nrgjeff

No reason to panic. I agree with Andy and Quincy it is quiet at the moment but it is also early. OK, you are down 12-4 in the opening minutes of a basketball game. Do you panic? Of course not! Sure the score is 3:1 but it is also only 8 points with over 30 minutes to play. We are in the first quarter NBA or first 5-8 minutes college. It's April 19. Relax and smoke some pot tomorrow. So the weeklies are bad. They are useful out to about 3 weeks in spring/fall. The only reason we have 4-6 weeks is for the depth of winter or peak of summer, gauging persistence or not. If not, do not use for reliable changes any time of year. Again in spring, do not worry about the 4-6 even if it is persistence. CFS dashboard seems quiet around May 7 considering what its own weekly chart shows. From the weekly chart I infer a southwest low. Probably not chase material, unidirectional bowling ball verbatim, but still a system. Can't forecast 3 weeks out, but one can cast doubt on the very quiet dashboard. Analogs include some very awful years, but analogs are just one tool which happen to average out things. One can have a low tornado count, with few systems and no big outbreaks, but still a couple sequences worth chasing. That might not assure local chasers, but a chase vacationer only needs one good sequence. If down 8 points with a minute to go, maybe panic like some people are now. However it is April 19 not May 19. While we lack evidence for an active season (trend, weeklies, analogs) we also lack evidence to give up (early, low 4-6 week skill). Just enjoy April 20 even without severe weather.

Saturday was such a dud. I figured it was not a chase day, obvious line of storms, but I was hoping for something a little more interesting to track. Only thunder was in the evening well after the initial band. April 22 now looks like rain not severe, perhaps cool rain again. Sigh.. First of May indeed a ridge followed by trough is forecast to track from the Plains through the Mississippi Valley. Approaching trough could gin up something in the Tennessee Valley; or, it could dig into a mean East trough and be cool. Too far out for details, but I'm continuing Jax's thoughts. Perhaps the system would be warmer in early May..

Enhanced Risk for North Alabama Saturday / tomorrow. Gee, it must be mid-April in Dixie! System will not have much directional shear at upper levels, but surface to mid-level (700 mb) turning is good. Plus we have decent CAPE near the peak of Dixie Alley season. That said, I expect a squall line with mainly straight wind. Models have shown glimmers of a wave along the front, or even meso-low, in Alabama. Such a feature would create a locally chasable target iff over decent terrain. Central Alabama won't work, but parts of North Bama would. North Alabama issue is possible midday rain stabilizing everything though. Atmosphere does not have that April feel. No outing is planned for me attm. Enjoying warm temps ahead of the front might be a better use of time. The April 22-ish storm is still on the models. Saturday (tomorrow) and 4/22 seem to take warmer tracks. Then the GFS 11-15 day goes back into March weather; and, Euro Ensembles plus both weeklies concur. Hopefully that dreadful late April forecast is wrong, esp in the wake of warmer systems. UPDATE (for Saturday): 1730Z SPC Day 2 uses stronger words/hatches. While CAMs have mean looking storms, LLJ 850/925 mb wind speed forecast is not particularly robust for this time of year. Direction is there 700 mb under, but not speed. Plus it's unidirectional farther up (though strong). A meso-feature and outflow would make up for all above deficiencies. Plus if no midday rain-out the CAPE instability will be there. Still no chase planned for me - a lot has to happen - but I will keep an eye on the mesoscale situation. UPDATE 2 for Saturday: Hello 12Z Euro (Fri) and your robust low level jet LLJ. OK, give me an outflow boundary Saturday and we might talk. OFB would be from morning/midday rain Middle Tenn that does not spread into Alabama. Still a big, we'll see, for me.

Weeklies don't commit to much weeks 4-6, but maybe the SSW hangover will end sometime in May. @Holston_River_Rambler and @Carvers Gap I think you got a handle on it. Sorry I was out of town a few days for a mix of learning and leisure. If a big system develops, like with any time of year, weeklies would probably not show a strong signal until it's within 3 weeks. I look for a few passing troughs everywhere in May - more progressive pattern. Might be mean ridge west mean trough east, but nothing like the lock-in attm. Progressive pattern would be more variable. In another thread @John1122 noted the Winter that could have been, except for the January drought. I concur. And we dreadfully wasted a late timed SSW!

