WPAC: NEPARTAK - Post-Tropical

[CrazyC83]

Looks like about a T7.0 to me, so yeah I would probably go with 140 kt. If the eye warms up, maybe about 150 kt (CMG all the way around is T7.0 or T7.5?)

[Yellow Evan]

Looks like about a T7.0 to me, so yeah I would probably go with 140 kt. If the eye warms up, maybe about 150 kt (CMG all the way around is T7.0 or T7.5?)

T7.5, assuming a WMG eye.

[Extratropical94]

The BT data is quite conservative.

02W NEPARTAK 160705 1800 18.0N 131.8E WPAC 130 926

[Yellow Evan]

Code: Select all

             ----- Current Analysis -----
     Date :  05 JUL 2016    Time :   183000 UTC
      Lat :   18:04:57 N     Lon :  131:42:34 E

     
                CI# /Pressure/ Vmax
                5.7 / 949.3mb/107.2kt

     
             Final T#  Adj T#  Raw T#
                5.7     5.7     7.2

 Estimated radius of max. wind based on IR : 10 km

 Center Temp : +19.7C    Cloud Region Temp : -78.2C

 Scene Type : EYE 

[Yellow Evan]

Code: Select all

TPPN10 PGTW 051826

A. TYPHOON 02W (NEPARTEK)

B. 05/1810Z

C. 17.97N

D. 131.80E

E. ONE/HMWRI8

F. T7.0/7.0/D3.5/24HRS  STT: S0.0/03HRS

G. IR/EIR

H. REMARKS: 01A/PBO EYE/ANMTN. [b][i]OW[/i][/b] EYE SURROUNDED BY CMG YIELDS
AN E# OF 6.5. ADDED 0.5 FOR EYE ADJUSTMENT TO YIELD A DT OF
7.0. MET YIELDS A 5.0. PT YIELDS A 7.0. DBO DT.

I. ADDITIONAL POSITIONS: NONE


   DREW

Eye is wMG, not OW.

[1900hurricane]

That's a very warm eye too, especially for its size (Himawari-8's spatial resolution also helps). Also put me in the camp that 130 kt is a bit too conservative.

[1900hurricane]

Like JTWC, JMA is forecasting their CI 7.0, a violent typhoon.

TY 1601 (Nepartak)
Issued at 18:45 UTC, 5 July 2016

<Analysis at 18 UTC, 5 July>
Scale -
Intensity Very strong
Center position N18°00' (18.0°)
E131°55' (131.9°)
Direction and speed of movement WNW 35 km/h (18 kt)
Central pressure 925 hPa
Maximum wind speed near center 50 m/s (100 kt)
Maximum wind gust speed 70 m/s (140 kt)
≥ 50 kt wind area ALL 110 km (60 NM)
≥ 30 kt wind area NE 330 km (180 NM)
SW 280 km (150 NM)

<Forecast for 06 UTC, 6 July>
Intensity Very strong
Center position of probability circle N19°30' (19.5°)
E128°35' (128.6°)
Direction and speed of movement WNW 30 km/h (17 kt)
Central pressure 925 hPa
Maximum wind speed near center 50 m/s (100 kt)
Maximum wind gust speed 70 m/s (140 kt)
Radius of probability circle 70 km (40 NM)
Storm warning area ALL 200 km (110 NM)

<Forecast for 18 UTC, 6 July>
Intensity Violent
Center position of probability circle N20°40' (20.7°)
E125°40' (125.7°)
Direction and speed of movement WNW 30 km/h (17 kt)
Central pressure 920 hPa
Maximum wind speed near center 55 m/s (105 kt)
Maximum wind gust speed 75 m/s (150 kt)
Radius of probability circle 110 km (60 NM)
Storm warning area ALL 260 km (140 NM)

<Forecast for 18 UTC, 7 July>
Intensity Violent
Center position of probability circle N22°50' (22.8°)
E121°30' (121.5°)
Direction and speed of movement WNW 20 km/h (11 kt)
Central pressure 920 hPa
Maximum wind speed near center 55 m/s (105 kt)
Maximum wind gust speed 75 m/s (150 kt)
Radius of probability circle 200 km (110 NM)
Storm warning area ALL 350 km (190 NM)

<Forecast for 18 UTC, 8 July>
Intensity Very strong
Center position of probability circle N24°40' (24.7°)
E118°35' (118.6°)
Direction and speed of movement NW 15 km/h (8 kt)
Central pressure 945 hPa
Maximum wind speed near center 45 m/s (85 kt)
Maximum wind gust speed 60 m/s (120 kt)
Radius of probability circle 240 km (130 NM)
Storm warning area ALL 350 km (190 NM)

[NotoSans]

Eye temperature is nearing 20C as per latest ADT estimate. The agencies seem a bit conservative with this storm though - JMA goes with 100 kt (corresponding to T6.5 on their Koba scale) and JTWC goes with 130 kt despite their T7.0 estimate.

And I personally don't buy JMA's intensity forecast. It's basically impossible for a typhoon to enter the strait with such a high intensity after crossing Taiwan.

[Yellow Evan]

I'd likely go with 145 knots now, only due to lag.

[cycloneye]

Oh boy Taiwan.

[euro6208]

WOW!

