Quincy

Severe thunderstorm prospects for the foreseeable future are quite bleak. The CFS has had a consistently quiet signal for the first two weeks of April, while this is supported by yesterday's Euro weeklies. The weeklies try to improve a bit around mid-April, only to reload the eastern U.S. trough around April week 3. A more favorable pattern is advertised for the last week of April, but model confidence decreases into this range. At the very least, climo favors increased activity around the end of April, even commonly in most years that were otherwise quiet.

Severe prospects for Sunday through Tuesday are muddled, as neither day stands out, despite having a slow-moving trough moving from the Southwest into the southern Rockies. Sunday remains fairly conditional, but there does appear to be a narrow corridor, somewhere near the Red River Valley across the southern Plains, that could support an isolated supercell threat. Forcing remains the largest concern, but model forecast soundings are a little bit more aggressive with boundary layer heating in the afternoon. This may be enough to erode surface-based convective inhibition. A larger area is expected to see favorable deep layer shear and instability on Monday from Texas to eastern Kansas, but the issue here is that wind profiles show veer-back-veer signatures. Hodographs are somewhat elongated, but very messy looking. Mesoscale details may determine the scope and magnitude of any severe threat, although it does not look like a big day, any way you slice it. A sagging frontal boundary becomes increasingly parallel to the deep layer shear vectors by Tuesday, suggesting the potential for more of a squall line type feature, from the southern Plains into the Arklatex and lower Mississippi Valley region. While severe weather may not be widespread, as mentioned earlier, heavy rain will probably be the biggest story. There is not much hope for substantial rainfall over the High Plains, but areas from I-35 and points east have the highest probability of seeing above to well above average rainfall over the next 3-5 days.

Sunday is very conditional and I don't like to pick apart soundings this far out, but just a few notes: Convective temperatures in the vicinity of the dryline bulge are in the mid-80s, while models show temperatures in the low to mid-70s. (Areas that do reach 80+ are on the dry side of the dryline) Forecast soundings show very little CAPE in the lowest 2km AGL, indicative of a capping inversion. Also, large scale forcing appears limited, with only very modest 12-hour 500mb height falls, in the ballpark of 10-20 meters. Regardless, we do appear to be rounding the bend and thunderstorm threats are increasing across the southern Plains. We should see several days with at least spotty severe reports over the next 5-7 days. At the very least, much-needed rainfall across the area should help ease some drought concerns, although there are signs that the bulk of the rainfall will stay closer to I-35 and points east, but we'll see. As some recent years have shown us, a pattern change can knock out a drought pretty darn quick.

Not sure if it's accurate, but M40 just shot up to 70/70 on the latest ob. Seems suspect. Tupelo was 58/57 at the top of the hour, so that cluster is likely on a track just north of the warm front based on the current storm motion, at least in the short term.

I don't know about moisture recovery not being an issue with the upcoming systems. The 12z Euro looks awful tame now with 60F dews staying south of the Red River on Sunday and struggling to reach into Arkansas on Monday. The overall pattern is too messy, especially for March, given such a large trough over eastern North America. With relatively small systems reoccurring in a fast-flow pattern, there isn't much reason to believe there will be substantial moisture recovery. More of a robust south/southeasterly wind trajectory over the southern Plains/lower Mississippi Valley is needed than what is progged with the expected pattern. If it was later in the season, it wouldn't take as much to moisten the warm sector, but we're only in mid-March and next week doesn't look too promising. I wouldn't be overly concerned though, as it is barely meteorological spring and not even the spring equinox yet. I wouldn't rule out some spotty severe next week and maybe the evolution of one or two of the systems will improve, but it definitely does not look like an outbreak setup and doesn't even look like a scenario for anything impressive for mid-March standards.

The 00z 3km NAM wasn't impressive at all, showing substantial cloud-cover ahead of the dryline with surface temperatures 5-10F shy of convective temperatures, even in the vicinity of a dryline bulge in the eastern Texas panhandle. Reflectivity progs concur with no convection. Meanwhile, the GFS came in a bit warmer in the western Oklahoma to central Kansas region, although still not quite robust enough for convection. I was intrigued to see the RGEM spit out convection in far southwestern Oklahoma between 21z Sun and 00z Mon. It makes sense based on what appears to be surface temperatures heating into the mid-70s in the presence of upper 50s to near 60F dew-points. I am still inclined to lean toward a non-event with cloud-cover mitigating surface heating (poor sfc-850mb lapse rates), despite favorable wind fields and nice looking thermodynamic profiles above 800mb. A highly conditional threat could still produce if surface heating improves, so I'd hold with a MRGL risk outlook for tonight's day 2 update.

