3/21/2007 FCST: TX / OK / KS / NE / IA

[Michael O'Keeffe]

I agree with Ray. With the amount of instability from Beaver county, OK to Pawnee county, KS and moisture along with a weaker cap over SW Kansas where storms could initiate along the dryline better. CAPE in upwards of 2500j/kg is plenty to break the cap IMO. Though storms will stay quite isolated if they do so it could become quite the supercells with very large hail and a few tornadoes. Still a few more model runs and they can jump around still, but as of now I like the dryline setup better.

 

[Jim Bishop]

It's amazing how setups can change in just 24 hours. To me this setup screams bust. The latest WRF has the main vort max going even further north through Central Nebraska, leaving little to no upper support over the triple point or dryline over Northern Kansas. It also shows a more banna low type surface feature, which in my experience usually causes the surface winds to veer, even though the models indicates southerly winds.

So the low level moisture will likely mix out quite a bit, given the likely veered surface winds, the southwesterly 850mb flow and temps in the 15 to 18C ballpark. The model does fire convection along the cold front. But I'd say storm mode along the cold front will not be supercellular, or will only be supercellular for a brief period. I'm not convined anything will fire on the triple point even though the WRF shows the cap breaking. And even if it does I would be concerned about the storm struggling with cap. None of the above is favorable for tornadic supercells.

The southern target looks like a bust too with the lack of upper support. If anything there should be large scale sinking due to 500mb ridging. The GFS even suggests a cirrus deck moving through late in the day, a final blow in any chance for convective initiation. So you're going to need some upper support to break that cap. Mixing along the dryline isn't going to cut it.

 

[Chris C Sanner]

I'm beginning to agree with Jim. On the dryline, I don't see any real upper support to get these storms going and I've chased these setups many a times and busted almost always. If we can get a little disturbance or something to come out unexpectedly (or a strongish outflow boundary) we might be able to initiate convection, but I'm seriously starting to doubt this week as a whole. I'm on the fence about going now as I do have some previous engagements I probably should attend anyways, but I'm going off the day-of observations tomorrow on my decision, not the models which can't seem to make up their mind. The day to chase to me might be Saturday but even then it looks like we might have a squall line or a big mess more than anything.

 

[matt patterson]

Im somewhat perturbed about this whole set up... A week ago this looked like an awesome set of events and the closer we get to it the worse it has become... Im about ready to write tomorrow off and wait for the whole system to eject and hope it doesn't squall out like chris said.... On the BRIGHT side we stay in a troughing pattern (per the goofus) through next week, so the odds are in our favor that we might get the ingredients lined up at least once before we get into april....

 

[Mark Farnik]

Given the overall low confidence in this setup and what looks like an increasing bust potential, I am going to call off my previously planned chase on Wednesday. I figured out that it would cost me over $100 in gas and food by the time all was said and done, and I just don't think this scenario is going to be the outbreak we once thought it was. Hell, we might be lucky to get supercells on Wednesday with this strong cap in place.
That money I would have spent on the chase will be better spent on the laptop I'm purchasing this week; hope to have it by this weekend, get it all set up with GR Level 3, and be ready to roll when the next big system rolls in mid to late next week when I'm on Spring Break!
For all those chasing, I wish you the best of luck and hopefully the storm gods will be kind to at least a few of you.

 

[Brandon Sullivan]

Well.. I know I probably am TOTALLY screwing myself by saying this.. But frankly, I dont see what all the pecimisity is over.. Lots of good parameters coming together.. I guess it must depend on what we are searching for.. Severe weather really looks likely here... No, it wont be an "outbreak" but somewhat favorable, and not to bad for an early season event.

Discussion... Plenty of things falling nicely into place.. New SREF shows some really cool things... With the lift the way it is, and the composite severe params, prolly see some supercells fire in the warm sector, before become linear later in the period.. Capping is somewhat of an issue, but wth 700mb omega at -6, frontogenesis, MPV's somewhwere round .05 and lets not forget the all important CAPE hovering AOA 1500+.. Cap should be broken.. And development could be rather rapid.. Storms should be organized with rotating updrafts, given 40-60 KTS of 0-6 KM bulk shear..

My spring break was last week.. So don't know if timing will work out... But my plans just got cancelled tommorow, so maybe head to NW MO... I'm greatly anticipating the 1730 SPC SWODY 2.. And the 15 z SREF...

 

[Craig Maire II]

I still plan on chasing tomorrow but in central or eastern Iowa and not in south central Nebraska as I had previously planned. Seems as though there will be just enough instability and plenty of strong shear in place along that southward moving cold front for severe thunderstorms including supercells. Whether the cap breaks during the day or at night won't matter to me as long as it breaks and I see some storms! (Would prefer to see some surface based daytime storms though but any will do right now).

 

[bbarjenbruch]

I have to say this is tough to predict because I don't necessarily believe the models at this point. Well... some of their attributes anyway. I've been focusing in the Lincoln area as obligations won't allow me to stray far from home.

