEL CONSENSUS WHILE
FAVORING THE ENSEMBLE MEANS WHILE THE INTENSITY FORECAST FAVORS THE
HAFS AND HWRF GUIDANCE TO STAY A LITTLE ABOVE CONSENSUS.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: MEDIUM
TRACK 72-120 HR: LOW
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: LOW//
NNNN

[Sciencerocks]

[cycloneye]

WDPN31 PGTW 100300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (LAN) WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 25.2N 143.9E
INITIAL INTENSITY: 65 KTS
GEOGRAPHIC REFERENCE: 143 NM EAST OF IWO TO
MOVEMENT PAST 6 HOURS: WESTWARD AT 06 KTS
SIGNIFICANT WAVE HEIGHT: 30 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY OVER THE PAST SIX HOURS
SHOWS A SUBSTANTIAL INCREASE IN ORGANIZATION AND CONSOLIDATION
WITHIN THE CORE OF TYPHOON 07W (LAN). DEEP CONVECTION HAS
COMPLETELY ENCIRCLED THE LOW-LEVEL CIRCULATION AND AN EYE HAS
DEVELOPED. THE SYSTEM IS ALSO SHOWING IMPROVED SYMMETRY. ANIMATED
WATER VAPOR IMAGERY SHOWS THE SYSTEM IS STILL BENEFITING FROM
IMPROVED OUTFLOW TO THE NORTHEAST BUT IT IS MOVING AWAY FROM THE
EQUATORWARD OUTFLOW CHANNEL. DRY AIR ENTRAINMENT IS DECREASING.
THE CURRENT INTENSITY ASSESSMENT IS BASED ON A JTWC DVORAK
ASSESSMENT OF T4.0. THE JMA ESTIMATE IS LOWER BUT BOTH RCTP AND
KNES ARE UP TO T4.5. CIMSS OBJECTIVE GUIDANCE SUCH AS ADT AND AIDT
AND DPRINT ARE ALSO HIGHER AS THEY HAVE BEEN FOR SEVERAL CYCLES. IT
WAS TEMPTING FOR A MOMENT TO GO ABOVE THE JTWC DVORAK DUE
TO THE IMPROVED LOOK IN SATELLITE ANIMATION BUT A 092008Z SAR AND A
092025Z SMAP PASS AS WELL AS THE DMINT DATA CONFIRM THE VALIDITY OF
THE JTWC DVORAK. TS 07W IS TRACKING THROUGH A LOW SHEAR ENVIRONMENT
WITH 30-31C SEA SURFACE TEMPERATURES AND THE WATER REMAINS WARM ALL
THE WAY TO WITHIN 50NM OF THE COAST OF HONSHU. THE SYSTEM IS BEING
STEERED POLEWARD BY THE SOUTHWESTERN FLANK OF THE SUBTROPICAL RIDGE,
WHICH EXTENDS FROM A 595DM 500MB HEIGHT CENTER NEAR 25N 170W ALL THE
WAY ACROSS NORTHERN HONSHU.

INITIAL WIND RADII BASIS: SMAP DATA FROM 092008Z.

CURRENT STEERING MECHANISM: THE WESTERN FLANK OF THE SUBTROPICAL
RIDGE.

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T4.0 - 65 KTS
RJTD: T3.5 - 55 KTS
RCTP: T4.5 - 77 KTS
KNES: T4.5 - 77 KTS
CIMSS ADT: 74 KTS AT 092330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 5-10 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
INITIAL POSITION: MEDIUM
INITIAL INTENSITY: HIGH
INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TYPHOON LAN WILL STEADILY INTENSIFY AT A
CLIMATOLOGICAL RATE ALONG ITS POLEWARD TRACK. THE DEEP LAYER
STEERING RIDGE TO THE WEST OF THE SYSTEM WILL PREVENT RECURVATURE
AND FORCE THE SYSTEM TO REMAIN ON A POLEWARD TRACK. THERE IS GOOD
CONFIDENCE THAT THE SYSTEM WILL MAKE LANDFALL WELL ABOVE TYPHOON
STRENGTH BUT BELOW 100 KNOTS AND IMPACT THE KANTO PLAIN AND
YOKOSUKA AREA. A BALANCE OF FAVORABLE AND UNFAVORABLE ENVIRONMENTAL
CONDITIONS WILL ALLOW TY 07W TO INTENSIFY AT A NEAR CLIMATOLOGICAL
RATE. SUBSTANTIAL SUBSIDENCE AND DRY AIR NORTH OF THE 30TH
LATITUDE WILL CAP THE SYSTEM AT UNDER 100KTS AND PREVENT RAPID
INTENSIFICATION. 29-31C DEGREE SEA WATERS AND LOW VERTICAL WIND
SHEAR EXIST ALL THE WAY UP TO NEAR THE COAST. THE KUROSHIO CURRENT
IS VERY NEAR THE COAST WITH ONLY A SHORT ZONE OF COOL WATERS PRIOR
TO LANDFALL SO THE SYSTEM IS EXPECTED TO MAKE LANDFALL AT WELL
ABOVE TYPHOON STRENGTH.

