Thundersnow12

NAM and more so the Nest are an absolute train wreck across the Chicago metro area, as well as being slower. Cut off on the SE side ends up being further NW, and the NAM has a 10" spread from GYY to extreme northwest Cook

Blog post is done and up https://piechotawx.blogspot.com/2018/11/112518-major-winter-storm-with-possible.html

Love where I sit here. 12z Euro looks almost as good as last night. Going to try to have a blog post up by late afternoon/early evening.

12z NAM and nest pretty sizable shifts south. Main wave coming out of the plains is slower and less phasing to aid in pulling it north.

Omg the Euro. Hottest run locally since GHD II. Widespread 14-18". Would be paralyzing shutdown blizzard

Nearly all of the 0z GEFS members are south of the op...

Still worried about a miss NW here. We will see.

The new hotness. Talking B word now for sure

Southwest portion of the LOT CWA destroyed this run, really I-80 and south do well and far northern Illinois does not.

Yeah you look good out there for sure from a ratios perspective. Would be more worried into the eastern half of the LOT CWA

Be careful of using 10:1 snowfall maps (yes I know some sites only offer that) but ratios will be higher than that back in the cold air in Iowa and near the river but could be a cement snow closer to the Chicago metro area. Going to try to make more an effort to get back on the forums, at least with this system with it looking to be a fairly impressive event for northern IL and the LOT CWA as it looks now (as Hoosier mentioned) Still a lot to be worked out but hopefully some details by tomorrow nights 0z runs with partial sampling. I like where I sit with this one, maybe favoring a little more west but nearly all 0z runs shifted south to an extent. Further west should have better ratios/more cold air earlier on to help with amounts. Good thing though is there is a nice GOM moisture feed looking at PWAT's which Euro has been most bullish with (2.0" of liquid totals across northeast IL) on the 12z run. See if it backs off that bullish juiced run shortly. The wind aspect is intriguing and impressive and given the pressure gradient on the northwest side of the surface low, it could be really nuts for awhile once the flip to snow occurs and regarding the flip, I could see it flip earlier given the nice UVV signal that is being shown (look at H7 UVV's on the 0z NAM run).

Ended up with 2.2" here from the Friday morning snow

Fairly obvious trend/uptick on 0z runs with NAM leading the way and the GFS followed to extent but GEM really impressive across northern Illinois and the RGEM is impressive at 48hrs.

Hi

Hoosier, get the winter thread going

Chased two different times yesterday being so close to home. Initially went WNW after the first storm to move NE through Kane county that was outflow dominate the entire time I was on it from about NW of Kaneville to east of Burlington. Then ended up going back home only to go back out when new storms were developing south of ARR/I-88 coming northward. Let that ARR storm continue northward to Elburn, letting that go with eyes on the two smaller storms SW of ARR/hwy 30. Positioned SW of Big Rock, a little south of hwy 30 and lapsed the organizing low topped supercell (the southern storm of the two was the one to eventually take off.) It had a lot of good rising motion and inflow feeders into the updraft region and what looked like a little meso hand off early on as a new base and eventual lowering/wall cloud developed to the NNE of where I was, more so along the forward flank almost. I finally stopped lapsing and got back in my car as the left side of the wall cloud really began to spin. Hauling back north across hwy 30 and on a few gravel roads, the area of interest was a big bowl shape wall and the entire thing was spinning. I really believe if surface temperatures were a little warmer/steeper low level lapse rates, this storm would've put down a really sizable tornado as it had the look like it wanted to (the Manhattan storm I believe had slightly warmer surface temps and had better low level structure/clear slot and that was even closer to a really nice large cone tornado.) Anyways, I eventually got back to a north/south road (Dauberman rd) and continued north as really nice funnel formed as the meso hit the boundary and stretched that thing as much as it could. I was looking NW when I took the picture below, on Dauberman rd just south of Kaneville, IL. Another chaser was quite close and had video of ground contact/swirl circulations in a field next to him to confirm that it was a brief/weak tornado. All in all a cool little day and my first tornado in my home county.

The parameter space on the NAM is still impressive, more so than previous few runs while the nest has a different solution but given its at its end range I would toss that until we get closer. The potential Tuesday is probably the best we've seen across northern Illinois this year, as we should have plenty of flow with the upper low around...but a lot of ways for things to not work out. See if that makes it to Twitter

The 18z NAM is interesting and fairly impressive from DVN-ORD on Tuesday

No talk of tomorrow? ND looks good tomorrow and eyeing srn MN myself on Wednesday

Victor Gensini and myself will be out tomorrow in probably northeast KS as it looks now. We are leaving tonight for DSM. Synoptically, it looks like a really nice setup but the CAM's aren't really having it and seem to be really struggling with storm mode/morphology. The 18z NAM came in even stronger with the mid-level streak owing to even better bulk shear values coupled with big CAPE, dew points in the upper 60's, backed surface flow and very steep mid-level lapse rates.

Victor Gensini and I have 5/14-5/25 blocked off for a trip to the plains, dependent on the pattern of course.

Victor Gensini and I are leading trip 3 with COD and we are out June 2nd-June 11th. Both optimistic as things look currently.

Departing Friday morning and probably chasing northeast/eastern NM on Saturday then some better days to follow across the plains. We'll see how the models shake out

Leaving on CoD's trip 2 next Friday.. 12z op GFS run looks like it came around to the GEFS members idea the last several runs of a good trof signal by next weekend and the week beginning 5/16 along with a good EML being able to come out with an open Gulf. We will see how things shake out but I'm fairly optimistic

Yeah the 12z Euro looks pretty nasty on Tuesday from srn KS to the Red River, dryline stays west of I-35 with 55kt flow at H5, upper 60 dews and 3,000-4,000 J/kg.