Quincy

SPC maintains hail/wind-driven enhanced risk for northeastern Iowa into southeastern Minnesota and west-central Wisconsin. They did bump tornado probabilities back down to 5%. With that said, morning trends are favorable if you want severe thunderstorms. CAMs show less early day convection disrupting the environment near a warm front in southern Minnesota. 14z observations show dew points already in the mid to upper 60s across southwestern Iowa. SPC mentioned possible moisture field disruptions from an MCV over Missouri, but it looks like moisture recovery is well underway. Confidence is highest in convective initiation by mid to late afternoon around south-central/southeastern Minnesota. Initial storm mode should be discrete or at least semi-discrete. Storms that track near the warm front, especially as the low level jet strengthens this evening, may pose the greatest tornado threat.

The main thing that worries me is a series of perturbations that swing through the Upper Midwest around late morning/midday. That could overturn the environment and disrupt return moisture flow. Hence why some CAMs only manage to initiate 1-2 storms right before 00z. With that said, the model, ensemble and analog consensus continues to show a potentially volatile environment along the warm front near MSP toward southwestern Wisconsin by peak heating. There are even some signs that a broad area of conditionally favorable instability/shear could evolve over much of Iowa and southern Minnesota across the warm sector by 00z. This is why some CAMs are rather aggressive with a broken line of supercells erupting by early evening near the IA/MN border.

Today looks interesting across Minnesota, but I’m not sure that the moisture and wind profiles will support anything more than brief/transient supercells. Upper level support is there, but some veering low level flow will likely limit SRH. CAMs show a broken line of marginally organized storms, which seems realistic given the environment. Thursday has bigger potential. SPC is playing it a bit conservatively for now. The CIPS analogs show a very strong signal for severe thunderstorms around the northern Iowa/southern Minnesota area, which lines up with the jet axis and expected warm front placement.

A pair of intense bow echoes are moving across central/eastern Kansas tonight. There have already been several measured wind gusts to 75+ MPH.

Just barely squeaked out 90F at DFW today, but it counts. The streak probably won’t break until Saturday, but there is a strong signal for a cold frontal passage this weekend, which could make it as far south as the Gulf Coast.

As we approach the climatological peak of the severe weather season, the threats for severe storms should continue in various forms through the balance of this week. Tuesday: The fringe of enhanced northwest flow across the Missouri Valley/Midwest may glance appreciable instability across the Central Plains vicinity. Scattered to numerous strong thunderstorms are anticipated, along with at least isolated severe thunderstorm activity. Wednesday: As the upper level flow pattern resets, a belt of enhanced winds should eject from the Northern Rockies toward the central/northern Plains. Only modest instability is expected across the northern tier, as well as over the High Plains. Regardless, a few strong to severe storms appear possible in both regimes. While somewhat greater instability becomes displaced to the east, a more appreciable severe threat may evolve across the eastern fringes of this sub-forum, before moving towards the Ohio/Tennessee valleys. Thursday/Friday: A more expansive and potentially active severe weather setup could evolve across the Central U.S.. Details may still change, but seasonably strong upper levels winds are progged to eject from the Rockies across the plains and toward the Great Lakes/Ohio Valley by the start of the weekend. While the trajectory of the ejection is not classic for mid/late May, (trough appears more elongated and progressive) it should spawn at least scattered severe thunderstorm activity. Beyond Friday, there are signs of another pattern reset, which could result in a few days of less active than usual conditions, from this weekend into early next week.

CAMs have been struggling with the MCS this morning. Trends look to be a bit more robust and somewhat farther SW. It looks like the convection will move toward the KS/MO/OK border area. Still think some isolated supercell development is possible on its southwest flank over eastern Oklahoma, but keep an eye to see any outflow shunts the threat farther S/SW. (not as far as OKC though) Edit: Now that l look, the NSSL that was posted above seems to be the closest to current obs. That model shows more of a supercell threat down near I-40 and into southeastern Oklahoma. Seems to line up with trends, also considering the system will likely accelerate faster than progged.

