ATL: ERIN - Tropical Storm - Discussion

[GCANE]

Two low-level vorts are associated with this system. Erin west of the CV islands and a weaker vort just south of the islands. This creates a Fujiwhara effect imparting a counter-clockwise force on Erin. Thus the shift in forecast track. Need to watch how this evolves.

SAL is also very strong all the way to the islands, which will limit development of Erin.

IMHO, we should see future forecast track shifts to a more westerly track and Erin may impact the islands.

[Nimbus]

 https://x.com/BenNollWeather/status/1955218534096834622

Erin has a small core which may win the battle against the SAL as she gets over warmer SST's.
In the mean time it looks like the track will be weak and west which is not a good trend for the islands.
And the new AI forecast runs are showing different ridging than earlier so that AI hype is still garbage in garbage out.

Felt good for a few days to see Erins track rounding the bend OTS inside Bermuda though.

[GCANE]

The east vort currently has much stronger convection associated with it than Erin.

[GCANE]

It appears Erin is more a product of LL TPW forcing. This may get pinched off in a couple days.
IMHO the east LL vort has a chance to take over.

https://tropic.ssec.wisc.edu/real-time/ ... anim=html5

[GCANE]

GFS does show the TPW forcing being pinched off when Erin hits 50W.
Also, not a lot of inflow from the Amazon until 65W.

Virgin Islands and Puerto Rico needs to keep a close eye on this.

[Blown Away]

LLC naked, but well formed and maybe moving WSW now.

[LarryWx]

Tuesday will be a important day to see how far down in latitude, the circulation goes.

The good news in the short-term for the US is that Erin climbed slightly from 17.4N to 17.6N (275 degree heading) since the previous advisory vs a prog to stay at 17.4N (270 degree heading). Could be a good sign regarding keeping the latitude instead of losing much. We’ll see!

Followup to above: Per the 5AM advisory, Erin dropped back down slightly from 17.6N to 17.4N with a 265 degree heading. The new track has a low point of 17.0N tomorrow instead of 17.1N. The 17.0N will be a key latitudinal benchmark to compare to tomorrow.

[TomballEd]

The one thing about saying models are missing the weaker vorticity back by the CVs is implying the models aren't initialized with satellite derived products. CIMMS is satellite products for academic and public consumption.

It will be interesting if the runs a bit further S/W, passage closer to the NE Caribbean and Carolinas, is windshield wiping or a trend. If it keeps creeping, it is a trend and 'the trend is your friend.

Other thing is comparing models to actual Erin satellite, coldest cloud tops now only -50C, if Erin becomes a shallow naked swirl it should get farther W.

[cycloneye]

12z Best Track down to 35 kt.

AL, 05, 2025081212, , BEST, 0, 173N, 354W, 35, 1005, TS

[AutoPenalti]

Moving WSW now.

[ColdMiser123]

Personally have lower confidence than normal on track, since it will be dependent on intensity. The weaker this remains for a longer amount of time, the farther west it will likely get. The flip side is also true. How much Erin continues to deal with dry air limiting its intensity in the short to medium term will be key.

[wxman57]

Look for the NHC to adjust their track in the 3-5 day time frame farther south. They're about 1.5 degrees north of consensus now. Fast storms almost always track farther south than predicted. I have the track passing 60W well south of 20N, taking TS wind to the northern islands, including San Juan. It should turn north after passing the eastern Caribbean, staying well off the U.S. coast. However, it will look very scary, as I think it's heading for Cat 4 by next Mon/Tue.

[Cachondo23]

Look for the NHC to adjust their track in the 3-5 day time frame farther south. They're about 1.5 degrees north of consensus now. Fast storms almost always track farther south than predicted. I have the track passing 60W well south of 20N, taking TS wind to the northern islands, including San Juan. It should turn north after passing the eastern Caribbean, staying well off the U.S. coast. However, it will look very scary, as I think it's heading for Cat 4 by next Mon/Tue.

TS winds in San Juan? Interesting, I would expect the worst part of the storm to the north of the Islands like it normally occurs with systems passing just north of NE Caribbean Islands.

[msbee]

From the 5 AM discussion:

The official forecast track is a little left, or
south, of the previous one in 3-5 days, and very close to the
latest dynamical model consensus. This also very similar to the
mean of the GFS and ECMWF solutions.

https://i.imgur.com/CLSzzMt.png

watching this very carefully here in the NE Caribbean. I have too often been surprised by storms coming at us in unexpected ways.

[Keldeo1997]

Is there a chance that it gets so far south that it runs into the shredder, stays too weak that it misses the weakness and gets into the gulf?

[WeatherBoy2000]

Is there a chance that it gets so far south that it runs into the shredder, stays too weak that it misses the weakness and gets into the gulf?

There's always a chance, but there's pretty much no model or ensemble support for this happening.

[MEANINGLESS_NUMBERS]

Is there a chance that it gets so far south that it runs into the shredder, stays too weak that it misses the weakness and gets into the gulf?

No reason to think this

[cycloneye]

 https://x.com/DCAreaWx/status/1955250432218898800

[AutoPenalti]

Is there a chance that it gets so far south that it runs into the shredder, stays too weak that it misses the weakness and gets into the gulf?

No reason to think this

I wouldn't say that, it really just depends how far South it gets under the lower level steering flow.

[kevin]

Based on the latest ARCHER fix at 12:40pm UTC Erin has started a more distinct WSW motion of 260 degrees (compared to ~266 deg 6 hours ago). The ARCHER fix puts it at 17.20N two hours ago, which was about 0.1 deg south of the forecast track. Still too small deviations to draw conclusions from, but it's worth keeping an eye on the coming hours/day.