Major Pattern Change Coming Up ??

[Drew.Gardonia]

While not negating the transient ridge in the West during the first week of May, it could definitely verify weaker than anticipated, which would allow the ridge to break down more at the end of the first week of May when a storm system moves in off of the Pacific. This will hopefully reset the pattern and push us into an active severe weather pattern as we head into the second week of May.

god I hope you're right.

Drew,

Don't panic, there isn't any mention of "death ridge" it's just me being paranoid. I'm hearing different reports/views and outcomes, for instance... one of my friends saying repeat of 2006/2009 but two of my very highly regarded chase friends within the chase world saying more Northern Plains chases this year. Unless theres a ridge sitting over the US when I arrive, I'm not gonna worry

Steve Smithson.

just the mere thought of any type of ridge, let alone Death Ridge is sending me into "panic mode". I'm so desperate to see a tornado this year, it HAS to be this year, I can't take it any longer, I must see a tornado! THIS IS THE YEAR! I've waited much too long.

 

[Chip Redmond]

It appears to me that the mean of the ensemble members are hinting at a +PNA... This would reflect a summer pattern of precipitation further west than currently and more wet conditions (and perhaps drought relief?) to the western and southern Plains. Even then, I tend to look at ENSO predictions more than PNA as it seems to have a greater connection.

Currently the La Nina forecast models are showing quite a spread in thinking for the upcoming months. The mean however, tends to take it to a neutral period which would mean about average precipitation and temperatures and a shift westward of the systems as well.

Chip

 

[Mark Ellinwood]

It appears to me that the mean of the ensemble members are hinting at a +PNA... This would reflect a summer pattern of precipitation further west than currently and more wet conditions (and perhaps drought relief?) to the western and southern Plains. Even then, I tend to look at ENSO predictions more than PNA as it seems to have a greater connection.
Chip

It figures that, as soon as I'm done looking at the graphics and post the -PNA just barely holding that the new CPC graphic shows a slight +PNA

Looking at the latest 00z and 12z ECM and GFS ensemble runs... they generally have it closer to neutral (GFS: 0.0 to -0.5) or slightly negative (ECM: -0.5 to -1.0) during approx. the first week of May. The GFS and ECM ensembles have been battling it out as far as skill in the 6-10 day and 11-15 day in recent weeks, but the ECM's currently the skill leader over North America.

 

[Jeff Duda]

And no this is not a "Future of the chase Season" Thread

Paul, this sounds EXACTLY like another future of the chase season - sucks thread. Sure, perhaps there will be a lean week or two in May. So what? Ever heard of June? July? August? There was an EF4 tornado on June 25th in IA and August 7th in MN/ND last year. We're just barely getting into the heated part of the chase season, so don't get so down when you see a ridge in one deterministic model 10 days out. I just checked the 00Z ECMWF, and I don't see any hints at any semi-permanent western US ridging in the next 240 hours. Also the GEFS shows all sorts of troughs in its spaghetti plots up through 384 hours out.

 

[Kevin Walters]

Paul, this sounds EXACTLY like another future of the chase season - sucks thread. Sure, perhaps there will be a lean week or two in May. So what? Ever heard of June? July? August? There was an EF4 tornado on June 25th in IA and August 7th in MN/ND last year. We're just barely getting into the heated part of the chase season, so don't get so down when you see a ridge in one deterministic model 10 days out. I just checked the 00Z ECMWF, and I don't see any hints at any semi-permanent western US ridging in the next 240 hours. Also the GEFS shows all sorts of troughs in its spaghetti plots up through 384 hours out.

I thought the same thing, lots of troughs and short wave lengths. Seems like many times there is a lull in early May and then things take off mid and late May. April has been so active, a period of less activity is probably in the cards.

 

[Paul Sherman]

Paul, this sounds EXACTLY like another future of the chase season - sucks thread. Sure, perhaps there will be a lean week or two in May. So what? Ever heard of June? July? August? There was an EF4 tornado on June 25th in IA and August 7th in MN/ND last year. We're just barely getting into the heated part of the chase season, so don't get so down when you see a ridge in one deterministic model 10 days out. I just checked the 00Z ECMWF, and I don't see any hints at any semi-permanent western US ridging in the next 240 hours. Also the GEFS shows all sorts of troughs in its spaghetti plots up through 384 hours out.

