nrgjeff

Well that would suck the life out of severe. I place my order for cooler weather central tropical Pac. Keep warm east. TNI boom!

I'm ready to see that MDT Red on the SPC charts instead of the WPC charts. Can it just be April yet? 12Z QPF progs are not quite as bad East, but still there Mid-Tenn. Trouble there is double whammy of daytime rain and then the squall line.

We got almost an inch more overnight. Apparently it all ran off. @dwagner88 was I seeing things or the creek was almost up to the bridge by Food City Jenkins and EB Rd?

MRX rightly is/has been more concerned about flooding. SPC has caved, lol. OK seriously, they did not cave. Shorter Term data not available or reliable at Day 4 shows the problems with the set-up now as we move in to Day 2. It's too damn warm at the mid-levels. Oh this wind field would be amazing with April or even March surface temps. Winds with height turn almost 45 deg. Usually Dixie has about 30 deg. Rooted supercells would spin up in a hurry, but... CAPE is hard to come by. They talk about low-CAPE high shear events. This is almost NO CAPE. Looks like skinny cape above 700 mb and questionable if any below. Lack of low-level CAPE juxtaposed (vertically) with low-level turning is a deal breaker. So, I have zero interest in chasing. I'm not really even worried about severe at home. I will be peacefully relaxing and watching Kansas at West Virginia. Uh, actually I'll probably be barking at my TV, lol! Actually the ESPN crooks put it on + which I boycott. OK, hope for severe!

Rare High Risk and large Moderate Risk of flooding is quite significant for the South. Due to the high impact of this event, please share with your fiends on social media. Make sure the graphic comes up on the post. Date it and make it public too. (just change back to friends your next post.) I went through Thursday, though the High is through Tuesday. This is going to be bad from rivers down to streams and low areas.

Lookout Valley west of Chattanooga, flooding on I-24 per Covenant Transport Met. I-24 was closed as of 3pm Eastern Wednesday.

Enhanced risk for central Mississippi into northwest Alabama! Well Dixie has a funny idea of how to do an overnight rave. Jokes aside, I'd ditch the hatched but 10% might be OK. I'd introduce 30% wind though. But the HRRR! But the SFO run? OK back to weather. Both versions of the NAM temper things compared to the HRRR. NAM looks believable given all the cloud cover. However the marine warm sector has made it well north in Mississippi. North Alabama is still conditional on precip. I actually like the wind fields not pegged out, just seasonably strong. However the low level CAPE lacks. Don't take much at night in Dixie, but it needs to be more than 50. LI looks good because it is above the warm layer aloft. Figure storms can root for a couple Mississippi tornadoes this afternoon. Alabama might get to sleep well with just wind if it does not destabilize in the low levels. Believe the sounding is a bigger problem than upper level wind directions relative to the boundaries. It's a quasi-lifting boundary not a CF in the risk area. Either way, I think it's mainly wind. 2pm Central Update: South Mississippi supercell rooting on the marine later warm front. Other cells coming out of Louisiana may root in Mississippi.

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.

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.

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.

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.

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!

SPC still has Monday highlighted. Lots of kinematics including close to the surface, so a little straight line wind would not surprise me. However now the 850 mb level is veered off and precip may be sloppy. 925 mb is trying not to veer off and surface to just aloft is south. Still I think given the frontal orientation along the upper winds, it's a mess. Models continue to trend more positive tilt on the trough. At one point a few days ago it was almost neutral, but that's long gone. Can't imagine anything more than 15% even on game day. Not all D4-8 go big. This one was just evident on the synoptic scale, but slight all the way.

Always fun to saber rattle severe in December, a holiday tradition for me, though I enjoyed the snow yesterday. Moisture looks a little JIT and the wave has a slight positive tilt on the ECMWF. I can see why SPC waits. However the upper level wind fields are robust. Currently no VBV issues and 500 mb is nearly straight west. Things like this can work out in December when it's more about dynamics than thermodynamics. We'll see... If Monday does not work out there's always Christmas severe saber rattling. Big warm-up is forecast that holiday week before a front. Little more of a West trough is forecast for a few days before advancing into the Plains and Mid South. Funny a few days ago one GFS run had snow for Christmas. Anything is possible 2 weeks out!

I infer from Lezak's public forecast that the dominant pattern is the trough Plains, which gives 3-4 winter storms for KCMO. Secondary pattern is not discussed in the public forecast; however, the LRC usually has one. I don't have access to the subscription, though maybe I should. Anyway I figure the secondary pattern is northwest flow. That's less juicy your way but probably my only hope over in Tenn.

I'll put in an order for Trans Nino by spring. Thank you!

Saturday has more instability than Tuesday night's debacle. However Saturday low level winds look a bit veered. Probably be more interesting Friday in the Plains. At any rate Saturday would require some sort of meso-scale boundary set-up if those 850/925 winds don't back a bit on the models. I'm not counting on that. Good thing we have plenty of football, basketball and other sports this long weekend. Happy Thanksgiving!

If the IOD stays on full-tilt, it does kind of promote a Modoki shadow/imprint. However like pointed out above, sub surface is warm east. Perhaps most important, will be weaker convection when it's over/near Indonesia - thanks to cool SST anomalies. That's typically the warm phase, so muting it could help keep colder MJO phases.

China Met Admin is going fairly mild for China this winter. If the current wavelength holds (Asia Bering North American) ABNA the USA could be mild too. Of course different wavelengths and MJO pulses will add variability. Like right now, brrrr.

Oh lovely. Anything really happening up that way? How much wind is really mixing down? Appreciate ground reports.

PDO is trying to drop. If it continues it'll be hard to get Nino 1-2 to warm up. Modoki could be wasted on -WPO instead of -EPO. Mild and wet SE? Still lots of grand solar min talk. Big blocking could be wasted on an out of phase PNA. Good to be in the Plains though.

Sure enough MEM damage survey rates EF-1. Little drama for the Mid South to round out an active 12 hours starting back in OK/AR and of course Dallas.

Sunday afternoon SPC gave the Monday outlook a haircut. Probably valid. LLJ weakens going into eveing. That's just ugly. One looks for it to strengthen going into evening. HRRR has stuff ahead of the line, but it's the HRRR out 36 hours LOL. WRF versions don't and I think I'll believe meh for HSV to CHA. Wake me up in May. Edit: Wake me up when Mahomes is back.