2023 Global Model Runs Discussion (Out thru day 16)

[cycloneye]

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https://i.postimg.cc/NGRWg8FH/ecmwf.png

This is getting more serious now.

[Category5Kaiju]

https://i.postimg.cc/q7gP096J/fff.gif

https://i.postimg.cc/NGRWg8FH/ecmwf.png

This is getting more serious now.

We have yet to experience the 2023 Atlantic hurricane season, and at this point exactly how active it will be, what storms it will bring, and so forth remain a mystery. But one thing's pretty clear: this season does not seem to be afraid to produce pre-season storms.

[wxman57]

Looks like a frontal low. Models have problems with this type of setup. Not concerned yet.

[cycloneye]

The happy hour GFS 18Z has nothing.

[ThunderForce]

The 00z GFS run also appears to have backed off somewhat with development for now.

Although, I am pretty curious. I'm aware SSTs are rather favorable for this time of year right now, but doesn't wind shear tend to hinder development? Each GFS run seems to be showing a projected wind shear between 45 to 50+ kts in the majority of the Gulf and east of the Florida Peninsula during the period this seems to form, which is rather high.

00z and 18z seem to show the wind shear being strong enough that it appears to prevent the low from strengthening. Yet... GFS's previous runs such as 12z and 06z show a sudden small break in the wind shear in the area the low forms, and it seems to be just enough to allow it to start organizing.

EDIT: Now it seems that the current 06z run has went back to some development of the low. This time it seems it tries to develop near Louisiana and Mississippi before moving onto land.

[Orlando]

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https://i.postimg.cc/NGRWg8FH/ecmwf.png

This is getting more serious now.

Our locals in Orlando are talking about a "Could Be" possibility for this one.

[wxman57]

Note that the GFS & EC both have solid wind shear 50-70 kts over the Gulf and off the SE U.S. Coast. Looks like a frontal wave/low. Definitely not a tropical system.

[SFLcane]

Note that the GFS & EC both have solid wind shear 50-70 kts over the Gulf and off the SE U.S. Coast. Looks like a frontal wave/low. Definitely not a tropical system.

[wxman57]

WSW jet stream of 80-110 kts over the NE Gulf next week. Looks like a non-tropical west Gulf low. Not uncommon in winter and early spring.

Tremendous shear:

[Nimbus]

So some of the models projected this back on Wednesday and there is is cloud rotation on Thursday.
Looks dry and Shear might keep precip totals down but in Florida we have lawns.

[ThunderForce]

The current 00z GFS run seems to have this develop into what looks like a 994 mb tropical storm or possibly high-end tropical depression before making landfall in Louisiana, despite the very high wind shear in the Gulf.

[wxman57]

I do think that a low pressure center will develop south of Louisiana next Tue-Wed, but it will not be remotely tropical. Winds may reach 35kts along the SE LA coast by Wednesday. We see these type of low centers often during the winter months. Wouldn't put it past the NHC calling it STS Arlene. Winds may peak at 35-40 kts, with little chance of becoming stronger, given the extremely high wind shear over it. High pressure to its north will produce the gradient north of the low center.

[cycloneye]

Euro ensembles.

[cycloneye]

Already Accuweather is taking notice.

 https://twitter.com/breakingweather/status/1644371545056321539

[SFLcane]

[JetFuel_SE]

I do think that a low pressure center will develop south of Louisiana next Tue-Wed, but it will not be remotely tropical. Winds may reach 35kts along the SE LA coast by Wednesday. We see these type of low centers often during the winter months. Wouldn't put it past the NHC calling it STS Arlene. Winds may peak at 35-40 kts, with little chance of becoming stronger, given the extremely high wind shear over it. High pressure to its north will produce the gradient north of the low center.

Oh cmon Grandpa, let the kids enjoy the funny model runs.

[wxman57]

I think that the 12Z Euro looks pretty good. Winds 30-35 kts north of the low center along the coast Tue night. Completely non-tropical, though. Likely weakening by Wednesday PM. Winds of 30-35 kts will not make it inland. I suppose there may be a 30% chance NHC calls the low a STD or STS. Regardless, impacts will be the same. Rough weather along the coast and offshore north of the low. Don't trust anything the GFS puts out.

[AJC3]

I think that the 12Z Euro looks pretty good. Winds 30-35 kts north of the low center along the coast Tue night. Completely non-tropical, though. Likely weakening by Wednesday PM. Winds of 30-35 kts will not make it inland. I suppose there may be a 30% chance NHC calls the low a STD or STS. Regardless, impacts will be the same. Rough weather along the coast and offshore north of the low. Don't trust anything the GFS puts out.

They'd really have to do some serious mental gymnastics not to analyze fronts attached to whatever develops. As you mentioned, the environment is decidedly baroclinic all the way down to the surface.

[AJC3]

Already Accuweather is taking notice.

https://twitter.com/breakingweather/status/1644371545056321539

Are they not looking at the actual structure of this system? Sure, they can throw around terms like tropical and subtropical if only looking at the SLP fields, but it's ridiculously easy to infer an XTC with fronts from the temperature and moisture fields. Not surprisingly, the strongest solution (GFS) has, by far the greatest discontinuity in the temperature fields. (i.e. it shows the fronts most readily). This is clearly a gale/near-gale in the making.

[wxman57]

I think that the 12Z Euro looks pretty good. Winds 30-35 kts north of the low center along the coast Tue night. Completely non-tropical, though. Likely weakening by Wednesday PM. Winds of 30-35 kts will not make it inland. I suppose there may be a 30% chance NHC calls the low a STD or STS. Regardless, impacts will be the same. Rough weather along the coast and offshore north of the low. Don't trust anything the GFS puts out.

They'd really have to do some serious mental gymnastics not to analyze fronts attached to whatever develops. As you mentioned, the environment is decidedly baroclinic all the way down to the surface.

If the NHC starts seeing obs from offshore platforms at 30-35 kts, they tend to be a bit "lenient" with classification in the Gulf.