andyhb

Can we not...

That time of year for the annual thread as spring is less than three months away once more. Following another extremely quiet year with a record low for EF3+ tornadoes and zero violent tornadoes for the first time since at least 1900 (going back through Grazulis' records), we look to be coming out of a weak El Nino event with some potential for maintenance through the spring, along with a PDO that may hover from neutral through positive. Last spring saw an amazing lack of troughing activity through peak season in the western/central states, with winter essentially flipping to summer. Would not be terribly surprised if this season blooms (if it does) a bit later. Curious to hear general thoughts going into next season, hard to imagine one more quiet than this one for the Plains at least, although I thought 2014 took the cake in that department... Number of Tornadoes: 1170 First High Risk: April 23rd

Hmm, that has to be one of the more direct in situ measurements ever gathered of a tornado.

Looking like we're on track for the first year without an F/EF4+ rated tornado since at least 1880, extending the database back through Grazulis' archives. Speaking of that, I am getting my hands on both volumes of the new Significant Tornadoes out next year come hell or high water.

Gotta wonder what this exact setup would've done with spring time thermodynamics at the surface. Not even necessarily "prime" spring time thermodynamics, I'm talking like 67-71 T/60-64 Td here. 00z ILX sounding had a classic sickle shaped hodograph with over 400 m2/s2 ESRH, with most of that concentrated in the 0-1 km layer, not to mention 100 J/kg of 0-3 km CAPE. Pretty solid mid level lapse rates ~7.5 C/km as well thanks to 500 mb temps below -20˚C, that was the key here. Should note that none of the global models had surface winds even close to that strongly backed over the area.

Overheads of the damage in Taylorville.

Will likely be driving southbound on 35 tomorrow towards Austin, wonder if I might take a detour or two along the way... I have strong doubts that initiation will hold off until 00z given the synoptic setup. That is a pretty potent, negatively tilted wave ejecting right overtop of the warm sector, which should provide plenty of forcing for ascent and the cap is not overly strong. Have seen some funky looking wind fields in a few forecast soundings, but most of them don't seem to be too crippling in terms of storm mode problems. Speaking of storm mode given the degree of forcing, have to wonder if it is a relatively quick transition to linear, some more low level backing would certainly help.

DDC gusted to 62 mph at the 15z obs.

That one has some similarities as well, although I think that shortwave was a bit flatter. Something splitting down the middle with maybe a bit more weight on 2015.

Haven't been paying attention to this as much due to other priorities, but I'll be damned if this setup on a synoptic scale doesn't remind me of GHD 2015. Quite a similar 500 mb evolution. And yeah the 12z Euro is a crush job for Chicago and vicinity.

If the Euro is on the right track (and it has been fairly steady), we could be dealing with a very significant severe weather event Monday evening continuing into Tuesday afternoon from E Texas and SE Oklahoma extending into AL and GA. Sampling one of the parameter spaces at 06z in along the I-55 corridor in MS reveals SBCAPE of 1000-2000+ J/kg, deep layer shear of 60-70 kts and low level shear in places in excess of 50 kts (this type of environment is generally in place through the whole period in one place or another). This would be an environment capable of long lived supercells with significant tornadoes. Moreover, this trough is quite low amplitude (compared to its wavelength) and would likely portend a long period of discrete/semi-discrete storm mode. Extent of the threat will be dependent on moisture return of course, but it is important to note that notable destabilization in this case will occur nearly independent of the diurnal cycle given the strong advective processes (WAA, moist advection) vs. diabatic insolation.

That trough early next week showing up across guidance, including quite a strong signal on the ensembles, has my attention for a potential severe wx threat (and a widespread one at that) assuming enough moisture return is available. There already is an established low amplitude trough across the central US and a powerful jet max slides SE into it and somewhat amplifies/kicks the trough negative tilt. The 12z Euro was getting 60s dewpoints all the way into Michigan. There are, as it sits right now, some similarities synoptically to the 10/18/07 severe wx event.

The more problematic event might be early next week with a very favorable 500 mb pattern for a larger scale severe episode across the S US showing up on the ensembles. Going to hinge on how much moisture return can take place since there could be a FROPA or two through the Gulf prior to then, but that definitely looks to be something to watch especially since it may fall on Election Day.

Don't let the fact that Kansas beat Texas in football distract you from the fact that Michael was a Cat 2 at landfall.

That is quite a robust shortwave trough passing through the northern portion of the sub forum tomorrow. Storms will be flying with very strong wind fields in place.

10% hatched tor added for the ND-SD-MN junction. Dare I say the setup doesn't look too bad with plenty of low level moisture and backing surface winds in this vicinity. Issue may be tendency for HP transition given the lack of flow aloft and also 0-1 km shear magnitude isn't ideal especially if storms fire earlier on. Addendum: Man is it hard to analyze setups in a season like this, motivation is at an all time low personally.

Thanks guys, and yeah I'm starting to think me joining seven years ago was the catalyst for the severe seasons going downhill in a hurry lol.

Well that red colour looks nice. Unfortunately the severe season still does not.

Hey all, figured I'd drop my first post in here as a red tagger. ...now can we get an actual setup to talk about (who am I kidding, it's 2018 still)

Not very much shear this far south, more liable to be multicells with some hail given the steep mid level lapse rates.

18z 3 km NAM had a number of long tracking semi discrete cells across much of the Northeast, including a very strong one crossing the entirety of NH and VT. Difference this time compared to most NE setups is that we have the thermos, especially the thermos aloft, in place almost unquestionably (barring convection tonight). If those surface winds can take more of a SSW (or even SW) component tomorrow afternoon, there's liable to be tornado problems given the degree of low level instability and moisture along with very strong deep layer shear for bowing segments and supercells. It would be nice to perhaps have a bit more of a pronounced shortwave, but I'm rather impressed nonetheless.

That EML for tomorrow looks absolutely nasty. You''re all getting better severe than I got on my Plains trip lol.

HREF is going pretty nuts tomorrow across the northeast, albeit convection from today is certainly a factor. Certainly don't see lapse rates that close to dry adiabatic this far east very often at all, and when they are juxtaposed with rather strong shear -> higher end severe possible.

Lol @ not being able to get 40 kts of flow at 500 mb in f*cking May.

I can sense the annoyance/boredom both in that and even in the SPC outlooks recently.