WDPN31 PGTW 052100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 02W (NEPARTAK)
WARNING NR 12//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON (STY) 02W (NEPARTAK), LOCATED APPROXIMATELY 715 NM
SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED WEST-NORTHWESTWARD AT 18
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS THE SYSTEM HAS BECOME MORE COMPACT, SYMMETRICAL, AND
HAS ACQUIRED ANNULAR CHARACTERISTICS AS THE EYE EXPANDED TO 13 NM.
THE INITIAL POSITION IS BASED ON THE EYE FEATURE WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY OF 130 KNOTS IS BASED ON CONCENTRIC
DVORAK FIXES FROM PGTW, KNES, AND RJTD. UPPER LEVEL ANALYSIS
INDICATES THE CYCLONE IS IN AN AREA OF LOW (05-10 KNOT) VERTICAL WIND
SHEAR AND EXCELLENT DUAL OUTFLOW. IT IS ALSO DRIFTING OVER VERY WARM
SSTS IN THE PHILIPPINE SEA. STY 02W IS BEING STEERED NORTHWESTWARD
ALONG THE PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING BULLETIN.
B. TY 02W IS EXPECTED TO CONTINUE TRACKING GENERALLY NORTHWESTWARD
TOWARD NORTHERN TAIWAN ALONG THE PERIPHERY OF THE STR OVER THE NEXT
48 HOURS. STEADY INTENSIFICATION IS ANTICIPATED IN THE NEAR-TERM AS
ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE. SOME WEAKENING WILL OCCUR
PRIOR TO LANDFALL AS OUTFLOW DECREASES IN RESPONSE TO CHANGES IN THE
UPPER-LEVEL FLOW PATTERN. AFTER LANDFALL OVER NORTHERN TAIWAN AT TAU
48, TY 02W WILL BEGIN TO ROUND THE STEERING RIDGE PERIPHERY AND
WEAKEN FURTHER DUE TO LAND INTERACTION. NUMERICAL MODEL GUIDANCE
REMAINS IN GOOD AGREEMENT WITH THE OVERALL FORECAST SCENARIO WITHIN
THE 72 HOUR FORECAST PERIOD, LENDING HIGH CONFIDENCE TO THAT PORTION
OF THE TRACK FORECAST.
C. IN THE EXTENDED PERIOD, TY NEPARTAK IS EXPECTED TO ROUND THE
STEERING RIDGE AXIS AND TRACK POLEWARD OVER THE EASTERN COAST OF
CHINA. LAND INTERACTION, INCREASING VERTICAL WIND SHEAR, AND PASSAGE
OVER COOLER WATER WILL RESULT IN STEADY WEAKENING DURING THIS TIME.
NUMERICAL MODELS ARE IN GOOD AGREEMENT REGARDING THE OVERALL FORECAST
SCENARIO, ALTHOUGH THERE REMAINS SIGNIFICANT SPREAD IN THE LOCATION
AND TIMING OF THE TRACK AROUND THE RIDGE PERIPHERY. GIVEN THIS SPREAD
IN THE EXTENDED PERIOD, THERE IS LOW CONFIDENCE IN THE EXTENDED
FORECAST TRACK.//
NNNN

[euro6208]

Incredibly small eye...This looks like a category 5...

[euro6208]

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

----- Current Analysis -----
Date : 05 JUL 2016 Time : 191000 UTC
Lat : 18:06:27 N Lon : 131:26:02 E


CI# /Pressure/ Vmax
5.7 / 949.3mb/107.2kt


Final T# Adj T# Raw T#
5.7 5.7 7.1

Estimated radius of max. wind based on IR : 10 km

Center Temp : +13.6C Cloud Region Temp : -78.3C

Scene Type : EYE

Positioning Method : RING/SPIRAL COMBINATION

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

Tno/CI Rules : Constraint Limits : 1.3T/6hr
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

C/K/Z MSLP Estimate Inputs :
- Average 34 knot radii : 143km
- Environmental MSLP : 1008mb

Satellite Name : HIM-8
Satellite Viewing Angle : 23.9 degrees

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

[1900hurricane]

Dear JTWC,

This tropical cyclone is not annular. Symmetric? Yes. Annular? No.

Best,
1900hurricane

[Yellow Evan]

At least the JTWC is factoring in other T number estimates not just their own for a change.

[1900hurricane]

One thing I will say, and JTWC did point it out in their discussion, is the ridiculous outflow pattern. This is one of the best you'll see.

[euro6208]

As mentioned from a previous poster, Nepartak looks a lot like Super Typhoon Megi back in 2010.

Recon found 175 knots in this monster. Both were similiar as they occurred after post nino...

[1900hurricane]

Is SSD trying to say the embedded shade is white?

TXPQ28 KNES 052102
TCSWNP

A. 02W (NEPARTAK)

B. 05/2030Z

C. 18.3N

D. 131.1E

E. ONE/HIMAWARI-8

F. T7.0/7.0/D2.5/24HRS

G. IR/EIR

H. REMARKS...DT=7.0 BASED ON WH EMBEDDED GRAY SHADE WITH WMG EYE
SURROUNDED BY CMG. PT-6.5. MET=6.0. FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...SCHWARTZ

Ummm? What am I missing?



I'm not trying to badmouth a professional agency or anything, but that looks pretty clear-cut cold medium grey to me.

[1900hurricane]

The sun is now rising over Nepartak.

 https://twitter.com/DanLindsey77/status/750446255919099904

[1900hurricane]

Nothing important for me to say or analyze at the moment, I'm just taking in the early morning visible imagery.