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

Some nice thoughts being presented in this thread. Tomorrow looks like it has the potential to kick our butts yet again. If I had my choice tomorrow, I'd probably get up closer to the TP in south/central to east/central Neb ... for nothing else than forecast storm motion alone at this point. But also because I think vorticity will be maxi-crazy up in there.

Missouri and Iowa are looking like another screaming, frightening day setting up. I'm leaning toward storm initiation east of 35 in eastern Kansas by 0z, but likely earlier in the afternoon (if we are going to use 4/11/01 as a template, these COULD initiate much earlier, ladies and gentlemen ... so keep your eyes open all day). The storms should then sweep across the already battered and bleeding Missouri hills moving N/NE at 50-60kts, leaning more toward the 60s.

So ... take it from someone who just had his rear handed to him on a platter with a side of everything on it ... and is feeling a little humbled at this point. We're all going to have to watch our backs tomorrow.
 
If the 12z NAM is to be taken as valid (or we assume the forecast will verify perfectly), I will most likley sit this one out. For whatever reason (intense mixing, etc) the NAM is now moving the dryline considerably farther east during the afternoon. Instead of being just east of the I35 corridor by mid-late afternoon as indicated several runs ago, it now appears as though the dryline will be located near a line from Tulsa to Emporia by 18z, before rocketing east into western MO by 0z. The 850mb flow looks quite veered overmuch of OK and southeastern KS, with SW or even WSW (over southern OK). This is likely helping to usher in very dry air air, which may be mixing downward and helping to move the dryline eastward.

The current progs show the mid-level and upper-level low centers located south of the surface low, which is resulting in an interesting shear profile for areas north of the NE/KS border. Winds seem to be back substantially in the 850-250mb layer (which isn't surprising given the location of the sfc low relative to the upper-level low). Instability may be significant in NE, but I'm very worried about the winds aloft, and the affect that they will have on storm evolution. Storm motions should be nearly due north (or even with a slight westerly component looking at the mid and upperlevel flow).

I'm still hoping that the system develops differently than the models are currently forecasting. With slightly flatter flow aloft (south of I70), shear profiles are decent in the southern 1/2 of the risk area, but I can't imagine I'll chase if the dryline forecast really appears as though it'll verify. I chased 3/12 when the DL was in eastern KS and OK, but I probably won't if it's in western MO. Maybe I can close my eyes, click my heels together thrice, and the forecast will revert back to the way it looked yesterday morning...

EDIT: I should note that OUN apparently feels that the dryline will be located near I35 by 4pm, per a graphic on their website. I thought this was old, but I see it was updated a little before 11am (several minutes ago), so I assume they've looked at the 12z model output...
 
Jeff,

OUN has been showing the dryline in that same position for the past couple days. I haven't noticed much of a change in their placement of the dryline.

They may have some different thoughts than what the models are showing...I guess I'll be looking at the Mesonet data in the morning to see where the dryline is developing, and where it looks to be moving.

Of course, I think I'll be sitting this one out for a few reasons:

a. Work
b. Storm motions (I'm getting disappointed in all of these storms that are rocketing to the east)
c. Having to take the Ranger in for service.

Depending on how long © takes, I may be available for nowcasting for those who are out.
 
04/05 12Z NAM and GFS output have fantastic hodograph profiles with significant CAPE and surface moisture extending from northern MO and along the anticipated dryline into northern AR ... southern Iowa and back into Nebraska aren't looking too hot for me to chase when things look so great and so close.

I'm thinking of traveling only slightly westward from St. Louis and north to set up and await storms to come to me seeing as how fast things will be flying.
 
In my best judgement i see this as a situation like some in the past
we need to wait until Thursday morning to be making judgements
on where to chase for one, i think the models could be wrong on
basically blasting the dryline into extreem ern ok into ar by thurs
afternoon... we need to closely watch central ks into central ok,
into n tx also very closely... the models have in the past have
done this, so i say its best if we wait until thurs mornin before
making decisions... attm iam thinking the front will be along
or e of i-44 to near highway 81 across central ok by 18z,
so we would have to watch for poss delvopment across
the central body of ok for poss delvopment.. just gotta
see what this dang dryline does....
 
