andyhb

What I seem to be seeing on the recent ensemble guidance is a tendency to shift high latitude ridging eastward over central Canada past the first week of June. Should this happen, it would likely open up an opportunity for the Aleutian low to slide east and allow a relatively open path for its associated jet to the West Coast (with an accordingly active pattern downstream).

-EPO block is going to be a problem through the next week at least, need that to break down/slide east a bit so the jet from the Aleutian low can advance east. Until then, might be more nickel and dime setups vs. bigger events.

We still haven't had that bigger event/outbreak to accent the season yet. There will likely be moisture in spades, just a question on whether the Pacific cooperates. A northern shift will help with the EML situation, with more favorable 700 mb trajectories.

June 1957 and June 1958 also had some bigger events in the N Plains and Upper Midwest (F5 in Fargo on 6/10/57 and F5 in Colfax, WI on 6/4/58).

Late May-June 2004 showing up a ton in the CPC 8-14 day analogs today.

Not sure about the Euro weeklies, but the monthly forecast from the CFSv2 for June looks pretty favorable currently. Strong northern stream on the 200 mb U-wind anomalies plowing into the Pacific NW with net troughing in the Gulf of Alaska, cool temp anomalies across the western/central CONUS and warm in the east.

Pretty spectacular sounding from AMA @ 00z Wed from the 12z NAM (with supercells in the area as well). Will start a thread on this later if some consistency is shown.

W TX setup on Tuesday looks to hold some potential with any decent amount of destabilization.

I'll send him an NARR loop of late May 04 if it helps.

Mark can you hack Ian's computer?

Might want to mention that there is a very nice W TX/E NM setup showing up next week (5/19) on the 12z GFS.

Gonna need a pretty deep eastern trough to have any appreciable affect on the Plains this time of year.

12z GFS certainly appears to show a fairly healthy EML being advected over the warm sector Friday night looking at 700 mb RH. Significant increases in instability through the day Saturday as opposed to previous runs (18z/00z/06z) despite some early convection still being there. Also appears to show stronger wind fields.

Well, the 00z Euro looks pretty similar to 12z at first glance through most of the fields. H85 temps/winds in particular are almost identical to the 12z run at 00z 5/17. Will get a look at the morning convection/EML situation a bit later. The 12z run did have widespread favorable thermodynamic profiles across a large chunk of the warm sector at 18z, 00z was partially contaminated by convection (not from the morning).

Will probably start a dedicated thread to this tonight, but yeah the 18z/00z GFS runs would certainly not have too high of a ceiling. The 12z Euro would be very volatile though, whether that goes towards the GFS tonight is the question. The 00z UK is in, although I can't see any of the wind fields on it for that timeframe so that's a bit of a mystery of what everything actually looks like. I'll also add that the hits seem to keep on coming with repeated western troughing on most ensemble guidance/etc. I'd have to think that something bad (or good, for chasers) is going to happen (in spite of the 5 fatalities over the weekend) one of these times if this type of pattern continues. That's not to mention all of the flooding.

Would be best to wait until we get better sampling. The upgraded GFS hasn't necessarily been stellar recently, nor has the Euro at times. I agree that the 12z Euro would have some pretty nasty potential, if we see a consolidation towards its solution, people in the Plains (over a large area) better be paying attention.

Might add that another thing that could screw this up is if the ULL closes off significantly before the trough ejects. This would cause problems with backing upper level winds and EML advection (shown by the 18z GFS verbatim and some previous Euro runs). Also worth mentioning that the 18z run appeared to suffer from some possible convective feedback in the 81-84 hr period.

I already handled it, no need to pile on at this point.

I actually disagree a bit here just on initial signal, especially from the 12z GFS/Euro. This looks to spread stronger flow over most of the warm sector and has a stronger low level response earlier than the most recent system.

I'll also add that in the areas that didn't see cold pool stabilization, the GFS and Euro were both underdoing instability values rather significantly on Thursday, Friday and the weekend.

You're asking for fairness now after your behaviour on Saturday while the event was going on? Sorry to disappoint you, but that's not exactly how things work. Brett and Jim absolutely did not conduct themselves the way you did both before and during this recent event, end of story. I think Saturday could be a significant day, large upper troughs like that in May will almost always will afford some kind of severe risk. Also, the GFS has been showing a fairly decent looking EML being advected over the Plain states (not extremely strong, but not negligible either). How is a negatively tilted trough bad for severe weather? It may cause problems in the wind profiles in some locations, but it also generally means a stronger surface low, with accordingly stronger low level flow and stronger mid/upper flow overspreading the warm sector. Positively tilted troughs generally cause a lot more problems in the setup in the Plains.

So we're already going to start with this? Fantastic.

Pretty major league setup on the 00z GFS for next Saturday.

12z Euro agrees with the GFS in general, i.e. things are probably going to get very interesting towards the end of next week and beyond.

Optimism should be had (and is, based on his and Victor G's material over the last week or so).