WPAC: FAXAI - Post-Tropical

[euro6208]

WDPN31 PGTW 052100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FAXAI) WARNING NR
017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 14W (FAXAI), LOCATED APPROXIMATELY 682 NM
EAST-SOUTHEAST OF IWO TO, JAPAN, HAS TRACKED NORTHWESTWARD AT 10
KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS A PARTLY EXPOSED LOW LEVEL CIRCULATION (LLC)
WITH THE ASSOCIATED DEEP CONVECTION OFFSET TO THE EAST. THE INITIAL
POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE EIR LOOP. THE
INITIAL INTENSITY OF 40KTS IS BASED ON THE HIGH END OF AGENCY AND
OBJECTIVE DVORAK ESTIMATES OF T2.5-T2.7 AND REFLECTS THE SUSTAINED
EIR SIGNATURE. UPPER-LEVEL ANALYSIS MAINTAINS A TUTT CELL TO THE
NORTHWEST AND TROUGHING SOUTHWARD OF IT IS CAUSING STRONG SUBSIDENCE
ALONG THE WESTERN PERIPHERY OF THE CYCLONE, CONSEQUENTLY RESTRICTING
WESTWARD OUTFLOW AND INHIBITING VERTICAL DEVELOPMENT. HOWEVER,
MODERATE SOUTHEASTWARD OUTFLOW INTO ANOTHER TUTT CELL TO THE
EAST PROVIDES VENTILATION TO THE OFFSET CONVECTION. TS 14W HAS A
FAVORABLE VERTICAL WIND SHEAR (VWS) ENVIRONMENT WITH VALUES OF
5-15KTS. TS 14W CONTINUES TO TRACK OVER WARM SST (30C) WHILE A
SUBTROPICAL RIDGE (STR) TO THE NORTHEAST INFLUENCES THE STEERING OF
THE SYSTEM.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS 14W WILL CONTINUE ON ITS CURRENT TRACK, STEERED BY THE STR.
AFTER TAU 48, THE TRACK WILL TURN MORE NORTHWARD AS IT BEGINS TO
ROUND THE STR AXIS. BY TAU 72, IT WILL MAKE LANDFALL OVER HONSHU,
JAPAN, NEAR TOKYO. THE OVERALL FAVORABLE ENVIRONMENT WILL PROMOTE
SLOW THEN RAPID INTENSIFICATION TO 80 KTS BY TAU 48 AS POLEWARD
OUTFLOW INCREASES WHILE THE SYSTEM MOVES AWAY FROM THE TUTT CELL
INFLUENCE AND APPROACHES THE PREVAILING WESTERLIES. PEAK INTENSITY
WILL LIKELY BE 90KTS AT TAU 60 AS THE SYSTEM CRESTS THE STR.
AFTERWARD, TY 14W WILL WEAKEN TO 70KTS AFTER LANDFALL.
C. BEYOND TAU 72, TS FAXAI WILL BEGIN EXTRA-TROPICAL TRANSITION
AND ACCELERATE NORTHEASTWARD BACK INTO THE PACIFIC OCEAN, RAPIDLY
DECAYING DUE TO INCREASING VWS AND COOLER SST, TRANSFORMING INTO A
STRONG GALE-FORCE COLD CORE LOW WITH AN EXPANDING WIND FIELD BY TAU
96 WELL SOUTHEAST OF HOKKAIDO. NUMERICAL MODELS ARE IN TIGHT
AGREEMENT, LENDING HIGH CONFIDENCE IN ALL PORTIONS OF THE JTWC
FORECAST TRACK.//
NNNN

[1900hurricane]

In the battle between Faxai and the TUTT cell to its NW, it looks like Faxai is finally winning. Even though it was sheared for a good while, the sustained convection looks like it has significantly weakened the upper level low. Additionally, it looks like the distance between Faxai and the upper low have increased to where the shear is significantly less and the upper low is pulling outflow from the system. Faxai has responded in kind with a significant increase in organization. It is traveling through the subtropics a bit north of where the WPac typically observes its stronger systems, but I think chances are good that it can become a moderate strength typhoon. Now, this is where things could get interesting, with guidance in very good agreement on a track towards Honshu.

[1900hurricane]

ASCAT missed the circulation center (because of course it did), but I was able to partial together MetOp-B and MetOp-C data to narrow the data gap.

