WPAC: LAN - Typhoon

[mrbagyo]

Lan is becoming more symmetrical

[Alyono]

Due to the large size and fast movement, a major tidal surge is likely for southern Japan, including Tokyo

[toad strangler]

Wilma like eye when landfalling in FL

[1900hurricane]

Lan has gone crazy. 18Z intensity is set to 130 kt, the second super typhoon this season, joining Noru.

[aperson]

Lan has gone crazy. 18Z intensity is set to 130 kt, the second super typhoon this season, joining Noru.

Holy crap it picked up fast once convection on the NW side got closed off properly. It looks like a CMG ring should form soon http://www.ssd.noaa.gov/PS/TROP/floater ... -long.html

[Alyono]

the JT forecast as well as JMA is too slow. This makes landfall around 18Z Sunday. This will be FLYING

[WAcyclone]

LAN is now forecast to become a Cat 5 by JTWC.
Very impressive structure:

[euro6208]

Incredible.

WDPN32 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 25W (LAN) WARNING NR 22//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON (STY) 25W (LAN), LOCATED APPROXIMATELY 383 NM SOUTH-
SOUTHEAST OF KADENA AB, HAS TRACKED NORTHEASTWARD AT 06 KNOTS
OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY DEPICTS A RAPIDLY CONSOLIDATING SYSTEM WITH A 50NM ROUND
EYE, WHICH PROVIDES GOOD CONFIDENCE IN THE INITIAL POSITION. STY 25W
HAS RAPIDLY INTENSIFIED (RI) OVER THE PAST 24 HOURS FROM 75 KNOTS TO
130 KNOTS (55 KNOTS). UPPER-LEVEL ANALYSIS INDICATES EXCELLENT
OUTFLOW, PARTICULARLY POLEWARD, WHICH IS TAPPING INTO THE
MIDLATITUDE WESTERLIES OVER JAPAN. A 201838Z NOAA-19 89GHZ IMAGE
INDICATES A SYMMETRIC EYEWALL WITH FRAGMENTED SPIRAL BANDING. THE
INITIAL INTENSITY IS ASSESSED AT 130 KNOTS BASED ON DVORAK INTENSITY
ESTIMATES RANGING FROM T6.0 (115 KNOTS) TO T7.0 (140 KNOTS). STY 25W
IS TRACKING POLEWARD ALONG THE WESTERN PERIPHERY OF THE DEEP LAYERED
SUBTROPICAL RIDGE.
3. FORECAST REASONING.
A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE. HOWEVER, PEAK INTENSITY IS NOW SET AT
140 KNOTS BASED ON THE ONGOING RI PHASE. ADDITIONALLY, INITIAL WIND
RADII HAVE BEEN ADJUSTED BASED ON A DETAILED ANALYSIS OF A RECENT
ASCAT IMAGE, WHICH SHOWS UNUSUALLY EXTENSIVE GALE-FORCE WINDS.
B. EIR IMAGERY INDICATES SOME EYE WOBBLE, HOWEVER, STY 25W IS
TRACKING GENERALLY POLEWARD TOWARD CENTRAL JAPAN. STY LAN SHOULD
PEAK WITHIN THE NEXT 12 HOURS THEN WEAKEN AS IT APPROACHES JAPAN AND
BEGINS TO INTERACT WITH THE BAROCLINIC ZONE BY TAU 24. AFTER TAU 24,
STY 25W WILL ENCOUNTER STRONG VERTICAL WIND SHEAR, BEGIN TO INTERACT
WITH LAND AND WILL WEAKEN SIGNIFICANTLY. THE SYSTEM WILL COMPLETE
EXTRA-TROPICAL TRANSITION BY TAU 48 AS IT GAINS FRONTAL
CHARACTERISTICS AND BEGINS TO ACCELERATE NORTHEASTWARD. STY 25W IS
FORECAST TO MAINTAIN EXTENSIVE GALE-FORCE WINDS DUE TO THE VERY
LARGE SIZE OF THE SYSTEM, AND PROXIMITY OF COLD-SURGE WINDS AND
GRADIENT WINDS ASSOCIATED WITH THE FRONTAL ZONE CURRENTLY SITUATED
OVER JAPAN. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT,
THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.//
NNNN

[euro6208]

TPPN11 PGTW 201829

A. TYPHOON 25W (LAN)

B. 20/1800Z

C. 20.68N

D. 130.73E

E. FIVE/HMWRI8

F. T7.0/7.0/D2.5/24HRS STT: D1.5/03HRS

G. IR/EIR

H. REMARKS: 34A/PBO LARGE EYE/ANMTN. WMG EYE SURR BY W (+1.0
ADJ FOR CMG) YIELDS A DT OF 7.0. PT AND MET BOTH YIELD A 6.0.
DBO DT. BROKE CONSTRAINTS DUE TO DT REMAINING CONSTANT AT 7.0.

