nrgjeff

Chattanooga got it Saturday! Several thousand power outages were reported, something like 12K+ I estimate about 50 mph gusts at my location. Other parts of the city, instruments measured 60-70 mph. Saturday in Chattanooga and surrounding areas was a classic bow echo.

Mid-range models are hinting at Friday Hoosier Alley. Wrong Region? Nah, ours is the best region and it's close, ha! Also unruly outflow boundaries south of progged could push that closer to our Mid-South, though probably not anything rotating. Better shear is Hoosier Alley. SPC hints at it in their 4-8 day text but I agree it's a bit early for a 15% valid Friday. I just gotta talk weather. Ventured into the off-topic toilet bowl this morning. SOS!

Yes this weather is unusually comfortable for the beginning of June now. Too bad we're smoked out. While social media argues about the +/-Bz and Aurora Sunday night, we can just go to bed early. No chance with the smoke anyway. So, enjoy the mild temps and low RH.

Given the PDO is erratic, their study may be valid. Who knows if the Atlantic will ever cool off? Scientific consensus across all Journals is evolving. Or, we lack understanding to model the causation. Either way, the historical record may be useful. What's North American 2m temperature do with different states of the Atlantic and Pacific (and combos)? Instead of treating them as predictable oscillators, just take the Ocean temps at face value during this or the upcoming season. Both negative is going to be a cold possibly snowy winter for many. Both positive is going to be grill out and drink for many. If I was going to pick on oscillator to quit, I'd punt the QBO. It's rate of change could be useful, but its steady state has not been useful since George Bush was president.

Soon we are due to go negative AMO. Keep in mind soon is measured in years. Here is a smoothed chart from an energy climate page. Yes, some energy companies acknowledge it. We better, if our demand forecasts are going to be worth anything. Then the PDO has been a little flaky. It faked out cool phase a few times since 2000. Will it be able to hold? Perhaps the warmer background makes it harder to stick. So, I'm very curious how the AMO goes in the coming decade. Both negative could be epic winters!

I took a little Sunday drive to South Pittsburg, Tenn. No it's not far. South Pittsburg shelfies! Separately thank you to all Veterans to who serve(d). Especially we remember those who are fallen for our freedom.

SPC is talking outflow boundary isolated tornadoes both Saturday and Sunday. The Saturday boundary and outlook is south of most of us, as expected with a morning through midday MCS. Sunday is below. Smaller morning MCS is forecast, and it could break up and allow redevelopment Sunday afternoon. Monday could be similar. While it's 3 days in a row it's Marginal-Slight, so not a huge deal. Still I find it quite interesting so late in the season. Sunday is below, updated Friday afternoon.

Unfortunately lots of scattered but significant damage is reported in North Alamba. James Spann posted. Also saw text reports from EMs. Sad deal more like an April event. Haven't heard much from the Nashville 'burbs. Meanwhile sups split Chattanooga so we lucked out here. I was unable to truly chase on Tuesday due to work requirements. However during a lull between the Cherokee, AL / Pickwick Reservoir tornado and evening trouble I was able to get out locally. A severe warned cell (actually the Cherokee cell hours later) tracked from Monteagle, to Dunlap, to Soddy Daisy all Tennessee. I-24 is a no-fly zone for me at rush hour, so no Monteagle, but I was able to track it from Dunlap to Soddy just north of Chattanooga. It was between 6-7 pm EDT before the Madison, AL and Huntsville stuff got really ugly. Here are my low-lights. While the first is arguably structure out of the spotter's guide, less crisp but good for East Tenn... the rest is scuddy crap. Oh well! At least I got out of the house. So while the Cherokee cell stopped producing tornadoes, it retained supercell characteristics for several hours. I believe it was on the intersection of the outflow boundary and a prefrontal trough. Evening cells were associated more with the main surface trough - enhanced by the same outflow boundary.

And just like that.. Mississippi, Alabama and Tennessee boundary ahead of the Delta front is back. 00/06Z too much midday rain was forecast, keeping it stable. Now most progs have the morning rain dissipating, leaving a cooking boundary. Satellite shows very little cloud cover in its wake. Just bake. 10:45 CDT and the RRFS later, not that it'll really verify that bullish. Just remember Southern weather forecasting is like a box of chocolates.

Reading between the lines, the Hail outlook tells a lot. True supercells are only going to be out by the Delta. The pre-frontal trough farther east now looks like it'll be a little less volatile. Much of the severe farther east may end up bows and line segments. They can produce tornadoes, but yeah 45% wind seems to be the right issue on which to focus.

Same forecaster Bentley issued the early Day 2 today and early Day 3 yesterday. Bentley went from 'a little veered for tornadoes' to possible strong tornadoes. In between (Day 3 update) Leitman gradually moved that bar. Agency wide trend is steady, but the same forecaster trend is really useful to read between the lines. Should be just enough turning with height, especially given the instability forecast. Local low-level shear will be enhanced along the lifting boundary into Kentucky. Then Tennessee will have the main synoptic boundary and likely a pre-frontal convergence zone. Low levels might be slightly veered; however, mid-level vector crosses those boundaries at a slightly greater angle than the west-east boundary farther north. WF is in Kentucky. Prefrontal trough will move from West to Middle Ky/Tenn. Synoptic front will start in Mo/Arkansas and then cross the Mississippi River. Most models have storms on all 3 boundaries. Update 17:30Z: They expanded the wind ENH east and dropped 45% wind (still ENH not hatched). Tornado is also nudged east, but not far compared to wind. 06Z Chart below is still my most favored area(s). Enhanced risk (early Day 2) probabilities are 30% wind and 10% tornado both lined up at (06Z version).

Tuesday it appears that the warm front will be up along the Ohio River again. Outflow should at least start out in Tennessee. System should be strong enough to lift it north again. However the timing is just a little faster than on Friday.. So we get other prefrontal convergence line(s) in Tennessee. That's not necessary a recipe for upgrade. As SPC notes it's a bit veered off. Shortwave could also outrun storms, which would really help keep things in check. Slower wave than what the globals show would tee up the Valley a bit.

That early watch text seemed a little bullish. I'd be more concerned about tonight. MRX remains most concerned about tonight and that makes sense. Outflow boundary has lifted into Kentucky which should reduce the Tennessee threat this afternoon. Then tonight the line should sag south from Kentucky. Those Missouri cells will probably have a filed day riding the Kentucky boundary until they turn southeast into Tennessee and go mainly wind.

Looks like an MD for a watch downstream of morning Kentucky severe storms in progress. John, MRX had a non-public EM graphic for later this evening (a second round) just south of the MD blue zone which would include you. MRX actually backed off tornado language in favor of damaging wind. Sorry that's probably not what you wanted to read. Separately the RRFS is talkin' dirty. It covects the outflow boundary in Tennessee south of the synoptic front still in Kentucky. Even has cells near Crossville up on the Plateau with that greater surface inflow (elevation). We'll see with lots of mid-level clouds. If not enough surface heating the outflow will be capped. Some models keep the capped solution. Even this RRFS simulation has the Tennessee cells pretty small - a sign of possible cap bust.

Ope! Moderate risk is posted for Friday (night). But hey, John is just 15% in the hail genre. So how badly did my post age? Moderate is a wind hatched 45%. They keep the worst hail NW Tenn into Kentucky. The 10% TOR is along and north of a line from Dyersburg to Clarksville. For most of us this is a straight-line wind storm on Friday night. ENH is our 30% wind. Perhaps we are due to blow some trees down on I-40? It's been several years, ha!