WPAC: SURIGAE - Post-Tropical

[Iceresistance]

This thing looks MEAN!

[euro6208]

20210417 1130 12.0 -129.3 T8.0/8.0 02W SURIGAE
20210417 0530 11.3 -130.2 T7.0/7.0 02W SURIGAE
20210416 2330 10.7 -131.1 T6.0/6.5 02W SURIGAE

[mrbagyo]

Himawari-8 AHI Band 13 "Clean" Enhanced Infrared (SSEC Real Earth)

10 minute interval


Rapid Scan (2.50 minutes)

[TorSkk]

I think it's quite strange that we have two dvorak fixes 10 minutes apart and they yield such different values

[Hayabusa]

JMA 110 knots, that is between 140 to 155 knots 1 min but they forecast to go 115 knots, equivalent to 155 knots 1 min

Analisys at 04/17 12 UTC
Category TY
Scale -
Intensity Violent
Center Position N12°5′(12.1°)
E129°20′(129.3°)
Direction and speed of movement NW 20km/h(12kt)
Central pressure 905hPa
Maximum wind speed near the center 55m/s(110kt)
Maximum wind gust speed 80m/s(155kt)
50-kt wind area S220km(120NM)
N185km(100NM)
30-kt wind area WIDE390km(210NM)

Forecast at 04/18 12 UTC
Category TY
Intensity Violent
Center of probability circle N13°40′(13.7°)
E126°50′(126.8°)
Direction and speed of movement WNW 15km/h(7kt)
Central pressure 900hPa
Maximum wind speed near the center 60m/s(115kt)
Maximum wind gust speed 85m/s(165kt)
Radius of probability circle 95km(50NM)
Storm warning area WIDE310km(170NM)

[Iceresistance]

I think it's quite strange that we have two dvorak fixes 10 minutes apart and they yield such different values

That meant that the storm went on RI or VRI

[Meow]

JMA 110 knots, that is between 140 to 155 knots 1 min but they forecast to go 115 knots, equivalent to 155 knots 1 min

Here’s the track map.

[cycloneye]

Is this the first category 5 in April for WPAC?

[Hayabusa]

Officially (JMA) and unofficially (JTWC) Surigae is now the strongest April typhoon and on par with the monsters in peak season (SOND)

[Meow]

Is this the first category 5 in April for WPAC?

Maysak was still Cat 5 at 00Z on 1 April 2015.

[Hayabusa]

Is this the first category 5 in April for WPAC?

From JTWC best track a total of 4 typhoons were Cat 5 during April. Plus Surigae, so a total of 5 now but the strongest.

[Hayabusa]

Mission successful, CI now 8.0, the first ADT CI@170 knots, last time it happened was Patricia CI@8.2 but that was an older ADT version

2021APR17 124000 8.0 890.3 170.0 8.0 8.1 8.1 NO LIMIT OFF OFF OFF OFF 20.18 -84.63 EYE 20 IR 79.9 12.04 -129.06 ARCHER HIM-8 19.5

[Fancy1001]

This is a great birthday present lol

[Highteeld]

Totally bonkers to get back to back seasons with T8.0 typhoons.

[aspen]

So....is the JTWC going to change its 12z best track with the T#8.0 Dvorak fix and ADT estimate?

[euro6208]

Wow back to back 8.0 typhoons. Incredible.

[kevin]

If they don't go all in with the next update I would be very interested to know what there reasoning is. Because looking at sat & ADT I don't see any way you could reason this isn't at least 160 - 165 kts (1-min) and sub 900 mbar at this stage.

[mrbagyo]

KNES is 8.0

TXPQ29 KNES 171223
TCSWNP

A. 02W (SURIGAE)

B. 17/1130Z

C. 12.0N

D. 129.3E

E. ONE/HIMAWARI-8

F. T8.0/8.0

G. IR/EIR

H. REMARKS...WMG EYE IS SURROUNDED BY AND EMBEDDED IN CDG RESULTING IN
A DT OF 8.0 AFTER ADDING 1.0 FOR THE EYE ADJUSTMENT. PT AGREES. MET IS
7.5 BASED ON RAPID DEVELOPMENT OVER THE PAST 24 HOURS. THE 6 HOUR AVERAGE
DT IS 7.8. THIS JUSTIFIES BREAKING CONSTRAINTS AT THIS TIME ESPECIALLY
SINCE THE DT HAS BEEN AT AN 8.0 FOR THE LAST 4 HOURS.

