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05/10/05: TALK: NE/IA/IL

Definately hoping those dews can make it here this afternoon... They did just bump up slightly with my station now showing 53 degrees... Temp sitting steadily at 73...winds from the SW at 12 mph.... Tonight could be fairly interesting after dark as Mike points out...
 
Me, Andrew Ashley and Gary Eccles are sitting at a food court type thingy in Lincoln. Debate over whether to head west towards LBF or to stay in OAX area was ended by grunge cover over C NE. I think the RUC is pulling a fast one on moisture return but LCL heights are still the biggest concern. If anything, we'll probably drift Nward towards Wahoo.
 
I'm sticking here in Lincoln at the moment... I'll probably stay here as long as I can, as I have fast, free data. Looks like I'll end up moving north a wee... but not much. Storm motion today will be ENE, which means I-80 may come into play. The roads out here are generally pretty darn good. Hope this one pans out.

It's probably been said already, but keep your mind on the rivercrossing if you're out chasing this way. Omaha is a perfect place to cross, if it's not "rush hour". (Rush hour in OMA isn't exactly like you'd expect in L.A., but it'll still slow you down.)

Just noticed that SPC upgraded this area to MDT, with hatched tube threatbox. Makes me feel better for not driving west this morning. :)
 
Interesting new day 1 - I think it is the first time I've seen 5% tornado and hatched????? Confidence bolstered by SPC agreement with earlier forecast. So, I'd still suggest hanging close to the OMA area until a more clear target is evident.

Glen
 
SPC has just upped the ante today by issuing a mod risk for the OAX area and a hatched tornado risk. Definitely getting my hopes up a little bit
 
SPC certainly seems confident in NAM solutions for heavier moisture and precip initiation in eastern Nebraska. Tornadoes almost seem to be a passing comment in the forecast language (odd with hatched probablistic), but as expected - it will be imperitive for chasers to maintain diligence when it comes to keeping track of WF position later this afternoon, as storms rooted along the front should be seriously spinning. Will be leaving for Neb City/Omaha by 1:30-2:00 to re-check data. Storms should be moving straight east along the boundary up there. Hopefully we won't be chasing after tail end charlies all afternoon under a massive bow echo.
 
The 15Z RUC is showing basically the same thing as the 12Z RUC as far as moisture availability, or lack thereof according to the model.

However, the SPC wording (heavily dependent on the NAM model) may encourage me to take a little outing to the Omaha/Lincoln areas, but still not sure of yet. I may leave by 1:30 should conditions warrant to make it to Nebraska City around 3:30-4:00-ish.
 
I will be departing at about 1pm today and will head west to the Shelby county area.

As of 11:30am, surface analysis placed a northward-moving warm front extending from Lamoni to Clarinda to Nebraska City with excellent shear profiles setting up along the boundary. So excellent, in fact, that one could argue there is close to 180 degrees of turning in the lower levels of the atmosphere starting with E-SE surface winds at the surface, shifting to a more southerly flow at 850mb, then coming full circle to a west wind at 500mb.

This set-up looks excellent for at least rotating storms, and possibly more than that. The 1630z SPC outlook reflects this concern with the addition of a "hatched area" for today's tornado outlook chart. This indicates a higher chance of F2-F5 tornadoes. I am not saying these types of tornadoes are going to happen, just saying one should pay attention to things like this the SPC does to signal an increasing concern about the day's potential.

Whatever happens, this is the type of set-up us Iowa chasers live for, so break out the camera and good luck to all chasing today.

Sincerely,

Ben McMillan
 
Yeah, I think the basic concept behind the forecast is that confidence in convection developing on the warm side of the boundary is still low - whereas elevated supercells capable of generating very large hail (supporting the mod risk area) is quite likely. Hatched comes in as a safety measure, as if storms become surface-based - potential is fairly good for a few strong tornadoes given expected conditions in the area. I guess I'd aim for the Columbus area based on current trends.

Glen
 
Well Mike johnston and I should be leaving Lee's summit within an hour, headed north, positioning ourselves around Nebraska City. Good luck to all out there, and be safe.
 
Cirrus deck eroding to the N and W, so won't become an issue with today's convection. Cu field trying to go up, but is mixing out slowly. Mid 60's Td's sneeking up through NE KS. Looks like it's all lining up with the NAM.
 
I'm going to bite, I am going to leave Overland Park, Kansas in about 30 minutes to an hour to head to I-29 and Exit 10 - (IA-2) or into Nebraska City. Good luck all!
 
I have a 4:30 appointment here in Omaha that I'm reluctant to cancel, but I have a feeling initiation will be late enough (and close enough) that it won't be much of a problem. So, I'll be monitoring close to home.
 
