ATL: ERIN - Hurricane - Discussion

[sasha_B]

Looks like the north and east side of the storm is recovering a little in recent frames, with cooling cloud tops and a more symmetrical look overall. The subjective Dvorak fix from NOAA for 18z is T3.5 (as at 12z) but MET up to 4.0...Erin is also gaining latitude faster now, with that fix placing the center near 16.6N.

[cycloneye]

18z Best Track is in same position of Dvorak. 16.6N-50.4W. Moving west at 275 degrees.

AL, 05, 2025081418, , BEST, 0, 166N, 504W, 50, 998, TS

[StormWeather]

18z Best Track is in same position of Dvorak. 16.6N-50.4W. Moving west at 275 degrees.

AL, 05, 2025081418, , BEST, 0, 166N, 504W, 50, 998, TS

https://i.imgur.com/SAH5IrM.png

I expect that this will be a hurricane by early tomorrow morning.

[cycloneye]

18z Best Track is in same position of Dvorak. 16.6N-50.4W. Moving west at 275 degrees.

AL, 05, 2025081418, , BEST, 0, 166N, 504W, 50, 998, TS

https://i.imgur.com/SAH5IrM.png

I expect that this will be a hurricane by early tomorrow morning.

Well, it depends on recon if they find or not hurricane force winds.

[cycloneye]

@AndyHazelton
I will be curious to see what recon finds in #Erin tonight. The convection is healthy, but it looks like the TC is still tilted due to E/NE shear, with the low-level center northeast of the mid-level center. Some of the hurricane models such as the experimental version of HAFS-B maintain this tilt for a while, slowing intensification.

At some point the shear vector will start to come more out of the west, which may allow for better alignment at least for a time. We won't see significant intensification til it gets better vertically aligned.


 https://x.com/AndyHazelton/status/1956075390361055339

[wxman57]

Here is a 1330Z today direct hit by ASCAT. Interesting that it has no 35kt winds. Yeah, it will be interesting to see what recon finds, though I'm not sure the plane will have SFMR.

https://manati.star.nesdis.noaa.gov/ascat_images/cur_25km_METC/zooms/WMBds100.png

[cycloneye]

Tropical Storm Watch issued for Northern Leewards

The Meteorological Service of Antigua/Barbuda has issued a Tropical
Storm Watch for Anguilla and Barbuda.

The Meteorological Service of France has issued a Tropical Storm
Watch for St. Martin and St. Barthelemy.

The Meteorological Service of the Netherlands has issued a Tropical
Storm Watch for Saba and St. Eustatius.

The Meteorological Service of St. Maarten has issued a Tropical
Storm Watch for Sint Maarten

[cycloneye]

[TampaWxLurker]

At least we get intermediate advisories every 3 hours instead of having to wait every 6.

[msbee]

Tropical Storm Watch issued for Northern Leewards

The Meteorological Service of Antigua/Barbuda has issued a Tropical
Storm Watch for Anguilla and Barbuda.

The Meteorological Service of France has issued a Tropical Storm
Watch for St. Martin and St. Barthelemy.

The Meteorological Service of the Netherlands has issued a Tropical
Storm Watch for Saba and St. Eustatius.

The Meteorological Service of St. Maarten has issued a Tropical
Storm Watch for Sint Maarten

Yep, that’s me!

[msbee]

Tropical Storm Watch issued for Northern Leewards

The Meteorological Service of Antigua/Barbuda has issued a Tropical
Storm Watch for Anguilla and Barbuda.

The Meteorological Service of France has issued a Tropical Storm
Watch for St. Martin and St. Barthelemy.

The Meteorological Service of the Netherlands has issued a Tropical
Storm Watch for Saba and St. Eustatius.

The Meteorological Service of St. Maarten has issued a Tropical
Storm Watch for Sint Maarten

Yep, that’s me!

[MarioProtVI]

71 kt FL @ 700 mb

Note: Other sites show 68 kt but someone in a Discord server I’m in has inside info which showed 5s intervals with 71 kt

[StormWeather]

71 kt FL @ 700 mb

So it’s possible that this could already be a hurricane, we just need more data to see. This is why it’s so good to have recon for the Atlantic. NHC’s most recent advisory mentions satellite intensity estimates of 45-55 kts, so estimates can be deceiving on satellite.

[CrazyC83]

Looking through all the data, the best estimate for the intensity is 60 kt.

[StormWeather]

Looking through all the data, the best estimate for the intensity is 60 kt.

I feel like it’s too early to say that. They just got started recently with investigating the storm.

[zzzh]

North side is the strongest side so 60kt seems reasonable

[aspen]

Center is a lot further north than I expected (~17.0N, vs something like 16.7-16.8N). Also a little more tucked under the convection, although the center is still slightly decoupled.

[sasha_B]

Central pressure (according to the dropsonde) is around 1000 hPa which is a bit high for a storm producing at minimum 55～60-kt winds (if not hurricane-force). Not unheard-of but unusual. Wonder if they missed the center or if Erin is just producing unusually high winds relative to its depth.

[wxman57]

Central pressure (according to the dropsonde) is around 1000 hPa which is a bit high for a storm producing at minimum 55～60-kt winds (if not hurricane-force). Not unheard-of but unusual. Wonder if they missed the center or if Erin is just producing unusually high winds relative to its depth.

Agree. This morning's ASCAT hit had no 35kt wind at all. That was about 9 hrs ago. It may have some 45-50kt winds, but the plane won't be measuring surface wind.

[sasha_B]

Central pressure (according to the dropsonde) is around 1000 hPa which is a bit high for a storm producing at minimum 55～60-kt winds (if not hurricane-force). Not unheard-of but unusual. Wonder if they missed the center or if Erin is just producing unusually high winds relative to its depth.

Agree. This morning's ASCAT hit had no 35kt wind at all. That was about 9 hrs ago. It may have some 45-50kt winds, but the plane won't be measuring surface wind.

That's......not what I was saying. ASCAT has known sampling issues and while I understand that FL winds aren't equivalent to surface winds, every indication at the moment (from official sources) is that this was a 50kt+ storm 9 to 12 hours ago & has been strengthening since then. Erin was obviously not a tropical depression at 12z this morning and no one else, at the NHC or on this forum, has made that claim. You'd have to use a conversion factor of 0.66 to reduce 68-kt FL winds to 45 kts at surface, well below the factors in general use.