Severe WX April 4th-6th, 2022 Severe Weather Threat

[KevinH]

I might modify the dates of this thread as the event comes closer, but more people are bringing this up here and on social media.

If this thread ends up not being needed (which I doubt because, APRIL), I will delete it.

 

[Fred Gossage]

There's a lot of back and forth with this system in especially the deterministic/operational output since it involves how different pieces of energy phase together (or don't), but the ensemble data... especially the GFS ensemble data... has been getting increasingly meaner looking with this system for next Tuesday. I guess we're going to start doing this on a weekly basis now. There will be periods behind a system where we get transient eastern troughing and temporary shots of quiet and cool weather, but after this system this week, ejecting troughs going into April will be overall of a lower amplitude nature. That's going to mean less in the way of these meridional systems with narrow moisture axes and strong linear forcing. Most long range signals, teleconnections, etc., point toward you guys across Dixie Alley needing to make it a point to make sure your safe spots are cleaned out, your emergency kits are stocked, and your helmets and air horns are at the ready over the next few weeks.

 

[KevinH]

There's a lot of back and forth with this system in especially the deterministic/operational output since it involves how different pieces of energy phase together (or don't), but the ensemble data... especially the GFS ensemble data... has been getting increasingly meaner looking with this system for next Tuesday. I guess we're going to start doing this on a weekly basis now. There will be periods behind a system where we get transient eastern troughing and temporary shots of quiet and cool weather, but after this system this week, ejecting troughs going into April will be overall of a lower amplitude nature. That's going to mean less in the way of these meridional systems with narrow moisture axes and strong linear forcing. Most long range signals, teleconnections, etc., point toward you guys across Dixie Alley needing to make it a point to make sure your safe spots are cleaned out, your emergency kits are stocked, and your helmets and air horns are at the ready over the next few weeks.

And why am I not surprised by anything you just said? Sigh… Oh! I have an idea why…

 

[MattPetrulli]

Latest GFS runs have trended towards an MCS just clearing the warm sector and there not really being an event outside of the coastline. Will see if that continues, pretty far out, but it has been a present trend since 00z last night so worth noting. However, 00z Euro didn't really show this.

 

[bwalk]

 

[CheeselandSkies]

View attachment 12966

That's an old tweet referencing yesterday's 12Z run, today's 12Z run had an MCS washout with the instability confined to the immediate Gulf coast, as @MattPetrulli alluded to.

 

[Fred Gossage]

Even modeled as is today, that morning MCS would be a severe threat of some caliber, probably with a tornado risk as well. However, at least in today's data, it has definitely trended toward a more disjointed and less phased solution. There is still back and forth in the data, and there likely will be for a few days, until some of that disturbance initially starts coming onshore. It seems like the more we "upgrade" and update these models (all of them, not just the NCEP/American ones) the worse and more inconsistent they become, and within the 7 day period. I'm missing enough hair at 37 already...

 

[Tennie]

Even modeled as is today, that morning MCS would be a severe threat of some caliber, probably with a tornado risk as well. However, at least in today's data, it has definitely trended toward a more disjointed and less phased solution. There is still back and forth in the data, and there likely will be for a few days, until some of that disturbance initially starts coming onshore. It seems like the more we "upgrade" and update these models (all of them, not just the NCEP/American ones) the worse and more inconsistent they become, and within the 7 day period. I'm missing enough hair at 37 already...

Personally, I wouldn't be surprised if the coarseness of the current global weather observation networks (as compared to the increasing resolutions of the models) is at least one of the reasons for the increasing trend of run-to-run inconsistencies. As such, I would wholeheartedly support a major expansion of the global weather observations network.

 

[MattPetrulli]

Little bit of an uptrend on latest GEFS runs, still looks like a confined threat for southern MS/AL/LA


12z vs 00z

 

[Taylor Campbell]

@WesL, @Lori, @KoD can either of you please get this thread pinned to the top now. The GFS, EURO, and Canadian models all show severe weather likely to occur with the lead shortwave Monday/Tuesday and then also with the cold front Wednesday/Thursday. Thank you.

