Future of the Season Pt 3

[Ross Lazear]

Some good news in that the 18Z GFS is drastically different than the previous runs by day 8 or so.... The latest trends show the ridge breaking down much faster than previous runs showed....Not that one model run that far out means much, but things do look a bit better at least... Hey, I'm an optimist.

 

[rdale]

the 18Z GFS is drastically different than the previous runs by day 8 or so.... The latest trends show the ridge breaking down much faster than previous runs showed

Since the 18Z input is very similar to the 12Z, all that does is show you the lack of predictability at that timeframe (a pseudo-ensemble.) It is certainly nothing you would base a forecast off of.

 

[joel ewing]

That's understood, RDale. But it's always reassuring at this stage of my pre-chase to know that the models aren't all saying the same thing. Like I said earlier....this is my annual nail-biting dance I go thru. It drives my chase partner wild. He's not even answering my emails..where all I do is whine, lol. Hell, you think I'm some newbie greenbean. But.....(breaks out into Sinatra's...."I gotta be meeee"...

 

[Dave Lewison]

....geez, I guess we'll be visiting the largest hand-dug well and the biggest ball of twine soon..

Well, unfortunately you won't be visiting the hand-dug well for at least a few years. It was in the middle of Greensburg KS.

What did look like this:
http://www.facethewind.com/chase2007/greensburg-3.jpg

Now looks like this:
http://www.facethewind.com/chase2007/DSC1238.jpg

I believe they will be rebuilding that well (or at least the gift shop above it that was destroyed), along with the entire town. I'm amazed at the resilience of those people!

As for the models, I've been somewhat disappointed at the performance of the GFS recently. While its upper flow pattern progs seem to have done reasonably well...it was the model that predicted the amplification of the trough currently happening in the northern plains. The ECMWF was much shallower and faster. However, the GFS has this nagging tendency to drive cold fronts into the Gulf, which so far hasn't materialized. It forecasted this for last week's system, and again for this week's. Also, as a rule of thumb, I usually don't look at the 06Z and 18Z GFS runs. They tend to stray pretty far from the 00Z and 12Z...I'm not exactly sure why. Maybe they are ingesting data that's not current?

 

[Andrew Pritchard]

DENIED.


Fwiw... I also tend to avoid even looking at the 6/18z runs. They always seem to divert away from whatever trend the models may be showing.

 

[Ross Lazear]

Since the 18Z input is very similar to the 12Z, all that does is show you the lack of predictability at that timeframe (a pseudo-ensemble.) It is certainly nothing you would base a forecast off of.

Right, and that's why I said that it was only one model run, but if you look at the trend in the GFS past day 7 or so, what had originally appeared as a longwave ridge from the E. Pacific to the central Plains in yesterday's runs, now has a far less broad ridge, and introduces more troughiness in the Pacific northwest (the whole pattern looking rather omega blocky).

 

[Ilya Neyman]

The period Tuesday through Thursday may feature increased chances of upslope events across portions of CO, NM?, and adjacent plains of KS, TX, NE, and maybe OK...as progs have been consistent in amplifiying and closing off an upper low over the northern and central Rockies over the course of the coming days. While lower level flow isn't really all that much to write home about just yet it does give the indication that it will be at least modestly moist and more importantly upslope in nature, underneath strengthening mid-upper level wind fields veering with height. As the system may be slow to move out there could be several days of potential severe with maybe a decent possibility or two thrown in the mix. This will be largely dependent on the exact placement of the synoptic features, how much moisture/instability can develop and any outflow boundaries that may be cruising around. The models have had a tough time with closing/slowing lows this season but the general area mentioned above will probably be the area to be for chasers currently out in the field these next few days.

 

[Mike Hollingshead]

I may be on crack with the gfs, or looking too hard, but it seems like to me there *could* be some decent chasing around the central NE area(gasp) Wed-Fri. The front doesn't seem to be too severe and or move too far, leaving a moist boundary layer. Then the upper low hangs around and slips south, with moderate mid-level winds out of the west over this airmass. The low levels will surely suck each day, but it seems like something to keep an eye on. It seems like I can remember some decent days with such flow. June 12, 2002 seems to be one, with several flying eagle radar signatures in central NE....though it was more of a zonal setup with weak low levels.

Edit: It's very nice to see each new run of the gfs looking more promising in the extended range.

 

[Jim Tang]

Forget the GFS... look at what the Euro is showing! That's a classic plains outbreak setup...

And the solution is not really that far-fetched. As the vortex over the Gulf of Alaska starts breaking up, it will send impulses into the western U.S, given that we don't have a strong, firmly entrenched heat ridge yet. Could be an active early June.

 

[Michael O'Keeffe]

Though I have virtually no faith in the GFS I am starting to see more SW flow around next Wed. A strong low and very deep moisture along with moderate CAPE to 4000j/kg in C/E KS. You can also see lots of energy behind this too. So my guess is the first two weeks of June...get ready we may have an interesting few weeks!

 

[Chris Hayes]

Though I have virtually no faith in the GFS I am starting to see more SW flow around next Wed. A strong low and very deep moisture along with moderate CAPE to 4000j/kg in C/E KS. You can also see lots of energy behind this too. So my guess is the first two weeks of June...get ready we may have an interesting few weeks!

Let's hope you're right, Michael. Ed Berry still seems to think more troughs are going to come into the west coast during June. I have a few more weeks to chase so I should get a few chances. The GFS seems to be predisposed to throw in an east coast trough after days 7-10 just about every run. It throws in the east coast trough and amplifies it to unbelievable proportions. It's done this repeatedly so I'll believe it when I see it.

 

[Michael O'Keeffe]

See it ain't much, but its a start

 

[Dan Robinson]

We're definately into the summer pattern - all the action is likely going to be Nebraska northward. The troughs showing up for June look OK, but are not that potent-looking, and still pretty far north. That's what you'd expect in June-July. I don't think we will see another deep, strong western trough this season. You could always hope for another 6/24/03, but even that was an unusually deep trough for that time of year.

 

[Mike Hollingshead]

That looks deep enough to me. And who knows what to expect after that.

 

[Jim Tang]

The 0Z (May 28) run was significantly more impressive than the 12Z run (with a 500mb pattern similar to May 4-5). But it is 240hr out, so obviously we can't take it verbatim. But I think they're overall starting to latch onto a solution that will favor more severe wx that what we've been seeing in the past two weeks.