Looking ahead the MJO is forecast to die off leaving the North American atmo hanging in a cold phase. However we are on week 6-7 of a cold pattern. Going much past 8 weeks would be a shocker even after a SSW hangover. During the SSW hangover most systems have been too cold (except March 19 and April 3). Day 6-10 severe ends up 1-5 day cold rain. Severe enthusiasts want that to stop. Weeklies are not as cold starting week 3, but still show meandering troughs. Twice this season Dixie had severe with mean troughs on both coasts, but we can't have a full latitude trough in the East. In the severe episodes the West system regrouped sliding into Dixie.

Winter 2010-2011 was cold December and January, with multiple snow events. I thought, wow, I think I'm back in an area that gets snow. LOL X 100! OK Chatty did well in 2014 and 2015 too. Anyway the similarity came to an abrupt end in March, when we got cold this year 2018. March-April 2011 were warmer than normal. Hopefully the divergence also means no 2011 severe. That was awful even if one likes severe wx.

Well I was just poo-pooing the MDT on a PM. Prefer ENH for wind but we have potential. Indeed appears a slight wind shift in Middle Tenn. Could we get a pre-frontal trough going? Upstairs it does appear the LLJ will increase around 00Z. It is not a strong as up north, but it does strengthen over much of Tenn. I will keep my chips on straight wind, and perhaps several reports, but we'll see. It is April!

Michigan fans are the worst. They were total jerks in Atlanta (Final Four). Syracuse fans are great though. Anyway I have to cheer for Villanova tonight. Nova's Coach Wright gave words of encouragement to KU's Devonte Graham after the game, very classy. Game should be high scoring and entertaining.

Chattanooga booked our third straight pitifully awful winter in a row. I know we live in the South, but this is ludicrous. Will give it a D, avoiding F only due to a trace. Like storm chasing it's all local though. Other parts of the South got B to A+ (Griteater recap). Congrats there!

Time to start the warm season banter thread. Before Final Four talk, I want to write the following weenie post. Can we lock in the 11Z HRRR? Late afternoon LEWP for Chattanooga!

Operational models are beginning to show more surface low press in the 11-15 day which lines up with the discussion above. GFS is more consistent than a day ago, sending stout low press through the Ohio Valley. Euro ensembles surface low spaghetti plots are mighty active too. Early season one often looks for the warm front. Most readers know I also favor outflow boundaries OFB. Going into April the classic severe signature is actually low press to the north, with a trailing surface trough through the South. Said trough should also show a bow shape through the southern states. Shape is from a surging cold front or pre-frontal trough. For chasing I still like OFB intersections, but down the trough is as active or moreso than the warm front in a textbook April setup. Like with snow, the 11-15 day is fantasyland. Those with severe wx concerns need not be worried. Enthusiasts keep looking for that surface pattern, plus strong upper level winds turning with height. West Pacific tropical storm adds uncertainty to the 11-15 day. UPDATE: Last 24 hours of NWP have trended cooler in the 11-15 day. Could zig zag some more before settling. West Pac TS keeps churning. US Navy and Japan Met Agency both have it gradually strengthening to 50 kts before slowly winding down. Turns north away from the Phils and into open sea. Back home, cooler 11-15 is lower risk severe. THIS WEEK 3/28-29: Diurnal timing looks off for severe. Wave and surface low try to strengthen Wednesday, but over the Ozarks southward. Cool pool also stabilizes. System passes through Thursday morning and weakens during the day. So, just heavy rain here. Deep South is closest severe threat. If interesting I'd post Southeast sub/region.

I joked we'd have Feb in March after having March in Feb. Apparently the temperature data supports it, lol. I also wonder if the Feb warmth was a precursor to the SSW. It all started with a near record MJO pulse IMHO. Did it go tropo, to strato, back to tropo? SSW was near record too. The other issue I saw going into the SSW is the cold strato was on our side and warm strato was over Asia. Cold started that side of the World. Then Europe and the British Isles got the Beast from the East. Finally the USA is still seeing the hangover. Going forward the CFS and Euro weeklies diverge sharply. We'll see if the Euro finds some mild weather tonight. MJO is muddled so I like more variability. Plus that West Pac tropical storm. CFS can and occasionally does beat the ECMWF. Hopefully the Euro comes around..

