nrgjeff

A little rest from the heat will be nice when Barry related rains pass through Sat-Mon, but the heat should return by Wednesday next week. Too early for a tropical system to truly break the heat. Later in August, especially a system to our east, might help shut down summer. July, with a system to our west, just drags in more humidity after the rain ends. Plus the latent heat release upstairs contributes to the heat ridge. Global AAM is also low. Combine that with continued blocking in the northern latitudes, and it's a hot signal for the South. In this case it looks like a Midwest problem too. Great Lakes could get a break when the Alaska ridge rebuilds. Regardless, no rest for the South until maybe July 26-29-ish. Hopefully the ECMWF weeklies still have that less hot look starting the 26-29th like the CFS does. Elsewhere, good that Japan did not get the Meiyu treatment too bad. Farther southwest, it seems that baroclinic zone is stuck in South China year-round. They had an awful two-week cloudy stretch the exact same days as the Tennessee Valley last winter. Yuck!

Back on Friday the double squall line or double MCS was able to survive because both had open access to the LLJ and inflow. They were moving somewhat in parallel, instead of one immediately following the other. Eventually they somewhat merged in the Ohio Valley before continuing through the Tennessee Valley and off the Carolina coast. @Jim Marusak @It's Always Sunny The MCSs were impressive.

Should be a Friday night gem. Hope it rolls down I-24 all the way to Chattanooga. Enhanced is probably the right call. We lack the ingredients for Moderate. No 500 mb short-wave or height falls helps avoid the D-word. In fact 500 mb is neutral to slightly rising. Still we have all kinds of WAA at 700/850 mb from the southwest to feed the beast. How about those MEM surface obs? Yeah the scientific word for that is gross, lol! It's evidence of great instability. However it's capped until the MCS arrives. Another MCS is forecast Saturday, but I'm thinking this first one will be the best. Pure undisturbed airmass is ready to rumble.

North Chattanooga and especially Hixson got it this morning (Thursday). Not bad for a sunrise special. Friday and Saturday more MCSs may move through Tennessee and our Regional forum. Reservoir of impressive instability looks to camp out in the region along and south of outflow boundaries. WAA is forecast at 850/700 mb which would help maintain convection. Don't see any robust 500 mb waves so it should not get too crazy. In fact 500 mb heights are neutral or slightly rising both days. Still it is the season for southeast propagating MCSs.

Wed. June 19: Northern half of the MD has a watch out. Since the MD has more forecast information than the watch, and covers areas that could see storms later, I'll post the MD. Mesoscale Discussion 1134 Mesoscale Discussion 1134 NWS Storm Prediction Center Norman OK 1235 PM CDT Wed Jun 19 2019 Areas affected...Parts of southeast Missouri...northeast Arkansas...western Tennessee and Kentucky...and adjacent portions of southern Indiana Concerning...Severe potential...Watch possible Valid 191735Z - 191930Z Probability of Watch Issuance...60 percent SUMMARY...A further increase in thunderstorm intensity and organization appears possible through 3-5 PM CDT. This may be accompanied by an increase in severe weather potential which could require a watch within the next couple of hours. DISCUSSION...An ongoing increase in thunderstorm development appears to be associated with a secondary band of large-scale ascent pivoting from the Ozark Plateau into the lower Ohio Valley, within the leading edge of larger-scale low-amplitude mid/upper troughing. As this is occurring, inhibition for seasonably moist boundary layer parcels continues to weaken in response to insolation, with mixed-layer CAPE approaching 2000 J/kg. At the same time, westerly deep-layer ambient mean fields and vertical shear are also beginning to increase, as a 40-50 kt 500 mb speed maximum gradually propagates eastward from the south central Plains. Into mid to late afternoon, the environment across western into central (middle) Kentucky and Tennessee, and surrounding portions of the lower Ohio Valley, may become conducive to increasingly organized convection. It is possible that this may include a few supercell structures, then perhaps one or two upscale growing clusters of storms accompanied primarily by a risk for potentially damaging wind gusts. ..Kerr/Guyer.. 06/19/2019

Thursday one might watch the High Plains from Denver to Cheyenne in upslope flow. SPC has the other area of interest as LLJ gets going over a boundary Kansas into Nebraska Thursday evening. Thursday could be the sleeper day for photogenic activity, esp if High Plains goes. Friday June 21 could be the bigger coverage day, but maybe not as photogenic as on Thursday. Storms may have to go right on the boundary due to warm mid-levels (700 mb temps). Still parameters look robust up on the warm front. I'd avoid the cold front. However if something can go on the dry line in Kansas, oh boy! Wave coming out might be able to bust the cap.

