Severe WX Severe Weather Threat - February 22-23, 2023 (MO, IL, IN)

[UncleJuJu98]

One thing I'd like to learn is how to tell wether a area is stream wise, I've always thought it's critical angle but I'm not sure. I've always gone off the basis of a 90 degree angle being stream wise but I don't think that's it. We can. Have this massive SRH Helicity but unless it's gone streamwise than I've heard its not at it's full potential.

*Found a video to explain it some*

 

[UK_EF4]

UKMET, ECM and GFS continue on from this morning with significant severe next Wednesday. Yes, they may not be all in perfect agreement - but they all show significant severe setups. The GEM is a bit of an outlier with poor moisture, but otherwise the stage seems to be being set for a *potentially* significant severe event, though as others have said better ensemble support probably needed before we charge full steam ahead with this - Though it’s worth saying the parameters shown on some models are the most significant we’ve seen this year, and enough that discrete supercells or not, significant tornadoes would hypothetically be possible.

 

[Penitentes]

Seeing suggestions that the high amount of forcing would tend to produce a QLCS instead of discrete development—at what point in the modeling/forecasting process does that distinction really kick in? I.e. will we be on our toes until the day of, or if the setup remains this way will we be able to call for an intense squall line sooner?

 

[UncleJuJu98]

Seeing suggestions that the high amount of forcing would tend to produce a QLCS instead of discrete development—at what point in the modeling/forecasting process does that distinction really kick in? I.e. will we be on our toes until the day of, or if the setup remains this way will we be able to call for an intense squall line sooner?

I always like to wait until mesoscale models to forecast what the storm mode would be, but just off a quick look yeah it seems favorable for a QCLS. Need more drier air and veered winds in the atmosphere. At this point a QCLS with embedded rotations and possibly some supercells ahead of it would be a smart assumption. If it starts out semi discreet everything will grow upscale into a line fairly quickly with that look.

Minor tweaks could change this but, this setup still needs more consensus the GFS has been on board with this for a few runs now. I'd wait on mesoscale models though.

Based on the synoptic placement of the upper level low it's a pretty favorable look for tornadoes in Alabama. So I'm going to go with what @ARCC said and give it the hmm test. Generally that placement and negative tilt evolution will result in your more robust deep south tornado days.

Best course of action now is to wait until more data comes in!

 

[UK_EF4]

I always like to wait until mesoscale models to forecast what the storm mode would be, but just off a quick look yeah it seems favorable for a QCLS. Need more drier air and veered winds in the atmosphere. At this point a QCLS with embedded rotations and possibly some supercells ahead of it would be a smart assumption. If it starts out semi discreet everything will grow upscale into a line fairly quickly with that look.

Minor tweaks could change this but, this setup still needs more consensus the GFS has been on board with this for a few runs now. I'd wait on mesoscale models though.

Based on the synoptic placement of the upper level low it's a pretty favorable look for tornadoes in Alabama. So I'm going to go with what @ARCC said and give it the hmm test. Generally that placement and negative tilt evolution will result in your more robust deep south tornado days.

Best course of action now is to wait until more data comes in!

These compact and potent shortwave troughs with very strong kinematics often go linear because flow is typically more meridional and we get boundary parallel shear vectors - and of course very strong forcing. So a qlcs is probably almost a certainty here. Yet I see a few people on twitter saying QLCS will be the only mode, and comparing to March 2022 events - except most models have a much broader and larger warm sector which naturally makes discrete development more likely than a small pinched off warm sector (like that event). So I have to agree with you in the fact we can’t dismiss a bi-modal threat at this stage, and the fact we are still 5 days out and like you say I should probably wait for more model data before I start getting bogged down with the details like this haha

 

[UncleJuJu98]

These compact and potent shortwave troughs with very strong kinematics often go linear because flow is typically more meridional and we get boundary parallel shear vectors - and of course very strong forcing. So a qlcs is probably almost a certainty here. Yet I see a few people on twitter saying QLCS will be the only mode, and comparing to March 2022 events - except most models have a much broader and larger warm sector which naturally makes discrete development more likely than a small pinched off warm sector (like that event). So I have to agree with you in the fact we can’t dismiss a bi-modal threat at this stage, and the fact we are still 5 days out and like you say I should probably wait for more model data before I start getting bogged down with the details like this haha

The low pressure needs to be more broader for a substantial tornado threat, was just looking through at to why the winds were not veered like they normally would in a barreling upper level low in this type of ejection. The trough as it digs pushes to a point not conducive of a serious tornado threat. Would be a heck of a damaging wind threat though lol.