Warning system worked well from TV Mets publicizing the Convective Outlook, though the Watches, and of course good lead-time Warnings. Wish they all ended this way! Severe weather is quite possible in the South middle to late next week. However it might be south of our Region, more Deep South. We'll see how that low/wave tracks along the quasi-stationary front. Either track the wind fields are forecast to be there. One thing with confidence, as Jax mentions, flooding will be a factor. UPDATE: Going with an ECMWF/ICON compromise and throwing out the GFS rubbish.

I really want to be in Winter Place Ski Area (WV) this weekend, but we have a commitment in Chatty. I'm never tired of snow, lol! Figure the snow talk is reduced since the lower elevations are out of it. However for the Mountains, it appears snow chances roll on. This weekend I believe the temp gradient Holston mentions will indeed set up again. Looks like it's elevation driven. Of course we have mountain ranges either side of and parallel to I-81. However at the same time I-81 really rises going into Wytheville. Believe cold air drains from the Blue Ridge toward Wytheville. Meets the Valley warm nose just southwest of there. Temp gradient results. Partial thicknesses and 700 mb temps indicate warm nose risk for northeast Tenn. Vort max tracks north which takes away the chance of dynamic bail-out. However I think the mountains will get snow. Also just up I-81 in Virginia could get snow. TRI could get Valley heartbreak this system, but I do like farther northeast in VA. I really want to be in southern West Virginia in case it jogs north.

My guess is that air flowing parallel to those two mountains converges on the lee/back side. Low level convergence helps precip. Similar process can happen with a peninsula sticking out into water with an onshore (sea)breeze. Air converges and showers pop on the penninsula. A difference is the mountain example today also involves wake processes. Good meso/micro scale observation for all to remember. Thanks!

Congratulations @*Flash* with the successful intercept! Looks about like my Dixie intercept last August in the remains of Harvey (down on Alabama I-22). I gather you were on state highway 24? Is it a good highway with open views and somewhat flat? Google terrain looks OK. Except for a ridge between Hwy-24 and US-72-Alt I may get to expand what I call the chasable area. Thanks! Anyway I did not go out yesterday. My concerns were mainly timing and terrain. Figured the morning cluster out of Mississippi would be really sloppy into western Alabama; elevated trying to root usually is slop. Second cluster out of Mississippi was a little better. Reed Timmer documented a low contrast tornado out that way. Then we see Flash got Russellville! I figured it would take all day for the central Alabama airmass to recover. Then I was worried about northeast Alabama terrain. Actually it recovered well before dark, and back in reasonable terrain, per the above. Should I have chased? Probably. Target forecast was right. However the action looks similar to what I documented in August. Advantage of a desk chase, in addition to being in my cozy home, is being able to follow everything at once. At nightfall east Alabama really got going. Can't chase at night, but one can sure follow Twitter and scanner radio by Broadcastify. I'm sure other apps are available. Anyway I'm glad nobody was seriously hurt.

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 type of -NAO forecast is similar to that in winter 2010-11 when we got some good snows. Note it was not as cold as winter 2009-10 but at least Chattanooga did better with snow 10-11. I would say the current -NAO is a little more traditional than the oddball previous one. Generally -NAO is a cold snowy signal for our part of the world. However other pieces need to be in place for snow. Bone chilling northwest flow only helps the mountains. Need a westerly component to the jet stream. Unfortunately in spring the only result of this -NAO is dreary cool weather. It becomes not cold enough to snow in the valleys and not warm enough for interesting severe. Air mass dividing line looks to set up in the Tennessee and Ohio Valleys. In May that's severe. Now it's just rain and clouds.

Euro weeklies want to continue the SSW hangover for a few weeks. CFS is warmer, hinting a brief warm interludes. My gut says hard to verify an AN 7-day period. Most may verify slightly BN. Ohio River Valley boundary looks nearby some of those weeks, which would add variability - also could be dreary. Still that SSW hangover...

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.