[1900hurricane]

 https://twitter.com/1900hurricane/status/1169839643635806208

[euro6208]

WDPN31 PGTW 060300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FAXAI) WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM (TS) 14W (FAXAI), LOCATED APPROXIMATELY 601 NM EAST
OF IWO TO, JAPAN, HAS TRACKED NORTHWESTWARD AT 17 KNOTS (KTS) OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (AMSI)
DEPICTS A LOW LEVEL CIRCULATION (LLC) UNDER THE ASSOCIATED DEEP
CONVECTION. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED
ON THE CURRENT AMSI LOOP. THE INITIAL INTENSITY OF 45 KTS IS BASED ON
THE HIGH END OF AGENCY AND OBJECTIVE DVORAK ESTIMATES OF T2.5-T2.7
AND REFLECTS THE SLIGHT INTENSIFICATION OF THE SYSTEM. UPPER-LEVEL
ANALYSIS DEPICTS A TUTT CELL LOCATED TO THE NORTHWEST AND TROUGHING
SOUTHWARD OF THE SYSTEM. THIS ENVIRONMENT IS CAUSING STRONG
SUBSIDENCE ALONG THE
WESTERN PERIPHERY OF THE CYCLONE, THUS RESTRICTING WESTWARD OUTFLOW
AND CONSTRAINING VERTICAL DEVELOPMENT. HOWEVER, MODERATE
SOUTHEASTWARD OUTFLOW INTO ANOTHER TUTT CELL TO THE EAST PROVIDES
VENTILATION TO THE CONVECTION. TS 14W HAS A FAVORABLE VERTICAL WIND
SHEAR (VWS) ENVIRONMENT WITH VALUES OF 10-20 KTS AND CONTINUES TO
TRACK OVER WARM SST (30 CELSIUS) WHILE A SUBTROPICAL RIDGE (STR) TO
THE NORTH INFLUENCES THE STEERING.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. TS 14W WILL MAINTAIN ITS CURRENT TRACK, STEERED BY THE STR.
AFTER TAU 48, THE TRACK WILL TURN MORE NORTHWARD AS IT BEGINS TO
ROUND THE STR AXIS. AROUND TAU 66, TS 14W WILL MAKE LANDFALL OVER
HONSHU, JAPAN, NEAR TOKYO. THE FAVORABLE UPPER-LEVEL ENVIRONMENT WILL
PROMOTE SLOW THEN RAPID INTENSIFICATION TO A PEAK INTENSITY OF 85 KTS
BY TAU 48 AS THE SYSTEM CRESTS THE STR. THE POLEWARD OUTFLOW WILL
INCREASE AS THE SYSTEM MOVES AWAY FROM THE INFLUENCE OF THE TUTT CELL
AND TOWARDS PREVAILING WESTERLIES. TS 14W WILL WEAKEN TO 65 KTS AFTER
LANDFALL.
C. BEYOND TAU 72, TS 14W WILL BEGIN EXTRA-TROPICAL TRANSITION
(ETT) AND ACCELERATE NORTHEASTWARD, EXITING BACK OVER THE PACIFIC
OCEAN. THE SYSTEM WILL CONTINUE TO RAPIDLY DECAY DUE TO INCREASING
VWS AND COOLING SST, TRANSFORMING INTO A STRONG GALE-FORCE COLD CORE
LOW WITH AN EXPANDING WIND FIELD BY TAU 96. NUMERICAL MODELS ARE IN
TIGHT AGREEMENT, LENDING HIGH CONFIDENCE TO ALL PORTIONS OF THE JTWC
FORECAST TRACK.//
NNNN

[euro6208]

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 9.0
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 06 SEP 2019 Time : 044000 UTC
Lat : 23:19:51 N Lon : 150:45:28 E


CI# /Pressure/ Vmax
2.8 / 996.8mb/ 41.0kt


Final T# Adj T# Raw T#
2.8 2.9 3.2

Center Temp : -64.2C Cloud Region Temp : -65.0C

Scene Type : UNIFORM CDO CLOUD REGION

Subtropical Adjustment : OFF

Extratropical Adjustment : OFF

Positioning Method : FORECAST INTERPOLATION

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

Tno/CI Rules : Constraint Limits : 0.7T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 101nmi
- Environmental MSLP : 1009mb

Satellite Name : HIM-8
Satellite Viewing Angle : 29.5 degrees

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

[Hayabusa]

STS

STS 1915 (Faxai)
Issued at 07:05 UTC, 6 September 2019

<Analysis at 06 UTC, 6 September>
Scale -
Intensity -
Center position N23°50' (23.8°)
E150°05' (150.1°)
Direction and speed of movement NW 35 km/h (18 kt)
Central pressure 996 hPa
Maximum wind speed near center 25 m/s (50 kt)
Maximum wind gust speed 35 m/s (70 kt)
≥ 30 kt wind area NE 280 km (150 NM)
SW 170 km (90 NM)

[Hayabusa]

2019SEP06 115000 3.5 986.0 55.0 3.5 3.9 5.5 0.5T/hour OFF OFF OFF OFF -30.89 -69.80 EYE -99 IR -3.0 24.80 -148.40 FCST HIM-8 30.2

[1900hurricane]

Don't think it's a true eye in this case, but it is getting there.

