Severe WX April 11th-13th, 2020 Severe Weather Threat

[Taylor Campbell]

All the forecast models show a significant severe weather event this period across the Southeast states. UK, EURO, ICON, GFS, CMC, ACCESS-G. Everything is nasty in the warm sector.

 

[darkskys25]

Still a threat but there are significant differences between the gfs and euro. GFS has the low placement much further North. Euro is more favorable for severe weather. We have seen these models battle it out all winter and spring. Euro has just been off for whatever reason so that makes me cautious. With that said both the GFS and Euro show a severe wx threat but Euro shows a more potentially significant one. Noticed SPC now has 15% for much of AL on Sunday. We have a long ways to go and a lot can and will change.

 

[jmills]

Its worth noting though that the GFS has been slowing down and trending towards the more ominous ECMWF/UKMET solution with a broader, deeper warm sector and with more time for destabilization.

The SPC mentions upgrading the outlook in later discussions if the idea of the deep warm sector from the Euro and the UKMET holds.

 

[Kory]

I honestly can't find a fly in the ointment on some of the modeling (UKMET and Euro). Both of those keep capping along the Gulf Coast preventing convection from firing down south stunting northward progression of the warm sector. A very unstable warm sector over MS/AL with supercellular convection fires off starting around midday and into peak heating. Widespread 0-1km SRH is on the order of 300-400 m2/s2 with 0-3km >500 m2/s2. Storms that are able to establish themselves will be spinning like a top.

The GFS and CMC on the other hand have a large complex of storms that fire off mucking up the wind fields and instability over a good portion of the warm sector. We have seen some NW trend over time, but it's still not optimal for widespread severe wx.

The NAM through the end of the run looks like it's leaning more GFS-ish with a slightly faster progression of the cutoff than the Euro and UKMET. Although the NAM tends to run a bit fast at longer range. Lots to see here with many moving parts. We are far from a slam dunk forecast.

 

[Taylor Campbell]

PDS tornado soundings showing on the globals in the warm sector. All the models are just mean.

 

[Equus]

Modeling has been hurt by the significantly lower number of flights collecting data lately but this definitely has an ominous look. Upper level kinematics are on the very highest end of climo; if 70+ dews do manage to spread over the warm sector then looks like we have to eat our Easter dinner in the basement.

 

[Kory]

Holy cow the euro is bad for Sunday.

 

[Equus]

Puts a nice little surface low south of Nashville backing low level winds at just the right time. Hoo boy. Definitely hoping both the Europe models are overdoing it again.

Southern Lamar County on 12z Euro run

 

[Richardjacks]

Puts a nice little surface low south of Nashville backing low level winds at just the right time. Hoo boy. Definitely hoping both the Europe models are overdoing it again.

 

[Kory]

Those lapse rates. Checkbox #1 of big Dixie events are very steep lapse rates.

 

[Equus]

Now we wait and see if the GFS follows the trends or stays an outlier... if it jumps on board too (seems to be slowly trying) I'm gonna prepare my basement nest lol

 

[Bamamuscle]

Is it too early to pin down how far N this threat will be? Will extreme N al be in play?


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[warneagle]

Definitely too far ahead to resolve things like placement of the warm front, there's still a lot of spread on the timing.

 

[bwalk]

Classic sickle hodo for Sunday.

 

[Taylor Campbell]

I'm looking at the newest GFS run and I'm truly disturbed.

 

[Richardjacks]

I'm looking at the newest GFS run and I'm truly disturbed.

Yes, still a little faster then the Euro, so the threat not as far north as the warm sector is a bit limited. Tonight's 0z Euro will be interesting to watch for any change to the speed as it ejects from the southwest.

 

[Taylor Campbell]

Yes, still a little faster then the Euro, so the threat not as far north as the warm sector is a bit limited. Tonight's 0z Euro will be interesting to watch for any change to the speed as it ejects from the southwest.

It continues to trend north, but yeah regardless if it doesn't make it as far north as the EURO we still have a major tornado outbreak with multiple strong to violent long track tornadoes in the warm sector.

 

[Kory]

 

[gangstonc]

Are we going to see the typical NW trend with the low?

 

[Equus]

If that northward trend holds, gonna bring north AL potentially into play. Don't like seeing the GFS slowly trying to fall in line with Euro/UKmet