The main limiting factor appears to be the quality of the warm sector. As discussed above, only a narrow area around the southwestern Oklahoma vicinity is progged to have (somewhat) favorable low level moisture, along with at least a possibility of convective temperatures being approached. The issue is that even within NAM range (taken with a large grain of salt at 72hrs), only a very tiny area (1-3 counties) comes within a couple of degrees of convective temperatures. The 00z NAM also shows no convection along the dryline. In addition, the NAM, too, favors the idea of >75% cloud cover across areas east of the dryline in Oklahoma. Synoptically, Sunday resembles 2/28/12, however, the warm sector this weekend is significantly smaller and far less impressive. If we had a deeper trough, a la 2/23/07, better forcing and mid-level cooling would result in much greater certainty of convective initiation along the dryline. Even the evolution of the surface low is not entirely clear. The 12z ECMWF shows a 995mb low up near I-80 in central Nebraska at 00z Mon, while the operational NAM still shows a focused low over western Kansas at the same time. The 18z GFS was somewhere between, while the 21z SREF shows substantial variability, ranging from an OP NAM solution to a more elongated low over the mid-Missouri Valley/Siouxland. Once we get into higher resolution model range and the operational models have some time to converge on a solution, then confidence may increase. Right now, the severe threat appears fairly conditional and perhaps more than one would expect for such a scenario in early March. The ongoing drought and (expected) relatively meager warm sector don't help matters either. As stated in the previous reply, the forecast shear profile won't need much to take things off. The low level thermodynamics just need to be improved...

Where are you seeing lower 70s on the GFS with upper 50s dew-points and minimal capping? That was my main point.

Regarding moisture... notice how the dryline surges east on the GFS, outrunning the greatest surface heating, leaving only a narrow sliver of favorable low-level temperatures and moisture. Even though progs are in the ballpark of 70/60 near the Red River, warming around 850mb results in a sizable capping inversion, especially south of the KS/OK border. For reference, readings are in Celsius on this map, where 20C = 68F.

A 995mb low in western Kansas would be much more interesting even just a month from now. Still, cold air aloft is promoting some fairly steep lapse rates in the model progs, along with modest instability. Low level moisture looks better across the southern High Plains, but forcing will be weaker there, along with less steep mid-level lapse rates. Moisture looks awfully marginal (low to perhaps mid-50s) in western/central Kansas, but lapse rates become quite steep (8-9C/km) closer to the surface low, where forcing will be maximized. We are getting into March, so it wouldn't be completely uncharted territory for some severe hail in the area. Anything beyond that seems too early to speculate at this point.

Watch two areas this afternoon: 1. Far northeastern CO into SW NE. The environment appears unimpressive given a dearth of low level moisture (dews in the 40s), but shear is highly favorable to support rotating updrafts given sufficient buoyancy. Any cells that remain discrete/semi-discrete into SW NE may pose the greatest risk to produce very large hail and an isolated tornado. 2. West-central to NW KS. Stronger low-level flow resides here, along with much more favorable low level thermodynamic profiles. CAMs have more or less shown one robust updraft going up near what appears to be faint boundary in the vicinity of Leoti. If a sustained cell can form here, a long-lived supercell would seem possible, if not probable, continuing into north-central KS early this evening. The parameter space around 23-02z would easily support a tornado given boundary layer dews in the lower 60s, lowering LCLs (already lower than areas to the NW this afternoon) and a low-level jet strengthening to 40-50+ knots at 850mb.

A long-lived supercell has lasted for more than 200 miles from southeastern Montana into South Dakota this evening. Hail was the biggest impact, as Newell, SD was hit the hardest. I was able to photograph the storm, mainly from its southwest side and here are a few of the scenes, including hail up to ~1.75 inches in diameter. Large hail-producing supercell just north of Belle Fourche, SD. Large hail in Vale, SD. Closing out the day's storm chase with a shot from Sturgis, SD of the supercell.

