ATL: ERNESTO - Models

[aspen]

18z HMON seems to be showing some dry air entrainment on Thursday, disrupting the eyewall and any attempt at RI. Which is odd because it doesn’t seem like there’s significant shear.

[IcyTundra]

I find it interesting how some models like the GFS and the HAFS (A and B) stop the NNE movement as it approaches Bermuda and briefly turn it due north or slightly west of due north before resuming the NNE movement. This could result in Bermuda avoiding the worst of Ernesto and down the road it could make Atlantic Canada impacts more likely.

[kevin]

06z models are quite bullish in terms of strength.

ICON: 939 mb at 108 hrs, probably a high-end cat 4.
HWRF: 953 mb at 108 hrs with peak winds of 105 kt, a strong cat 3.
HMON: 950 mb at 87 hrs with peak winds of 117 kt, a cat 4.
HAFS-A: 957 mb at 114 hrs but with unusually low winds of 'only' 85 kt, cat 2.
HAFS-B: 956 mb at 123 hrs with peak winds of 93 kt, a high-end cat 2.

These models together would blend to a cat 3 hurricane (around 951 mb / 105 kt assuming ICON's 939 mb would result in ~130 kt).

[aspen]

18z hurricane models are a little stronger in the short-term and took a significant westward shift, some getting Ernesto to 70-71W before getting kicked back east. The timing of shear impacts has seemingly been moved mostly to Friday.

[Hybridstorm_November2001]

18z hurricane models are a little stronger in the short-term and took a significant westward shift, some getting Ernesto to 70-71W before getting kicked back east. The timing of shear impacts has seemingly been moved mostly to Friday.

I don't like how the second (weekend) trough tilts neutral and then evaporates over the East Coast, especially on the GFS. It doesn't look right to me, but we'll see.

[Woofde]

18z hurricane models are a little stronger in the short-term and took a significant westward shift, some getting Ernesto to 70-71W before getting kicked back east. The timing of shear impacts has seemingly been moved mostly to Friday.

Notably all four of them now bring Ernesto to a peak of 100kts or higher. HAFS-B at 125 kts is the highest of the bunch. If it keeps the decent intensification pace before the shear, I'd say Ernesto has a solid shot at becoming our second major.

[Ptarmigan]

Looking at the forecast models, there is a general consensus that Ernesto is looking to be a major hurricane.

[PavelGaborik10]

Threat to Nova Scotia looks to be dwindling, Newfoundland still has a chance at some impacts

[LarryWx]

Threat to Nova Scotia looks to be dwindling, Newfoundland still has a chance at some impacts

0Z Euro: unlike 12Z which went 150 miles E of Bermuda, this run swerves W and misses Bermuda W by 175 miles followed by a LF on E Nova Scotia and SW Newfoundland!

[kevin]

Today's 06z models are still very bullish.

ICON: 944 mb at 108 hrs, probably a cat 4.
HWRF: 948 mb at 60 hrs with peak winds of 108 kt, a strong cat 3.
HMON: 955 mb at 51 hrs with peak winds of 116 kt, a cat 4.
HAFS-A: 947 mb at 108 hrs with peak winds of 109 kt, a strong cat 3. Intensification is much more gradual though.
HAFS-B: 957 mb at 48 hrs with peak winds of 110 kt, a strong cat 3.

These models together would blend to a high-end cat 3 or low-end cat 4 hurricane (around 950 mb / 113 kt assuming ICON's 944 mb would result in ~120 kt).

[PavelGaborik10]

Threat to Nova Scotia looks to be dwindling, Newfoundland still has a chance at some impacts

0Z Euro: unlike 12Z which went 150 miles E of Bermuda, this run swerves W and misses Bermuda W by 175 miles followed by a LF on E Nova Scotia and SW Newfoundland!

GFS and Euro essentially completely flipped, this is going to be a real damn headache if others follow suit later today as we enter the 5 day frame.

