4/06/06 FCST: KS/NE/IA/MO/OK/AR/TX

[Mike Peregrine]

One reason I tend to put more faith in the model's fast handling of the dryline tomorrow is simply the depth of low pressure we are dealing with ... around 980-982mb ... So thinking about this in terms of how the real atmosphere tends to react (not much actual 'scientificky' meteorology here - just me talking outta my butt), there is that much more energy involved in the system as a whole, and so the short waves and the dryline swinging around the low will have fast motions - - typical of those seen in early spring events. My guess is that RUC will agree with NAM tomorrow morning and we will have fast moving storms ahead of the dryline, which will want to quickly progress east, making targets further east in Missouri and Iowa (where a person can be ready to intercept them) ... or slower motions closer to the low in Nebraska, more attractive to me personally. I outlined a simple forecast discussion in my blog. Areas further west, in Kansas especially, will be more difficult to nail, since a person will have to be confident in points of initiation, and that will be very tough on a day like tomorrow.

 

[Mike Hollingshead]

4pm Forecast Sounding for Norfolk NE

Quite the fcst sounding in ne NE still. CIHN gone by then with 4135 CAPE(I believe Earl's is usually higher than others, but still...). LI of -10.2! Cape at 3km 341 :blink: Nice lower LCL which could be even lower right on the front. Low level turning remains nice and will probably be quite strong as far as speed goes. I think the trick will be where to target from the sfc low. Due east just north of the apex of the bulge, or more wnw of there? I guess if you stay more to the east the upper flow isn't as backed and you would still get the nice low level backing. I guess at this point I'll say that I will be somewhere east or ne of the sfc low....perhaps even north of it. I really doubt I'll be anywhere south of a due east line. I could see an early target of Ord or Albion NE.

 

[Mike Peregrine]

I don't know why I'm particularly fascinated with targeting this, but there's nothing better to do at this point. H, if this turns out like last week ... which there are several things pretty similar to 3/30 in my mind ... then I would target just southeast - or maybe straight east - of the low if I were in your neck of the woods ... by about 20 miles or so. We may end up with another situation of deep convection firing in the warm sector and then possibly trying to feed into cooler air for a while until instability comes up. In that case, I would stay just ahead of where the deep storms are firing and just keep intercepting them until you get a hot one. I think if you're in that area, you'll probably get more than one shot at it.

The only inhibitor I'm going to put on that target is the fact that we'll be dealing with mongo-dynamics - so hopefully updrafts will be able to survive the turbulence and maintain severe levels.

 

[Mike Hollingshead]

Well I guess the dryline would arc to the southeast so I shouldn't say I won't be south of a due east line of the low. I should say I won't be south of a point where the dryline starts to be more n-s...at least up this way. I'm sure somewhere further south with stronger capping and more veered mid/upper flow will have something nice too.

http://www.wxcaster2.com/CENTRAL_ETA_1000-...PRPTHK_36HR.gif]ETA 0z Precip[/url] doesn't go very crazy south of that point I mentioned. I hate eta forecast precip, I'm not sure why I'm even posting it.

 

[Edward Ballou]

4pm Forecast Sounding for Norfolk NE

Quite the fcst sounding in ne NE still. CIHN gone by then with 4135 CAPE(I believe Earl's is usually higher than others, but still...). LI of -10.2! Cape at 3km 341 :blink: Nice lower LCL which could be even lower right on the front. Low level turning remains nice and will probably be quite strong as far as speed goes. I think the trick will be where to target from the sfc low. Due east just north of the apex of the bulge, or more wnw of there? I guess if you stay more to the east the upper flow isn't as backed and you would still get the nice low level backing. I guess at this point I'll say that I will be somewhere east or ne of the sfc low....perhaps even north of it. I really doubt I'll be anywhere south of a due east line. I could see an early target of Ord or Albion NE.
[/b]

If you're going to link to soundings...
4pm Forecast Sounding for Sioux City

I'm not discounting the boundary at all, it just seems that by going by pure soundings...KSUX seems the best. However the WRF gives greater interest to Council Bluffs. I guess all this seems to agree with the NWS outlook in that the storms will have a hard time getting going along the boundary but then turn into well-formed supercells after that. The low level shear is pretty amazing though.

I'm interested in the Theta-e over northeaster NE at about the same time frame. Let's see here, I think I was looking at the GFS on that one.

Over all, I'm thinking about the east/west front that things will be popping on first, then fill back down the dryline.

 

[bbarjenbruch]

For the sake of creating a Day 2 target, I think I agree with both of the above solutions. The area along the warm front from about Columbus to just west of Albion is mighty tempting. The only "problem" would be that most of the tornadoes would probably tend to be short lived as they are moving perpendicular to the warm frontal boundary, becoming more elevated with time. However, any cell crossing the boundary has great potential to produce with such backing in the winds.

I also think that a bit farther south, perhaps on the northern edge of the proposed bulging in the dryline. Perhaps the Fairbury to York to St Paul area would be a good place to start. Here, the storm motion could stay with the boundary a little longer. Heck, I don't know, York and Columbus really aren't that far apart, haha.

I think if I had my choice, I would head for Columbus in the morning, grab some online info at the library or one of the hotels there, and then make a play probably a bit farther west to set up for initiation. However, since I don't have my choice (morning obligations), I'll be sitting in Lincoln till about 2 or so and waiting for something to look great enough for me to try and pick it off. Good luck to all.

