Major Pattern Change Coming Up ??

[Eric Bucsela]

I am very excited about May 22-24, so much I am going to put down a small wager on it. Hemespheric flow looks very unstable, with shortwaves propagating out ahead of depending trough, strong return flow already in place and surging warm front and upper level temperature gradients increasing with this second round of Z anaomolies...I have more confidence in the 22-24th wave than the currently situated high amplitude wave

Still lots of waffling from the models, hence SPC's reluctance to post an outlook so far. The ECMWF has been trending slower over the last 72 hours for this upcoming system, and GFS has been jumping back and forth - sometimes slower, sometimes faster than ECMWF on a given run. For now, looks like Mon the 23rd will be the best day, especially as of today's 18z run of the GFS, which really pushes things east by Tues (but given GFS progressive bias, I wouldn't be surprised if Tues action was still focused near/west of I35). Sunday 22nd is also possible; although mid-level flow over the S Plains will still be weak, CAPE progged by the GFS is impressive (>4000 J/kg). Same on Mon & Tues. Given the good directional shear, if this verifies AND there are no capping issues, we could have a string of 3 active days in the Cntrl/S Plains.

BTW, the NAM, which is now picking up on Sunday 22 shows much lower CAPE/moisture than GFS. In general, NAM, GFS and RUC seem to differ not only in the way they forecast CAPE but also in their analyses (not sure I understand why). However, it's pretty clear instability will be much greater for the next system than the current one.

 

[Drew.Gardonia]

Day 12 of my chase tour produced the results I have yearned for, for so long.

on Saturday 5/21/2011 at 6:40 PM CDT, myself, Jeremy Holmes, Terry Schenk, and Doug Geiss (spelling?) witnessed a large tornado, with a secondary funnel about 50-100 yards to the left of it on the ground in Highland, KS. We had a scary moment, because the hunters became the hunted, and the tornado turned on us as we cut in front of it and the tornado came over the hill and behind my car about 100 yards and we were straight flying down a road alongside the Missouri River to get away from it!

(for some reason I still can't post in the Target Area, so im just sharing my good news here )

 

[jshields]

well it looks like the death ridge never really did take effect during May, however it looks like it will starting the beginning of next week and according to the models last the next 10 days. i know we are getting later and later in the season so maybe it's not that irregular for this to happen, but it's horrible timing for myself as this was the week i took off, LOL!

 

[Derek Heide]

You may be able to get in on some action in the Dakotas possibly. Maybe up here in Manitoba or Saskatchewan. Big central ridges have brought some real good setups here in the past.

 

[Bryan Stokes]

well it looks like the death ridge never really did take effect during May, however it looks like it will starting the beginning of next week and according to the models last the next 10 days. i know we are getting later and later in the season so maybe it's not that irregular for this to happen, but it's horrible timing for myself as this was the week i took off, LOL!

Monday is showing some potential to be a good chase day. After that, things get a little uncertain, but it always is when you're looking that far out!

Bryan

 

[Derek Weston]

Just me or did it become 'summer' quite quickly? (not just in temperature... but overall weather pattern)

This may be a rather quiet June.

 

[Jeff Duda]

Yep, Derek, a large wavelength, decent amplitude ridge has set up right over the center of the country, thus providing very quiet weather across much of the central US. There had been a pretty big trough that came off the Pacific over the last few days, but like most systems this season it stalled over the intermountain West before lifting off to the northeast. Thus it's areas like Montana, North Dakota, and Saskatchewan/Manitoba that are seeing the best action right now. The long range models are not in great agreement, and some don't give much hope for the rest of the month. The 00Z GFS last night points at some enhanced WSWly flow over NE/IA later this week with some random small disturbances over the northern Plains, so there may be a few sleeper days coming soon. Of course, more than a few days out, the long range models disagree on any specifics, but most show generally zonal flow with occasional weak disturbances moving across the northern US.

