WPAC: VONGFONG - Post-Tropical

[Hayabusa]

And TCFA

WTPN21 PGTW 100300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 7.2N 131.7E TO 9.9N 129.0E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 18 TO 23 KNOTS. METSAT
IMAGERY AT 100000Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 7.2N 131.5E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 05
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 95W) PREVIOUSLY LOCATED
NEAR 6.7N 132.8E IS NOW LOCATED NEAR 7.2N 131.5E, APPROXIMATELY 180
NM WEST OF PALAU. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A
092102Z NOAA-19 89GHZ SATELLITE IMAGE DEPICT AN OBSCURED LOW LEVEL
CIRCULATION WITH SOME CONVECTION OVERHEAD AND WEAK FORMATIVE BANDING
TO THE NORTH. INVEST 95W IS IN A FAVORABLE ENVIRONMENT FOR
DEVELOPMENT WITH LOW (<15 KTS) VERTICAL WIND SHEAR, WARM (28-30C)
SEA SURFACE TEMPERATURES, AND GOOD EQUATORWARD OUTFLOW. GLOBAL
MODELS ARE IN AGREEMENT THAT INVEST 95W WILL CONTINUE TO INTENSIFY
WHILE IT TRACKS NORTHWESTWARD. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 18 TO 23 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1005 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
110300Z.
//
NNNN

[Hayabusa]

[aspen]

Hmm yes finally first TD of the year

WWJP27 RJTD 100000
WARNING AND SUMMARY 100000.
WARNING VALID 110000.
WARNING IS UPDATED EVERY 6 HOURS.
TROPICAL DEPRESSION 1008 HPA
AT 07.3N 131.8E SEA EAST OF MINDANAO MOVING WEST SLOWLY.
POSITION POOR.
MAX WINDS 30 KNOTS NEAR CENTER.

Yeesh, that took a while. 2016 may have had an extremely late first named storm, with Nepartek in July, but its first depression was back in January.

[Nancy Smar]

 https://twitter.com/dost_pagasa/status/1259381857633746944

[mrbagyo]

PAGASA have just assigned the name "AMBO" to this depression.

[mrbagyo]

Historical TC track database

[doomhaMwx]

The system remains rather broad though and recent VIS images also indicate the presence of multiple low-level centers around the mean/dominant center. It's broad nature may initially limit intensification. ASCAT passes earlier showed 25-30kt winds south and east of the center(s), or underneath the main convective activities, with weaker winds elsewhere.

[Hayabusa]

https://s6.gifyu.com/images/2020-05-10.png

Historical TC track database

Another analogy is 2004's Nida at least if using the recent GFS solutions.

[Hayabusa]

[1900hurricane]

Some solutions are popping up intermittently stronger, but I still much prefer the weaker solutions (TS intensity). I think guidance, in particular American guidance, is struggling with how 95W will interact with the TUTT that is draped across the South China Sea all the way back east across the basin.

[aspen]

It seems like the GFS is trying to keep 95W further from the Philippines. Last run, it had a landfall on May 14th, but now the system is further away so it only skims the coast about a day later.

[dexterlabio]

It seems like the GFS is trying to keep 95W further from the Philippines. Last run, it had a landfall on May 14th, but now the system is further away so it only skims the coast about a day later.

GFS previous 4 runs are pretty much the same to me. Although my money is on the ECMWF solution atm, both track and intensity wise.

[1900hurricane]

Current thoughts here peaks the system in the 50-55 kt range before landfall in the region near the SE tip of Luzon, but with plenty of uncertainty (there still isn't even a fully established vortex yet!).

*Edit to fix my landfall location.

[aspen]

18z GFS is relatively unchanged. 95W doesn’t become a significant TS until Wednesday, just before its sharp W turn.

[cycloneye]

95W INVEST 200511 0000 8.7N 129.8E WPAC 20 1007

[1900hurricane]

I'd say definitely keep an eye on the TUTT cell currently over the South China Sea in particular.

[dexterlabio]

I'd say definitely keep an eye on the TUTT cell currently over the South China Sea in particular.

Aside from the intensity, how can these TUTT cells affect this system's future track?

Also would like to note that NAVGEM is now showing a weaker scenario but is now keeping the storm moving west towards the Visayas.

[1900hurricane]

I'd say definitely keep an eye on the TUTT cell currently over the South China Sea in particular.

Aside from the intensity, how can these TUTT cells affect this system's future track?

Also would like to note that NAVGEM is now showing a weaker scenario but is now keeping the storm moving west towards the Visayas.

They probably won't be able to affect track much. TUTT cells are typically strictly upper level features (hence the name), and the wind shift with this TUTT in particular only extends down to about 400 mb. The vorticity from them is almost indiscernible on a 500 mb chart, which further reinforces this notion. Only a very strong vortex with a tall and deep steering layer would probably have any steering affects from them at all.

This is actually a big reason why I'm watching the SCS TUTT cell in particular with interest. In a typical case, because they lack any kind of surface or low level signature/reflection, it makes them a little harder to measure/quantify, and harder to predict. If guidance is clearing out or filing the TUTT cell too fast, that's going to be an issue for 95W, especially since it could get tangled in the SCS cell.

[1900hurricane]

In the meantime though, organization is taking place. This is only a partial pass, but it did hit the west side of the circulation, which has been the side that was not closed based on earlier microwave and scatterometer data. On the latest F-17 pass though, shallow banding seems to be curving inwards as would be consistent with a closed circulation. I might be one scatterometer pass away from wanting my first WPac renumber of the year.

[Hayabusa]

UK is still null on this...

GLOBAL MODEL DATA TIME 0000UTC 11.05.2020

TROPICAL DEPRESSION 95W ANALYSED POSITION : 8.7N 129.0E

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 11.05.2020 0 8.7N 129.0E 1008 18
1200UTC 11.05.2020 12 CEASED TRACKING

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 138 HOURS
FORECAST POSITION AT T+138 : 12.7N 116.2E

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 17.05.2020 144 13.6N 116.1E 1003 33