WPAC: USAGI - Post-Tropical

[aspen]

Man, the northern Philippines cannot catch a break this month. Potentially another major landfall coming up if that pinhole is anything to go by. Probably somewhere between 95-110 kt right now.

[xtyphooncyclonex]

Could be 100-120 kts next advisory. Terrifying.

[dexterlabio]

2009 Parma-esque...you can tell something's affecting its overall structure but that didn't stop it to get a really intense core. Let's see if this pinhole eye develops further.

[mrbagyo]

Structure is indeed kinda similar to Parma (09) and also Phanfone (14)

[WaveBreaking]

No comment

[kevin]

Absolutely speechless, Usagi might be making a run to become one of the fastest intensifying TCs in the modern database. Raw T# keeps rising and is now up to 6.6 (130 kt). It was still 75 kt at today's 06z advisory.

[MarioProtVI]

Definitely making a run for Milton’s intensity here. Easy Cat 5 at 18z if JTWC is smart.

[Subtrop]

TPPN13 PGTW 131508

A. TYPHOON 27W (USAGI)

B. 13/1430Z

C. 16.32N

D. 124.79E

E. ONE/GK2A

F. T6.5/6.5/D2.5/24HRS STT: D0.5/03HRS

G. IR/EIR

H. REMARKS: 01A/PBO EYE/ANMTN. DG EYE SURROUNDED BY W YIELDS AN E#
OF 6.0. ADDED 0.5 EYE ADJUSTMENT FOR CMG, TO YIELD A DT OF 6.5.
MET YIELDS 5.0. PT YIELDS 5.5. DBO DT. BROKE CONSTRAINTS AS T#
CHANGES ARE MORE THAN FOR 6, 12 AND 18 HOURS DUE TO RAPID
STRENGTHENING.

I. ADDITIONAL POSITIONS: NONE


PETERSEN

[xtyphooncyclonex]

And the eye is still warming

[mrbagyo]

James Reynold has already pre-positioned himself in Sta Ana, Cagayan to hunt Usagi. (i dont even know how he managed to reach that place given the flooding in Tuguegarao)


Btw. Usagi is a lil bit south of JTWC's forecast track

[Hurricane2022]

[mrbagyo]

[aspen]

Easy Super Typhoon right here, and it’s insane that it’s only officially put at 115 kt. Thanks to its pinhole eye, I’m doubtful the JTWC will place it at 130-145 kt.

[mrbagyo]

Easy Super Typhoon right here, and it’s insane that it’s only officially put at 115 kt. Thanks to its pinhole eye, I’m doubtful the JTWC will place it at 130-145 kt.

I think they will upgrade to Cat 5, they acknowledged in their 12z prognostic that 115 knots was on the low side.

THE INITIAL INTENSITY IS A BIT MORE CHALLENGING, WITH A
WIDE RANGE IN THE AVAILABLE INTENSITY ESTIMATES. PGTW IS THE MOST
AGGRESSIVE, WITH A T6.0, WHILE THE OTHER AGENCIES RANGE BETWEEN
T5.0 TO T5.5. WITH THE PINHOLE BEING SO SMALL, THE OBJECTIVE
ESTIMATES ARE STRUGGLING TO HOLD ONTO THE EYE, THOUGH AT ONE POINT
THE RAW ADT WAS UP TO T6.3. THE INITIAL INTENSITY IS SET AT 115
KNOTS, WHICH IS LIKELY A BIT ON THE LOW SIDE BUT ON THE HIGHER END
OF THE AVAILABLE DATA. CLEARLY THE ENVIRONMENT IS HIGHLY FAVORABLE,
NEARLY IDEAL IN FACT, WITH WARM SSTS, HIGH OHC, LOW VWS AND STRONG
RADIAL OUTFLOW.

[ElectricStorm]

This is what I thought Toraji had a chance to do but looks like it's Usagi instead

[Hurricane2022]

A very tiny but persistent eye, with very cold convection surrounding it. Usagi is likely rivaling Hurricane Milton and Typhoon Gaemi now. minimum pressure in the eye should probably be around 915 - 905 mb at this time, if not lower. It looks like a merger of Typhoon Parma and Hurricane Wilma

[Hurricane2022]

Looks reasonable to me

Intensity/Category Very Strong Typhoon

Center Position 16.4N 124.7E

Direction and speed of movement WNW 25km/h (13kt)

Central pressure 950hPa

Maximum wind speed near center 45m/s (85kt)

Maximum wind gust speed 60m/s (120kt)

≥ 50-kt wind area ALL 110km (60NM)

≥ 30-kt wind area ALL 280km (150NM)

[mrbagyo]

