4/5/10 FCST: NE,KS,OK,IA,MO

[Brett Roberts]

GFS continues with its one and done Monday play. As of this 0z... would be a huge day in So. Kansas if it came to fruition. (hopefully no big cap issues... we've got some impressive parameters)

Do remember the GFS winning out at times over ECMWF... be interesting to see how this all unfolds.

I think you raise a good point here. I've read numerous statements the past couple days using the "superior" recent performance of the Euro as a basis for believing its solution next week, including in a few AFD's. But if I recall, the GFS led the way in correctly predicting the very progressive nature of the trough moving through tonight/tomorrow, while the ECMWF was the most stubborn of all the medium-range models and incorrectly held onto a slower, more closed off solution over the SW until a few days ago.

While I generally favor the ECMWF for medium-range forecasting, this week's debacle makes me pause in this particular case. In fact, the 00z ECMWF just now rolling in looks lower-amplitude, more positively-tilted, and faster than last night's run, by a fairly significant margin. The GGEM and UKMET look a bit faster than previous runs, by my estimation, and both have a strong surface low in NW KS by 00z Tue with the 500 mb trough axis at a relatively similar longitude to the GFS.

Note that I'm not just saying this because I'm pulling for a Monday outbreak close to home. Actually, I'm kind of worried about a compromise solution verifying where the trough is low-amplitude and progressive like the GFS shows, but just a bit slower such that Monday remains capped and Tuesday is a MO/IA/IL event. Last night's ECMWF with the multi-day event and more time for moisture recovery would be preferable, but it seems quite rare to get back-to-back solid Plains chase days this early in the season, which is another reason for my skepticism.

Just a thought. The model disagreement on this one is so high that it's still anyone's guess.

 

[Brandon Lawson]

It seems like every year the models have a certain trend to them. If the GFS continues to speed up the forecasted movement of these low pressure centers within the 1-2 day time-frame, (and the moisture isn't so under-forecasted that I gouge my eyes out), Monday has the makings of the first potential outbreak of the season. Too many things change, though, even this far out. I'll wait till Sunday to make sense of the models.

 

[Michael O'Keeffe]

The 06z GFS went back to a more progressive solution and that may sound bad but it really isn't as it allows for cooler 700mb temps to push in C/E Kansas reducing the cap and the 06z GFS agrees with that showing a line of storms firing along the dryline from NE Kansas down into SC Kansas. Tuesday however will likely be a Great Lakes event as the low races into the Michigan area.

The 12z NAM should show 0z Monday for us but based on its 6z run the trough is still hanging back near CA/NV so it may slow down a day but we will see I guess.

 

[Chris Wilburn]

The 06z GFS went back to a more progressive solution and that may sound bad but it really isn't as it allows for cooler 700mb temps to push in C/E Kansas reducing the cap and the 06z GFS agrees with that showing a line of storms firing along the dryline from NE Kansas down into SC Kansas. Tuesday however will likely be a Great Lakes event as the low races into the Michigan area.

The 12z NAM should show 0z Monday for us but based on its 6z run the trough is still hanging back near CA/NV so it may slow down a day but we will see I guess.

Well the 12z run of the NAM is now out and shows 7pm for Monday. I really like what I see on the 84 hour NAM. It does have the main part of the trough hanging back just a bit, but still yields 40-50kt 500mb southwest winds as it begins to enter the region. Dryline runs from northern KS to western TX with a nice WF along the KS/NE border to the IA/MO border. Forecasted surface td's are forecasted 65-70 which is higher than the GFS a bit. As usual they will be somewhat off, but nice to see regardless. CAPE ranges from 2,000 J/kg to 3,000 J/kg along the dryline. Wind shear is very good too. I did notice a slight veering of the 850mb winds for a hodograph in NW OK, but it's not that much and may not cause a problem.

