andyhb

Yeah there's definitely something eerie about a potentially significant severe threat one day before the 50th anniversary of, hands down, the worst tornado outbreak to ever affect the Ohio Valley.

Probably should consider a separate thread for this one soon. The 12z NAM also brought back a significant threat after losing it at 00z.

Yes the 18z NAM is absolutely nasty on Tuesday. Granted, that probably won't hold, although its 500 mb setup isn't much different than the other models. The low levels will make or break this along with prior convection from Monday.

Well yeah, you used to live in Florida.

Tuesday looks potentially volatile in the OV on the 12z GFS and Euro. 40-50 kt SW/WSW LLJ with a potent vort ejecting out of the Plains positive tilt trough. Moisture looks like a non-issue, the primary fly in the ointment looks to be the degree of veering in the surface winds, which will also be tied to the timing of the ejecting wave/potential phasing with the northern stream.

7 tornadoes confirmed thus far in the ILN CWA.

Now high end EF3. Have some suspicion that there are a few points that may be consideration for EF4. The Taco Bell and the church that were both completely destroyed in particular.

I'm not sure on the number of confirmed dead. The last more official statement I saw was 3 dead with the likelihood to rise. Also I believe the Lakeview tornado has been upgraded to EF3 from the earlier EF2 PNS in Orchard Island.

The fatalities in Winchester were redacted later. I think someone got "casualties" lost in translation or something of the sort.

https://www.whio.com/news/local/injuries-storm-related-damage-reported-mercer-county/ZE7JIPWZNNAFVKOUSCV3VTT5N4/ Fatalities confirmed in Logan Co. OH from the Wapakoneta/Lakeview tornado.

Need a separate thread for this.

00z ILN sounding is very favorable for strong tornadoes.

Tornado in Lakeview OH earlier.

Winchester IN just had a tornado go right through the middle of town. This is turning into a tornado outbreak very quickly.

Big wedge tornado approaching Lakeview OH.

Thursday will depend highly on the degree of cyclonic curvature within the mid/upper level flow. Most guidance is not in agreement with the 12z NAM/NAM 3 km idea of having a substantial shortwave eject ENE and induce stronger surface cyclogenesis and LLJ response. The 18z NAM also backed off on that idea. Moisture looks like a non issue and I don't see much concern for a washout especially further south, but the wind fields will be strongly affected by how amplified that feature is.

18z NAM is absolutely nasty in the Midwest (IA/IL) on Thursday. Other models generally are not as favorable although they appear to be shifting towards a solution where a coherent shortwave ejects ENE/NE after Wednesday, which would increase the threat. Very, very cold air aloft with temperatures approaching -20 at 500 mb and -45 to -50 and 300 mb means that you won't need a lot of moisture to get strong updrafts.

Blocking pattern looks to setup beyond mid month given the ongoing significant SSW and prolonged disruption/decay of the stratospheric PV (perhaps the final warming). Would think moderation of some of the warmth should occur during that period along with a decrease in severe weather chances.

New Euro seasonal is pretty ridiculous for this season. The numbers for mean ACE (165+), named storms (17+), and hurricanes (9) in the Atlantic through September (so not even including late season) are all pretty much off the charts. Granted, forecast skill for such predictions is modest at best in March, but also a signal like that has never been seen previously in the ECMWF long range forecasts.

Just went right through town.

Anyone here on that Atkinson storm? Looks pretty close to producing.

Good moisture depth and quality in this 19z observed sounding from UIUC (Champaign).

Recent CAM/short-range guidance seems to be on the upswing for tomorrow's threat. For one, that subtle embedded wave aloft that induces surface cyclogenesis along the surface trough seems to be returning (e.g. the earlier Euro runs) that could increase the low level wind response. The RAP in particular has a fairly potent surface cyclone and pseudo-dryline. Moisture seems sufficient across most models as well. I'd be wary of the HRRR overmixing and being too far east at this range. The MPAS from NSSL also seems to have an issue with that, although it has improved from the 00z to the 12z run.