PDS severe thunderstorm watch for southeastern South Dakota and vicinity says wind gusts up to 105 mph are possible.

Day 1 wind-driven moderate risk issued today for parts of the eastern Dakotas and western Minnesota. Based on wind profiles and model simulations, looks like storm mode will go linear very fast. This definitely has the feel of a summer setup, but it should help usher in somewhat cooler temperatures for the north-central states.

Relatively messy storm mode so far. Keeping an eye on an arc of semi-discrete cells around the Sioux City area. Those may have the least disrupted inflow environment to work with. Storms farther north appear to be clustering and interacting with cooler outflow, while storms to the west near the MCV center are likely elevated.

Localized supercell potential evident today in the front right quadrant of an MCV, which is moving into Nebraska late this morning. The threat should maximize between far northeastern Nebraska and southwestern Minnesota, where supercell wind profiles impinge on large/locally extreme instability late this afternoon. The main limiting factor I see is that there may be some subtle veer-back signatures in the wind profiles, due to the MCV moving NNE (southerly component to 500mb flow). Wind fields should improve toward 00z and especially with northward extent, with a lifting warm front, moving north across southern Minnesota. I’d expect an arc of semi-discrete supercells to intensify and tend to cluster, as they track across the NE/IA/SD border area. There is certainly a window for a few tornadoes, but storm mode may limit this from being a higher end localized event. If any isolated cells form ahead of the main arc of storms, they could pose a somewhat greater tornado risk across southern Minnesota.

We hit 92F in Oklahoma City today. Wichita Falls, TX hit 103F. Believe it or not, that only tied the record for May 8th.

Sunday the 8th looks like it will mostly remain capped, but maybe there will be isolated severe storms. Monday appears to have the most apparent potential through this period. Most likely in or near Iowa. The 10-13th is forecast to be an odd pattern for early/mid May. Pronounced ridging across the central U.S. and a cutoff low across the Southeast. I’m not sure there will be much overlap between appreciable forcing, shear and instability. Still, I could see a few severe storms, somewhere between the central High Plains and Upper Midwest.

What a mess for chasing. I doubt anyone saw tornadoes unless they were right up close. And many chasers (and tourists) were way too close. Witnessed many chasers, including tour vans, fragrantly breaking traffic laws on the roads.

21z FWD sounding still shows a cap holding on. Warm front is basically stalled just north of the Red River. Thinking OKC is going to be spared the worst, but we’ll see how it continues to evolve.

Relatively quiet this far. Panhandle storms appear to be overrunning the warm front and ingesting cooler air. Low level lapse rates are still unfavorable across most of Oklahoma. A cell tried to go up near Abilene, but weak forcing seems to be the issue there. Focus moves toward a dryline bulge, just east of Lubbock. It looks like we may have convective initiation now after a failed attempt earlier.

18z sounding from OUN is ugly if you want tornadoes. At least for the next several hours, as there’s a stable near surface layer.

Trying to save data, so embedding tweets instead of uploading more images. Low level lapse rates look to be a noteworthy limiting factor for central Oklahoma, in terms of tornado potential this afternoon. Not all that much different from 5/20/19. If lapse rates stay low, as is expected through 6-7 PM, the tornado threat may be limited to closer to the Red River. This doesn’t mean that tornadoes can’t happen, but that the threat with northward extent may be more marginal and could hold off until after 00z/7 PM.

HREF ensemble probability for intense (>150 m2/s2) helicity tracks. Keep in mind these don’t explicitly/necessarily indicate tornado potential, but given low level moisture and wind fields today, there is a bona fide tornado threat. The cluster near/NE of OKC is mostly FV3 driven, but still plausible near the warm front, IF low level thermodynamic fields improve enough to support supercells rooted near the surface.

It’s concerning that HRRR is not showing much of any convective initiation through mid-afternoon. Some elevated activity races north with the warm front, but it looks like the WF is going to be draped close to the I-40 corridor. Right now, low level lapse rates are pretty bad (< 5 C/km across all of Oklahoma) and capping will probably limit CI for a while. Not really sure how convection evolves, but any discrete/semi-discrete cells initiating after 3-4 PM will need to be watched very closely. Based on near term trends, those cells coming out of the panhandle later will probably remain at least semi-discrete as they move into southwestern Oklahoma. Looks like odds are increasing for at least 1-2 long-track, intense supercells, with other tornadic supercells possible in the warm sector and near the warm front.