Oh wow I did not notice that Monday. Kept redeveloping over Chatty though. The usual stabilize and quit did not happen. That Bledsoe Co storm was locked on. We had a true short-wave in contrast to typical summer pop-up season. Also a veered moist LLJ fed the storms. Veered played a role in the training, promoting back building and redevelopment. My lawn is very happy!

Yes a real short-wave is forecast midweek. Today (Monday) the Marginal held with modest flow aloft. Looks like little more flow is forecast Wednesday. NWP is mixed on how much turning. At least some bows and perhaps good shelfies should be on-deck for Wednesday.

In the mid-term I agree any heat will be short-lived. Also looks like ridge height anomalies are more up over Canada and the GL. Puts us on the soft underbelly with chances of rain to temper daytime highs. Nights may be muggy though. In the long-term I also agree July may not be too bad this year. We'll get our heat bursts, but no big heat wave signals are seen. Should get breaks too; maybe not true cold fronts, but soft ridges. Way out there term, it's tough to fight the climate signal. Doesn't the JMA always freeze blast winter in the Southeast US? Looks like it's all-in more El Nino.

I put my chips on 3-4 chase days next week. However I don't see any big outbreaks. It is typical June chasing, but could be quality chasing. First half of the week starts with the Upper Midwest. Tuesday the ECWMF shows a true system in chasable terrain of the Northern Plains. Wednesday goes into the MN/WI forest, but maybe something can get going down in Iowa. End of next week moderate flow is forecast to remain in the Plains (almost unseasonable NE/northern KS). LLJ is forecast to respond. Might get a couple days out of that if cap is not thermonuclear. Placement is uncertain attm. So I propose we have two pairs of possible chase days. Take out one for terrain and/or bust. Nets 3 chase days?

Somebody tweeted this is like a Greek Tragedy play. Despite NOAA claims the FV3 is better, the energy industry believes it is worse than the GFS. Opinions are our own, not of our employers. Still I think it's a sick joke! I just can't figure out what crony is benefiting. Most government mistakes are due to cronyism. This one is not. I mean it's NOAA vs NOAA so I guess just an honest and huge mistake. Think Hubble Space Telescope mirror.

Alex, I'll take outflow boundary for $400. Actually Knoxville does look at bit stable. Chattanooga might at least get a good Marginal thunderstorm later. Modest flow is aloft at SPC notes. LLJ may be a little veered off. 850 mb is forecast to veer off. 925 mb is trying but still SSW, and the surface will be from the SSE. Moisture might be the main question. Did I just write that in June? Honestly, much as I like storms, I love low humidity in summer. Every day with low humidity is one less of (root canal without Novocaine) misery.

ECMWF still points to a little more activity starting on Friday, and through the end of the model run. ECMWF Para/Beta (2nd deterministic) looks even a little better. The latter keeps westerly flow instead of that northerly junk end of EC Op. Both have modest LLJ response most days starting Friday. Moisture quality is slow to return, but by Friday is enough for central/high Plains. Moisture gradually improves each day, esp on the EC Para. Given what happened Saturday, Colorado and Goodland, chasers may be able to seek meso-scale events again. Good luck to those June-ing!

Trial lawyers chasing that ambulance. Perhaps a lawsuit is in order though.

Crap I missed it! Friday featured a notable LLJ over the area with modest WSW flow at 500 mb. I'm not surprised to see reports of a small tornado and landspout. However I'm quickly losing interest in severe. I have fallen hard in love with the East trough on-deck, and associated 50s dewpoints.