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.
 
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.
 
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.
 
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.
 
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.
 
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.
 
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 ...
 
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 :p haha
 
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.
 
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.
 
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.
 
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.
 
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.
 
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
 
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?
 
I finally got my BUFKIT profiles working, and i must say it really throws a wrench in any severe weather happening tomorrow. The dryline has almost no shear for tornadoes. At the peak heating, sites such as Topeka and Tulsa have almost no directional shear... after that, the winds go to the exact opposite of what you want for tornadoes.... near westerly at the surface and near easterly aloft. Just about the only good place for tornadoes is along the warm front in far eastern Nebraska, southwest and central Iowa, and some parts of Missouri.
Unfortunately it just not look very good for supercells along the dryline tomorrow.... maybe severe but tornadoes are not looking all that likely. They will only happen along the warm front tomorrow if we can get good heating and moisture influx for the storms to be surface based. We may all be out of luck for a big day.
 
I finally got my BUFKIT profiles working, and i must say it really throws a wrench in any severe weather happening tomorrow. The dryline has almost no shear for tornadoes. At the peak heating, sites such as Topeka and Tulsa have almost no directional shear... after that, the winds go to the exact opposite of what you want for tornadoes.... near westerly at the surface and near easterly aloft. Just about the only good place for tornadoes is along the warm front in far eastern Nebraska, southwest and central Iowa, and some parts of Missouri.
Unfortunately it just not look very good for supercells along the dryline tomorrow.... maybe severe but tornadoes are not looking all that likely. They will only happen along the warm front tomorrow if we can get good heating and moisture influx for the storms to be surface based. We may all be out of luck for a big day.
[/b]



Where are you getting this? there is more then enough shear for supercells tommorow, i somehow see a lack of tornado potential but, theres alot of potential for supercells tommorow.. i feel storms will fire around the triple point and work south due to the cap down there, ? unelss things have changed is till see alot of potential tommorow...

:)
 
OK, my prediction 18 hours out.

I think the models are overdoing the dry line punch just a bit. At 1700 the dry line in Kansas will be about halfway between Manhattan and Topeka, trailing southward. Storms fire up along the dry line and move rapidly NE/ENE just after noon. Segmented supercells at first eventually congealing into a squall line by the time they reach the eastern edge of the KC Metro. There will be several rotating cells with wall clouds, some funnels, but only one or two small tornadoes in far eastern Kansas and western Missouri. Lots and lots of hail and wind though.

Not sure about what happens in Nebraska/Iowa along the warm front. Have to study that some more.
 
I really couldn't agree much more with you, Alex. My extreme concern is for central/eastern MO and central AR. This forecast sounding for 0000z at Little Rock (NAM) shows why:

3110.GIF


I'm afraid that once the moderate cap breaks, the storms will explode over NE OK/ERN KS. They will move east into an enviorment of 75-90° of directional shear in the first 5000' of the atmosphere, including an intense LLJ. To sum up:

45day2.GIF
 
As it would happen tommorow is the only day I cannot take any time off. So, im reduced to screaming south at 4:30 to hopefully arrive in Sioux City by 6:30. With not much CINH remaining at 21z, im expecting some isolated development along the WF sometime between 22-0z. Shear/Instability looks supportive for supercells and possible tornadoes if we can get intiation. NAM forecasts 60+ Td to reach as far north as Sioux City, with 12-13C Td at 850hPa. Though, it appears that the NAM may have over-forecasted dewpoints for today for our region. Even so, the target area still appears attractive, with my main concern being intiation along the front. More likely area for storm development should be the triple point, NAM and GFS both indicate development and strong moisture convergence should be present along the low/Triple Point. As already noted, the storm motions are more reasonable than what was previously forecast, most likely in the 20-30kt range. Also worth noting that the 8km NMM WRF shows strong development from KYKN to KOAX and in other locations around 0z. With increasingly strong theta-e convergence through the 21z-0z period. So I'll take my chances even with a late departure to try and catch something towards Sioux City or Onawa, IA.

-Scott Olson
 
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