[NotoSans]

 https://twitter.com/Notosans_s2k/status/1170052342416175104

[Highteeld]

TXPQ21 KNES 062126
TCSWNP

A. 14W (FAXAI)

B. 06/2030Z

C. 26.3N

D. 145.6E

E. THREE/HIMAWARI-8

F. T4.5/4.5/D1.5/24HRS

G. IR/EIR/SWIR/VIS/AMSR2/SSMIS

H. REMARKS...THIS INTENSITY ESTIMATE WAS DERIVED USING 4 KM IR
DATA. LLC EMBEDDED IN BLACK RESULTS IN DT OF 5.0. MET IS 4.5 DUE TO
RAPID INTENSIFICATION. PT IS 4.5. FT IS BASED ON MET DUE TO UNCERTAINTY
IN LLC POS.

I. ADDL POSITIONS

06/1535Z 25.4N 147.0E AMSR2
06/1928Z 26.0N 146.0E SSMIS


...LEVINE

[Hayabusa]

Typhoon

TY 1915 (Faxai)
Issued at 21:45 UTC, 6 September 2019

<Analysis at 21 UTC, 6 September>
Scale -
Intensity -
Center position N26°10' (26.2°)
E145°35' (145.6°)
Direction and speed of movement WNW 35 km/h (18 kt)
Central pressure 970 hPa
Maximum wind speed near center 35 m/s (70 kt)
Maximum wind gust speed 50 m/s (100 kt)
≥ 50 kt wind area ALL 110 km (60 NM)
≥ 30 kt wind area NE 330 km (180 NM)
SW 220 km (120 NM)

[Hayabusa]

Wow 95 kt near Tokyo according to JTWC

[mrbagyo]

[1900hurricane]

JTWC went 75 kt at 00Z, which looks acceptable to me, but I would have pushed for a little more. Structure on AMSU MetOp-B looks very good, which can be saying something considering the lower resolution of the pass. The pass does also show some dry air to the south, so that does bear watching, but that might honestly be Faxai's only impediment right now. The upper air environment is rather favorable, with perhaps only very light southeasterly shear since Faxai is moving at nearly the same velocity (magnitude and direction) as that upper level flow.

[1900hurricane]

Also, I think JTWC's wind radii are too big. ASCAT has been avoiding Faxai like the plague, but it doesn't appear to be that large a system based on both conventional imagery and the partial passes that I've been putting together.

WP, 14, 2019090700, , BEST, 0, 267N, 1449E, 75, 976, TY, 34, NEQ, 130, 105, 60, 105, 1007, 140, 5, 0, 10, W, 0, , 0, 0, FAXAI, D,
WP, 14, 2019090700, , BEST, 0, 267N, 1449E, 75, 976, TY, 50, NEQ, 70, 40, 20, 50, 1007, 140, 5, 0, 10, W, 0, , 0, 0, FAXAI, D,
WP, 14, 2019090700, , BEST, 0, 267N, 1449E, 75, 976, TY, 64, NEQ, 35, 20, 10, 25, 1007, 140, 5, 0, 10, W, 0, , 0, 0, FAXAI, D,

[1900hurricane]

AMSU estimate for the pass I mentioned above is 85 kt/959 mb. SATCON is up to 83 kt for 00Z now.

CIMSS/NESDIS-USAF/NRL AMSU TC Intensity Estimation:
TYPHOON 14W
Friday 06sep19 Time: 2354 UTC
Latitude: 26.35 Longitude: 145.38
Storm position corresponds to AMSU-A FOV 22 [1<--->30]
-----------------------------------------------------------------
| Estimated MSLP: 959 hPa
| Estimated Maximum Sustained Wind: 85 kts
| Estimate Confidence: Fair ( +/- 11mb +/- 13kts )
-----------------------------------------------------------------
Storm is sub-sampled: Bias correction applied is -4.5 hPa
Channel 8 (~150 hPa) Tb Anomaly: 2.23
Channel 7 (~250 hPa) Tb Anomaly: 2.25
RMW: 14 km
RMW Source is: JTWC
Environmental Pressure: 1007
Satellite: NOAA-90
ATCF data for Month: 09 Day: 07 Time (UTC): 0000

For imagery, go to http://amsu.ssec.wisc.edu
For all comments and questions mailto:chrisv@ssec.wisc.edu

[1900hurricane]

The unanimity of guidance in the Tokyo region is actually rather remarkable. You have to look really, really hard to find some sort of outlier, even amongst every ensemble member.

 https://twitter.com/1900hurricane/status/1170184085857349632

[NotoSans]

Historically there haven’t been a lot of intense typhoons making landfall near Eastern Japan.
 https://twitter.com/philipslau681/status/1170192651271827456

[euro6208]