700mb temps are in the 8-10C range so that may cause a problem. 700mb temps. forecasted higher than that at 10-12C in SW OK/NW TX. There does appear to be a decent amount of CINH left to be burned off by 00z with the exception of extreme western OK. All of these details are so subtle 4 days out they really aren't worth mentioning now. Moisture, instability and wind shear look very nice on this morning run of the NAM just to sum things up. Also, storm motion is only 20-25kts forecasted since the main part of the trough is still out in the desert southwest. Capping may be a concern, but it looks like everything else is primed and ready to go.

 

[Brandon Sullivan]

From the 12z NAM I would be playing the warm front across north central MO..

Good looking hodographs, with SE flow @ SFC to SSE @850, moisture and capping not a problem at all.

Decent instability on top of this along with good strong westerly flow @ H5 and impressive 0-6 KM Shear, and a composite reflectivity forecast showing a nice lone cell on the warm front have me itching for a warm front play..

Would like the dryline play but real worried on capping, low level wind profiles, and moisture with northward extent...

 

[Darren Addy]

The NAM is pretty consistent with what I was seeing earlier with the ECMWF for 00Z Tues. It is way too far out to target, but I was liking Belleville, KS the other day and looking at the NAM I would only move slightly S and W to the Beloit/Osborne area. The moisture axis seems to point into that area. Main concerns are a combination of moisture depth (beggars can't be choosers this early in the season) and CAP. Think we'll need some dryline magic to get some lift, but if something can get going before sundown on Monday it will have some terrific 0-1 EHI to work with.

The other big problem will be how fast these storms will be screaming. Am I reading right: 55 kt? If so, starting too far south from initiation could be problematic - to say the least.

 

[Mike Hollingshead]

The other big problem will be how fast these storms will be screaming. Am I reading right: 55 kt? If so, starting too far south from initiation could be problematic - to say the least.

http://www.wxcaster2.com/CENTRAL_ETA_ATMOS_STORM-MOTION_84HR.gif

That wouldn't be bad with an e-w highway obviously. (Relatively/April 5th speaking)

Nasty HODO's on warm front in MO on Monday...

But hell if I know how to target those warm front setups, like further out on it from the sfc low. 700mb temps along the whole thing on the nam are 6-7c so not bad. Good thing about over there is how close you'd be to the Tuesday outbreak on the 12z GFS lol. I only wonder if being further east will hurt moisture or not, the way it is returning off the gulf and from that high.

It's at least nice to feel more like something on the NAM and the GFS this morning might be what happens.

What a different April 5th than the blizzard April 5th in eastern NE last year.

 

[Chris Wilburn]

The NAM is pretty consistent with what I was seeing earlier with the ECMWF for 00Z Tues. It is way too far out to target, but I was liking Belleville, KS the other day and looking at the NAM I would only move slightly S and W to the Beloit/Osborne area. The moisture axis seems to point into that area. Main concerns are a combination of moisture depth (beggars can't be choosers this early in the season) and CAP. Think we'll need some dryline magic to get some lift, but if something can get going before sundown on Monday it will have some terrific 0-1 EHI to work with.

The other big problem will be how fast these storms will be screaming. Am I reading right: 55 kt? If so, starting too far south from initiation could be problematic - to say the least.

I didn't look at things too closely when I posted above. I was more painting an overall picture, but after reading your post I went back and looked at some things. I agree with your assessment and with Brandon as well. I think the best play may be along the dryline/WF intersection around the Osborn area that you mentioned. The CAP looks to be more friendly here and the 0-1 SRH and 0-1 EHI values are much higher than compared to along the dryline from SW KS and points south. Along the WF in northern KS and northern MO looks very nice as well. I am seeing 35-40kts on Earl Barkers page using the bunkers method. I posted 20-25 kts earlier which is what twister data was showing under its storm motion tab. With say 20kt surface winds and 55kt 500mb forecasted winds I would say 30-35kts may be an accurate estimate. I really really like that are you pointed out Darren now that I have looked at things more. Very nice indeed. Anywhere from the dryline/WF intersection in NW KS and east along I70 looks very good. Just the placement of the surface features alone on this run make me think May 22nd and May 23rd of 2008.

 

[Michael Riedl]

I pretty much agree with what is said above, and wow, that is a nasty HODO.

