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Wow @Holston_River_Rambler those are great satellite interpretations on page 4. I think in some cases winds converge lee side of a single mountain or narrow range. Bernoulli effect accelerates air moving around the mountain; then, it converges lee side. This does not explain the effect perpendicular to long ranges. Could be some kind of wave interaction. Finally Sunday night it seems some sort of low level wave was retrograding down the front from the northeast. Could have resulted from low level air sloshing around mountain ranges at FROPA. Also could have been some sort of gravity wave. Yeah it's billiard ball meteorology again, lol!

LOL @tnweathernut Panic and Banter are pretty similar during winter in the South. KCHA did have flurries this morning, I mean just a few spits of flakes barely even flurries. Looks like elsewhere had more fizzards and snow showers per surface charts and the Obs thread here.

Panic room is in effect. Cold pattern forecasts fell apart like the Houston (blue) lead over KC (red) last weekend. That Asheville flight would have come in handy for AMS, but I did not go. Instead I'm in the panic room. Oh well. Everyone have a good weekend!

I'm breaking up with Himawari. That fell apart horribly in just a few days. What did the models miss? I wonder if a Southern hemisphere tropical cyclone threw off things earlier. Massive flare up of convection in the Modoki zone (Mon/Tue) ended up drifting south of the Equator and a topical cyclone developed. Early week models assumed sustained that convection, with or without a TC. The TC takes most of the energy south with it. North of the equator convection has calmed down. Indonesia and Malaysia have some new thunderstorms, though mostly diurnal. Anyway it is not a favorable area for SE cold. Models want to flare up the Indian ocean soon, with a ridge over South China in several days, which is not helpful for us either. Massive cold fail is a disappointment. However the US southern stream remains active. Next week is cold/dry. Models still show a cuter Jan 24-25. After that Ensembles are all over the place with storm tracks. Even the warm EPS has a few lows south, but yeah cutters too. One just hopes for south with cold air in place (from somewhere, lol).

An even bigger version around the Smokies. If south or southeast low level winds accelerate around mountains it would enhance low level inflow. Then farther off the ground south to southwest winds could be guided to turn with height due to the direction of the Valley. I'm just speculating on a hypothesis. Similar debate is ongoing for central Oklahoma (Moore/Norman) and the southeast facing Canadian River Valley. That's low levels only of course. The Plains can take care of its own mid-levels. In both cases it is hard to prove causation, but correlation is notable. They have tried to model the OK case.

Just in European weeklies might. And the 12Z EPS is Frozen. Sadly I don't remember anything in 2017 though. Must have been the one that broke the snow drought for Mid Tenn. Southeast Tennessee was missed. Our last gems were 2015 and 2014. That does not count travelling to Calhoun, GA I think December 2017. At any rate it's time for some action forum wide! Keep our fingers crossed. ECMWF weekly charts are lit for 3 straight weeks starting next week. Big AK ridge AND above normal heights Western Canada. It's +PNA though not textbook Bering Sea / Aleutians. Important thing is cold dumps east of the Rockies. None of that West tough BS. It's full tilt trough Greenland to SE USA. Please be right.

Porch chase Saturday, January 11, 2020: East Brainerd, Chattanooga, Tenn. Friday evening I noticed actual and forecast soundings still lacked low-level CAPE. The skinny mid-level CAPE would have been plenty with more low level push. Frontal lift is just forced, and gives that squall line. More low-level CAPE would have given convective push for a broken line. Then I saw videos from Texas of the lowest contrast Dixie slop one can imagine. Decided not to chase Saturday. Saturday morning I awoke to a chase partner discussing an outing to North Alabama. I encouraged him like I believe is the right thing to do, but reiterated my plan to stay home and watch sports on TV all day. He had one other; so, I felt OK encouraging him not solo. He started to reel in his target to Lookout Mtn. I reminded him if he's going out, he might as well go all the way to Sand Mountain. The latter is flatter, bigger, and has lots of agriculture - which means fewer trees up top. Indeed tornado warnings were issued from Cullman Co. northeast. Meanwhile back in Chattanooga Kansas hoops was laying an egg at home so I switched to Weather Nation via Roku TV. Sling has zero weather. Then when it got real locally over-the-air TV for coverage was appropriate. Goodness I felt like I'm back in Wichita waiting to get slammed! I was tempted to drive 10-15 minutes to either US Express or Costco because either place has excellent visibility. Tornado warning went up for Soddy Daisy; so, maybe I could see that at at distance from US Express. Another area of weak rotation was approaching Ringgold; and, one can see a little bit at one of the I-75 exits. Costco was removed from the list, sitting between areas of interest. NFL Playoff started so I stayed home. Usually indecision is not rewarded well. In this case, the porch chase was a gem! High winds to 60 mph buffet the house. A few minutes prior I am pleasantly surprised at how much one can see through trees in the winter. I know that from watching sunsets, but had to remember for severe. No real shelfie, so I was glad I did not go to another spot for nothing. However the clouds are ominous and exciting. It gets dark and one can see the flat rain look behind the leading edge of angry rolling clouds. Occasional CG flashes bright with booming thunder. As low clouds race from south to north the wind picks up markedly. Sheets of rain about two blocks away rush from my left to right, looking west. Lightning thunder flash boom! The curtain of wind blown rain approaches quickly, but I can discern it enveloping each house and group of trees. Some sheets of rain are separated while the wall rapidly advances at me. Rain is horizontal as it sweeps over my home and locations. It slams against south-facing windows. I get to a north-facing window. Yeah center of the house is what we preach. Wind whips between the houses like TWC hurricane videos. Probably 60 mph this case but only for a couple minutes. A couple more CG strokes are vivid with sharp cracks of loud thunder. Trees sway but not like they would with leaves. Torrential rain continues along with 40-50 mph winds another 5 minutes. Wind dies down but occasional CG and thunder continue. About 2 hours later moderate rain ends with an orange sunset and rainbow. That my friends, is so Great Plains!

