nrgjeff

You guys should be stable enough to avoid trouble in northeast Tenn.

Yep, the front cell of the cluster is dominant. Farther north cell in Tennessee also now appears to have enough space with which to work. Improvement after a hiccup is not unusual when the LLJ gets going close to dark, especially in Dixie. Could be a wild evening indeed. EDIT for below: One of the only things good about Dixie is fewer chasers. Still the terrain is one reason I sat out this one so close to home.

Agree the Alabama cluster (responsible for the Russellville tornado) is blocking the LLJ into the Tenn/Bama Border cell. It is like blocking out in basketball. Really it is. Maybe it can get ahead and come into Chattanooga. Actually, maybe I should be careful what I wish for after dark. NWS just TOR warned the little cell that could...

Here we go! I was a skeptic until seeing Saturday indeed produced the EF-0. Perhaps that Etowah Telilico Plains tornado was the atmosphere tipping its hand. Local WFOs had noted a slower than forecast warm front; however, low clouds are breaking up on VIS. Apparently SPC is expects a robust warm sector in North Alabama. Kinematics, no question, yield SRH 300 J/kg+. Now appears the forecast CAPE values are within reach. Middle Tennessee has a tornado risk, but the low contrast sloppy variety. North Alabama is the clear chase target in the more established warm sector with better visibility. Cells should track from west to east, which is convenient for a chaser on US-72 or Alt-72. However one needs to be mindful of the Tennessee River and limited crossings. A forecast of the outflow boundary position will be more crucial than usual due to the River. One chases either south or north of the River, except for those limited crossings. All that said, my chase status is still TBD. Prefer new cells over that one in Mississippi trying to root. New would have better contrast.

Monday the NAM appears too amped. What's new? Getting NAM'ed. I favor the less intense GFS/ECWMF combo. They have strong/severe but not a tornado set-up. Spann was tweeting which got my attention, because he does not really hype. For now, as of Saturday, I am not greatly concerned/interested but we'll see how it goes... I also had Virginia going to the Final, lol!

The PNA is trying to go negative on the extended models, which is bullish severe. Indonesia is stormy, another bullish sign. However the MJO is muddled with other convection in cold zones for NA. My biggest concern on the bearish side is SSW hangovers usually last longer than forecast. We say that about any blocking, but SSW is the hard liquor or 'shine of blocking. I am not too concerned about March. April is still ahead. Also we have a few forum members who really do not like severe, so a quiet March would not be a total loss.

Temps should warm up the 3rd week of March. Late March is getting close to prime time for Dixie Alley. Above scenarios are reasonable.

2% Strong! Or was it less than 2%? We need Tyler on this Board. Here is how those radar images turned out - tornado on the ground. Really crazy part is that's almost exactly where I documented a tornado August 31, 2017. Mile marker 30 on I-22 for me.

La Nina will fade out this year. We just do not know when. Later would be better for storm chasers. After May I no longer have a dog in the hunt.

Holston may be onto something with -1 NAO if it's coming out of a deeper NAO. We like to talk transition storms. Regrettably I cannot look into it more now. Bottom line, I think everyone is making good points. Nice!

Euro is pretty stout later next week too, but in the Deep South which is more favored by climo. I'm not sure whether to wish for that or pray against it. TODAY Mid South I am reluctantly staying home. Some CAMS - convective allowing (high res) models show lead cells. My gut says they will not be supercells. They are ahead of the best low level shear. If I'm wrong, it would not be the first time LOL. NAM and ARW versions of the WRF both have mainly linear. HRRR is the one introducing cells ahead, but I'm not biting. Plus I got two very important college basketball games on ESPN mid-afternoon. Also, that thing next week... UPDATE: Clarksville tornado warning had exceptionally long lead time from the NWS. Great job in Dixie at night! On a brighter note, Kansas is now the solo record holder for consecutive regular season Conference Championships!

