jojo762

Latest HRRR run is nuts... Not looking very messy at all + many discrete/semi-discrete supercells. Not able to look at forecast soundings right now, but I suspect it’s forecasting an EML that’s *just that much stronger* than last night’s 00z run..

Broyles mentions violent long-track tornadoes will be possible. Even name checks STP increasing to ten. Not sure how often I’ve seen violent long-track tornadoes or STP mentioned in an outlook discussion.

HRRR seems to be becoming progressively **less messy with each run. Not a good trend. If it means anything to you, 04z HRRR also pops a 200+ mile long UH track.

This might be of interest to some, but Broyles will be doing the 06z D1 update.

If you want a good idea of what our lapse rates are going to be looking like tomorrow, take a peak at the MAF and DRT 00z RAOBs.

Good ole Shawn has had his Twitter account on private for ages...

For reference that day was very prolific... and didn’t get upgraded to a high risk until the 20z update.

Anyone want to make predictions for tomorrow basing off of forecast guidance/gut feeling? I’d personally go with dozens of tornadoes (take that as you will as far as raw #s) and several intense, long-tracking tornadoes. I think we’ll have a mix between messy and several intense supercells. Sort of like the convective evolution of last week EXCEPT supercells/tornadoes will likely be much more intense. In my mind, even a messier outcome tomorrow still yields quite a few tornadoes, whereas a higher-end solution yields numerous intense tornadoes across a very large area (maybe super-outbreak type stuff??). Altogether think we’ll meet in the middle of the two. This will be a noteworthy day/analog to mention in the future, regardless of what happens (bust or outbreak).

00z WRFs are.... aggressive? Yikes.

I wanted to be that aggressive with calling out how awful/suspect that thermo profile looked (from a forecast output perspective), but I couldn't.

I'm going to go ahead and say what the NAM NEST shows of ZERO convection firing along the pre-frontal trough will not happen.. If every other CAM is showing plenty of pre-frontal convection, while the NAM NEST shows absolutely nothing because of some strong 700-800mb inversion , and the NAM NEST ends up being right..... If that happens I will eat a shoe.

Meanwhile the 00z NAM in Mississippi at 18z tomorrow...

Biggest difference to me seems to be the degree of instability that has built up by early afternoon. However, the HRRR still shows relatively similar levels of MLCAPE and 3CAPE at 22Z further north in KY/TN so (18Z v 00Z. run)... All of this is mostly a product of early-firing convection AND more messy/blobby storm modes. 18Z HRRR MLCAPE valid at 18z Thurs: 00Z HRRR MLCAPE valid at 18Z Thurs:

00z HRRR is a touch more tame than the 18z run was... But still shows many discrete/semi-discrete supercells across AL and MS during the afternoon and evening -- toward evening it really starts to light up KY/TN with a broken line of what I would assume would be a mixed-bag of supercells and clusters, given the forecast parameter space across both these area i'm not exactly sure it is going to matter how "discrete" convection can stay.

MY GPTTC/hypothetical target was Jonesboro, TX... Feeling pretty good about it

Unsurprisingly, WFOs JAN, BMX, and HUN all referenced strong, long-track tornadoes in their afternoon AFDs. What kind of made me laugh a bit was the casualness of the MEG AFD considering half of their AFD currently has MDT risk caliber tornado probabilities.

NAM NEST is on an island of its own wrt convective evolution across MS/AL... I suppose it should not be totally ignored, but outliers ought to be given minimal preference in a forecast. Latest NAM is very impressive. As has been discussed, it expands the area of higher-end tornado potential further north. CAMs generally show a consistent convective evolution (some supercells, some mixed-mode) up and down most of the cold-front/pre-frontal trough so such a situation could prove to be quite problematic if this were to materialize. 18z HRRR generally agreed with the NAM in a larger warm-sector (though, perhaps not as broad as the NAM shows) so that's something. **If the warm sector were to surge that far north by mid-afternoon, with the same thermodynamics as currently forecast, it would not be a stretch to say this could be a historic day, as forecast soundings across most of the progressively expanding warm sector would support high-impact tornadoes. If this trend continues the ENH and MDT risks would need to be expanded significantly.

Gleason differs high risk upgrade to tomorrow. Reasonable call. Nobody but Chris Broyles (probably the most bullish forecaster) has ever issued a D2 High from SPC.

If I’m being honest I’m not sure that even last Wednesday is a good “low bar” comparison given the upper-tier forecast environment. We didn’t see many (if any?) intense, long-tracking tornadoes last week. Tomorrow will *likely feature at least one, if not multiple — unfortunately.

I dunno. Sure seems like there’s plenty of model agreement. SREF pops a large area of 75% or higher on the significant tornado ingredients combo prob. The 12z HREF also pops 70% or higher probabilities of UH >75 m2/s2 over parts of Mississippi and Alabama tomorrow. I get everyone is gun shy because of *gasp* junkvection in Dixie, but it’s really just a reality of setups down there. Albeit, I certainly agree that the lack of CINH (and resulting potential for many more storms) is at least a slight concern for tomorrow reaching its max potential. Quincy, as always, outlined potential scenarios for tomorrow quite well. If last Wednesday was a *verified high risk*, and a copy of last week is probably the lower-end of possibilities with tomorrow then... you get the rest.

NAM NEST is much more toned down than the HRRR was. In fact it basically shows zero intense convection across most of the MDT risk area during its run. Not gonna buy that.

The 12z HRRR radar loop reminds me of a particular day... wonder what that could be...

Overall though, the HRRR did quite well wrt convective evolution. Better than most CAMs did. The HRRR doing better than most CAMs is quickly becoming the norm and not the exception, anyways.

00z CAM run down: HRRR: Plenty of supercells, but also a fair amount of junk in the warm sector. NSSL-WRF: Numerous discrete supercells traverse the warm sector... Much less junkvection. WRF-NMMB: Most aggressive with junk in the warm sector. Maybe some tornadic supercells, but looks awfully junky. WRF-ARW: Much like the WRF-NSSL is fairly aggressive developing numerous discrete supercells across the warm sector. NAM NEST: Numerous discrete supercells across the warm sector. Pretty substantial agreement in CAM output that a significant threat will evolve on Thursday... Perhaps the biggest question relates to northward progression of the warm sector with both the HRRR and NAM, as well as the globals being substantially further north than most other CAM guidance was.

As could be expected the 00z HRRR depicts a mixed bag. Yes, there will likely be many storms in the warm sector as should be anticipated in the deep south when there is weak/no CINH and large CAPE, but there will also be many dominant supercells. Pretty classic for a "big" setup in this region. Almost certainly looking at a sizable Moderate Risk here in about 3.5 hours.