Pretty classic localized outbreak setup unfolding, around the SE Texas panhandle/far NW Texas vicinity. Morning radar and water vapor imagery suggest little to no airmass disruption will evolve SW of a lifting warm front across NW Texas. High res model consensus shows deep shear vectors (~50 knots) just about perpendicular to the dryline. Point forecast soundings show a reservoir of 8-8.5 C/km mid-level lapse rates, favoring large to very large hail. Low level hodographs enlarge as early as 21z in the SE panhandle, as storms initiate. As I see it, the three main limiting factors from this being a higher end regional (vs localized) event are: 1. Convective overturning is still possible from western North Texas into SW Oklahoma, where warm air advection showers/storms could still blow up by early afternoon. This would limit how far east the significant tornado threat (associated with discrete/semi-discrete supercells) could extend into Oklahoma. 2. Storm mode near the triple point could get messy as storms interact with the warm front. Clustering and storm interactions might disrupt potential longevity of discrete storm modes. 3. Several models show discrete supercells firing farther south across West Texas ahead of the dryline, but here, hodographs are more straight and elongated, suggesting less of a tornado threat. While the epicenter may be near the SE Texas panhandle, look for isolated storms as far south as Southwest Texas, while mixed storm modes with embedded supercells will also be possible across North Texas and much of Oklahoma.

This setup reminds me a bit of 5/16/15 (Tipton/Elmer tornado). I remember that was a grungy HP setup. I started chasing in the Texas panhandle and then bailed east just in time for Tipton. I recall that the northern threat area (N of I-40) was convectively overturned and mostly a bust. There were nocturnal tornadoes into northeastern Oklahoma, which could happen again. Interestingly, CIPS analog data pegs 5/19/15 as the top analog, but 5/16/15 seems to fit the pattern a bit better. 5/16 has some differences, so I’m not saying that it’s a perfect match synoptically. HRRR seems to be on the higher end of the ceiling here. ARW also goes kinda bonkers with discrete/semi-discrete cells over a broad swath of the southern Plains. 3km NAM blows an MCS through NW Texas/southern OK in the morning, chewing away at most of the threat area. As a result, the NAM is on the lower end of the spectrum. Still a complicated setup, but I’d think that areas west (dryline) and south (tail end Charlie near FST?) have the greatest potential for at least semi-discrete storms. Oklahoma is a wildcard, but it could be more of a late show there. North Texas might even get in on the action, if early convection isn’t too disruptive.

The two major 18z CAMs show very different convective evolutions tomorrow: 3km NAM shows a morning MCS that effectively overturns the environment from much of northwest Texas into southwestern Oklahoma. Isolated cells by the dryline (near I-27) struggle to mature and blobby convection affects parts of North Texas into southern Oklahoma. HRRR shows minimal early day convection, resulting in a cluster of intense supercells forming off the dryline, near the Caprock, and moving east into southwestern Oklahoma. I think in this setup, I’d lead toward the messier convective evolution, but let’s see how trends lean tonight.

Today looks like a quieter day, but Texas could see a few isolated severe storms. Some CAMs show a supercell or two trying to form in East Texas, although deep layer shear looks marginal. Another area of focus would be the Edwards Plateau/Hill Country area. Isolated supercells seem likely over in Mexico, but a storm or two could form over or move onto the Texas side. Tomorrow could be much more active, although the effects of early day convection complicate the forecast. I’d tend to think that areas near and north of I-40 will probably be overturned and miss out on the strongest storms. There seems to be more confidence for isolated/scattered supercells in west/northwest Texas. Oklahoma is a wild card, but storm mode will probably be more messy, rather than discrete, in these parts.

Chased a supercell for almost two hours from SW of OKC to east of Norman. The sunset tonight back home in Moore really topped off a successful local storm chase.