A late season severe threat targets the southern Plains later today. The focus will be maximized along a composite front/outflow boundary from northwest Texas into Oklahoma. Although favorable deep layer shear (30-45kts) should juxtapose with large CAPE (3000-4000 J/kg mixed layer), relatively weak flow in the 0-2km layer should keep the main threats as large hail and damaging winds. A tornado can't be completely ruled out, given enhanced low level vorticity near the boundary. CAM guidance has been inconsistent with details of convective evolution, which is not surprising given subtle details regarding the boundary. Given the parameter space, including 7.5-8.5C/km 700-500mb lapse rates, I wouldn't be surprised to see a few intense supercells with very large hail, although the window for discrete activity may be limited given shear vectors oriented nearly parallel to the W-E oriented boundary. S to SE low-level winds should help somewhat, especially if those winds are/become a bit stronger than progged. My guess is that NW Texas/SW Oklahoma will have the greatest relative severe threat late this afternoon, where remnant outflow intersects with a wave of low pressure. Obs in SW Oklahoma at 10z include temperatures already in the mid-80s with low to mid-70s dew-points and SE winds near the surface. Discrete/semi-discrete convection should also initiate in an upslope regime across northeastern New Mexico, but less favorable boundary layer moisture should limit the threat there. There would appear to be potential for one or forward propagating convective systems later tonight as well, perhaps one from SE OK into AR and another farther west, pending convective evolution.

Synoptically, tomorrow is somewhat similar to today. There should also be an early day MCS that may eave outflow boundaries and keep LCLs down a bit. The two red flags that I see are a weaker low-level jet and convective overturning, as the morning MCS may fragment the boundary layer wind fields. Watch the southern flank of the aforementioned MCS (lower Missouri Valley) and the NE/SD border region, assuming the latter has adequate airmass recovery and wind fields aren't too disjointed.

Witnessed some deep hail with that same cell near Dalhart. 4-6"+ covering US-54, causing some apparent stranded vehicles. Not the best photo, but:

Aside from some pronounced western CONUS ridging in the June 16-21 window, today's new Euro weeklies suggest that the late June to early July period stays relatively active in the north-central states. Yes, the severe season south of I-80 should largely be done after next week, but that's climo for you. After mid-June it's pretty tough to get anything significant in Kansas and points south, barring some anomalous trough or unusual mesoscale accident. As for ridging, the weeklies keep that across the southern tier with generally AOB average 500mb heights across Montana/Dakotas into at least the first third of July.

That cell is drifting south toward AMA. Boundary layer moisture and low-level shear are marginal, but hodograph size is enlarging with >250 m2/s2 0-3km SRH.

Addressing the 500mb wind threshold, the median value for northern Plains significant tornadoes in the summer is about 40 knots (Grams et. al 2011), with less than 25% of significant tornado cases featuring 500mb winds below 35 knots. With that said, Chapman (5/25/16) was associated with 31 knots of h5 flow (00z TOP) and the northeastern Nebraska tornadoes of 6/17/14 also saw about 31 knots, based on the 00z OAX sounding. Dodge City's 19z sounding from 5/24/16 sampled 36 knot winds at h5. Bowdle was much stronger at 500mb with 52 knots sampled by the 00z ABR sounding. I prefer 30 knots at 500mb as a lower bound for tornado favorability, but would like to see at least 40 knots. Substantial 0-3km SRH (and/or extreme instability) can make up for otherwise marginal 500mb speeds, but I can't immediately come up with any long-track tornadoes that occurred with <30 knot winds at h5.

Agree with the points above. If I had Friday off, I'd venture north, but I concur that this weekend not a setup to make a long haul out for. I'm taking the down time to get work in, as we may have a lengthy active stretch coming up. Saturday may end up being an in between day before the late weekend/early next week pattern looks to feature at least a couple of solid severe potential days. The 00z Euro was very encouraging, but remember that models will adjust a bit in the medium range, so details are TBD. Speaking of models, the CFS has been consistent in showing a sharp turn around in the pattern. While high-end days don't seem likely, it appears that down days next week will be more the exception than the rule. While the CFS has little to no skill over climo beyond day 10 (so don't get too excited about the second half of June being a blockbuster period just yet), in my experience, it's quite good at general patterns inside of 7 days. For positioning, it looks like a bit of a late June/early July-like period with the northern Plains/upper Midwest being the favored areas. You may see some threats shift east into the Great Lakes vicinity, while capping becomes a big concern with southward extent over the Plains given the strength of a ridge over the South.