CMA currently at 58 m/s - 925 hPa




ZCZC
WTPQ20 BABJ 131800
SUBJECTIVE FORECAST
SuperTY USAGI 2425 (2425) INITIAL TIME 131800 UTC
00HR 16.7N 124.0E 925HPA 58M/S
30KTS WINDS 300KM NORTHEAST
300KM SOUTHEAST
250KM SOUTHWEST
250KM NORTHWEST
50KTS WINDS 150KM NORTHEAST
150KM SOUTHEAST
120KM SOUTHWEST
120KM NORTHWEST
64KTS WINDS 70KM NORTHEAST
70KM SOUTHEAST
70KM SOUTHWEST
70KM NORTHWEST
MOVE NW 23KM/H
P+12HR 18.4N 122.2E 920HPA 60M/S
P+24HR 20.1N 121.1E 925HPA 55M/S
P+36HR 21.0N 121.0E 935HPA 52M/S
P+48HR 22.6N 121.6E 955HPA 42M/S
P+60HR 23.8N 122.7E 975HPA 33M/S
P+72HR 24.9N 123.9E 990HPA 23M/S
P+96HR 25.9N 125.7E 1000HPA 15M/S=
NNNN

[kevin]

Since the eye is very small, Usagi is most likely underestimated by most automatic estimates. As such, I thought it would be better to look at Milton, a similar storm in terms of ERI and a small eye, and see how far that storm was lagging behind Dvorak estimates. Currently Usagi is fluctuating around 5.2/5.5/6.8 for Final T#, Adj T# and Raw T#, respectively. This changes quite a bit for each fix, most likely not due to Usagi fluctuating in strength, but due to small errors in some Dvorak center fixes. The current Dvorak fix for Usagi is as follows:

2024NOV13 153000 5.1 966.5 92.4 5.1 5.4 6.8 1.7T/6hr OFF OFF OFF OFF -1.57 -76.92 EYE -99 IR 0.0 16.43 -124.61 ARCHER HIM-9 26.7
2024NOV13 160000 5.3 962.7 97.2 5.3 5.4 6.7 1.7T/6hr OFF OFF OFF OFF -7.93 -76.87 EYE -99 IR 0.0 16.45 -124.47 ARCHER HIM-9 26.8
2024NOV13 163000 5.3 962.6 97.2 5.2 4.4 4.6 0.7T/6hr ON OFF OFF OFF -73.38 -77.39 UNIFRM N/A 0.0 16.67 -124.54 FCST HIM-9 26.9
2024NOV13 170000 5.3 962.7 97.2 5.2 5.5 6.8 1.7T/6hr ON OFF OFF OFF -10.71 -77.98 EYE -99 IR 0.0 16.54 -124.23 ARCHER HIM-9 27.1
2024NOV13 173000 5.3 962.7 97.2 5.2 5.5 6.8 1.7T/6hr ON OFF OFF OFF -12.35 -77.91 EYE -99 IR 0.0 16.57 -124.12 ARCHER HIM-9 27.2

Milton also had a time period with very similar Dvorak fixes during its ERI phase. Namely the following:

2024OCT07 114020 5.2 961.0 94.8 5.2 5.8 6.6 1.3T/6hr OFF OFF OFF OFF -32.55 -74.37 EYE -99 IR 39.9 21.82 92.23 FCST GOES16 32.0
2024OCT07 121020 5.2 961.1 94.8 5.2 4.9 4.9 NO LIMIT OFF OFF OFF OFF -73.13 -75.55 UNIFRM N/A 39.9 21.65 92.47 ARCHER GOES16 32.0
2024OCT07 124020 5.2 961.1 94.8 5.2 4.8 4.8 NO LIMIT OFF OFF OFF OFF -65.64 -75.45 UNIFRM N/A 39.9 21.77 92.13 FCST GOES16 31.9
2024OCT07 131020 5.4 957.3 99.6 5.4 5.9 7.0 1.3T/6hr OFF OFF OFF OFF -24.22 -76.37 EYE/P -99 IR 41.5 21.75 92.08 FCST GOES16 31.8

At these timesteps Milton operational intensity based on recon was set to 940mb/130kt, about 20 mb more intense than Dvorak and 30 - 35 kt stronger. If we assume a similar deviation for Usagi this results in an estimated current intensity of 945mb/130kt. Around this intensity the WPAC runs about 20 mb lower than the NATL for Dvorak (f.e. 927mb in the WPAC and 948mb in the NATL for T6.0) so the correction might be even bigger and up to 925mb/130kt. On the other hand, Milton's eye was even smaller than Usagi's so that could be an argument to not increase Usagi's intensity estimate by exactly the same amount but instead by a little less. Either way, Usagi is intensifying rapidly and will most likely be +140 kt if it stays like this for a little longer.

[Hurricane2022]

 https://x.com/CIRA_CSU/status/1856765157700997282


 https://x.com/Carl225126302/status/1856765104957608032


 https://x.com/Carl225126302/status/1856771397214765158