3/30/07 FCST: MO/IL/IA/KS/TX/OK/AR

[Brandon Sullivan]

The sharp trough discussed in the 3/28 FCST will continue to move E across the Central US. 12z WRF very nice looking with this system.. By mid afternoon on Thursday, forecast sounding put K's at 34 and TT's at 51. With a Theta E ridge to move across the area.. Hodographs somewhat favorable for rotating storms with EH of 369 and SREH of 277... Speed parameters put storms moving at 227 at 24 mph.. Overall.. Early indications look pretty nice.. If timing works, Ill be out chasing this one!

This data came from WRF model.. GFS slower with the system.

 

[Brandon Sullivan]

Well, Im getting bored. So I thought I would talk about the 18z models.. While I cant discount the GFS, I don't like it in terms of severe weather.. It is slowing the system down, and not showing really any good area for severe.. Since it probably has feedback problems, and didn't handle yesterday very well, I will worry more about the setup shown by the NAM..

Discussion, the more and more I look I'm trying to pick a nice target.. It is far out.. But I need to plan because I am gone all the 28th.. I am really wanting to think St. Louis with preliminary thoughts... This model image shows it well..

Of course I have looked at other things, but I know things will change.. But forecast soundings from there show a fairly nice setup. And things look a little more favorable between forecast hours.. Unless any major shift happens, I may be heading to the arch! Go Cardinals!

Edit: New 00 UTC NAM out.. Hinting at maybe I will get lucky enough to see a local chase.. Im ready for SWODY3

 

[Andrew Pritchard]

I'm not really big on Thursday. I think if any day is going to go around this area it's going to be Friday.

The NAM is the only model that pushes the system out here that fast. The GFS and ECMWF have both been consistant in amplifying the shortwave trough on the southern end of the longwave and closing the low off and letting it just crawl to the east. I think Thursday might pose some severe threat, but likely off in western Missouri and far eastern Kansas, possibly up into Iowa.

So, since the NAM is the outlier, I wouldn't put my money into it. And even if you do want to buy it, the set up isn't much. The set up it does show leads me to believe the only threat is going to be back in the hills of Missouri, and even that won't be much of a show as upper level winds are lagging FAR to the west on the NAM.

Going to be hard pressed to find any severe weather in Illinois with upper levels winds like this...

http://rap.ucar.edu/weather/model/eta72hr_500_wnd.gif

Things can change, but right now I'm not impressed.

 

[Brandon Sullivan]

I agree APricthard.. I think I have to acknoweledge that it is slowing down.. I if the next moderator to read this could change the thread to the 30th, that would be great!

 

[Brandon Sullivan]

3/30/07 FCST IA/IL/MO/WI/TN/AR

Looks like everyone is caught up in tomorrows forecast... No question why either... Looks like a good setup...

Back to my world:
Im still really looking at a target around LSX.. Not very impressed with helicity.. But CAPE values semi impressive at 1500.... Im not liking the continuing south trend... Or the fact that the column is VERY saturated.. But a big threat is going to be the flooding.. With PWATS of around 3.00! Im thinking right now that could be the biggest concern..

Im gone all day tommorow.. But will be able to read posts.. So hopefully people can chime in..

 

[Travis Carlson]

Hey, Brandon

I looked over some of the models and parameters...not really impressed as much as I was back last week at the potential. Definately a major threat for flooding for sure with heavy convective rains and with the system slowing down. As far as the severe wx goes looks to definately be shifting farther south each day which is disappointing. Still 3 days out so hopefully we will get some decent model runs coming up to pin it down. I wouldn't mind chasing this one but I chased with some chasers in Wisconsin this weekend and got busted and this setup doesn't look as promising as that setup was...so might be sitting this one out. We'll see though...in the coming days as we get closer...