I. ADDL POSITIONS

NIL


...COVERDALE

[Subtrop]

THE INITIALINTENSITY OF 15KTS

WDPN31 PGTW 171500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 02W (SURIGAE) WARNING
NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
SUPER TYPHOON (STY) 02W (SURIGAE), LOCATED APPROXIMATELY 324 NM
EAST OF LEGAZPI, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 12 KNOTS
(KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS A HIGHLY-SYMMETRICAL SYSTEM WITH A CENTRAL
DENSE OVERCAST (CDO) THAT CONTINUED TO DEEPEN WHILE MAINTAINING A
SHARPLY OUTLINED 16-NM EYE. FEEDER BANDS HAVE SHORTENED AND THINNED
OUT AS THEY SPIRALED TIGHTER INTO THE CDO. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE OVER THE WELL-DEFINED EYE. THE INITIAL
INTENSITY OF 15KTS IS BASED ON AN OVERALL ASSESSMENT OF AGENCY DVORAK
ESTIMATES OF T7.0/140KTS (PGTW/RCTP), T7.5/155KTS (RJTD); AND THE
OBJECTIVE ESTIMATES OF T7.9/167KTS (ADT) AND 152KTS (SATCON) THAT
REFLECTS THE GREATLY IMPROVED EIR SIGNATURE OF THE SYSTEM.
ENVIRONMENTAL ANALYSIS INDICATES ROBUST EQUATORWARD AND POLEWARD
OUTFLOW, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND WARM (29-30C) SEA
SURFACE TEMPERATURES IN THE PHILIPPINE SEA CONTRIBUTING TO AN OVERALL
FAVORABLE ENVIRONMENT. STY 02W IS TRACKING TOWARD A BREAK IN THE
RIDGE TO THE NORTH.
3. FORECAST REASONING.
A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
B. STY 02W WILL CONTINUE ON ITS CURRENT NORTHWESTWARD TRACK AND
INTENSIFY THROUGH TAU 12 TO A PEAK OF 135 KTS. AFTERWARD, IT IS
EXPECTED TO SLOW AS IT ENTERS A WEAK STEERING ENVIRONMENT. BY TAU 24,
THE SPLIT SUBTROPICAL RIDGE (STR) TO THE NORTHEAST WILL BUILD,
REORIENT AND TAKE OVER AS THE PRIMARY STEERING MECHANISM, DRIVING THE
CYCLONE TO A NORTHWARD TRAJECTORY. AS THE SYSTEM GAINS LATITUDE,
DIVERGENCE ALOFT WILL DECREASE AND CAUSE THE SYSTEM TO SLOWLY WEAKEN,
DOWN TO 110KTS BY TAU 72. NUMERICAL MODELS ARE IN FAIR AGREEMENT
DURING THIS PORTION OF THE FORECAST WITH A GRADUAL AND EVEN CROSS-
TRACK SPREAD TO 186NM BY TAU 72. THEREFORE, THERE IS FAIR CONFIDENCE
IN THIS PORTION OF THE JTWC FORECAST TRACK WHICH IS LAID OVER BUT
SLIGHTLY SLOWER THAN THE MULTI-MODEL CONSENSUS DURING THE SLOW
PROGRESSION IN THE WEAK STEERING SEGMENT.
C. AFTER TAU 72, STY SURIGAE WILL CONTINUE NORTHWARD ALONG THE
WESTERN PERIPHERY OF THE STR, CREST THE AXIS, THEN ACCELERATE
NORTHEASTWARD ON THE POLEWARD SIDE. AS IT MOVES FURTHER NORTH, THE
ENVIRONMENT WILL SLOWLY BECOME LESS FAVORABLE AS UPPER LEVEL
DIVERGENCE CONTINUES TO DECREASE LEADING TO GRADUAL WEAKENING,
DOWN TO 85KTS BY TAU 120. NUMERICAL MODELS HAVE CLUSTERED CLOSER AND
NO MEMBER TRACK TOWARD LUZON ANY LONGER. THE CROSS TRACK SPREAD IS
NOW DOWN TO 442NM AT TAU 120, LENDING FAIR CONFIDENCE IN THE EXTENDED
PORTION OF THE JTWC TRACK FORECAST.//
NNNN

[Hayabusa]

I guess a side question can Surigae pump the ridge?