05/21/05: TALK: KS/NE/IA

[nickgrillo]

This is probably my last chase day on the Plains this May, so hopefully it will send me off with another smile on my face. NAM is bringing some really good prospects for SAT, especially across NE KS/SE NE. We'll have rocking instability with >4500J/KG SBCAPE, with very strong vertical shear that will be very sufficiant for supercells and tornadoes...

It's still 36HRS out, but decided to make a TALK thread...

 

[Chris Hayes]

As of right now I'm targeting NE Kansas. The cap can be a chaser's best friend and worst enemy. I like the cap in Kansas because it will keep storms isolated if they develop, but it could also break a good kansas day. With the weaker cap further north we could see too many storms develop. NE Kansas is my best bet. Head there early in the day and see what happens.

 

[Chris Allington]

Well...looks like many things are pointing twoards NERN KS or SERN NE on saturday. But, just as you guys mentioned the extent of capping across Kansas is yet unknown...with many people thinking that the cap will not break farther south than the NE/KS border...hopefully we can get a little more moisture up here with DP's now hovering in the mid 50's. The OAX AFD mentions that DP's may even approach 70 with CAPEs going over 3000 across much of the area. And bulk shear values around 50 kts.
My only concern is that things will go to lines fairly early...but we will see...

I am by no means a good forcaster...lol

Preliminary Target- West of Lincoln, NE

 

[nickgrillo]

We have so many things in place, but I myself am worried about the CAP. NAM doesn't show the CAP breaking until 0Z, which means tomorrow could be May 10th II, which is fine with me... Just as long as it does BREAK!

 

[Chris Allington]

which is fine with me... Just as long as it does BREAK!

Yes agreed... new runs making it look fairly good for SERN NE on saturday... probably leave Omaha around 12...

 

[Glen Romine]

I took a quick look at some of the forecast models this morning, and thought I'd offer my 2 cents on what I see based solely on model guidance. Consensus is for an MCS to track from the Dakotas down the Mo. River valley overnight - and die out late morning around the vicinity of southern IA. Strong shortwave ridging during the day will reinforce the capping inversion across the northern plains - and potentially widespread cloudiness across much of eastern NE during the day. By late evening, convection redevelops over northeast KS on the nose of the LLJ and tracks southward across eastern KS. Wind fields are relatively modest - but show considerable veering with height - which might be tolerable given the expected degre of instability. Deep layer shear looks great - as is often true for northwest flow events. But - with the expected strength of the capping inversion and apparent lack of strong convergence - it might be extremely difficult to get convection during daylight hours. The front is held up well north of where evening convection initiates - but low-level wind fields near the front look horrible. Really need for convection to develop well to the southeast - ala residual outflow boundary if it can press down into this region. NAM provides little evidence of this happening - but chasers should rejoice if a strong MCS is indeed ongoing in se NE -sw IA tomorrow morning. Since it is imposible to know if or where this boundary will set up - I'd probably target the optimal place for it to end up - around Topeka KS.

Glen

 

[Kevin Walter]

Good luck to all going out. Better take some sunscreen.

 

[Jayson Prentice]

Well... I'm going to give this talk a shot...

A lot of people are liking the capped areas of KS/NE and parts of southern IA. This is because the skies will be clear, instability high, but the cap will also be tough to break. But, if it does like any other severe outbreak, it will break hard! So, current thinking for those liking the southern option should target an area around KS/NE border.. Storms may not break until nightfall there though, so it is a difficult decision.

As for myself, I won't be chasing anyway due to graduation... But, the northern option will include the areas of NE/IA that should see the first initiation of convection in the afternoon as the front begins to move through. Right now, the target area in this area is going to be the Storm Lake or Carroll/Denison areas. These should be on the front at peak hours, making them good choices.

Right now that models are looking a little off on front positioning... GFS is faster at moving the front though, they have it past the nw IA area by 00z, while the NAM has it right on the SD/MN/IA/NE corners by this time. If the NAM verifies it will turn out better for many chasers in the northern option becuase this gives the air plenty of time to destabilize with capes in the 2500 j/kg range. Looking at Carroll skew-t for 00z, shows great shear (EHI at 2.9/SRH nearly 300), cape at 2000 j/kg, cinh is negative, and LCL height is at a great 690 meters...

 

[Mike Hollingshead]

For Lincoln NE.

http://www.wxcaster.com/modelskewt.php3?mo...&STATIONID=klnk

Eeek!

http://www.wxcaster.com/modelskewt.php3?mo...&STATIONID=klnk

Back at 21z and no cinh. I suppose I'd target the Grand Island area right now.

 

[Ryan McGinnis]

Looking at the 12Z NAM run, I'm pretty much stuck with the same target -- perhaps a bit north, to just north of the KS/NE border in SE Nebraska. I could probably just hang around in Lincoln and wait for them to pop. If the NAM is to be believed, the cap erodes at some time just after 21Z or so with big, sloppy bucketfuls of CAPE. (Check out the Skew-Ts for KLNK). LCLs still a bit high as someone else mentioned, but I don't care because I want to chase some storms! :lol: Winds look like they back a bit in this area too on the 850 at the 0Z.

Storm motion should be SE at around 20 to 25kts Saturday. I think I might try to get south and west a bit of Lincoln since this is NW flow. I'm not a big fan of core punching. Man, here's hoping for a nice front-lit tornado at golden hour.

 

[Chris Hayes]

I decided to target Grand Island hours ago. I would like isolated supercells in eastern Kansas but the cap looks to hold strong. With a cape bullseye of more than 5000 over eastern Nebraska and some decent helicities and supercell potential of 90% I think there'll be a chaserfest in eastern Nebraska tommorw. Here's to what might very well be the best day of 2005 so far

 

[Chris Allington]

Well... weve had a few more hours of updates now... moisture is supposed to be arriving tonight with DP's up to as high as 70 mentioned... CAPE is expected to be around 4000 j/kg and fairly decent directional shear looks to be in place... my concerns are that the better upper level support will be farther S in KS... and still everything going into a squall too quickly... it is a coldfront after all...

good luck to all....

 

[nickgrillo]

What is my biggest concern? Time of initation... But, I guess I'm feeling a bit more confident that the CAP will break by evening (likely BEFORE dusk)...

 

[Jason Montano]

As of now I would target good ol' Beatrice, NE for initiation and look to drop down to KS/NE border where with the SE traveling storms will encounter better Helecity values. 1km helicity, per eta, looks rather weak except for extreme NE KS and SE NE. 3km helicity looks nice througout the target area. Tomorrow could be good we will see how it unfolds, unfortunatley I will chairborne chasing this one from VA. If anyone needs a nowcaster feel free to PM me and I will give ya my cell number.

 

[Mike Hollingshead]

my concerns are that the better upper level support will be farther S in KS... and still everything going into a squall too quickly... it is a coldfront after all...

Quite often there are boundaries ahead of a cold front that can and do make the day worthwhile. With overnight convection and a sfc low in the region I imagine we'll have a good boundary to work with. Plus the southern portion of that front doesn't look to be very cold with temps in the upper 80s behind it.

http://www.wxcaster2.com/CENTRAL_ETA_SFC_S...INDSLI_30HR.gif

http://www.wxcaster2.com/CENTRAL_ETA_500_G...NDVORT_30HR.gif

Upper level flow is certainly better the more north you get.

I would expect an almost due south storm movement tomorrow. I hope the sfc winds do not back more than due south as I don't care for too much turning. Something say 150 degrees or less will make me happy.