ATL: SAM - Models

[KirbyDude25]

The 18Z HWRF is starting to come in, and I don't know what the heck it's thinking. It has a 99-knot hurricane 9 hours after initialization (which, need I remind everyone, is under 4 hours after this comment's writing) with a pressure of 990 mbar. Can a Category 3 even have a pressure that high? We might need to throw this run out.

[Woofde]

The 18Z HWRF is starting to come in, and I don't know what the heck it's thinking. It has a 99-knot hurricane 9 hours after initialization (which, need I remind everyone, is under 4 hours after this comment's writing) with a pressure of 990 mbar. Can a Category 3 even have a pressure that high? We might need to throw this run out.

I think you're looking at the wrong level of the atmosphere. 10m winds are where you should be looking. Definitely no where near a Cat 3, it's a Cat 1 at 9 hours out.

[Teban54]

The 18Z HWRF is starting to come in, and I don't know what the heck it's thinking. It has a 99-knot hurricane 9 hours after initialization (which, need I remind everyone, is under 4 hours after this comment's writing) with a pressure of 990 mbar. Can a Category 3 even have a pressure that high? We might need to throw this run out.

You're looking at max winds at the 850mb level, not surface winds. The 10m wind speed at 9 hrs is 70.1kt, which is still quite high but more in line with a pressure of 990 mb.

[johngaltfla]

The new GFS model has body slammed the ECMWF all season. My money is on a fish recurve based on every model that uses the GFS base data and it's own performance this season.

That'd be nice but the GFS didn't present an OTS solution.

Watch the pattern in the Western US. There are more cold fronts coming.

[tolakram]

HWRF 24 hours

[KirbyDude25]

I think you're looking at the wrong level of the atmosphere. 10m winds are where you should be looking. Definitely no where near a Cat 3, it's a Cat 1 at 9 hours out.

You're looking at max winds at the 850mb level, not surface winds. The 10m wind speed at 9 hrs is 70.1kt, which is still quite high but more in line with a pressure of 990 mb.

Oops, my bad! Guess I had the wrong thing selected on Tropical Tidbits. 70 knots makes a lot more sense than 100.

[tolakram]

Stay on topic please, I had to move a few posts to moderation. Remember some kind of humor doesn't work well in text.

[aspen]

Interestingly, after a period of rapid intensification between tonight and Saturday morning, both the HWRF and HMON have Sam level off as a Cat 3. I’m not sure what causes this — maybe an eyewall meld, or a bit of shear, or an outflow channel closing, or it’s not over warm enough waters to get any stronger.

[ElectricStorm]

Interestingly, after a period of rapid intensification between tonight and Saturday morning, both the HWRF and HMON have Sam level off as a Cat 3. I’m not sure what causes this — maybe an eyewall meld, or a bit of shear, or an outflow channel closing, or it’s not over warm enough waters to get any stronger.

NHC mentioned shear could increase in a few days so that might be why.

[IcyTundra]

The new GFS model has body slammed the ECMWF all season. My money is on a fish recurve based on every model that uses the GFS base data and it's own performance this season.

That'd be nice but the GFS didn't present an OTS solution.

Watch the pattern in the Western US. There are more cold fronts coming.

The GFS is taking that into account but is still showing a Nova Scotia landfall.

[aspen]

Interestingly, after a period of rapid intensification between tonight and Saturday morning, both the HWRF and HMON have Sam level off as a Cat 3. I’m not sure what causes this — maybe an eyewall meld, or a bit of shear, or an outflow channel closing, or it’s not over warm enough waters to get any stronger.

NHC mentioned shear could increase in a few days so that might be why.

HWRF soundings don’t seem to show shear, but it’s weakening by Sunday night. Doesn’t seem to be an EWRC either.

[Ubuntwo]

My guess is upwelling. 12z HWRF P shows it well. Skin temps are high but Sam will be pretty slow moving and OHC is not stellar.

[Spacecoast]

[aspen]

Looks to be a brief EWRC as well, at least on the HMON. It seems to go from 09z Monday through 06z Tuesday.

[Blown Away]

My guess is upwelling. 12z HWRF P shows it well. Skin temps are high but Sam will be pretty slow moving and OHC is not stellar.
https://i.imgur.com/uUG9IzY.png

18z HWRF a full degree S and W of 12z at day 4.

[aspen]

Both the HMON and HWRF show the intensity of Sam leveling off for a day or two, and it appears to be a combo of some upwelling as Sam slows due to the weakness in the ridge, as well as some kind of EWRC or eyewall meld. Both models show intensification resuming on Tuesday into Wednesday and show a 950s system at the end of their runs. However, the HWRF is nearly 3 degrees further south than the HMON.

[aspen]

Good thing this is going to miss the islands

[Geauxtigers_2019_9]

Good thing this is going to miss the islands
https://i.imgur.com/hZkh2md.png

I wouldn’t jump the gun. Very well could still hit the islands.

[Shell Mound]

Good thing this is going to miss the islands
https://i.imgur.com/hZkh2md.png

The 18Z HWRF shows a steady northwesterly heading on D3–5, during which time Sam ends near 17°N 56°W. This virtually guarantees an OTS path, on this run.

[AutoPenalti]

Good thing this is going to miss the islands
https://i.imgur.com/hZkh2md.png

The 18Z HWRF shows a steady northwesterly heading on D3–5, during which time Sam ends near 17°N 56°W. This virtually guarantees an OTS path, on this run.

Regardless it is another SW shift.