Wow. Well I like my Ansley target even MORE now. LOL. However front might not lift that far north. Broken Bow area under cloud cover. Front intersects I-80 where I am now in Lexington and it is very apparent visually; one of those boundaries with a big neon sign: chase me. And so I will and worry about sleep in July. moisture pooling south of the front nicely and RUC brings wrap around dews nearly to 60F here, CAPE to >2200 j/kg. Low cu already bubbling and front is lifting north of the highway a little now; much hotter than only 20 mins ago.


Originally posted by Amos Magliocco
As last night, I stilll like North Platte to Ansley, hopefully no further east and north of there. 12z RUC holds the front in place optomistically for us; I don't want to get far north of I-80 unless absolutely necessary. Forecasting as well a very tight temp gradient by 0Z. Storms moving along that boundary might be very interesting. Agree that OAX area looks good too. Checked their VAD profile (too impatient for the sounding), and showed excellent low level turning at 13z. Good luck all.
 
Wow some of the coolest and most wide spread ACCAS I have ever seen forming rapidly overhead here in eastern NE north of Omaha. I may have to go get ready. Wish I had my cam out here with me(at folks) so I could take their pic and stay here.
 
Surface winds now starting to back nicely from just N of KC Metro area up into E NE as dewpoints strengthen. As Dick mentioned, we will be leaving Lee's Summit shortly, to head N on I-29. We want to get up to Nebraska City and monitor/creep from there. As usual in this area this year, storms will likely wind up in LP mode, but our strategy on this one is to approach the risk area patiently from the south. Good luck to everyone!
 
Originally posted by Mike Hollingshead
Wish I had my cam out here with me(at folks) so I could take their pic and stay here.

You mean Hollingshead actually goes places without a camera? I thought it must have been surgically attached by now. hehe

Getting geared up now ... should be leaving St. Joe by 2:00 p.m. Ahh May ... and we thought you would never get here.
 
We have been sitting here at Sapp Bros. in Nebraska City monitoring the front waiting to make our next move. May see some of you out this way.

Dan
 
Calling in sick... 8) so i can chase later today... still have a meeting at 6 but if they call up activation I will cancel that too... SPC issued at PSWO today for NE and IA....interesting they mention the uncertainty of storms initiating south of the front but yet include that area in the hatched area...
Good luck to all...

EDIT: Surface winds backing nicely in Eastern NE and Western IA... dews reaching the 60 mark on the NE/KS border moving N-ward...
 
Band of weak mid-level ascent sweeping northward across CO (evident in water vapor imagery and vis sat as thin cirrus patch), and should cross over the somewhat moist northeasterlies in ne CO next few hours. Perhaps signs of developing convection there now already. Could see northeastward development from there toward LBF. Noteworthy is the fairly rapid breakdown in the stratus deck along the southern edge, now exposing the warm front. Waves in clouds along with RUC estimates of temperatures suggest the cap strength is still formidable, and may lead to a break in convection on the west and east side of the stronger cap. Strongest surface convergence has held around the GRI vicinity lately, which is supposedly near the northeast edge of the strongest cap. Animation of the Hastings radar shows the front still drifting northward. Hopefully the 18Z sounding from OMA and LBF will be available soon which should shed some light on how much heating will be needed.

Glen
 
Originally posted by Glen Romine
Hopefully the 18Z sounding from OMA and LBF will be available soon which should shed some light on how much heating will be needed.

Glen

Soundings are in - and the cap is indeed brutal. 700 mb temp at LBF = 10C, 9.5C at OAX. OAX convective temp of 97 can be toned down some by adjusting for best moisture in the area, but probably need temps approaching low 90's combined with convergent flow to break the cap. This still appears at least possible.

Glen
 
Originally posted by Glen Romine+--><div class='quotetop'>QUOTE(Glen Romine)</div>
<!--QuoteBegin-Glen Romine
Hopefully the 18Z sounding from OMA and LBF will be available soon which should shed some light on how much heating will be needed.

Glen

Soundings are in - and the cap is indeed brutal. 700 mb temp at LBF = 10C, 9.5C at OAX. OAX convective temp of 97 can be toned down some by adjusting for best moisture in the area, but probably need temps approaching low 90's combined with convergent flow to break the cap. This still appears at least possible.

Glen[/b]

That's the reason why I'm not too hot on tornado prospects today. Yes, there is strong low-level shear along and north of the front, but the low-90s needed for surface- based convection (ingesting the low-level shear) will make T-Td deficits in the 25-30F range, yielding very high LCLs. Typically, one wants T-TD deficit to be <15F , as that, generally, yields LCLs <1500m, above which tornadoes become increasingin unlikely very quickly. LCLs will lower with time due to diabatic cooling this evening and continued moisture advection, but I'm not sure that we'll end up with LCLs low enough to do much before storms become elevated / non-surface based.
 
Lets hope that some 90's can occure im thinking south of here should be able to do it, i give it a couple of hours 2 at the most with some clear sky and heating, this would suck though if CAP doesnt subside.... :?: hmmm what to do? but wait and see"
 
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