andyhb

April showers bring May...tornadoes? I don't think it is any time to panic. I've seen a number of mets with a mid-April lull as far as activity goes. There also hasn't been a dominant -EPO showing up on the ensembles to reinforce the E Pacific ridging being forecast (knock on wood). Even if a -EPO does develop, the wave shortening you mentioned will mean that it won't have the same effect that it did back in winter. There have been a number of very active May/June periods in particular where the EPO was predominantly negative.

Just to tease Brett, the 12z Euro had the best High Plains setup I've seen in several years on D9-10.

A lot of western troughing/ridging over the eastern 2/3 of the country. Speaking for possible severe wx implications of course. I apologize for the initial vagueness there.

Latest Euro weeklies are pretty "wow" through much of April.

Looking at that call looks pretty bleak right now as far as verification and current model guidance. Looks like we did/will have some warming mid-month, but the +PDO-enhanced +PNA ridge and eventual -EPO looks to dominate rather than the Aleutian Low sliding eastward, as seems to have been the overarching pattern over the past year and a half...sigh. Seems foolish to ever go against it these days.

Despite poor model performance as of late, I have a bit of a feeling that something may be coming down the track here as we pass mid month. Shorter range guidance has been consistent in developing another strong N Pacific jet extension (developing in association with the strong ULL currently over northeast Asia), which then progresses and develops into a strong Aleutian low, which pumps the heights in the west and torches western Canada in some solutions, which also blocks cross polar flow from developing. Obviously going further out is getting conjecture-heavy, but the breakdown/progression of said ridge eastward would likely open the door for the jet energy associated with the Aleutian low to move into the Gulf of Alaska and possibly open the door for a western trough/eastern ridge configuration to develop (probably transient as well). As long as the pattern doesn't become significantly blocked up, and with a persistent +NAO and lack of a strong -AO this seems somewhat likely at least over North America, a warming trend seems possible from mid month into the third week of the month, along with a storm or two developing out of the aforementioned western trough (obviously sensible wx impacts are nonsense to consider at this point, but I'm sure most can figure out what such a configuration may lead to). We'll see how this plays out in coming days. I wouldn't call it a forecast per say, more of a pattern recognition observation based on what similar progressions have developed into recently. This is of course rendered more volatile by the aforementioned problems with guidance recently, although large scale synoptic features seem to be relatively consistent across the suite currently at least in the earlier going over the west/central Pacific.

Looks like the 00z GFS came significantly toward the other guidance, although it is still more progressive than them.

Not only that, but the pattern across the N Pacific looks to become increasingly volatile over the next while with a series of strong systems making their way into the Gulf of Alaska region and a corresponding strong negative height anomaly off the NW coast, so the active period might not be over with this system. You can see it there on the Euro run with another very strong impulse in behind the trough of mention. Euro is showing CAPE of 1500-3000 J/kg over central and southern AR @ 150 hrs.

Agreement with the GFS is essentially non-existent with the other three main globals, the GGEM and UK also have a substantial trough dropping into the Central US this weekend.

That was one of the strange things about the 11/17 outbreak last year, the lapse rates that day were one of the things leading to that thermodynamic environment being more volatile rather than less. Helps when you have an absolute powerhouse of a system with a strong mid level dry punch of course.

October 9th, 2001 being the number one analog explains the Oklahoma bullseye. Also, October 4th, 1998 is up there.

The 00z Euro had a very impressive system late next week. The models have been toying with a large upper trough dropping into the west for some time now, and recent ideas have suggested a pretty robust ejection, with today's 00z suite being the strongest so far. Certainly something to keep an eye on for further continuity in later runs. There are two important things to watch first, one being the s/w dropping SSE towards the Gulf Coast early next week, which may have a substantial impact on moisture quality, and then the closed low migrating eastward and devolving into an open wave, after which the stronger impulse moving in from the Pacific NW drops in behind.

Looks like regardless of how that trough ejects, we might be dealing with E Pacific TC-contaminated lapse rates again with Odile's track.

D5 outlook out, that's quite a substantial trough the Euro has tracking through the Central/Northern Plains late this weekend.

Well after Wednesday went to a non-event rather quickly due to leftover clouds/etc, there appears to be a decent amount of potential near the WF on Saturday, especially on the 00z Euro, with a relatively strong/backed LLJ and good upper support over the E Dakotas and perhaps W MN. Again, leftover convection is going to be a question mark, since this evening could have relatively widespread storms ongoing.

00z GFS/NAM soundings are still really impressive on Wednesday afternoon/evening in (you guessed it) north central/northeast NE and south central/southeast SD with steep mid level lapse rates and strong directional shear in the lowest km. The area is very weakly capped at 21z so there should be a window for storm initiation in there, and with a well-timed shortwave impulse passing through the area, it screams a good August chasing opportunity as it looks now (who woulda thunk it) and does have several similarities to the June 16th/17th setups. It likely will come down to mesoscale placement again, but any supercell that goes up there will have good possibilities for significant severe given the parameters in place with a feed of 70 Tds along a corridor on either side of the NE/SD border. I would think that SPC has to revise that "no severe area" in the D3 with the upcoming D2. There seems to be increasing potential here.

Had a little flashback to mid June when I saw some of the model guidance today.

Figured I'd create another one of these since the old one got locked. Might be potential for a severe wx episode next week if some of the medium range model solutions are on the right track. Looks like a rather sizable upper trough for August dropping through the Pacific NW, then ejecting in some form towards the Northern/Central Plains.

If you had to put some sort of value of damage or casualty potential with a tornado, that one is almost certainly way up there, considering it's path length, size, intensity, longevity of maintaining said intensity and forward speed. The fact it killed 72 people (and the ratio of fatalities to injuries) without going through a town of more than 1500 people (per the 2010 census) speaks for itself.

Catastrophic flooding taking place in Alberta...75,000+ people are displaced, Calgary's downtown is flooded, the Saddledome is flooded. The Bow River has essentially turned into a raging torrent.

Wow, that is amazing.

EF1 tornado in Oregon yesterday per LSRs.

Made it to at least 84˚F here today, probably hotter.

Now officially 2 years since this event, kind of hard to believe to be honest.