I am really liking the Setup along the Dryline up to where it intersects with the Warmfront in Northwest/NC Kansas. CAPE is higher there but Helicity is MUCH higher along the warm front than any other place along the Dryline. I-70 Will be very busy with chasers that day I have a feeling.

I doubt I will be able to make it up there as my Class that day doesn't get over till 4. Hopefully something will fire up in SC KS as well.

 

[Matthew Piechota]

I wont be able to chase this day but both areas, the WF/DL interesection and further east along the WF in MO look pretty good. the cap being more of a problem the further west in KS with some impressive hodos in MO. if the trof could speed up a bit this could be a pretty good day.

instability >2000 j/kg with dew points nearing mid 60's with really nice shear. good 0-6km shear with nice looking soundings. also some high 0-1 EHI values on the 12z NAM. still 84 hours away so im sure some things are going to change.

 

[Darren Addy]

I really like the little triangle of <7.5 degree 700mb temps in north central KS (right where the nose of the 65+ dewpoints should be by 00z).

What are the chances it still looks like this at this time on Monday? (zilch) Who do I see about moving everything north an hour or so?

 

[Andrew Ryan]

Darren,

I noticed that too. But mesoscale details like that you can't really trust this far out. And as you alluded too, this will all change come Monday. I also think there will be enough forcing to overcome the cap. Given the consistency of the models, there will be a severe threat somewhere on Monday.

I think it's in a fair spot right now! I have a travel all the way from Oklahoma.

 

[Michael O'Keeffe]

The 12z NAM is looking pretty exciting for much of KS/MO especially along the warm front. I am liking two areas at this time 1) Dryline/warm front intersection in NC Kansas 2) Warm front in NC Missouri. I am favoring the more traditional intersection in Kansas mainly because I am more comfortable with these types of setups and I LOVE chasing in Kansas!! The cap is a bit stronger but definetly breakable which in a way is nice considering most setups this year have been ruined by early morning crapvection. Just my opinion but I think this is just a day before the day event by looking at the NAM. The trough is still hanging over the Rockies and the main upper low is still hanging off the coast of Oregon so even when the low ejects it probably wouldn't be in the Plains until Wed so I am guessing based off of the NAM that Tuesday will be a big day as well most likely in the same areas as on Monday with Wednesday being out east over the Mississippi Valley as the trough finally ejects.

Here is my forecast that I just whipped up on my blog and pasted it. I wanted to point out my thoughts on Monday just looking like a day before the day setup with the trough hanging back and the main upper low sitting off the coast of Oregon at 0z Monday so I wouldn't be surprised to see Tuesday being the main event likely in the same areas of the C Plains with the low finally ejecting on Wed pushing everything into the Mississippi Valley.

Either way Monday looks pretty good with a few isolated cells likely along the warm front.

 

[Dan Rupnow]

Well 00Z NAM is out, and it likes west central IL. Nice band of 1500-2000j/kg CAPE across this area already by 21Z, and a great looking sfc-500mb crossover as well. This area looks to be right on the warm front with sfc temps of 75-80F, and Td's of 60-65F. CINH looks great too with 700mb temps at 5C or less, and I also love the two supercellularish "blips" that the NAM CREF shows by 21Z. Still a lot of time to go on this one, and I am sure a lot will change though. It always does!

 

[Brandon Sullivan]

Well 00Z NAM is out, and it likes west central IL. Nice band of 1500-2000j/kg CAPE across this area already by 21Z, and a great looking sfc-500mb crossover as well. This area looks to be right on the warm front with sfc temps of 75-80F, and Td's of 60-65F. CINH looks great too with 700mb temps at 5C or less, and I also love the two supercellularish "blips" that the NAM CREF shows by 21Z. Still a lot of time to go on this one, and I am sure a lot will change though. It always does!

Noticed this as well. Continuing with my thinking that the eastern extent of the warm front will be the place to be.. Not really digging the CAP that we are looking at further west... Some definitely impressive hodographs along the warm front here in southeast Iowa and western Illinois..

Long story short, I am pretty set on chasing the eastern extent of the warm front on Monday, given the multitude of impressive parameters.