MODEL DISCUSSION: BOTH ALONG TRACK AND CROSS TRACK SPREAD HAVE
INCREASED OVER THE PAST TWO CYCLES BUT THE GUIDANCE CONTINUES TO
POINT TO A LANDFALL BETWEEN THE WAKAYAMA AND CHIBA PENINSULAS.
TIMING IS A GREATER CONCERN DUE TO THE UNSTEADY ALONG TRACK SPREAD.
WITH EACH PASSING CYCLE THE GUIDANCE SHOULD FOCUS MORE TIGHTLY.
THE JTWC TRACK FORECAST STAYS NEAR THE ENSEMBLE MEANS AND THE MULTI
MODEL CONSENSUS. THE INTENSITY FORECAST STAYS NEAR THE MEAN FOR
THE FIRST 36 HOURS THAN RIDES ABOUT TEN KNOTS HIGHER DUE AS IT
SPLITS THE MEAN BETWEEN THE HIGHER SKILLED HFAS AND HWRF MESOSCALE
AND COUPLED MODELS.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: MEDIUM
TRACK 72-120 HR: MEDIUM
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN

[Sciencerocks]

 https://twitter.com/VortixWx/status/1689459284612931585

[Hayabusa]

T2307(Lan)
Issued at 2023/08/10 06:50 UTC
Analysis at 08/10 06 UTC
Grade TY
Scale -
Intensity -
Center position N25°30′ (25.5°)
E143°30′ (143.5°)
Direction and speed of movement WNW 10 km/h (6 kt)
Central pressure 970 hPa
Maximum sustained wind speed near center 35 m/s (65 kt)
Maximum wind gust speed 50 m/s (95 kt)
Radius of 50-kt wind area 130 km (70 NM)
Radius of 30-kt wind area NE650 km (350 NM)
SW330 km (180 NM)

[MarioProtVI]

Apparently JTWC thinks this is “only” 75 kt. The worst take I’ve ever heard from them. They’re at least 50-60 kt off on this.

[Sciencerocks]

100 knots in my opinion. I'd like to see the colder convection wrap to be any stronger around to the northwest and west side.

[cycloneye]

WDPN31 PGTW 101500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (LAN) WARNING NR 012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 26.0N 143.2E
INITIAL INTENSITY: 75 KTS
GEOGRAPHIC REFERENCE: 85 NM SOUTHEAST OF CHICHI JIMA
MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 06 KTS
SIGNIFICANT WAVE HEIGHT: 32 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A COMPACT
YET INTENSE TYPHOON STRENGTH CIRCULATION WITH A LARGE (33NM) EYE.
OVER
THE PAST SEVERAL HOURS, THE ONCE CLOUDY EYE IS NOW MOSTLY CLEAR,
RESULTING IN WARMING EYE TEMPERATURES (10C TO 17C). A 100834Z SSMIS
89GHZ COLOR COMPOSITE MICROWAVE IMAGE REVEALS A ROBUST EYE WALL HAS
FORMED WITH NUMEROUS FEEDER BANDS OF CONVECTION IN ALL QUADRANTS
AROUND IT. A RECENT 101130Z ASCAT-B SCATTEROMETERY PASS INDICATES A
TIGHT AND MOSTLY SYMMETRIC WIND FIELD, SLIGHTLY FAVORING THE
NORTHEASTERN QUADRANT. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON EIR, SSMIS AND SCATTEROMETERY DATA. THE INITIAL
INTENSITY OF 75 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON
AGENCY DVORAK INTENSITY ESTIMATES WHICH MOSTLY SUPPORT 75KTS, WHILE
THE BULK OF THE REMAINING AUTOMATED INTENSITY ESTIMATES ARE
SUSPICIOUSLY HIGH, IN MOST CASES HOVERING NORTH OF 100KTS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR)

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T4.5 - 77 KTS
RJTD: T5.0 - 90 KTS
RCTP: T5.0 - 90 KTS
KNES: T5.5 - 102 KTS
CIMSS ADT: 115 KTS AT 101130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 5-10 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE EASTWARD

ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TY 07W (LAN) IS FORECAST TO CONTINUE TRACKING
NORTH-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE
EAST. OVER THE NEXT 36 HOURS, FUELED BY LOW VERTICAL WIND SHEAR,
WARM SEA SURFACE TEMPERATURES AND VIGOROUS OUTFLOW ALOFT, 07W IS
FORECAST TO REACH A PEAK INTENSITY NEAR 95KTS. AS THE STR TO THE
EAST REORIENTS AND SHIFTS, TRACK SPEEDS WILL INCREASE AS THE SYSTEM
PASSES 30N. BY TAU 72, SUBSTANTIAL DRY AIR AND SUBSIDENCE ALOFT
WILL CONSPIRE TO GRADUALLY WEAKEN THE SYSTEM AS IT STEADIES UP ON A
COLLISION COURSE WITH MAINLAND JAPAN. BASED ON THE OTHERWISE
FAVORABLE CONDITIONS OF THE SSTS AND SHEAR VALUES, 07W IS FORECAST
TO MAKE LANDFALL AS A TYPHOON, PROCEEDING INLAND AND IMPACTING THE
ISLAND OF HONSHU AND YOKOSUKA AREAS.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH ALL
MEMBERS GENERALLY FOLLOWING THE JTWC FORECAST TRACK AND IMPACTING
JAPAN BY TAU 100 WESTWARD OF TOKYO. THERE IS A SLIGHT AMOUNT OF
CROSS TRACK SPREADING WITH TIME, THOUGH NOT AS MUCH AS LAST CYCLE,
WITH THE BULK OF THE MEMBERS STILL CLOSELY FOLLOWING THE
MULTI-MODEL CONSENSUS. FOR THIS REASON THE JTWC TRACK FORECAST IS
PLACED WITH OVERALL MEDIUM CONFIDENCE. RELIABLE MODEL INTENSITY
GUIDANCE IS IN GOOD AGREEMENT WITH ALL MEMBERS INTENSIFYING THE
SYSTEM THROUGH TAU 36, AFTER WHICH A GRADUAL WEAKENING TREND
THROUGH LANDFALL. FOR THIS REASON THE JTWC INTENSITY FORECAST IS
ALSO PLACED WITH OVERALL MEDIUM CONFIDENCE.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: MEDIUM
TRACK 72-120 HR: MEDIUM
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: MEDIUM//
NNNN

[InfernoFlameCat]

why does it say only 75 knots when this looks like 120 knots?

[Sciencerocks]

~115knts...Eyewall convection has greatly thicken + much colder on the northwest and westward quads.

[Hayabusa]

07W LAN 230810 1800 26.3N 142.9E WPAC 100 949

T2307(Lan)
Issued at 2023/08/10 18:50 UTC
Analysis at 08/10 18 UTC
Grade TY
Scale -
Intensity Very Strong
Center position N26°20′ (26.3°)
E142°55′ (142.9°)
Direction and speed of movement NNW 10 km/h (6 kt)
Central pressure 950 hPa
Maximum sustained wind speed near center 45 m/s (85 kt)
Maximum wind gust speed 60 m/s (120 kt)
Radius of 50-kt wind area 130 km (70 NM)
Radius of 30-kt wind area NE440 km (240 NM)
SW330 km (180 NM)

[MarioProtVI]

07W LAN 230810 1800 26.3N 142.9E WPAC 100 949

T2307(Lan)
Issued at 2023/08/10 18:50 UTC
Analysis at 08/10 18 UTC
Grade TY
Scale -
Intensity Very Strong
Center position N26°20′ (26.3°)
E142°55′ (142.9°)
Direction and speed of movement NNW 10 km/h (6 kt)
Central pressure 950 hPa
Maximum sustained wind speed near center 45 m/s (85 kt)
Maximum wind gust speed 60 m/s (120 kt)
Radius of 50-kt wind area 130 km (70 NM)
Radius of 30-kt wind area NE440 km (240 NM)
SW330 km (180 NM)

Still too low, 110-115 kt is a much better estimate

[cycloneye]

