Quincy Posted June 5, 2020 Share Posted June 5, 2020 The ridge across the Central Plains should begin to break down this weekend. At the same time, a belt of seasonably strong upper level winds (60-80kts at 500mb) should pivot around the base of a Great Basin/Rockies trough. The trough will gradually move east, impinging on favorable low level moisture and thermodynamic profiles for severe storms Saturday through Monday. The action starts Saturday with a large area of convective activity likely from the Rockies into the High Plains and eastward across the Dakotas. At this point, convective modes look to be mixed with one or more sizable MCSs developing. The setup resets for Sunday and there is the potential for a break in the action as capping prevails during much of the day. The focus appears to be over the Dakotas/Minnesota vicinity. Convective modes could be more discrete than Saturday, but there is still a lot of time for the forecast to evolve. Yet another active severe weather day is possible on Monday, but models begin to diverge to some degree and Cristobal may influence the upper level pattern as well. Regardless, more severe storms may be possible from the eastern Dakotas/mid-Missouri Valley into the Upper Midwest. Throughout the period, deep layer shear will be more than sufficient for organized severe storms, along with dew-points rising through the 60s and sizable instability profiles. Saturday could even get a bit interesting over the Rockies, where seasonably impressive wind profiles may overlay just enough instability (generally less than 1,000 J/kg) for high terrain severe storms as well. Link to comment Share on other sites More sharing options...
Chinook Posted June 5, 2020 Share Posted June 5, 2020 I'm not really sure if the parameters will line up this well. As far as forecast soundings are concerned, I haven't seen a forecast SCP above 70 something, other than last night's 00z NAM run. I have heard that storm chasers are concerned about getting stopped at the borders of Native American reservations, due to COVID-19. The models seem to have a lot more in the multicell (squall line) modes developing tomorrow night, despite awesome supercell parameters. Link to comment Share on other sites More sharing options...
yoda Posted June 5, 2020 Share Posted June 5, 2020 25 minutes ago, Chinook said: I'm not really sure if the parameters will line up this well. As far as forecast soundings are concerned, I haven't seen a forecast SCP above 70 something, other than last night's 00z NAM run. I have heard that storm chasers are concerned about getting stopped at the borders of Native American reservations, due to COVID-19. The models seem to have a lot more in the multicell (squall line) modes developing tomorrow night, despite awesome supercell parameters. SCP of 107 lol Link to comment Share on other sites More sharing options...
Quincy Posted June 6, 2020 Author Share Posted June 6, 2020 Barring some evening miracle, today’s prospects for any surface-based supercells appear to be cooked. Link to comment Share on other sites More sharing options...
WhirlingWx Posted June 6, 2020 Share Posted June 6, 2020 And then Orlando gets rocked by a damaging tornado from Cristobal's outer bands. Heavily populated area and reports of roof collapses but hopefully no casualties. Edited to link a video of said tornado taken from Twitter... Debris lofted to nearly 20k feet as well per CC https://mobile.twitter.com/News6Justin/status/1269415099254673408 Link to comment Share on other sites More sharing options...
WhirlingWx Posted June 7, 2020 Share Posted June 7, 2020 Another confirmed tornado near Universal Studios. Orlando metro is having a rough night. And then we get a wind-driven 01z moderate risk for South Dakota Link to comment Share on other sites More sharing options...
Quincy Posted June 7, 2020 Author Share Posted June 7, 2020 Ongoing derecho across the High Plains. It’s not too common to see such expansive convective systems so far west in the states. The lack of discrete activity ahead of the line may have helped maximize potential instability downstream as well. Moderate risk is in effect for widespread damaging winds. Link to comment Share on other sites More sharing options...
jojo762 Posted June 7, 2020 Share Posted June 7, 2020 Today could be a big time day across South and North Dakota and into Minnesota... The whole gamut of severe weather is likely today. Strong tornadoes are possible with any discrete convection; but this presents the question of the day, how long, if at all, will storms stay discrete? If they do there’s a good possibility the plains sees its biggest tornado day of the year — if things get grungy quickly storms will still produce lots of severe weather, but probably not many tornadoes. Everything is there for an anomalous day in the northern plains, but will it happen? Stay tuned. 3 Link to comment Share on other sites More sharing options...