 

[Kevin Walters]

I wouldn't give up on the month of June just yet. It's true there is nothing synoptically evident in the models but the N Plains and Upper MW will be on the edge of stronger flow with moisture in place, or not very far away. Any little SW could make for a good day. Climatology begins to favor NW flow events as well as we move toward July. There have been many significant NW flow tornado events over the years so there is hope for chasers.

 

[Drew.Gardonia]

I wouldn't give up on the month of June just yet. It's true there is nothing synoptically evident in the models but the N Plains and Upper MW will be on the edge of stronger flow with moisture in place, or not very far away. Any little SW could make for a good day. Climatology begins to favor NW flow events as well as we move toward July. There have been many significant NW flow tornado events over the years so there is hope for chasers.

not to mention, it's evidenced by the fact that after the 4-27-11 outbreak, things were relatively quiet for a few weeks before mother nature recharged her batteries and things ramped up again in devastating fashion. I have a feeling this thing's not over just yet. In fact, it could be possible we have an unusually busy fall as well in terms of tornadic activity.

 

[Derek Weston]

well it looks like the death ridge never really did take effect during May, however it looks like it will starting the beginning of next week and according to the models last the next 10 days. i know we are getting later and later in the season so maybe it's not that irregular for this to happen, but it's horrible timing for myself as this was the week i took off, LOL!

Perhaps not a death ridge... but the long range models were basically correct in predicting a quiet first half of May.

 

[Warren Faidley]

I think the biggest negative factor has been the overall drought pattern. Multiple days towards the end of May had reasonable shear, but very warm 700mb temps and poor westward RH values combined with silly LCL's basically killed any chances out west. As noted, I think there may be a few good chases left in the far northern Plains, IL, WI, etc. Now of course, there is the smoke from AZ which makes for poor visibility.

W.

 

[jshields]

I know there have been some good nw flow events in the past, but if the pattern is changing to a "consistent" nw flow, it seems to me this has been an early change to this pattern?!
Overall, I have been pretty disappointed in the severe weather season. I know, I'm probably thinking too locally There have been 2 HUGE events that we probably won't see in our lifetimes again, and there have been some other other bigger days. April was a huge month for overall tornado numbers, but May was really slow until that 3-4 day period the 3rd week or so. Now June is looking really sketchy.
All the "experts" predicted a very active tornado season for the northern Plains area of Nebraska, Iowa, S. Dakota, and Minnesota, and that definitely hasn't happened.
Hopefully, the long range models aren't correct or we do get some good NW flow days. Looking at the GFS(with a grain of salt), most days have very weak overall shear or the instability doesn't line up with shear. Also there was a run recently where an upper level low just sat over the Gulf, cutting off any good moisture. The 60 degree dewpoint line only made it up to central KS, and the CAPE values anywhere were generally under 2000. Not an impressive value for summer and June to say the least!!
Well, I'm done whining now, thanks for listening

 

[Bryan Stokes]

Well, it's time for me to get on here and express my woes. Synoptically, the models don't show anything to look forward to.

Our chase vacation was scheduled for 31 May to 12 June, and we've been pushing it to the right in hope of a more active weather pattern, but it doesn't look like anything is coming up. We can't push it to the right much more, so it looks like we'll be heading out in a couple of days and will have to take our chances with the NW-flow.

So far, in my opinion, this is the "season that never happened" in regards to classic chasing in the Plains. No booming Supercells on the Texas Caprock. No dryline explosions in western Oklahoma. And no triple-point plays in west Kansas.

2010 was the year of photogenic tornados. 2011 (so far) is the year of death and destruction in the South-East.

Let's keep our fingers crossed and hope that a trough or two comes through later in the month and produces some classic storms in good, chaseable terrain...

Bryan

 

[bill mudd]

Bryan, I hear ya.
California has been in this pattern for what seems to be at least the last month. Basically, everything out of CA has been cold air, perhaps our coldest year on record. Our highs have not been out of the high 60's, quite rare for us for mid June. I am hoping for something after the 21st of June, but I'm sure it will be way north in nature! (if at all).

 

[Derek Heide]

Late next week could get really interesting in the Northern Plains. Long range models are showing some good stuff.