 

[Travis Carlson]

3/30/07 FCST IA/IL/MO/WI/TN/AR

Well thought I'd update this eventhough everyone is currently talking about the ongoing severe wx in the plains and rightfully so. Model differences still continue enough that SPC's day 4-8 outlook has not out-lined a certain area for severe wx. Very complicated scenario looks to unfold during Saturday. WRF has hinted a low pressure developing in Missouri and heading north into Iowa. GFS now hinting this as well. Moisture should be in place...question is overnight convection and how much sun if any we can get to boost temperatures and increase instablity during saturday afternoon. Thinking SLGT risk at this moment will be issued on the next day 3 outlook that comes out. If i had to gaze in a crystal ball and pick some areas in the potential it would be eastern Iowa, central Illinois could get into some action and a little farther south from there too. All subject to change of course. Setup looks better then it did a few days ago for severe wx and I'm crossing my fingers on this one cuz it would not be long of a drive for me. I'll try to update tomorrow if I can, got a synoptic test tomorrow here at NIU so my head will be buried in the books. Well that is my 2 cents...threat looks to be more sat then friday now

 

[Jesse Risley]

I think the main issue with this scenario will involve not only
the timing, but also the location of the warm front. The low
pressure system appears poised to track from western Iowa into
Wisconsin on Saturday. It appears that the warm front will lie
somewhere between I-74 and I-80 by around 1900Z on Saturday.
0-6KM shear appears favorable for a severe weather event (30+ knots),
but the question remains whether or not low level shear
will be unidirectional. Location and timing of the warm front, as
well as the location of the dry slot, appear to be the big factors
that will determine tornado vs. wind potential with this system.
I’ll be watching closely in the next few days.

 

[V. Gensini]

I agree...I think here in Illinois we may be able to catch supercell development along and North of the warm front on Saturday. Should be an interesting senario if morning convection doesn't muddy things up. 18z models are backing up this developing low further to the west than expected which may be a good thing for severe wx in Illinois. All in all, should be at least something to keep an eye on and I think the location of the warm front will play a critical role in any tornadic supercells that do develop.

 

[Brandon Sullivan]

Im still getting excited with this system.. I think the SPC did not issue slight because of uncertainty, rather that lack of severity. Soundings for PIA (Peoria) show cape of around 1500 Sat Afternoon.. I think the worst things may stay west of the MS river since the jet is strongest over there.. SREF looks very pessimistic. But WRF and GFS support a nice threat.. I just hope we can clear out, and get some insolation.. That would be crucial!

http://68.226.77.253/models/eta/central/CENTRAL_ETA212_ATMOS_CAPE_45HR.gif

Shear looks a little weaker with this mornings runs though.. Im not sure.. Wish SPC did 2 a day SWODY 3

 

[Brian Stertz]

Very favorable shear/instability combo (200+ 0-3km CAPE and 60+ kts of bulk shear) shown on the 06z MesoEta across WC Texas in the area between Midland-Abilene-Brownwood-Del Rio. This would be the likely area for the damaging supercells and tornadoes on Friday. Agree 110% with the SPC on their Day 2 outlook. Just not the greatest road network in the world for chasing.

 

[Doug Mitchell]

Well, after being disappointed that I didn't make it out yesterday and today turned to crud quickly on me, I've got the time, money (and pure unbridled RAGE) to do a marathon grudge chase in C TX. Problem again is precip bomb progged over the target area. More wishcasting in clearing that up. I'm going to chug some Nyquil at 9 tonight, hope to be on the road by 5am or so.

 

[Jim Bishop]

I'm heading to San Antonio where I plan to stop at the Flying J and look at data. I'm expect scattered tornadic supercells to fire from warm air advection and upslope between Del Rio to Junction to San Antonio between 11am & 2pm. Shear looks amazing and CAPE should reach 1500-2000 j/kg. The road network and terrain isn't the best, but I'll take what I can get after not being able to chase Wednesday's tornadofest!

 

[Tim Marshall]

TARGET: DFW-ABI - on I-20. TIME OF DEPARTURE: NOON. Very messy surface situation today but the RUC is painting an incredible dynamic event. PROS - Deep trough with short wave progged to lift out through central Texas, incredible 850 mb jet, great directional and speed shear. CONS - Morning conveciton continues, lots of boundaries, low clouds will prevent much surface heating, low CAPES. Trying to find a surprise in the fog. TM

 

[Mickey Ptak]

I am not going to get into detail because I am just about to head out to meet up the crew, but if we get a decent break in between on going activity in southern OK / NC Texas we could see a very large number of tornadoes today in this northern area, as upper air profiles support this. It all depends on the how much heating we can get in this area. Either way I still think there will be tornadoes in this area but perhaps not as photogenic as we would like them to be. Current sat image shows a little break in the activity over SW OK on then a little to the SW of there. Even a little heating could go along way with as much shear as we will have.

Good luck for those who go out and be safe because we will have some HP monsters on our hands today…


Mick