I. ADDITIONAL POSITIONS:
20/1302Z 20.13N 130.38E MMHS


MARTINEZ

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 8.2.1
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 20 OCT 2017 Time : 201000 UTC
Lat : 21:00:24 N Lon : 130:53:39 E


CI# /Pressure/ Vmax
6.3 / 936.6mb/122.2kt


Final T# Adj T# Raw T#
6.3 6.3 6.3

Estimated radius of max. wind based on IR : 45 km

Center Temp : +19.9C Cloud Region Temp : -75.7C

Scene Type : LARGE EYE

Positioning Method : SPIRAL ANALYSIS

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 : N/A
- Environmental MSLP : 1008mb

Satellite Name : HIM-8
Satellite Viewing Angle : 27.1 degrees

****************************************************

[mrbagyo]

Look at that poleward outflow

[Alyono]

JT is incredibly too weak at landfall. This is going to be MUCH stronger than 75 kts.

The 30-40 kt forward speed is going to result in winds closer to 100 kts at landfall, even though Dvorak may indicate 70-80 kts.

I am also not sure how tropical this will be when the eye reaches the coast

[mrbagyo]

Early morning glimpse of STY Lan via visible satellite imagery.

[mrbagyo]

Very rough sea is forecast for the Chiba Prefecture on the 23rd.


©surf-forecast.com

[mrbagyo]

LAN is now officially the strongest WPAC typhoon of the year ( per JMA) - triple tie on wind with Noru & Talim / but deeper in pressure at 925 mb

This year, all of WPAC's Cat 4 - 5 storms have occured N of 20°N latitude


TY 1721 (Lan)
Issued at 21:45 UTC, 20 October 2017
<Analysis at 21 UTC, 20 October>
Scale Very large
Intensity Very strong
Center position N21°00' (21.0°)
E130°55' (130.9°)
Direction and speed of movement NNE 15 km/h (8 kt)
Central pressure 925 hPa
Maximum wind speed near center 50 m/s (95 kt)
Maximum wind gust speed 70 m/s (135 kt)
≥ 50 kt wind area ALL 280 km (150 NM)
≥ 30 kt wind area S 950 km (500 NM)
N 750 km (400 NM)

[euro6208]

TPPN11 PGTW 202109

A. SUPER TYPHOON 25W (LAN)

B. 20/2030Z

C. 20.96N

D. 130.88E

E. FIVE/HMWRI8

F. T7.0/7.0/D2.5/24HRS STT: S0.0/03HRS

G. IR/EIR

H. REMARKS: 34A/PBO LARGE EYE/ANMTN. WMG EYE SURR BY W (+1.0
ADJ FOR CMG) YIELDS A DT OF 7.0. PT AND MET BOTH YIELD 6.0. DBO
DT.

I. ADDITIONAL POSITIONS:
20/1639Z 20.55N 130.55E AMS2
20/1700Z 20.57N 130.63E ATMS
20/1838Z 20.78N 130.75E MMHS


MARTINEZ

[euro6208]

Amazing how Lan was able to get up to 7.0 so quickly. In Irma's and Maria's, Dvorak was 6.0 to 6.5 when they were found to be upper end Cat 5's. Being underestimated here. Very warm eye with very cold cloud tops.

[CrazyC83]

Amazing how Lan was able to get up to 7.0 so quickly. In Irma's and Maria's, Dvorak was 6.0 to 6.5 when they were found to be upper end Cat 5's. Being underestimated here. Very warm eye with very cold cloud tops.

ADT is showing a lower estimate, probably due to the very large eye. It's tough when there is conflicting data - the eye is much larger than Irma or Maria had at peak intensity. That said, there isn't much experience with large eyes and areas of cold cloud tops in the Atlantic with Recon.

[1900hurricane]

135 kt for 00Z.

25W LAN 171021 0000 21.4N 131.2E WPAC 135 915

[doomhaMwx]

Impressive!

[supercane4867]

Amazing how Lan was able to get up to 7.0 so quickly. In Irma's and Maria's, Dvorak was 6.0 to 6.5 when they were found to be upper end Cat 5's. Being underestimated here. Very warm eye with very cold cloud tops.

ADT is showing a lower estimate, probably due to the very large eye. It's tough when there is conflicting data - the eye is much larger than Irma or Maria had at peak intensity. That said, there isn't much experience with large eyes and areas of cold cloud tops in the Atlantic with Recon.

AMSU estimate is also running way lower than Irma and Maria had at peak intensity. If you take the blend of data, 130kt seems to be a good fit.
The relatively loose structure with over-sized eye on microwave and visible imagery just don't scream CAT5 intensity to me.

CIMSS/NESDIS-USAF/NRL AMSU TC Intensity Estimation:
TYPHOON 25W
Friday 20oct17 Time: 1300 UTC
Latitude: 19.97 Longitude: 130.43
Storm position corresponds to AMSU-A FOV 27 [1<--->30]
-----------------------------------------------------------------
| Estimated MSLP: 934 hPa
| Estimated Maximum Sustained Wind: 107 kts
| Estimate Confidence: Fair ( +/- 15mb +/- 20kts )
-----------------------------------------------------------------
Channel 8 (~150 hPa) Tb Anomaly: 5.02
Channel 7 (~250 hPa) Tb Anomaly: 4.89
RMW: 49 km
RMW Source is: IR
Environmental Pressure: 1005
Satellite: NOAA-90
ATCF data for Month: 10 Day: 20 Time (UTC): 1200