Post by Chris Higgins on Apr 24, 2016 17:58:50 GMT -6
Looking at the 12z data today and the more and more I look at it, the more I think our better chance for severe storms will be Tuesday vs. Wednesday. The missing factor(s) for Tuesday will be a strong forcing focus for large scale ascent from a shortwave aloft...and marginal shear. The main limiting factor for Wednesday will be the muddied atmosphere from the events of the day/night before.
For Tuesday...I think the amount of instability with a surface boundary hovering near/just north of I-70 and just enough bulk shear (~30kts) will set the stage for multiple, multi-cell structures that will at times feature supercell characteristics. In fact, chances are storms will start as supercells but then mergers will lead to more clustered activity that will tend to migrate along the instability gradient...slowly. Tuesday afternoon...if storms do get rolling will have the potential for extremely large hail, damaging winds, tornadoes (especially in central MO) and flash flooding. The concern for me is that the effective surface boundary may start to ooze south thanks to rain-cooling processes at the same time the LLJ ramps up Tuesday evening/night. This will tap into a very large reservoir of high CAPE air resulting in the potential for not only multiple large hail events...but also training of heavy rain...resulting in flash flooding.
Wednesday...could be another active day...but only if the overnight activity dies down and clouds are allowed to breakup.
Pretty difficult forecast with the severe threat because the main upper low is not progressive. It seems to want to pivot and not truly get thru the area until late Wednesday night/early Thursday. The boundary will be wavering around here both Tuesday and Wednesday... so in a good spot for severe.
Looking at the mid level VVs it brings several pieces of energy out... first Tuesday evening, then Wednesday AM and last Wednesday evening. How it interacts with the available CAPE is going to be the key to how strong/severe the storms may be.
I agree with Chris... with the CAPE Tuesday afternoon/evening that will be the best chance for severe. Should be enough subsidence behind the Wednesday AM wave to clear us out on Wednesday with another shot late in the day.
Last Edit: Apr 24, 2016 22:26:18 GMT -6 by cozpregon
My opinion, there are several mitigating factors in play Tuesday that would preclude a high risk type outbreak in the plains. But from an ingredients based approach (the less of this, more of that, decent balance, perspective) it still has the potential to produce numerous severe reports. Especially hail and I wouldn't be surprised to see a 4"+ report or two. I think there will be some tornados with the better chance perhaps in south-central/southeast NE and north-central/northeast KS. Further south in OK initiation and coverage looks more iffy.
NAM is trying to muddy up the Tuesday scenario with a round of thunderstorms... maybe some hailers... tomorrow morning. How this impacts the potential late day stuff is a question. It's the NAM... so who knows, looks like some convective feedback may be an issue.
Upper system is just not making any eastward progress... so timing is going to be difficult. Boundaries from earlier rounds of thunderstorms will be impossible to forecast right up until the next round develops.
Last Edit: Apr 25, 2016 9:07:14 GMT -6 by cozpregon
gonefishin: Okay. I know these storms are no laughing matter, and I don't know if anyone has posted this, AND I know it's from the Weather Channel, which in and of itself causes it to lose some credibility, but this is one of the funniest things I've ever seen.
Sept 10, 2017 11:27:09 GMT -6
bellevillewxguy: Let's give a BIG Shout for the Great American Total Solar Eclipse! Here's to good viewing conditions for everyone!
Aug 20, 2017 19:09:33 GMT -6
MakeitRain: The 12z NAM wants to develop a line of storms through the metro around 1-2pm this afternoon. However, the HRRR is not picking up on this piece. I would not rule out the chance of severe weather as we head into the afternoon.
May 18, 2017 11:13:07 GMT -6
REB: 1.57 Wednesday. 2.31 since midnight. 5.92 since Friday. Total........7.49 and still coming down.
Apr 30, 2017 9:59:34 GMT -6
fojginmo: Glad I'm on higher ground & won't have to worry about flash flooding any more.
Aug 2, 2016 21:58:56 GMT -6
kkwhit: Would be nice to have 2 events this week!
Jan 18, 2016 23:21:16 GMT -6
evilmonkey: shout box, shout box, let it all out box
Jan 18, 2016 20:33:42 GMT -6
Jan 18, 2016 17:26:56 GMT -6
snowday_lover: I was thinking this was to start late tomorrow night...are we thinking earlier? I'm in Ironton, so I'm not holding my breath for much per the maps that have been drawn up. I'm thinking a little bit of sleet and frz drizzle. Is that correct? It's a balmy 18
Jan 18, 2016 14:32:51 GMT -6
dschreib: You know you make me wanna...
Jan 18, 2016 9:32:36 GMT -6