ATL: ERIN - Tropical Storm - Discussion

[cycloneye]

18z Best Track:

AL, 05, 2025081118, , BEST, 0, 174N, 293W, 40, 1004, TS

[eastcoastFL]

Unfortunately, Cape Verde has reported damages and 5 deaths from the newly-upgraded Tropical Storm ERIN.
 https://x.com/dtudo1poucocv/status/1954862958984540427

Who knows if PTC advisories could have avoided this situation. At least have them prepared that squally weather was in their geographical area.

That would've been a decision for the local authorities. They apparently didn't think it was necessary

[wxman57]

ASCAT-C descending pass from 11Z did not indicate an LLC or 35kt winds. This may still be an open wave. It's fighting another round of SAL coming in from the east now. May not really get going until it passes north of the eastern Caribbean on Saturday. 12Z EC shifted about 60 miles east, passing closer to Bermuda next Monday evening.

[Sciencerocks]

[JetFuel_SE]

ASCAT-C descending pass from 11Z did not indicate an LLC or 35kt winds. This may still be an open wave. It's fighting another round of SAL coming in from the east now. May not really get going until it passes north of the eastern Caribbean on Saturday. 12Z EC shifted about 60 miles east, passing closer to Bermuda next Monday evening.

would you be kind enough to show said ASCAT pass?

[sasha_B]

ASCAT-C descending pass from 11Z did not indicate an LLC or 35kt winds. This may still be an open wave. It's fighting another round of SAL coming in from the east now. May not really get going until it passes north of the eastern Caribbean on Saturday. 12Z EC shifted about 60 miles east, passing closer to Bermuda next Monday evening.

The official forecast and model intensity guidance suggests otherwise, and there was plenty of support for a closed circulation last night as assessed by the NHC. It's true that satellite intensity estimates have dropped off since last night, but scatterometer data from the same timeframe seems to indicate that there were winds of 35～40 kts and a closed albeit elongated circulation, at least at that time:

We also received scatterometer data at 1107 UTC
with a peak wind retrieval of 39 kt embedded in this convection,
with an ambiguity analysis suggesting the circulation is also
well defined, albeit still somewhat elongated on the eastern edge.

There's a lot of uncertainty in the forecast long-term but the support for for gradual intensification over the next 48 hours is strong, assuming the NHC's assesment of the 11z scatterometry was correct.

[Ian2401]

ASCAT-C descending pass from 11Z did not indicate an LLC or 35kt winds. This may still be an open wave. It's fighting another round of SAL coming in from the east now. May not really get going until it passes north of the eastern Caribbean on Saturday. 12Z EC shifted about 60 miles east, passing closer to Bermuda next Monday evening.

would you be kind enough to show said ASCAT pass?

Definitely no LLC based purely on this pass. ASCAT is pretty coarse however, and it's possible the circulation is too small for ASCAT to resolve

[aspen]

From the 5pm discussion:

There are some
indications there might some northwesterly shear impinging on the
cyclone in 96-120 h, so I elected to stay under these aids for this
cycle.

I noticed this too on the 12z HAFS runs. The southern eyewall starts to break from shear by 120-126hrs on both the HAFS-A and B, possibly the first signs that conditions may not be as favorable as anticipated west of 55-60W. But we’ll have to wait and see.

[BobHarlem]

Mark Sudduth on Erin


Link: https://youtu.be/D4ri900iFVQ