What I'm seeing for this area is a very nice setup with a few exceptions.
1.) With the EML, there is a significant cap which the NAM magically eliminates around 5 PM local time. I say magically, but it appears that it is actually bringing the shortwave through, a shift in wind, additional lift, and this is tending to erase the cap. However, I feel that much of this is convective contamination... contamination which may not happen at all if convective initiation is not reached. Stupid feedbacks! On the other hand, I feel that this northern shortwave, in conjunction with good left exit region jet support has the potential to at least aid in overcoming the lid out ahead of the approaching frontal systems.

2.) Another major concern of mine with this system is the potential presence of clouds. It's true that we have warm dry air predominant above about 825. However, the layer below is fully saturated for much of the morning and into the afternoon. I've seen low level clouds bust me before, and I wouldn't be surprised to see it happen again. The good news is that for once, it appears the NAM might not be blowing early spring smoke up our butts with these 60+ dewpoints. I only say this because they are already present in NE Oklahoma, and I anticipate a pretty good LLJ tonight. It will be interesting to see how this scenario plays out. Happy chasing to all who can get out tomorrow. Be safe, and try to be respectful to other people around you... chasers and non-chasers alike.

 

[matt patterson]

Well i knew i would eat my words as soon as the 12z GFS came out and it looks rather enticing.. It drops the SFC low back into western KS and even has little impulse over NW okla at or just before 00z... However the GFS did do terrible things to the 500mb wind fields up along the KS/NE border... Also the GFS is forecasting sub 15 degree 850 temps along the DL in NW Ok so the cap with a little luck may still break..FWIW... The OUN and TSA discussions did say that they were in preference of the GFS soln.... THis most recent run really tightens up the DL and is a little closer to what we were looking at a couple of days ago...

I hate FORECASTING and the MODELS

 

[Daniel Christianson]

Either way it goes for me , this has happened plenty of years models say a good setup then the next day it changes back to nothing, and then jumps foward to something... i hate when that happens and im not the brightest at forecasting yet but i plan on chasing , seemingly how i skip out on setups like this and i end up missing out.. of course im the king of Busting so therefore i have to go if i want to keep the tally up ;-).. ill keep my eye on things for awhile yet...

 

[Tony Laubach]

Us here in Colorado are watching the area along I-70 in Central Kansas for tomorrow and may be rocking out to Hays by early morning. Hastings AFD mentioning the development of a surface low with the dryline. If low clouds clear and allow for some heating, instability would increase and obviously with a developing low, low-level shear would as well. If the winds can back and storms can form, low LCLs would make for a semi-decent enviornment for tornado potential. I have a hard time believing the NAM's 3500j/kg CAPE and 62 degree dews, but even if you cut the CAPE in half, its still pretty good for this time of year.

All this flip-flopping... why do we do this to ourselves!?!?! LOL

 

[Brian Stertz]

True enough Tony...ride the model roller coaster and take some chances. This is what March chasing is all about. Sometimes it's the more sketchy dryline setups that end up being good ones in March anyhow. It's those 100 kt. jetcore ones that leave you literally screaming at the storm gods and the end result an early end to the chase. Tomorrow is one chance if the opportunity is there to take. I think I'll go for it on this one !!

 

[Mike Hollingshead]

Hebron NE 0z fcst sounding(from 18z nam)

That is the best one I can find for the northern target. Still not great but not terrible either. It seems tomorrow has a small area of some hope in southern NE, but if you go much further south you start getting capped worse.

CNK

SLN

That is going to hell in a short distance. I'd say stay as north as you can(at least if you are going for the north target), but a fair distance south of the sagging cold front. I think there is a small window in there near and east of the low for a storm to go up and move ene, before being ate by the cold front.

I guess west of Hebron a few miles is my target for now. Hopefully tonight's run will be able to magically give us a better dryline and sfc low....and improve on the capping issue.

Edit: While farting around I noticed the STP index was pretty high. I then find the cape/helicity for the 18z nam run but in a different location and note it seemed much more overlapped than what I had seen. Then I find it in another spot at less resolution and it's not nearly as overlapped looking. Now I'm wondering why they are different. Here they are.

Helicity/Cape

Helicity/Cape

Both say absolute helicity.

 

[Dustin Wilcox]

Cant beat a chase close to home during the Month of March, like many others have said it appears it is still possible for some action before the cold front comes smashing through. I will be out there tommorow, as of this afternoon I like the Republic County area I have been keeping my forecast updated here http://www.severechase.com/miscellaneous.html

 

[Tim Stoecklein]

I'm very reluctant to think the capping will be reduced further south, but that will be my play if I get out of the office. I will settle on the initial thought of Hwy 36 between Belleville and Smith Center. That would allow three good north options to shoot up to Hwy 136 if it's necessary to go north.

I'm a little skeptical of the surface temps, and I'd also like to see a more southerly flow..........but for a "backyard" go of it I may just be on the road.