WDPN31 PGTW 070300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FAXAI) WARNING NR
022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TYPHOON (TY) 14W (FAXAI), LOCATED APPROXIMATELY 581 NM SOUTH-
SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHWESTWARD AT 17 KNOTS
(KTS) OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS TY 14W AS A RAPIDLY INTENSIFYING SYSTEM, MAINTAINING
A VISIBLE EYE FEATURE. A 070000Z HIMAWARI-8 VISIBLE 1KM IMAGE ALONG
WITH A 062354Z AMSU 89GHZ MICROWAVE IMAGE REVEALS A 10 NM EYE
FEATURE, LENDING HIGH CONFIDENCE TO THE PLACEMENT OF THE INITIAL
POSITION. THE INITIAL INTENSITY (75 KTS) IS ASSESSED WITH HIGH
CONFIDENCE BASED ON MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES
OF T4.5/77KTS FROM PGTW AND RJTD, CONFIRMED BY AN ADVANCED DVORAK
TECHNIQUE ESTIMATE OF T4.4/75KTS. UPPER-LEVEL ANALYSIS REVEALS THE
SYSTEM REMAINS IN A FAVORABLE ENVIRONMENT WITH LOW TO MODERATE (10-
20 KT) VERTICAL WIND SHEAR (VWS) AND WARM (29-30 CELSIUS) SEA
SURFACE TEMPERATURE (SST). CURRENTLY, THERE IS FAIR POLEWARD OUTFLOW
SUPPORTING THE SYSTEM. TY 14W IS TRACKING ALONG THE SOUTHWESTERN
PERIPHERY OF A DEEP-LAYER STR CENTERED TO THE NORTHEAST.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. THROUGH TAU 12, TY 14W WILL CONTINUE ON THE PRESENT TRACK
AROUND THE PERIPHERY OF THE AFOREMENTIONED DEEP-LAYER STR. BETWEEN
TAUS 24 AND 36, THE SYSTEM WILL GRADUALLY SLOW AS IT ROUNDS THE STR
AXIS. AFTER TAU 36, THE STORM WILL SHIFT TO A NORTHEASTWARD TRACK AN
ACCELERATE THROUGH TAU 72. THE SYSTEM IS FORECAST TO MAKE LANDFALL
SOUTHEAST OF TOKYO AROUND TAU 36 AS A SIGNIFICANT TYPHOON WITH A
PEAK INTENSITY OF 105 KTS. THE ENVIRONMENT WILL REMAIN FAVORABLE FOR
THE NEXT 18 HOURS, MAINTAINING LOW VWS AND WARM SST. HOWEVER, MODELS
DEPICT DEVELOPMENT OF A TRANSIENT UPPER-LEVEL ANTICYCLONE TO THE
NORTHWEST OF THE SYSTEM, INDUCING A BRIEF BREAK IN THE POLEWARD
OUTFLOW AND RESULTING IN A SLOWING IN THE RATE OF INTENSIFICATION.
ONCE THIS ANTICYCLONE MOVES TO THE NORTHEAST OF THE SYSTEM BY AROUND
TAU 24, THE OUTFLOW WILL REINTENSIFY, ALLOWING FOR ANOTHER PERIOD OF
ENHANCED INTENSIFICATION PRIOR TO LANDFALL SOUTHEAST OF TOKYO.
FOLLOWING LANDFALL, AS THE SYSTEM TRANSITS NORTHEAST BACK OVER
WATER, COOLER SSTS AND INCREASING VWS WILL COMBINE TO OFFSET THE
STRONG OUTFLOW AND GRADUALLY WEAKEN TY 14W AS IT BEGINS
EXTRATROPICAL TRANSITION. MODEL GUIDANCE IS IN EXCELLENT AGREEMENT
THROUGH THE EARLY PORTION OF THE FORECAST, WITH ONLY 50 NM SPREAD AT
TAU 48 INCREASING TO 90 NM BY TAU 72 WITH ONLY NAVGEM AS A NORTHERLY
OUTLIER, LENDING HIGH CONFIDENCE TO THIS PORTION OF THE JTWC TRACK
FORECAST.
C. BY TAU 96, TY 14W IS FORECAST TO RAPIDLY MOVE NORTHEASTWARD,
BECOME EMBEDDED IN THE DEEP WESTERLY FLOW, AND TRANSITION TO A GALE-
FORCE EXTRATROPICAL LOW. MODEL GUIDANCE REMAINS IN OVERALL GOOD
AGREEMENT THROUGH TAU 96, WITH INCREASING ALONG AND CROSS-TRACK
UNCERTAINTY IN THE LATER TAUS. BASED ON THE INCREASED SPREAD IN THE
GUIDANCE BY TAU 96, THERE IS LOW CONFIDENCE IN THIS PORTION OF THE
JTWC TRACK FORECAST.//
NNNN