jojo762 Posted February 27, 2017 Share Posted February 27, 2017 9 minutes ago, Quincy said: NCAR ensembles are mixed with about 1/3 of the members showing robust convection over central AR by 00z Wed. Notable that a lot of the NCAR ensemble members that do actually develop convection develop it relatively early, compared to other models, between 19Z-21Z. Not sure how reliable they are, but looks like a mixed storm mode w/ supercells, but regardless, any storm in that environment will be capable of producing tornadoes, especially as we get closer to 00Z. Link to comment Share on other sites More sharing options...
bjc0303 Posted February 27, 2017 Author Share Posted February 27, 2017 2 hours ago, jojo762 said: Notable that a lot of the NCAR ensemble members that do actually develop convection develop it relatively early, compared to other models, between 19Z-21Z. Not sure how reliable they are, but looks like a mixed storm mode w/ supercells, but regardless, any storm in that environment will be capable of producing tornadoes, especially as we get closer to 00Z. I think global models have QPF between 18z-00z Link to comment Share on other sites More sharing options...
Jim Martin Posted February 28, 2017 Share Posted February 28, 2017 0z NAM sounding for tomorrow night in the Missouri Bootheel. Wow wow... Link to comment Share on other sites More sharing options...
Hoosier Posted February 28, 2017 Share Posted February 28, 2017 RAP is really mixing out the dewpoints in Missouri tomorrow afternoon. Link to comment Share on other sites More sharing options...
Jim Martin Posted February 28, 2017 Share Posted February 28, 2017 Would that mixing lower the dewpoints there Hoosier? Link to comment Share on other sites More sharing options...
Hoosier Posted February 28, 2017 Share Posted February 28, 2017 1 minute ago, Jim Martin said: Would that mixing lower the dewpoints there Hoosier? Yeah If it's right. Link to comment Share on other sites More sharing options...
bjc0303 Posted February 28, 2017 Author Share Posted February 28, 2017 Interesting to see deep mixing occurring in SE KS/SW MO on the RAP. Mixes down higher momentum SW flow from aloft resulting in a psuedo dry line looking feature. Probably helps with some convergence Link to comment Share on other sites More sharing options...
JoMo Posted February 28, 2017 Share Posted February 28, 2017 Looks like I'm probably going to get one of those squall line things with the spin up tornadoes tomorrow night along the cold front. I'm ready to skip to mid-summer already.... Link to comment Share on other sites More sharing options...
andyhb Posted February 28, 2017 Share Posted February 28, 2017 4 km NMMB/ARW both have supercells going in S MO/N AR by 00-01z, with the latter being particularly troubling. Link to comment Share on other sites More sharing options...
JoMo Posted February 28, 2017 Share Posted February 28, 2017 Pretty big 10% hatched TOR on the Day 1 SPC outlook. Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 Very large enhanced risk area in the 06Z D1SWO. Including a large 10% hatched TOR risk extending from Northern Arkansas northeastward into portions of western Indiana. SPC pointing toward the possibility of robust supercells with a few strong tornadoes, lots still to be figured out about storm coverage though. Imagine if confidence increases further for a particular corridor that we will get a MDT risk, as the parameters that will be in place are very impressive. Link to comment Share on other sites More sharing options...
SmokeEater Posted February 28, 2017 Share Posted February 28, 2017 Surprised nobody's discussing this morning, 10% hatched got even bigger last outlook. Would expect moderate once all the mesoscale details get worked out. Link to comment Share on other sites More sharing options...
bjc0303 Posted February 28, 2017 Author Share Posted February 28, 2017 7 minutes ago, SmokeEater said: Surprised nobody's discussing this morning, 10% hatched got even bigger last outlook. Would expect moderate once all the mesoscale details get worked out. Heading to joplin to start. RAP shows a dry line like bulge in NE OK resulting in backed flow. Very potent hodographs would resylt. must be picking up on a speed max Link to comment Share on other sites More sharing options...
cstrunk Posted February 28, 2017 Share Posted February 28, 2017 HRRR has some mostly isolated storms going up in Arkansas and southern Missouri this afternoon, I'd be surprised if we didn't see multiple tornado reports if something like that verifies. Link to comment Share on other sites More sharing options...
JoMo Posted February 28, 2017 Share Posted February 28, 2017 There's the mod risk Link to comment Share on other sites More sharing options...