The low does broaden as it gets into the Tennessee valley some. still to early at this point to focus on specifics, things will change for better or worse. We are in that funky period.

 

[CheeselandSkies]

View attachment 17983

Just pulled this sounding from 00z GFS for Mississippi on Wednesday.

Largest hodograph I've seen in quite a while.

That belongs in the hodograph/forecast sounding hall of fame right there. That in the presence of 82 3CAPE is terrifying. I'm not gonna say any date, but suffice to say that would be high risk worthy should a balloon/VWP actually take that sounding in real time.

 

[UncleJuJu98]

That belongs in the hodograph/forecast sounding hall of fame right there. That in the presence of 82 3CAPE is terrifying. I'm not gonna say any date, but suffice to say that would be high risk worthy should a balloon/VWP actually take that sounding in real time.

Lol it rivals the "bonkers" wind shear as quoted from the NWS of mobiles weather discussion from the coastal January tornado event hahah

 

[UncleJuJu98]

Update from trey.

 

[Clancy]

Should definitely wait for more consensus given the tendency for the models to wobble with the intensity of these systems as of late, but it definitely has a look to it. Interested to see what SPC says tomorrow.

 

[JPWX]

My current forecasted high for next Thursday is 85. Tupelo's record high for February is 84 back in 1996 and Aberdeen's record high for February is 87 set back in 1996. Tupelo's current forecasted high for Thursday is 84 while Aberdeen's current forecasted high is 86. We're either gonna tie or break the record high's in 1996. Either way, severe weather wise, you can't have these types of high temperatures without something significant happening.

 

[UncleJuJu98]

Trey says he would expect a 15% in tonight's outlook if model consistency continues. Dang man haha. And I thought I was being to aggressive for even getting into some of the details on the event haha

 

[UncleJuJu98]

Haven't crossed the Fred horizon so red flags are hindered currently haha

 

[Shakespeare 2016]

My current forecasted high for next Thursday is 85. Tupelo's record high for February is 84 back in 1996 and Aberdeen's record high for February is 87 set back in 1996. Tupelo's current forecasted high for Thursday is 84 while Aberdeen's current forecasted high is 86. We're either gonna tie or break the record high's in 1996. Either way, severe weather wise, you can't have these types of high temperatures without something significant happening.

That is phenomenal. Even high temperatures around 75.0°F to 80.0°F and dewpoints in the mid 60s to lower 70s always tends to work anytime of the year as long as you have the other ingredients/parameters for a major tornado outbreak.

 

[CheeselandSkies]

The GFS has generally stuck to its guns with that very potent, compact lead shortwave that comes up out of Mexico and consequent huge hodographs/insane SRH over portions of MS and/or vicinity. As impressive as that is, it almost seems like as depicted verbatim it's mucking things up for the jet streak that's shown punching into the base of the main trough further west, which would otherwise result in an even more widespread threat.

 

[UncleJuJu98]

00z GFS looks better than the last 3 runs I would say. Much more broader low or wave moving through it instead of a elongated point. And as a result soundings are more veered above the low levels.

 

[UK_EF4]

 

[UK_EF4]

 

[UncleJuJu98]

Much better looking for significant severe weather on 00z and 06z.
Supercell composite will be extremely high when this one gets in range over missippi and Louisiana. The SPC doesn't say what storm mode or initiators are.

*Actually 06z is less veered than the 00z.

 

[UncleJuJu98]

Kinda curious as if a more open wave
;zonal. in the upper levels would be more conducive for severe weather in this setup (tornadoes). less extreme forcing; but still very good shear and better veering with some height falls.