Quincy

Trend over the past 24 h since your post has been toward focusing the most interesting period on Monday over OK/TX, before the system becomes more barotropic thereafter. Right now it looks a bit too positive-tilt to get me excited about the hodo shape (particularly given that instability is likely to be seasonably modest), but it's nice to see the above-average November severe activity continue.

 

http://www.pivotalweather.com/model.php?m=GFS&p=03ehi&rh=2015111212&fh=108&r=sc&lat=33.5000&lon=-98.3780&metar=

 

ECMWF looks relatively similar this afternoon, with 1000 J/kg SBCAPE nosing into SW OK by Monday afternoon.

The focus has shifted earlier, but perhaps not enough for a big day on Monday. Although the evening looks interesting, the best environment seems to occur overnight across eastern Texas. It's the 06z-12z time-frame that instability is maximized, as the low-level jet really cranks and mid-level lapse rates steepen. 

Speed this up a bit and it could be really interesting. Tuesday looks messy, although I could see a potent squall line early in the day with embedded tornadoes.

12z model suite continues a strong signal for the lower Mississippi Valley and surrounding subforums to the east. Too soon for details, but this easily looks more impressive than what's going on today.

The GFS/Euro show another dynamic system in the Plains about a week from now. Not quite as impressive as this current system and a bit further south, but worth watching later forecasts and trends.

I wouldn't be surprised if this thing peaks severe wise on Wed from 12-18z over the E Plains and Lower MO Valley. Both the Euro and GFS are showing some appreciable instability there closer to the triple point where colder 500 mb temps will result in steeper mid level lapse rates on the nose of the LLJ.

Based on the GFS/Euro (12z), certainly have to agree with this.

The Euro actually shows the best instability in the east-central Plains at 12z on Wed, lessening with time with movement into Iowa and Missouri. Likewise, the GFS forecast soundings for eastern Missouri and southeastern Iowa are not as impressive as further west/earlier.

Eyes on the lower Missouri Valley tomorrow, but will have to check back in the morning to see how things are evolving. No signal at this point to believe anything other than another 2015 underperforming setup.

I've been casually watching Sunday across the north-central states. A lot can change and there has been some model adjusting, but keeping an eye on a vigorous shortwave forecast to eject across the northern Plains Sunday into early Monday. There may be somewhat of a disconnect between the best forcing, strongest wind fields and the warm sector, but details can be ironed out in the coming days.

Based on model indications now, I'd peg the focus on the eastern Dakotas into the Upper Midwest as an area to keep an eye on. Nothing significant and not outbreak-material, but the way this year has gone, at least it's something on the radar.

I wonder how this fall will shape up, if it may try to pull a 2013 or keep the trend of generally lackluster severe threats. I'd tend to lean toward the latter.

Well this got messy fast. NE and IA already looks like a bust.

One of the biggest flops of the year, I'd say. I don't think the models handled it all that badly. The HRRR was pretty much onboard with storms merging into a massive line fairly quickly. The parameters weren't off the charts either, so I'm not sure a 10% tornado threat over such a large area was warranted. Only two severe reports, period, north of Omaha. One in Minnesota and one in North Dakota. 

A prime example of #2015ing.

Mid-level lapse rates are just awful tomorrow. One of several mitigating factors. I do think that eastern Kansas to perhaps far southeastern Nebraska has a conditional risk for something interesting, severe-wise. The NAM is trying to keep the low-levels a bit backed, which would be more favorable than the typical cold frontal passage. Even with that said, storm mode and convection evolution looks rather messy across the board. 

Nice looking supercell (tornado warned) in far northwestern Minnesota. There were several reports earlier of baseball sized hail, including a 3" hail report out of Roseau, MN.

SPC going with higher confidence today is a potential tornado threat across South Dakota and adjacent Nebraska. Although instability and moisture return will not be nearly as favorable as yesterday, the overall timing with respect to peak heating and coverage of convective initiation should result in several strong to severe thunderstorms.

Forcing will be more focused with water vapor imagery showing a shortwave through moving east through Montana. Mid level temperatures are cooler, so capping is not a concern. Convection allowing model solutions include thunderstorms developing by midday to early afternoon. Combine the aforementioned setup with a weak surface low lingering across southern South Dakota/far northern Nebraska and the locally backed flow could support a few tornadoes.

HRRR has fluctuated a bit with respect to exact placement, however it has consistently showed convective initiation across South Dakota with at least a few more robust looking semi-discrete storms on the southern flank of the activity. 

Tornado touched down right around 9:00 just east of Elk Creek. I had a visual on it by 9:01 (wooded area). Began roping out and lifted at 9:11 p.m. 8 SE Elk Creek.

Cap winning out via TOP 00z sounding. Limited instability/poor low-level thermal profile at OAX:

Not surprised that the SPC toned up the wording a bit for day 2. Still some mixed signals, but a few signs are there for a potentially enhanced severe weather threat.

Both the NAM and GFS show enlarged hodographs and considerable shear, including in the low levels, from far eastern Nebraska into west-central/southwestern Iowa, coinciding with strong instability.

Some red flags/uncertainties arise from the high PW values forecast, some warming in the mid-levels, attributing to initially modest mid-level lapse rates and storm mode. While the 4km NAM is actually late with renewed storm development, the GFS shows more of a mass of convection developing over Iowa. I would suspect that the storm model will be fairly messy and if any semi-discrete or discrete storms do fire, they would be HP and merge relatively quickly.

Nonetheless, a tornado threat may exist, especially if any storms can fire in the vicinity of strong low-level shear, perhaps near any lingering outflow boundaries from early-day convection.