SmokeEater Posted February 28, 2017 Share Posted February 28, 2017 Big mod risk also. Really pushing the strong tornado nocturnal threat now too. Looks primed. Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 Definitely looks primed... Anywhere from S MO/NW AR northeastward into western Indiana looks to stand a good chance of numerous/several discrete tornadic supercells this afternoon into tonight. Very concerned about any supercells that remain discrete into the nighttime hours. Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2017 Share Posted February 28, 2017 18 minutes ago, jojo762 said: Definitely looks primed... Anywhere from S MO/NW AR northeastward into western Indian looks to stand a good chance of numerous/several discrete tornadic supercells this afternoon into tonight. Very concerned about any supercells that remain discrete into the nighttime hours. Upper 60s dew-points already up to central AR with 60F dews to I-44 in MO. Still some mixed signals with the placement of convective initiation. (AR vs. MO) The WRF/NAM members light up northern AR into southeastern MO. This area really has the most impressive parameter space, but CAMs have been inconsistent. The 15z HRRR has come around with a discrete, long-lived cell tracking across central to northeastern AR, but run to run variability highlights how nebulous the placement details are. 12z SSEO UH tracks from 00-03z Wed: Will follow up once the NCAR ensemble data from 12z is available. Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 Low-level winds are already screaming out of the southwest today... Mesoanalysis indicates 35-40kts at 925, and 50+ kts at 850. Very impressive. VAD derived hodographs should be pretty sick later when low-level winds (specifically at/near the surface) back a bit more. Gonna be one of those days where some storms will likely rotatte upon/shortly after initiation. Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 17Z HRRR is particularly ominous. Develops several discrete supercells by as early as 20Z in far NE OK/far SW MO and moves them up into Illinois, pops discrete supercells off in Illinois too later on (21-23z)... Also continues the idea of an isolated supercell in Central Arkansas. UH tracks aren't overly impressive, but not sure that that is total relevant given the obvious potential of any discrete supercells that develop within this parameter space. Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2017 Share Posted February 28, 2017 12 minutes ago, jojo762 said: Low-level winds are already screaming out of the southwest today... Mesoanalysis indicates 35-40kts at 925, and 50+ kts at 850. Very impressive. VAD derived hodographs should be pretty sick later when low-level winds (specifically at/near the surface) back a bit more. Gonna be one of those days where some storms will likely rotation upon/shortly after initiation. Several factors (in addition to what you mentioned) make this an especially unnerving setup: 1. Such a broad warm sector/threat zone. Not only the ENH risk area, but storms could fire as far west as far eastern KS, where recent guidance shows fast moisture recovery ahead of mixing across central MO. Tail end storm(s) in central AR may be on the fringe of SPC's outlook, but given the environment, there's a strong likelihood of a supercell producing significant severe down there, especially if such a storm remained at least semi-discrete. Of course you also have storm potential up to the Chicago area and points east across the Ohio Valley. 2. Several larger cities in the threat zone, particularly LIT and STL in this sub-forum. 3. Timing. Initial afternoon storms, but the nocturnal threat may be just as significant, especially with eastward extent. 4. Multiple rounds of strong/severe convection possible. 5. Lack of clarity with exact placement. This is a setup where you could see a large spatial distance between significant severe reports, but it's not always about the quantity as much as it is the severity. 5. While not completely unheard of for late winter, we're talking about near record low-level temperatures and instability more characteristic of an early spring setup. Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2017 Share Posted February 28, 2017 Local climo also favors backing of winds across the Arkansas Valley, potentially enhancing the tornado threat there, as we've seen numerous times over the past few years. Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 Indeed, always seem to get orthographically enhanced backing there. Looks like there's a dryline bulge building in across Eastern KS in front of the 140+ kt 300mb jet max. Anybody know if any WFOs are going to be doing special soundings? Haven't seen anything on twitter from them. Link to comment Share on other sites More sharing options...
bjc0303 Posted February 28, 2017 Author Share Posted February 28, 2017 4 minutes ago, jojo762 said: Indeed, always seem to get orthographically enhanced backing there. Looks like there's a dryline bulge building in across Eastern KS in front of the 140+ kt 300mb jet max. Anybody know if any WFOs are going to be doing special soundings? Haven't seen anything on twitter from them. SGF will at 18z Link to comment Share on other sites More sharing options...
jojo762 Posted February 28, 2017 Share Posted February 28, 2017 2 minutes ago, bjc0303 said: SGF will at 18z Looks like LZK just did one. Very strong inversion at roughly 850. Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2017 Share Posted February 28, 2017 4 minutes ago, jojo762 said: Indeed, always seem to get orthographically enhanced backing there. Looks like there's a dryline bulge building in across Eastern KS in front of the 140+ kt 300mb jet max. Initiation seems somewhat unlikely that far SW, but the trend is for a tongue of sizable CAPE advecting into SE KS later on with some backing of the low level wind fields. When the cold front comes through, maybe the tail end of the squall line taps into that? Link to comment Share on other sites More sharing options...
Quincy Posted February 28, 2017 Share Posted February 28, 2017 3 minutes ago, jojo762 said: Looks like LZK just did one. Very strong inversion at roughly 850. High convective temperature, but once height falls increase later on and steep mid-level lapse rates advect NE from Texas, that modifies to a bit of a loaded gun sounding. Link to comment Share on other sites More sharing options...
andyhb Posted February 28, 2017 Share Posted February 28, 2017 Not exactly looking too favorable for initiation further south with the cap stronger and moisture less deep than the HRRR forecasted. Link to comment Share on other sites More sharing options...
Indystorm Posted February 28, 2017 Share Posted February 28, 2017 Might have initiation trying to form south of Lebanon MO at this time. Link to comment Share on other sites More sharing options...
JoMo Posted February 28, 2017 Share Posted February 28, 2017 Jeff P on I-44 in SW MO.. starting to see storms developing in NE OK and SW MO. https://www.periscope.tv/w/1MnxnLzpjWmGO Link to comment Share on other sites More sharing options...
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