WDPN31 PGTW 102100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 07W (LAN) WARNING NR 013//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 26.3N 142.9E
INITIAL INTENSITY: 100 KTS
GEOGRAPHIC REFERENCE: 565 NM SOUTH-SOUTHEAST OF YOKOSUKA, JA
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 04 KTS
SIGNIFICANT WAVE HEIGHT: 36 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TYPHOON 07W (LAN) SURGED DURING THE DIURNAL MAX PERIOD AND IS NOW
UP TO TRIPLE DIGITS. DEEP CONVECTION ORGANIZED TIGHTLY AROUND A
24NM EYE AND THE SYMMETRY IMPROVED SUBSTANTIALLY. LAN IS A SMALL
SYSTEM OVERALL BUT THE EYE AND EYEWALL ARE BROAD AND DEEP. A
101904Z SSMIS SERIES VERIFIES EYEWALL INTEGRITY DESPITE DRYING AT
THE EDGE OF THE NORTHWEST QUADRANT. THERE IS IMPINGEMENT UPSTREAM
THAT IS AFFECTING THE PERIPHERY OF THE NORTHWEST QUADRANT, WHICH IS
REVEALED IN A SHARP LINE ON BOTH ANIMATED WATER VAPOR IMAGERY AND
THE PROXYVIS FROM CIMSS. THE IMPINGEMENT IS ASSOCIATED WTIH DRY AIR
AND SUBSIDENCE UPSTREAM. NONETHELESS, IN THE SHORT TERM THE STORM
IS MANAGING TO COCOOON ITSELF FROM THE HARSHER ENVIRONMENT
UPSTREAM. THE CURRENT INTENSITY IS ASSESSED BASED ON DVORAKS FROM
JTWC AND JMA. OBJECTIVE ASSESSMENTS FROM CIMSS ARE GENERALLY RIDING
HIGHER BUT THE GAP BETWEEN DVORAKS AND THE OBJECTIVE TOOLS HAS
CLOSED CONSIDERABLY OVER THE PAST 24 HOURS. LAN IS TRACKING THROUGH
A MIXED ENVIRONMENT CHARACTERIZED BY LOW VERTICAL WINDSHEAR AND
WARM SEA SURFACE TEMPERATURES, BUT LOW OCEAN HEAT CONTENT AND VERY
DRY AIR, ESPECIALLY NORTH OF THE 30TH LATITUDE. THE STORM IS
ENTERING THE 24 HOUR PERIOD WHERE IT IS EXPECTED TO PEAK IN
INTENSITY. IT IS BENEFITTING FROM A POLEWARD OUTFLOW CHANNEL
ORIGINATING IN A TUTT CELL CURRENTLY NEAR 34N 146E. THE CELL IS
KICKING TO THE WNW FAIRLY RAPIDLY. EQUATORWARD OUTFLOW HAS NOT
COMPLETELY CUT OFF, BUT IT HAS BEEN REDUCED SUBSTANTIALLY OVER THE
PAST 24 HOURS. AN ENTRENCHED ANTICYCLONE ANCHORED IN A 596DM H500
HGT CENTER NEAR 30N 175W IS IS FORCING LAN ON A POLEWARD TRACK.

INITIAL WIND RADII BASIS: SCATTEROMETRY DATA FROM 101201Z.

CURRENT STEERING MECHANISM: THE WESTERN FLANK OF THE SUBTROPICAL
RIDGE. THE RIDGE EXTENDS ACROSS NORTHERN HONSHU, WHICH WILL ACT TO
SLOW MOVEMENT AND PREVENT RECURVATURE. THUS, THE TRACK RUNS DIRECTLY
OVER THE JAPANESE ALPS.

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T5.5 - 102 KTS
RJTD: T5.5 - 102 KTS
RCTP: T5.0 - 90 KTS
KNES: T6.0 - 115 KTS
CIMSS SATCON: 92 KTS AT 101420Z
CIMSS ADT: 115 KTS AT 101730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 5-10 KTS
SST: 29-30 CELSIUS
OUTFLOW: MODERATE POLEWARD
OTHER FACTORS: DRY AIR ENTRAINMENT AND A GENERALLY VERY DRY
ENVIRONMENT NORTH OF THE 30TH LATITUDE WILL BE A MAJOR INFLUENCE ON
THIS STORM.

ANALYSIS CONFIDENCE:
INITIAL POSITION: HIGH
INITIAL INTENSITY: MEDIUM
INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: ALTHOUGH THE INTENSITY FORECAST WAS
RAISED 15 KNOTS, THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST
PHILOSOPHY.