Oh my that's even in a minor key. So depressing, lol! I really think it'll turn around though. If not, I'll look forward to Plains chase season.

So up there you get snow and tornadoes! Jealous, haha I wonder if low level winds whip around the ridge southeast of town. Accelerate a bit per Bernoulli effect? And a little farther off the ground I wonder if ridges nudge winds a little veered relative to below. On the other hand it could be random luck.

I'm several pages behind on this thread, so I'll keep it brief. 1. I want to make love to the Himawari satellite, literally the robot up in space. All kinds of convection in the Modoki El Nino zone. Just beautiful if you want some winter down here. 2. MJO index is also going into cold phases. Nice when it lines up with satellite photos. 3. SSTs have assumed the proper look for cold phases. Hopefully the atmosphere will settle there too. 4. Models remain consistent. Ensemble clusters are remarkably correlated. No guarantee correlation = correctness, but plenty of Pacific backing here. 5. Hesitate to post, but yeah the CFS (weekly crap shoot) lays down a defined swath of snow in the Valley about week 3. I don't see anything in the 6-8 day window for lower elevations. Days 9-10 could always surprise, just because it's the mid-range. As usual it'll take 2-3 cold fronts for the cold air to settle in. 11-20 day is where I hope for some action.

I expect supercells in Texas Friday evening. If things go early enough, maybe late afternoon. Trying to find positives for storm chasers that way, haha. LLJ indeed will increase with time, and do so quickly and substantially. SPC rightly talks about the line possibly breaking up into supercells. We normally discuss the more common opposite, sups congeal to line. However with a rapidly strengthening and backing LLJ lines can and do occasionally break up into supercells. It's most common right after the line develops (as opposed to sup line sup). In this case a line may develop; then within 1-2 hours, actually break up into supercells for a couple hours. In all cases sups eventually go linear (or go back to linear) this weather pattern. You won't see me travelling to chase this. However I know people closer who are watching it.

Questions remain in Alabama due to morning rain on Saturday. Euro has consistently hammered Mississippi and the GFS has now slowed down to do the same. NAM going nearly unidirectional upstairs is a real party pooper for fans of intense severe weather though. Saturday is still the back half of the NAM (as of Thursday writing) where NAM accuracy falls off. However the accuracy issue is usually on mesoscale details. Upper wind fields is a larger scale issue. I'm afraid the GFS/Euro will trend toward the semi-unidirectional NAM. Sure it has helicity off the charts, but that is mostly speed shear. Turning is meh on the NAM. It would be a strong but sloppy line. Now the GFS and Euro (globals) both still have a classic winter Dixie outbreak. Globals start turning 700 mb wind, with 500 mb southwest or better. NAM has 700 mb barely west of south and 500 mb still SSW. They all have a mess at 200 mb, but the globals have enough turning up to 500 mb for a lot of severe wx and some tornadoes. Plus they all have robust LLJs. Instability is marginal, but that is normal in winter severe weather. Tonight or Friday morning, one could check fcst soundings for where that instability lies Saturday; low level or mid-level. If low level (just a few thousand ft AGL) it only takes a few hundred CAPE for severe. If mid-level only it's tough to light the candle. Such mesoscale detail isn't clear until about a day to 36 hours ahead. If everything comes together, one would expect that secondary warm front, originating from the Gulf Coast front, to lift north of I-20 or even US-82. Worst action would be from there south. Otherwise it's a sloppy rain-out except down on the Gulf Coast. Most of this was copied from my Tennessee Valley post. However it looks like the worst of it will be this Southeast Region, because of central/southern Mississippi and Alabama. Even there it could underachieve if the NAM is right.