Quincy Posted June 7, 2020 Author Share Posted June 7, 2020 The NW MN/far NE ND area looks maximized for tornado potential. Dew points already in the mid to upper 60s with a warm front gradually lifting north. Some of that risk probably spills into Canada, but I think the front in NW MN is where the best shot at prolonged discrete/semi-discrete supercells is. There could be a secondary area farther south in South Dakota, particularly the tail end of where convection unzips along a front. Between the two areas, it’s probably quick to upscale growth. One positive factor is the cold front looks slow-moving at best, maybe acting more like a stationary front. That may allow for a few storms to thread the semi-discrete needle, but we’ll see. 1 Link to comment Share on other sites More sharing options...
jojo762 Posted June 7, 2020 Share Posted June 7, 2020 Looks like the potential storm of the day might be taking shape near Ashley, ND... Pretty solid circulation on going, with classic supercell characteristics taking shape on reflectivity. EDIT: Overall looking like a pretty tough day so far for chasers as most picked northeastern ND, which got ruined pretty quickly by a large temperature gradient on the N/S warm front, which given storm motions isn’t exactly favorable... Link to comment Share on other sites More sharing options...
janetjanet998 Posted June 8, 2020 Share Posted June 8, 2020 ULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE BISMARCK ND 713 PM CDT SUN JUN 7 2020 THE NATIONAL WEATHER SERVICE IN BISMARCK HAS ISSUED A * TORNADO WARNING FOR... SOUTHWESTERN LAMOURE COUNTY IN SOUTHEASTERN NORTH DAKOTA... NORTHWESTERN DICKEY COUNTY IN SOUTHEASTERN NORTH DAKOTA... NORTHEASTERN MCINTOSH COUNTY IN SOUTHEASTERN NORTH DAKOTA... * UNTIL 800 PM CDT. * AT 713 PM CDT, A LARGE AND EXTREMELY DANGEROUS TORNADO WAS LOCATED 9 MILES SOUTHWEST OF KULM, OR 18 MILES NORTHEAST OF ASHLEY, MOVING NORTHEAST AT 35 MPH. THIS IS A PARTICULARLY DANGEROUS SITUATION. TAKE COVER NOW! Link to comment Share on other sites More sharing options...
Quincy Posted June 8, 2020 Author Share Posted June 8, 2020 I played the southern target, not really expecting much. At least I had a severe storm this time. However, I bailed on the one right-moving storm that by some accounts produced a brief tornado in NE South Dakota. Go figure. I drove less than 300 miles in total, which is low for a chase day. Much better than hauling up to ND, even though that fluky storm near Ashley produced. Lots of failure modes today, including: 1 1 Link to comment Share on other sites More sharing options...
jojo762 Posted June 8, 2020 Share Posted June 8, 2020 On to tomorrow... models hinting at a narrow zone in Nebraska featuring higher tornado potential. Biggest failure mode appears to be upscale growth/clustering of convection. Link to comment Share on other sites More sharing options...
Quincy Posted June 8, 2020 Author Share Posted June 8, 2020 Red flags up all over the place today. To mix it up, I’m focusing on the disadvantages of each storm chase target. I still wouldn’t rule out a diamond in the rough somewhere, but today looks like another convective mess. Link to comment Share on other sites More sharing options...
WhirlingWx Posted June 9, 2020 Share Posted June 9, 2020 We've had a few confirmed tornadoes in MN and NE today, activity there will probably keep going a little longer. I hope some chasers are finally getting their nice plains tornadoes with minimal impact to other people and property 1 Link to comment Share on other sites More sharing options...