 

[MattPetrulli]

GFS has been kinda flip flopping all day, but think we're starting to stick to highest tornado potential being southern AL/GAin the morning to early-mid afternoonish Tuesday. Has been kind of consistent in that regard, doesn't look like anything too high end at the moment but seems like a conditional siggy threat for those areas. That's going off GFS, 12z Euro has the same idea to an extent but thermos look to struggle a little more compared to GFS. Wednesday seems a lot more uncertain, 12z Euro didn't have thermos making far north and was a lesser on wind fields compared to GFS which has instability making it very far north, and there being a tornado threat mainly around TN/PA/OH/WV/KY Wednesday afternoon. However, 18z GFS to 00z GFS was non-event to event so may be a fluke run or start of a trend. 18z to 00z GEFS also echoed that trend a little. So something to watch, SPC may outline an area tonight but they may not considering model inconsistency so we'll see.

 

[Taylor Campbell]

Sadly, unless things change substantially we are looking at a multi day significant severe weather outbreak with tornadoes.

 

[Taylor Campbell]

CIPS has a strong match Tuesday for dynamics similar, but stronger to May 3rd, 1984.

 

[Taylor Campbell]

Wow

 

[Casuarina Head]

Wednesday looks to be potentially the most significant day in terms of widespread tornadoes. One key difference vs. earlier systems is that the GEFS/EPS may be starting to converge on a lower-amplitude solution, with the -NAO being west-based and thereby contributing to lower heights than with an east-based -NAO. Historically west-based -NAOs are much more conducive to significant severe weather than east-based -NAOs. The trend toward a slightly +EPO also contributes to suppressed heights with less of a split flow. Overall height fields are lower on the most recent ensemble means. Of course, maybe future runs will trend back toward a more amplified outlook.

 

[CheeselandSkies]

00Z GFS has a gnarly focused triple point setup west of DFW Monday.

 

[CheeselandSkies]

For Dixie on Tuesday and Wednesday, GFS isn't really showing a classic setup with ingredients maxing out with afternoon/evening peak heating, but what it is suggesting is another potentially long-duration threat with multiple rounds of storms. Get ready for more QLCS whack-a-mole at 4 AM...

* Edit: ...and we have SPC outlook areas for Days 4-6 (Monday-Wednesday).

 

[Casuarina Head]

For Dixie on Tuesday and Wednesday, GFS isn't really showing a classic setup with ingredients maxing out with afternoon/evening peak heating, but what it is suggesting is another potentially long-duration threat with multiple rounds of storms. Get ready for more QLCS whack-a-mole at 4 AM...

* Edit: ...and we have SPC outlook areas for Days 4-6 (Monday-Wednesday).

The ML trough signature at 12Z on Wednesday looks to be more neutrally tilted vs. earlier runs. Previous runs showed a strongly positive tilt by then. Also, bear in mind that models are trending toward a dual surface low by 00Z on Thursday, so the extent and penetration of instability by that time will likely verify farther northwest than is currently depicted on the GFS, while also promoting stronger low-level shear that is more closely co-located with the axis of instability. The key is that the overall setup looks to be a classic low-amplitude configuration with a powerful ML trough, initially neutrally tilted during peak diurnal heating, trending toward a negative tilt through the evening/overnight hours. I actually think that the ceiling for this event is much higher than it was for any of the past several episodes. The consensus that instability during “prime time” will be notably higher than in recent events, and there will be a decent EML over the broad warm sector prior to initiation. The NPAC jet extension on 3–4 April is often a precursor to a significant lee cyclone that is often associated with major severe events. Probably the -NAO is one of the main factors that is preventing an even higher ceiling.

 

[tennessee storm chaser]

agree whenever u see a cyclone type slp setting up lee of the Rockies this time year spells trouble for Dixie and midsouth, still very interested i. The second half april as we trend towards positive nao. Something watch … edit your can already see on 0z euro run day 10 significant possible severe setup taking shape .

 

[Clancy]

Three days highlighted by SPC, D-4-6. For some reason can't upload them at the moment.