 

[Mike Peregrine]

You may even need to stay a little more patient if you're on a northern target close to the TP ... it really may take a while for the best instability to feed into that narrow corridor and start supporting the best development, in which case you'll just have to cringe and be patient if you hear of chasers making intercepts in Kansas or Oklahoma before you. As the instability then wraps around the low ... then you'll probably see additional storms becoming tornadic further to the north (storms up there might end up with some really crazy motions too ... I would guess a storm could move just about any way except south up there). If it turns out like last week, storms may fire first well to the south in broken linear modes along the dryline (still supportive of supes), and eventually work their way in closer and closer to the TP. I really don't know how that will work - just guesswork at this point. But still fun to guess ...

 

[Lisa Post]

I think as far as a target goes for me, I will be sitting outside my house in my lawn chair sipping on some lemonade, watching the storms form haha

 

[Mike Hollingshead]

For the sake of creating a Day 2 target, I think I agree with both of the above solutions. The area along the warm front from about Columbus to just west of Albion is mighty tempting. The only "problem" would be that most of the tornadoes would probably tend to be short lived as they are moving perpendicular to the warm frontal boundary, becoming more elevated with time. However, any cell crossing the boundary has great potential to produce with such backing in the winds. [/b]

Well I figure the storms will fire on the dryline, not the warm front. They'd probably lift due north with the dryline bulge and have the large area of backed flow with instability to use. With the dryline lifting and the wide area between it and the warmfront I don't think things will have too much trouble tornadoing for a while or becoming elevated.



I imagine things will go at the TP long before they go south.

 

[Justin Bailey]

unfortunately i will not be able to chase tomorrow due to classes. i'm goin to have to wait for the storms to fire here in TN and KY on friday. however if i were to chase i would have to target the slower moving storms up in eastern NE along the warm front. down south along the dryline i wouldn't be worried about finding storms i'd be worried about keeping up with'em. it probably wont matter where you set up at because the entire dryline will become active. i'd just pick a spot that is close to home with good road options. good luck to all. have fun. watch you back. and be safe.

 

[Mike Peregrine]

I just read the SPC language for the first time, and it looks like they are feeling that the cap will inhibit the southern stuff at least for a while, giving the TP time to go first ... so I don't know ... that aspect of it will be a wait-and-see thing, especially since reading this I'm really not fully convinced the juicy, deep moisture will be able to make it to the TP in time for it to pop before the dryline ... there's going to be some mixing issues going on at least part of the afternoon. This system should be digging fairly deep, and so I feel like any capping could be overcome earlier than they anticipate (especially in light of expected ongoing early convection in the target areas), but we'll definitely be watching how that plays out.

 

[Jason McKittrick]

Well I just finished looking over the 12z model runs and checking the sfc obs. The model IMO looks pretty ominous. The four ingredients for severe thunderstorms are all there at least in the models version of reality. Here in Omaha our sounding already showing the EML. (conditional instability). It seems obvious that there will be a dry line from eastern NE south to northeast OK.(lifting mechanism). Upper level wind profiles, at least here in Eastern NE at 1PM, surface winds ESE at 15mph, veering to SW at 50knts at 500mb. (wind shear). The thing I am most worried about is moisture. At 3PM mid 50's DP have reached southeastern NE, however DP's along the Gulf Coast were only in the low to mid 60's. Things are going to have to moisten quite a bit between now and noon tomorrow or else the +9 at 700mb here in Omaha might prevent an outbreak from materializing this far north. I think I am going to stick close to home no matter what things look like due to gas prices and since storm speeds will likely make for a less than ideal chase day just about anywhere in the plains. At this point in time I am planning on targeting either York, NE or Lincoln, NE depending on the dry line position at noon tomorrow.

I pray that the storms tomorrow do not critically impact any communities, and for everyone who is chasing tomorrow be safe.

 

[bbarjenbruch]

Well I figure the storms will fire on the dryline, not the warm front. They'd probably lift due north with the dryline bulge and have the large area of backed flow with instability to use. With the dryline lifting and the wide area between it and the warmfront I don't think things will have too much trouble tornadoing for a while or becoming elevated.
I imagine things will go at the TP long before they go south.
[/b]

Sorry, I should have been more clear. I was making a poor attempt to say that I would shoot for the storms that fire near the dryline, but make sure to try and intercept them by the time they reach the strongly backed winds near the warm front. Kind of using the old NWS 10/30 rule (10 miles south of the boundary to 30 miles north of the boundary for the most tornadic potential). I know rules are usually bad to use, but that was my thought.

 

[mikegeukes]

Based on 12Z NAM

Forecast Period: 00Z Fri 07
Surface low in Nebraska with a occluded front across Nebraska and Iowa with a warm front over Illinoiis
Indiana and Kentucky. Cold front (dryline)stretches from Missouri, Arkansas into Texas, 500 mb low over northern Kansas and southern Nebraska. Play the area by the triple point area of the occluded, warm and cold front (dryline)over eastern Nebraska and western Iowa and northwest Missouri area.

Did not have time to look at 18Z-21Z time period or the latest 18Z NAM run.

Mike

 

[samuel stone]

I happen to agree with models taking the dryline further east. I think that since 850 mb winds will be more southwesterly especially earlier in day that will advect in drier air at 850 mb (thus a thinner layer of moisture) causing the dryline to mix significantly further east.

Thoughts?