[Teban54]

 https://x.com/DCAreaWx/status/1823711754989506792




 https://x.com/webberweather/status/1823705939104428042

[LarryWx]

12Z UKMET: 50 miles SW of Bermuda (similar to 0Z) then moves ENE in N. Atlantic without threat to land then (0Z had crossed Newfoundland):

TROPICAL STORM ERNESTO ANALYSED POSITION : 20.1N 67.3W

ATCF IDENTIFIER : AL052024

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 14.08.2024 0 20.1N 67.3W 998 51
0000UTC 15.08.2024 12 22.5N 68.5W 995 51
1200UTC 15.08.2024 24 24.8N 68.9W 992 51
0000UTC 16.08.2024 36 26.9N 67.7W 989 50
1200UTC 16.08.2024 48 29.0N 66.1W 987 53
0000UTC 17.08.2024 60 31.2N 64.5W 981 62
1200UTC 17.08.2024 72 32.6N 63.7W 980 51
0000UTC 18.08.2024 84 33.0N 63.5W 979 56
1200UTC 18.08.2024 96 34.4N 63.0W 980 58
0000UTC 19.08.2024 108 36.4N 62.3W 975 64
1200UTC 19.08.2024 120 38.9N 60.3W 971 64
0000UTC 20.08.2024 132 41.7N 56.1W 967 72
1200UTC 20.08.2024 144 44.3N 49.0W 973 63
0000UTC 21.08.2024 156 46.9N 39.3W 978 54
1200UTC 21.08.2024 168 50.9N 28.6W 973 50

[kevin]

12z ICON would be a worst-case scenario for Bermuda. A 943 mb cat 4 hurricane slowing down on approach and impacting the island for about 20 hours without any significant weakening.

[ElectricStorm]

Intensity guidance is suggesting the chances for a major are decreasing. 0z cycle had the majority in the Cat 3 range with a few nearing Cat 4. 6z and 12z cycles have steadily decreased. If the 18z cycle looks similar I'd imagine the NHC will lower the forecasted peak a bit. Hurricane models still deepen it quite a bit but since the system is so broad I would think a low pressure (perhaps in the 950s or even 940s) may still not be enough to bring winds up to 100kts, especially if it develops a large core like the HWRF is suggesting. I'm thinking this peaks around 90-100kts with pressure in the 950s. Maybe something similar to Earl 2022.

[LarryWx]

12Z Euro: slightly W of 6Z but well E of the 0Z that had shifted so far W from yesterday’s 12Z: this run blasts Bermuda with a cat 2 and 9-13” of rainfall (heaviest W end) with center passing ~50 miles W of W end. Then crosses SE Newfoundland followed by ET transition and a move into W Norway.

Edit:
12Z EPS: centered around the operational with most members in the 970s to 960s near Bermuda

12Z JMA has strongest yet for any panel with 969 mb 250 miles NE of Bermuda

[MEANINGLESS_NUMBERS]

06z Euro slows the storm right down over Bermuda and leaves us in the eye for 12 hours. That would be wild.

[ElectricStorm]

18z intensity guidance (not including hurricane models) seem to be relatively similar to the 12z cycle with perhaps a few more Cat 3 members. I'm guessing the next NHC forecast peak will remain unchanged (100kts)

[LarryWx]

The 18Z ICON is brutal for Bermuda with 940 mb and 16-17” of rain due to it slowing near there. Hopefully both of these are way overdone.

The 18Z GFS is (nearly) a direct hit but with a not nearly as strong 966 mb. It has ~12” of rainfall. Hopefully rainfall like this, which I believe would be record breaking, won’t occur.

[MEANINGLESS_NUMBERS]

12z ICON would be a worst-case scenario for Bermuda. A 943 mb cat 4 hurricane slowing down on approach and impacting the island for about 20 hours without any significant weakening.

https://i.imgur.com/bZTBFIO.gif

Bermuda is tremendously well prepared and resilient but that would be challenging.