ATL: ERIN - Tropical Storm - Discussion

[cycloneye]

8 AM=90/90. TD or TS at 11 AM?

Eastern Tropical Atlantic (AL97):
Shower and thunderstorm activity has persisted and continues to
show signs of organization with a well-defined area of low pressure
located just to the west of the Cabo Verde Islands. If these
structural trends continue, the system is likely to become a
tropical depression or storm, possibly as soon as later this
morning. Locally heavy rainfall and gusty winds are expected to
continue today across portions of the Cabo Verde Islands, and
interests there should monitor the progress of this system.
Regardless of development over the next couple of days, the system
is expected to continue moving westward to west-northwestward at 15
to 20 mph across the eastern and central tropical Atlantic.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

[Jr0d]

8 AM=90/90.

Maybe a TD at 11am. I noticed the NHC likes to go in 10% increments when a storm is not an immediate threat.

Convection appears to waning the moment however. Also still going wnw not west or wsw. If this continues then the chances of a CONUS hit will continue to go down.

[NDG]

 https://x.com/NDGMETCHEF/status/1954879087199080714

[wxman57]

https://i.imgur.com/lymGUl1.png

With that wind barb and the low resolution, I'd go 35 kt for the initial intensity. If this was 24 hours ago, I'd classify it as TS Erin now to get the warnings out. But with the storm leaving the islands, there may be a bit of time to wait. If this trend continues, I'd start advisories early tomorrow (EDT), which I believe is 8 am CVT if 0900Z.

So far this summer, the Azores-Bermuda High has been much weaker than normal. The Subtropical Atlantic is dominated by lower pressure. This results in lower trade wind speeds and an easy avenue for developing storms to recurve east of the Caribbean, as I expect this one to do. I think it'll pass by Bermuda by next Tuesday as a major hurricane. Too early to determine if it might impact the northeast U.S.

[Nuno]

Surprised this still hasnt been upgraded

[cycloneye]

Moving west now per 12z Best Track. I would not be surprised if the famous NHC banner is up in less than one hour from this post.

AL, 97, 2025081112, , BEST, 0, 173N, 273W, 30, 1006, LO

[KirbyDude25]

Looks like the 12Z Best Track has been updated. We have Erin

AL, 05, 2025081112, , BEST, 0, 173N, 273W, 40, 1004, TS, 34, NEQ, 20, 0, 0, 30, 1010, 160, 20, 0, 0, L, 0, , 0, 0, ERIN, M, 0, , 0, 0, 0, 0, genesis-num, 016, TRANSITIONED, alA72025 to al052025,

[Hurricane2022]

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

[cycloneye]

It's Official - TS ERIN at 11 AM

 https://x.com/NHC_Atlantic/status/1954908302325744076

[TampaWxLurker]

So if they're jumping straight to TS Erin at 11am, its safe to say they could have started initiating advisories for a tropical depression or PTC at least 12+ hours ago, yes? I mean it was affecting the Cabo Verde Islands.

[Hurricane2022]

OUTLOOK VALID 16/1200Z 21.5N 60.0W
MAX WIND 100 KT...GUSTS 120 KT.
50 KT... 70NE 50SE 40SW 50NW.
34 KT...140NE 130SE 80SW 120NW.

[aspen]

:double:

OUTLOOK VALID 16/1200Z 21.5N 60.0W
MAX WIND 100 KT...GUSTS 120 KT.
50 KT... 70NE 50SE 40SW 50NW.
34 KT...140NE 130SE 80SW 120NW.

A little more aggressive than I thought they’d go for. I was expecting maybe 90 kt max due to this being the first advisory, and the slower rate of intensification over the next 2-3 days.

It’s been a long time since we had a long-tracking MDR hurricane form east of 30W before September. I think the last was Florence in 2018, and before that Irma in 2017. Both were after August 20th, much later than Erin. Wonder if this means the MDR will be a lot more favorable than expected this year (the precip plots from earlier in the summer looked pretty inactive), or if this is just a fluke.

[kevin]

Time to bring the list back once again. Here's a list of the most aggressive first advisories based on NHC advisories since 1998 (of which the 1998 - 2002 advisories only went to +72 hrs). Erin is one of only 6 TCs to get a first advisory with a 100+ kt forecast point. At the end of the name I have added the verified peak intensity in kt for each storm.

120 kt
2023 - Lee (145)

105 kt
2024 - Kirk (130)
2023 - Nigel (85)

100 kt
2025 - Erin (-)
2021 - Sam (135)
2010 - Tomas (85)

95 kt
2024 - Milton (155)
2024 - Helene (120)
2024 - Ernesto (85)
2022 - Ian (140)
2021 - Ida (130)
2020 - Iota (135)
2019 - Lorenzo (140)
2012 - Isaac (70)
2010 - Danielle (115)
2005 - Philippe (70)
2004 - Karl (110)

90 kt
2024 - Beryl (145)
2021 - Larry (110)
2017 - Jose (135)
2016 - Matthew (145)
2009 - Bill (115)
2007 - Dean (150)

85 kt
2020 - Delta (120)
2015 - Danny (110)
2014 - Gonzalo (125)
2011 - Katia (120)
2010 - Igor (135)
2010 - Earl (125)
2006 - Helene (105)
2005 - Wilma (160)

80 kt
2024 - Leslie (90)
2022 - Danielle (75)
2020 - Teddy (120)
2019 - Jerry (90)
2017 - Maria (150)
2017 - Irma (155)
2016 - Gaston (105)
2012 - Leslie (70)
2005 - Rita (155)
2004 - Earl (45)
1999 - Emily (45)

[cycloneye]

 https://x.com/philklotzbach/status/1954923193015369746

[cycloneye]

Kevin, that is a vey interesting archive that you have about those first strong advisories at peak intensity. Keep it up for years to come.

[cycloneye]

Good analysis from Levi Cowan.


 https://x.com/TropicalTidbits/status/1954925227198316794

[Beef Stew]

A recurve is definitely the most likely outcome here, but I won't feel reaching that conclusion for at least a few more days. Mid-August climo suggests that, while still less likely than a recurve, the sub-seasonal risk for a US east coast landfall from an MDR storm remains comparatively elevated. Until Erin completes her forecasted WSW motion and we have a better idea of the position and strength of the ridge over the North Atlantic, we won't be able to say where this storm ends up definitively. The synoptic pattern surrounding Florence was also favoring a recurve... until the building ridge turned out to be far stronger than originally modeled.

And even if the likely recurve does happen, I think it's important to remember that recurve ≠ fish storm. An impact to Bermuda or Atlantic Canada are both well within the range of realistic outcomes.

[Sciencerocks]

[Cachondo23]

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.

[Hurricane2022]

 https://x.com/MichaelIgbino10/status/1954920297930391715