SPC is amped 300 m2/s2 and strong tornado wording. They seem to like southern Ark. Probably for instability. I still like the low level kinematics near Memphis better. Issue will be getting things juxtaposed right (or wrong depending on your perspective). I see the main line starting over the Ozarks which is a no-fly zone - worse than almost anything this part of Dixie. Lead line might go near Memphis but too early for me to get there and probably before strongest kinematics anyway. Finally storm motion will be very fast, hard to manage. Given that Kansas is at Texas Tech mid-afternoon, and the game is for the Conference Title, I will not chase this set-up.

Parameters in the Mid South have improved overall on NWP. Unfortunately for chase concerns, initiation is shown back over the Ozarks instead of the Delta. Now appears morning rain will lift north of I-40, perhaps to Kentucky. Boundaries should remain over West Tenn. Also back into Arkansas of course. Low clouds should at least partially break up. Wind fields look great. VBV is indeed less shown on NWP. Wish such overall robust kinematics, a little VBV would not be a deal killer anyway. Finally low levels look to back as the trough approaches. I expect Enhanced by Day 2 (perhaps update if not first one), but ENH should be it. Biggest issue is Ozarks v Delta. Welp, at least some good college hoops is on Saturday.

IRI plumes are a Total Disaster for storm chasing. They quickly fade La Nina. Good though if you don't like severe.

I like the SPC discussion above. If one does not like severe weather, don't worry too much. Low clouds probably will not mix out, especially with ongoing precip. The 850 level is really warm which would actually prevent mixing; it does not promote instability this early in the season. Wind fields look robust, but probably with some veer-back-veer VBV which reduces tornado risk. None of that is too important yet. My chips are on clouds and rain prevent big severe. Then for those who like severe wx, it's only February. A loss in spring training does not count.

Yes it is a fundamental change. Southwest flow replaces northwest flow. Of course cold air has to be in place, waves timed right, etc. Sorry I don't have the paper author and title, but here is an oldie but a goodie. February is still game time.

My best guess is April could be a short but intense window for severe. March could be tempered if this SSW causes delayed effect blocking and cooler than normal temps. If the ECWMF is right March could be stormy, but it might be too warm. While I'm fading the SSW hype, I also think the Euro is too warm. April we should still have the La Nina signature which is correlated to severe. If it fades then May might calm down faster than usual in Dixie. Note overall May will still be the national peak. If the Euro is right March will get going quickly; otherwise, looks like we just have to get through April.

Twitter thread might be better news for Heartland snow lovers than me over in Tenn. Wavelength may be shorter than the January attempts (me). See his whole Twitter thread about cold in general..

Kelvin wave may save the first half of severe season. Dixie is due for a whippin'.

Yes sir. Let us keep jawboning and maybe we can will a good severe season. We can do without human impacts. Just give us stuff to chase!

Latest Kelvin wave should lock La Nina for a few more weeks at least. Dixie Alley should have an active season. We go earlier than the Plains, so it is indeed time to make the call. MJO is creating massive heat flux into the Mid Latitudes. SSW may not matter. Peer reviewed research shows a weak correlation for North America; better for Eurasia. So, I will go with the warm ECMWF weeklies. Weeks 5-6 introduce a West trough with southwest flow over Dixie. That'll light it up!

Normally La Nina is bullish the entire severe weather season from Dixie early to Plains late. However this year features trouble from a southern Plains drought and possible transition toward El Nino. CFS keeps La Nina but it is horrible predicting spring/summer during winter. More likely Nina fades which makes severe wx fade. Drought would indeed favor east of I-35 in the jungle. Still May is by far the climo peak out there. Last year we posted some papers about all four phases (Nina, Nino, and TNI both directions). After years of skepticism, research is revealing some correlations.

Just need it to hold on until May for my Plains trip. If the Euro weeklies are right about weeks 5-6, action should get rolling in Dixie in March. CFS would keep things quiet longer. With La Nina still going in March I have to learn toward the Euro here.

We might be able to make 2018 even more boring than 2017.

The Lezak and Heady cycles have a period similar to that of the MJO. Some years are great and some are tough. Majority work out. They combine all methods - including their own - for seasonal outlooks. I believe it's solid. Well all need a beauty from the central/southern Plains and Ozarks through the Tennessee Valley.