Jeff

I guess it affects the overseas travellers more that only get a 1-2 week hit on the plains more than members who live on the fringes of the alley. If you hit the pattern wrong you are a goner, definately NOT A Future of The Season as there will surely be more chasing later in the month of may etc, the main part of the thread was to try and find out from other people more experienced in longer range model watching what it might look like for our little window of opportunity and I think I have the answer in a few excellent replies above, Rubbish from the 29th and possibilities of the ridge breaking down around the 6-7th May and I thank all those for their input.

 

[David Wolfson]

The progressive wave pattern looks to me to have one more shot at a multi-day event in the May 5-10 period. After that I'd be a little nervous that the next pattern shift is to ridging off the west coast into the Gulf of Alaska and Hudson's Bay troughing. The Dreaded Northwest Flow is potentially even worse than a May Death Ridge. It's fun to guess, anyway!

 

[Tom Stefanac]

The progressive wave pattern looks to me to have one more shot at a multi-day event in the May 5-10 period. After that I'd be a little nervous that the next pattern shift is to ridging off the west coast into the Gulf of Alaska and Hudson's Bay troughing. The Dreaded Northwest Flow is potentially even worse than a May Death Ridge. It's fun to guess, anyway!

The consequence for mid to late may people like myself would be chasing deeper south into West Texas (Eagle Pass again?) and playing the thermal low supercells that form over eastern "impossible to chase in" Texas.

Although it seems even at this early stage the models every year hint at ridging of some sort towards the middle of the month. The NCEP output analysis guys always attribute these pattern changes to variations in the models seasonal biases and the transition of qusi-stationary upper level features back into their summer states. Last year the models had a strong ridge forecasted between the 15th and 22nd of May. Then around May 14th suddenly the ridge disappeared on the models even though it had been there for two weeks and boom huge high risk on the 19th and Bowdle on the 22nd.

In 2008 much the reverse happened, great forecast for mid to late may then suddenly two days out major ridging capped the alley for a good week or more.

So I don't trust long range models, especially with blocking patterns. They either want to extend or turn a typical pattern or even minor anomaly into a fixed feature or ignore the anomaly and it happens anyway. I only think large blocking patterns are really resolved well in mid winter and late spring entering summer, especially in the period between May 25th and June 10th.

So whatever happens, will just happen. I'm not going to loose sleep yet. I'll leave that for nocturnal supercells.

 

[Steve Smithson]

It's fun to guess, anyway!

Not if you've spent nearly £3,000 on a chase last 2 weeks in May and already looking doomed!!!

By the way, hello Dave I remember you from Cloud 9 Tour 2 in 2000

Steve Smithson.

 

[Derek Weston]

Seen the ridge for a bit. Better to get it out of the way with sooner than later... (or not, depending on when your alloted time is)

I'll take just about anything that isn't setting up across far eastern OK and Missouri... (then again, the veered cold-front setups across bad terrain have actually been paying off this year... just when I thought I had things figured out...)

 

[Marko Korosec]

For all those going for the mid season, take a look at the latest Joe Bastardi's video...

http://www.weatherbell.com/jb/?p=1326

Imo, there is just nothing to be worry about. Like he said... fading La Nina, NAO-, GoM SST++... nothing that would smell like a ridging pattern in May.

 

[Paul Sherman]

Marko
I am a lot happier with the way the GFS Is trending these last few days, could even be some chase Ops first week of may the way it is trending, also looking good with troughs lining up for 2nd week of May also. Phew at least I wont be touring Yellowstone and the Grand Canyon a la 2005 - Lol

 

[Paul Knightley]

Your best bet (and I don't do this, so I don't follow my own advice!) is to ignore the charts until a couple of days before you go. I remember in May 2008 when there was a ridge forecast as far as the eye could see. However, the ensembles (and that's all you should look at beyond day 5-6 IMO) showed a western US trough developing, and that's exactly what happened!

 

[Joerg Kudella]

Your best bet (and I don't do this, so I don't follow my own advice!) is to ignore the charts until a couple of days before you go. I remember in May 2008 when there was a ridge forecast as far as the eye could see. However, the ensembles (and that's all you should look at beyond day 5-6 IMO) showed a western US trough developing, and that's exactly what happened!

I definitely second that. One week ahead is the furthest I would go, and even that far out you can compare looking at the models with looking at a crystal ball.

 

[Michael Riedl]

The 12z GFS has a multi day trough coming for the plains in the long range.....is it going to happen? Maybe not but it goes to show you can't take too much stock outside of 192 hours or so.