The next week or so looks like a continuation of the pattern. It's fairly unusual to observe such a long period like this given the time of year to see the Plains so quiet. (We will probably end up with a 2-3 week run featuring substantially below average tornado activity during the climatological annual peak of late May/early June) Aside from a few tornadoes in the western part of the state, Oklahoma gets off the hook again without much substantial tornado activity, despite a few "higher-end" threats in the state to finish off May. The longer range guidance seems to be zeroing in on some pattern improvement by late next weekend or early the following week (beginning in the June 11-13 period), but given fairly prominent ridging over the Midwest, the area of focus may end up being from the northern High Plains into the Dakotas. While this is not completely unheard-of for June, it may mean a rare quiet spell for Kansas continues. Despite the above-average tornado activity, places like Kansas and Oklahoma have been relatively quiet. I guess all of the early season tornadoes in the Southeast and some increased activity in Texas account for much of the tornadoes so far this year. It's also been a year largely void of long-track and/or photogenic tornadoes. Going back to the quote above, weather likes to balance out in the long run. Aside from April 27-28, 2014 featured a putrid tornado season until a stretch in mid-June. While I remain cautiously optimistic, any such pattern change remains to be seen. Will it be dampened out? Will trough ejections be displaced too far north? Will the change continue to be pushed back later and later in June? Only time will tell.

Confidence in this range is relatively good through day 10 and just wow. There were hints from a few weeks out that this period would improve, but now that's far from the case. This may be one of the worst late May/early June stretches (at least for photogenic and/or longer-lived tornadoes) for tornadoes in a while. Yes, there were a few events and some local accidents, like Wisconsin, but otherwise it's largely been a dud in the Plains. Bigger days have largely been busts or filled with messy storm modes. There have been very few long-lived supercells over terrain west of I-35. Most events (from a chaser/photographer perspective) have been "right place at the right time," otherwise a lot of hair pulling, highly challenging events The last couple of CFS runs are as quiet for a 7-10 stretch as they have been since early May. The support across the board is fairly consistent with general troughing in the East and few, if any notable shortwaves impinging on the Plains. As we move into June, you'd expect that eastern Colorado and vicinity will have a few events (even with marginal/questionable environments) and northwest flow can eventually be more meaningful in terms of severe across the Midwest/Great Lakes as the calendar shifts deeper through June, otherwise, it looks like a snoozefest. There's always the potential for a mesoscale accident, but...

The overall CONUS pattern looks favorable for really the balance of May. That may not be saying a lot (as the period is active in most years), but general troughing in the West should allow fairly steady shortwave ejections into the Plains over the final 10-15 days of May. It's really a solid looking pattern for at least near average severe activity as we near the climatological peak of the season. The potential exists for a couple of bigger days, as one would expect with such a pattern, if things line up just right There has been volatility in the ensembles regarding the final days of May into early June, where the Euro weeklies suggest there may be a bit of a lull. I'm not too concerned about anything beyond week 2, as things could change substantially. Nonetheless, a relatively active pattern not only next week, but probably the week following should be on tap.

Had this funnel cloud a few minutes ago to the southwest of Morton, Texas.

Kind of underwhelmed right now. Surface obs across the New Mexico side of the watch show meager low-level moisture, with dew-points mainly in the 40s (and dropping at many sites). Mesoanalysis shows soaring LCLs and decreasing CAPE. A more bonafide tornado threat may not develop until after 00z as the low-level jet cranks and better boundary layer moisture backs westward. If the Clovis vicinity cell can hang on and eventually ingest richer quality low-level moisture, maybe then it can better organize. Any sig/long-track tornado threat seems highly conditional, unless something goes up soon across West Texas, or if low-level jet-aided moisture transport leads to modest airmass recovery across eastern New Mexico this evening. Such recovery seems fairly unlikely, although HRRR continues to show rapid moisture advection by 00-02z.

Convective evolution late tonight into early tomorrow across the OK/TX panhandles will be critical with supercell potential in the region Wednesday afternoon. There's a fine line between an MCS that leaves a significant cold pool and early day convection that lays down one or more outflow boundaries. There are some similarities to 5/16/15 as mentioned. As it stands now, CAMs and ensembles, including 12z HRRRX, show at least some discrete storm development from the panhandles into western OK. That remains to be seen. If there is at least modest airmass recovery, significant severe will be possible with any isolated storms as they mature, but it's also plausible that most of the area gets heavily disrupted by morning convection. It is May, so even the latter solution would still suggest some severe potential, even if it is shunted south a bit. (Again, similar to 5/16/15) Backing up to today, it looks like a better-than-yesterday setup across the southern target. Modest height falls, better quality low-level moisture and stronger shear profiles suggest a relatively high likelihood for a few robust supercells from southeastern NM into West Texas. The northern target (northeastern NM into eastern CO) looks messy with marginal low-level moisture, but you can't rule up a local-terrain driven spinup or two. This could also be an event that supports an intense rogue tail end Charlie cell going up down near I-20 in southwest Texas (near sunset and/or into the evening) with large CAPE and shear vectors nearly perpendicular to a dryline.