Yes at one point Alabama looked capped on the Euro following stabilizing Friday night rain. Euro has consistently hammered Mississippi Saturday. I'm less concerned about caps now. NAM going nearly unidirectional upstairs is a real party pooper for fans of intense severe weather though. Saturday is still the back half of the NAM (as of Thursday writing) where NAM accuracy falls off. However the accuracy issue is usually on mesoscale details. Upper wind fields is a larger scale issue. I'm afraid the GFS/Euro will trend toward the semi-unidirectional NAM. Sure it has helicity off the charts, but that is mostly speed shear. Turning is meh on the NAM. It would be a strong but sloppy line. Now the GFS and Euro both still have a classic winter Dixie outbreak. Still sloppy, but it's relative down here. GFS/Euro start turning 700 mb wind, with 500 mb southwest or better. NAM has 700 mb barely west of south and 500 mb still SSW. They all have a mess at 200 mb, but the GFS/Euro have enough turning up to 500 mb for a lot of severe wx and some tornadoes. Plus they all have robust LLJs. Instability is marginal, but that is normal in winter severe weather. Tonight or Friday morning, one could check fcst soundings for where that instability lies Saturday; low level or mid-level. If low level (just a few thousand ft AGL) it only takes a few hundred CAPE for severe. If mid-level only it's tough to light the candle. Such mesoscale detail isn't clear until about a day to 36 hours ahead. If everything comes together, one would expect that secondary warm front originating from the Gulf Coast front. Worst action would be from there south. Otherwise it's a sloppy rain-out and I'm watching college basketball all day Saturday.

ECMWF Op is slower than the GFS on the cold next week. However the EPS is colder than the GEFS in the 11-15 day range. Hopefully my Panic Room I post ages well. Darth Vader: I find your lack of faith disturbing. Thursday GFS runs have been cold in the extended, some stormy. Now those 11-15 day systems could go anywhere from Ohio to Florida; but, no worries if an 11-15 day storm cuts or is too buried. Main thing is the GFS has a cold 500 mb pattern. Is it just the dumb operational? GEFS isn't running as cold. Well, the EPS is running that cold. Perhaps the colder 500 mb weather pattern should be favored. EPS has also destroyed the GEFS recently; so, I kind of like a cold EPS. Also some evidence the EPS is handling the MJO and other tropical signals better. I'm not sure about the SPV jostling, but Holston I love those 3D graphics either way. Finally the CFS is frozen so maybe the GEFS will go that way. See what the ECMWF weeklies have tonight. They are based on the 00Z (previous am) EPS so probably cold. Closing with some non-model data. Jax has good posts in our ENSO thread. With the IOD relaxing but El Nino trying harder, perhaps the MJO will spend more time in true Pacific cold phases, vs just a secondary echo off the IOD. Still got convection in warmer phases, but there's plenty building in the colder phases too.

And 30% is posted for our parts of our Forum Region! Where's the siren emoji? My thoughts are similar to those from Monday. GFS is a bit fast, ECMWF is slower, truth may be in between. Regardless the 12Z Euro is total eye candy. Still early for soundings*; but, the constant level plots are lit. So is the surface. * Friend reminded me it's also too early for meso-scale forecasts (outflow, cap, etc) and that's right. However it is my decision point, more than a forecast. Mesoscale will determine my chase status. If not, plenty of college basketball on Saturday. KU hoops is on on CBS! As for my snow post from Monday, I'm sorry if I raised false hope north of I-40. What a disaster! Guess I was jacked up on severe wx thoughts.

The 12Z ECMWF is pretty lit (verbatim) Saturday. Oh I'm glad I saved the best for last. Winter is choking, so I'm ready to talk severe! Most notably, the Euro has a southern stream system to spark convection in the Deep South. Surface low going into the Midwest may have unidirectional winds aloft. The South, on the other hand, should have veering with height. Next feature is a long-shot in January, but the Euro shows a secondary boundary in North Mississippi to North Alabama, south of the synoptic WF. Should the coastal warm front merge with this boundary, it'll be more believable. At any rate Friday night rain sets up the possible outflow boundary OFB I'm talking about. Winter set-up means an even higher than usual possibility of a morning rain induced stable bust Tenn Valley. I'd need the coastal front to merge with the OFB to give it more spark. Now Alabama may be capped. This whole OFB and moderate cap would be wonderful in the Plains in May. Dixie in January? It could work, but I'm not holding my breath. Few more days to watch this. Mississippi looks less capped as the southern short-wave induces cooling aloft. Still great wind profiles ahead of the trough. Mississippi is also favored in winter climo. Alabama is more February and later. We'll see though. 30% generates a lot of social media hype, but this is typical Dixie in winter - very conditional. Wind fields are there but instability is always TBD. While I'm eagerly watching (though not holding my breath) chances are I end up watching college basketball most of Saturday in my nice dry living room.