Quincy Posted June 9, 2020 Author Share Posted June 9, 2020 I chased central Nebraska today. I was on the supercell that apparently produced a brief tornado near Arnold. Terrain was an obstacle both visually and WRT navigation. Prominent structure with the storm, either way. Link to comment Share on other sites More sharing options...
Quincy Posted June 9, 2020 Author Share Posted June 9, 2020 Tornado watch forthcoming for the central/eastern part of the KS/NE border area. Looking at obs, satellite and short-term guidance, there aren’t many negatives betting against the tornado threat. Yes, there is some backing of upper level winds and storms may cluster a bit... With that said, there’s already 2000-3000 J/kg MLCAPE wrapping around a seasonably impressive (near record low) surface low. Dew points are in the upper 60s to lower 70s, there is considerable backing of low-level winds and large low-level instability is evident. Storms should initiate soon near and just east of the surface low. Though narrow, the warm sector looks to be oriented favorably for storms to take advantage of the conducive environment for several hours. The main limiting factor may be mixed/merging storm modes, but a long-lived supercell or two appears possible. Storms farther north may have a tendency to run into cooler air, where winds are more out of the northeast, as opposed to southeast farther south. 1 Link to comment Share on other sites More sharing options...
Quincy Posted June 9, 2020 Author Share Posted June 9, 2020 Tornado watch and quick analysis: Link to comment Share on other sites More sharing options...
Chinook Posted June 9, 2020 Share Posted June 9, 2020 To me, today was sort of an unexpected tornado risk. I never thought the parameters would be this high, and the 500mb pattern is pretty strange, too. We've got a couple of severe-warned storms near the front in Nebraska. 1 Link to comment Share on other sites More sharing options...
Quincy Posted June 9, 2020 Author Share Posted June 9, 2020 8 minutes ago, Chinook said: To me, today was sort of an unexpected tornado risk. I never thought the parameters would be this high, and the 500mb pattern is pretty strange, too. We've got a couple of severe-warned storms near the front in Nebraska. Not only is one low 990s surface low strange this time of the year, but we have two... I remember looking at the 00z NSSL showing mid-70s dew points in NE Kansas and I thought it was out to lunch. Seeing 72-74 Tds pretty common over there right now. LCLs are relatively low considering surface temps surpassing 90F, but that moist advection has really helped. It’s an odd setup and I couldn’t find a close analog for this time of the year. Very intrigued to see how it plays out. Link to comment Share on other sites More sharing options...
Amped Posted June 10, 2020 Share Posted June 10, 2020 Christobal gets out of the way tomorrow night Might squeeze in some decent storms over OH and E MI. Euro and GFS also showing convection near the ULL center moving over IA and WI.. Could make for some odd looking radar images. Link to comment Share on other sites More sharing options...
Chinook Posted June 10, 2020 Share Posted June 10, 2020 Some of the storms/ supercells looked pretty good today in the Plains severe weather threat. The storms seemed to fire up right next to each other and merge somewhat. I don't think the enhanced risk verified for hail. There were only 2 tornadoes in Nebraska, which may have effectively verified a small-area enhanced tornado risk. Link to comment Share on other sites More sharing options...
Radtechwxman Posted June 10, 2020 Share Posted June 10, 2020 7 hours ago, Quincy said: Tornado watch and quick analysis: Looks like today found the one of the failure modes. Lol. Seemed like initial storms were too close to the front. Storm motions were kind of nw which took them across frontal zone. Seemed like storms struggled to acquire tight rotation today. Saw plenty of broad rotations on radar Link to comment Share on other sites More sharing options...
Quincy Posted June 10, 2020 Author Share Posted June 10, 2020 With the cold front/pseudo dryline surging so fast, storm motions were more N/NNW than I expected. Any storms that tried to turn right seemed to get undercut. I witnessed a brief funnel cloud near Axtell, KS, otherwise everything else was fairly junky. Maybe the relatively small 0-1km SRH away from the immediate surface low was another issue. Link to comment Share on other sites More sharing options...
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