FORECAST DISCUSSION: TYPHOON LAN WILL CONTINUE ON ITS POLEWARD
TRACK AND PEAK DURING THE NEXT 24 HOURS. THE ALREADY HIGH LATITUDE
AND MIXED ENVIRONMENT UPSTREAM WILL CAP DEVELOPMENT BELOW SUPER
TYPHOON STRENGTH. AS THE SYSTEM TRACKS POLEWARD IT WILL BE NUDGED A
LITTLE FURTHER NORTHWEST DUE TO THE INFLUENCE OF AN UPPER LEVEL
RIDGE ENTRENCHED OVER NORTHERN HONSHU. ALTHOUGH THE KUROSHIO IS
RUNNING VERY CLOSE TO THE COAST AND WARM WATERS EXIST ALL THE WAY
ALONG THE TRACK, THE PRESENCE OF INORDINATELY DRY AIR AND
DETERIORATING OUTFLOW CONDITIONS WILL BEGIN WEAKENING THE STORM AS
IT CROSSES THE 30TH LATITUDE, MAKING FOR A GRADUAL DECREASE IN
INTENSITY FROM TAU 36 UNTIL LANDFALL. GUIDANCE HAS BEEN FOCUSING ON
A STRIKE EAST OF OSAKA AND WEST OF TOKYO FOR SOME TIME NOW, WITH A
TRACK DIRECTLY OVER THE JAPANESE ALPS AND INTO THE SEA OF JAPAN.
THE UPSTREAM RIDGE OVER NORTHERN HONSHU IS TOO WELL ENTRENCHED TO
ALLOW FOR RECURVATURE. OPERATORS AND EMERGENCY MANAGERS SHOULD BE
HAPPY TO NOTE THAT THE WINDFIELDS ASSOCIATED WITH THE STORM ARE
TIGHTER THAN AVERAGE.

MODEL DISCUSSION: THE JTWC FORECAST LEANS TOWARDS THE AMERICAN AND
EUROPEAN ENSEMBLE GUIDANCE BUT DOES NOT DEVIATE FAR FROM CONSENSUS.
GUIDANCE HAS BEEN QUALITATIVELY STABLE AS FAR AS FOCUSING ON THE
AREA OF THE LAND STRIKE, BUT THERE REMAINS RUN TO RUN VARIATION
ESPECIALLY IN ALONG TRACK SPEEDS. THE INTENSITY FORECAST IS HEAVILY
WEIGHTED TO THE STATISTICAL-DYNAMICAL GUIDANCE, WHICH DOES WELL IN
CAPTURING DECREASES IN UPPER LEVEL DIVERGENCE AND FALLING MOSITURE
CONTENT. WINDFIELDS ARE EXTRAPOLATED USING THE RVCN GUDIANCE.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: HIGH
TRACK 72-120 HR: MEDIUM
INTENSITY 0 - 72 HR: MEDIUM
INTENSITY 72-120 HR: LOW//
NNNN

[ElectricStorm]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 10 AUG 2023 Time : 200000 UTC
Lat : 26:25:12 N Lon : 142:57:36 E


CI# /Pressure/ Vmax
6.0 / 939.3mb/115.0kt


Final T# Adj T# Raw T#
6.0 5.8 5.8

Estimated radius of max. wind based on IR : 27 km

Center Temp : +13.9C Cloud Region Temp : -66.6C

Scene Type : EYE

Subtropical Adjustment : OFF

Extratropical Adjustment : OFF

Positioning Method : ARCHER POSITIONING

Ocean Basin : WEST PACIFIC
Dvorak CI > MSLP Conversion Used : CKZ Method

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 83nmi
- Environmental MSLP : 1006mb

Satellite Name : HIM-9
Satellite Viewing Angle : 30.9 degrees

I'm thinking this is probably a low end Cat 4 right now. JTWC back to their old ways with this one

[aspen]

Lan looks like it’s probably around 125 kt, and in a few hours it could be worthy of STY status. Knowing the JTWC, they’ll probably go with a mere 115 kt.

[Hurricane2022]

Knowing the JTWC, they’ll probably go with a mere 115 kt.

07W LAN 230811 0000 26.8N 142.9E WPAC 115 936

[cycloneye]

TXPQ28 KNES 110033
TCSWNP

A. 07W (LAN)

B. 10/2330Z

C. 26.8N

D. 142.8E

E. ONE/HIMAWARI-9

F. T6.5/6.5

G. IR/EIR/VIS

H. REMARKS...A WMG EYE THAT IS BOTH SURROUNDED BY AND EMBEDDED WITHIN
B RESULTS IN AN ENO OF 5.5 AND AN EADJ OF +1.0 YIELDS A DT OF 6.5. THE
MET IS 6.0 BASED ON A RAPIDLY DEVELOPING TREND IN APPARENT INTENSITY
OVER THE PAST 24 HOURS. THE PT IS ALSO 6.0. THE FT IS BASED ON THE DT.

I. ADDL POSITIONS

NIL


...HOSLE