Weeklies try to bleed cold south week 3-4 but dang it's ugly. BN heights over the Great Lakes attempt to drive it. However the PNA looks neutral at best; never really goes negative. Some AK and Western Canada AN heights but US West heights are dreadfully BN. Could spit out energy I guess; but, also WAA ahead of each wave. Figure the SER torch fest will tone down, but not going full tilt cold though. On the optimistic look, it only takes one system to phase right in that choppy pattern noted above.

Extended is depressing. However the Upper Plateau and over by the Tri Cities may have a nice Tuesday. Does not look big, but looks like something. Upper Plateau and TRI, appears the column will cool enough up there thanks to dynamic cooling. Thickness and 850 both get down with QPF after the fall. Snow output is noted on most models, but I still like the thickness QPF method best. It looks good. Maybe only an inch or two (the 2 higher elevations). Daytime is a challenge, but not as much so in January compared to say late Feb. Meanwhile south of I-40 looks hosed, especially KCHA and southeast Tenn. Oh but we may have some severe fun this weekend. More in that thread after the 12Z Euro.

Great football weekend for Tennessee! First the Gator Bowl and then the Titans win at NE. Both were white knuckle affairs. We'll switch to Kansas for basketball, lol. Both KU and Wichita State had good wins. Now, what about the damn winter weather? Need a win there. Yoda, may the force be with us.

Recycle time If all else fails, my panic room is the open Great Plains in May.

Belated Merry Christmas and Happy New Year! I'm actually around but lulled by the mild weather. Don't get me wrong, I enjoy it! Yes Israel has great microclimates. It's not quite California, since the Med is warmer than the Pac. However the humid coast and desert inland is sharply divided by the mountains on which Jerusalem sits. Range is north/south most of the way. Far south the Negev Desert is pretty extreme, but with stunning diving in the Red Seas. Then you got that occasional snow skiing northeast Israel toward the Golan. Yeah snow!

Google Translate SPC: Tennessee Valley = North Alabama. Bama did get their obligatory tornado warnings, lol! In all seriousness SPC typically refers to the Lower Tenn Valley. Appalachians = maybe East Tenn. If you like severe wx you'll have to just hope, because something usually goes wrong. Except the Plateau might surprise. Also check the probabilities. IIRC they were never really there for East Tenn. Marginal used to be general, so it does not really count in my mind. I still have trouble giving Enhanced respect because it used to be Slight. However the science can discern the two now; so, I think breaking up the categories is correct. What else to include in Banter? Pacific convection is everywhere. Thunderstorms for everyone. Good luck forecasting the mid-latitudes though. Finally in sports, Kansas is #1 and Gonzaga is #2. Somehow this run feels like the GFS, and I'm not necessarily talking about the Zags. KU is at Villanova next. KU suffers the #1 jinx frequently.

I have heard, snow breeds more snow. Basically it says a cold weather pattern is in place so another snow falls. We've seen two in a row here. I've seen it back in Kansas. I wonder if we'll ever see it again, lol. As for the thunder, it is about an amplified pattern. It can go both directions, especially in the Plains. I think here it's more the warm to cold, due to slower recovery. This time looks like a Deep South system is wasted Sun/Mon. Then next week is forecast warm, but the 6-10 day has been less reliable than usual lately. Oh yeah this is the Obs thread. Decent wind rain thunder and lightning in Chattanooga Monday evening. While sub-severe IMBY it was still a notable December thunderstorm with intermittent vivid lightning and loud thunder. Calmed down overnight. Then just before dawn the winds cranked up as the cold front crashed over the Plateau into town.

Oh the weather outside is frightful, literally! Midday was robust in Louisiana including that tornado emergency for Alexandria. This afternoon looks a little more linear for North Mississippi. Strongest shear is ejecting away from Louisiana and southern Mississippi; however as of 3pm Central those south cells remain robust. Greater and forecast instability allowed this event to escalate day 1. Also it appears the LLJ was a little less veered through midday, compared to progged over the weekend. Little details make a big difference in Dixie. Y'all be safe!

Yes what Jax says at the end bleeds into the weekly versions. I almost mentioned it above, but didn't since it's week 3+. Well, why not? CFS locks up cold in Canada (BN heights) downstream of its AK ridge. Euro weeklies, on the other hand, go with AN heights in southwestern Canada and the US Pac NW. That's not a classic +PNA but it has some of the characteristics (including Hawaii). Euro surface is not too cold here in the SE US but it's better than the CFS furnace. While weeklies are not too useful past week 3, one can certainly see colder scenarios than the CFS shows.