Tomorrow's setup isn't all that much different from today. If anything, somewhat stronger instability, but forcing may be slightly weaker. I'd expect a similar outcome, although the storm mode and motion may be more on the messy side. Same area too, with storms firing over northeastern New Mexico and moving toward/into the Texas panhandle. 

Currently have a trio of intense supercells ongoing across the Texas panhandle. All are producing large to very large hail. The storm that passed over Channing dropped baseball sized-hail.

I find it a bit odd that the panhandle watch has <5% probs for 2+ tornadoes. I can't say I expect a bunch, but the environment looks increasingly favorable between AMA and LBB by 00-02z, IF storms can remain discrete. Dew-points are well into the 60s with backing low-level flow and moderate instability. Further north, the storms have already formed a line segment and may only pose a marginally severe hail risk with a higher likelihood of damaging winds.

A bit of a localized, conditional severe risk tomorrow - most notably around the TX/OK panhandles. A subtle vorticity lobe is progged to move from NE NM/SE CO through the southern High Plains with lee surface cyclogenesis late in the day/evening. Although boundary layer dew-points are rather low at the moment, in the mid-40s to mid-50s across the area, southerly flow beneath a retreating warm front should result in modest to moderate instability reaching the TX panhandle by 00z Thursday. 

Upper level flow is fairly anemic, but 0-6km shear should be sufficient for supercells and backing of low-level winds should result in sizable hodographs by early evening. 

A rather modest setup, but one that could result in a few robust supercells. I can see an isolated tornado threat developing, assuming moisture return is considerable enough and shear reaches the levels currently forecast. Storms may merge into a small complex into the evening, posing a marginal damaging wind threat eastward across the panhandles.

The way this year has gone, marginal/modest setups like this have been fairly common, although the results have generally been below expectations. I'm not an expert on climo for the panhandles, but I would venture to assume this is rather late in the season for a setup this far south?

All of this going on with no tornado risk area in the 20z outlook. I am having an increasingly difficult time believing many of Dial's outlooks. They have been weird for a long time now.

Could see some isolated severe storms on either side of the SD/NE border this afternoon. At least based on mesoanalysis, conditions seem more unstable than most progs. Large to very large hail appears to be the most likely hazard.

Tomorrow looks messy (#2015ing) with respect to storm mode/evolution. Perhaps the most probable significant threat will be damaging winds/hail via MCS in the evening. The focus is in SD and areas to the immediate east/southeast.

Multiple funnel clouds down here, but I haven't seen anything conclusive yet as far as touchdowns. In the Greenwood section at the moment.

Too much warming around 700mb, but the cap is starting to erode a bit. Would expect at least one or two intense supercells at the over the next 1-4 hours. Most likely in west-central Missouri. Perhaps lose to the southeast side of KC metro.

The severe potential is really going to heavily depend on the track and coverage of the morning MCS. The HRRR seems to be a bit more expansive, while the NAM is quick to weaken. The NAM solution shows strong to locally extreme instability developing in its wake. Even the latest HRRR shows moderate instability already in place near the MO/KS border by 17z. We'll have to see how convective trends look in the morning for more clarity. At the very least, as mentioned above, some areas are going to see quite a bit of rain. The NW flow and trajectories would probably favor some training too.

Seeing some intriguing forecast soundings from both the NAM and GFS for southeastern Kansas into west-central Missouri tomorrow. Ongoing convection is one of the biggest issues, although if some storms can develop on the southwestern flank of that action, they'll be tapping into a forecast environment that is very supportive of severe thunderstorms. Looking closer, it appears that the models want to develop a small area of low pressure near the KS/MO border. Another convoluted setup that has many issues, but nonetheless, SPC did introduce a SLGT risk area in the 1730 Day 2 outlook.

The Aberdeen sounding didn't make it past 400mb, but there was no shortage of shear observed. I wasn't monitoring this threat closely, but the setup now includes a modest 1008mb surface low in eastern ND with moderate instability, favorable wind shear, a nicely timed vorticity lobe and the region lies on the nose of a 45-50kt 500mb jet. 00z mesoanalysis was showing in excess of 250 m²s^-2 0-1km SRH near the most vigorous storms.

Looking at tomorrow, I don't think the setup is nearly as volatile, but I'd suspect there is a decent amount of severe thunderstorm activity across Missouri and vicinity. The directional shear does not look at favorable as today was. There is also a lack of clarity on the placement of a (secondary?) surface low. WPC was pinning this near the KS/MO border tomorrow afternoon with a warm front segment across northern MO. While the RGEM was similar, the NAM/GFS keep the main low moving SE through Iowa and a cold front dropping south through KS/MO. 

Nonetheless, any outflow boundaries from overnight/early day convection tomorrow could come into play tomorrow afternoon. Instability will not be an issue and shear would support supercells. This is echoed by the 4km NAM simulated radar progs. However, if we are dealing with more of a cold front and winds are out of the SW ahead of it, the tornado threat will probably remain low end/marginal. The upper level winds are progged to be NW to NNW, so there will still be decent directional shear, even without backing winds near the surface.

Analog guidance showed several events with a corridor of severe thunderstorm reports, including tornadoes, extending from the eastern Dakotas/Minnesota, down into Missouri.

The environment isn't particularly impressive to the south (weak shear), but moderate instability and steep lapse rates are helping. Can't imagine the southern storms latest severe too long. Much stronger wind shear across Nebraska and some guidance favors upscale growth with a cluster eventually making it to northern Missouri overnight. Wouldn't be surprised if that convection stays robust for a while.

As a front/boundary shifts south, may actually see some storms across Oklahoma and Arkansas tomorrow that could feature some severe wind/hail.