The Clash begins next week!

[Jason McIntosh]

Well I'm sure most of you have seen the latest long range model runs for the middle and end of next week. A southwest flow is going to develop 2 storms into the middle of the country by Wednesday. The first looks nice, but the second one looks like the first monster of the year! The gulf looks like it will finally open up for business, and give you people in the south some nadoes! Unfortunately I will be shoveling, but hey it's free money from God.

I hope to hear your inputs on this upcoming weather pattern change.
And good luck chasing if it all comes together!

 

[Robert Dewey]

Maybe I don't see it, or our definition of a "monster" differs. When I think of "monster", I imagine bombogenesis, MSLP dipping below ~985MB, etc.. The storms slated for next week barely drop below 1000MB.

What I DO see is a somewhat decent shortwave, a very tight baroclinic zone, and one heck of an overrunning setup.

 

[Jordan Gerth]

Not sure I see a monster, either. Nor would I be one to trust any forecast model or interim run to bet on snow for a given location 6 to 7 days out. There are an endless number of examples.

 

[Alex Lamers]

Well howdy Jordan! Good to see you around these parts

Of some consideration though is the SPC MREF analog tests (http://www.spc.noaa.gov/exper/mref_mars/) which suggest some potential for consecutive events Wednesday through Friday from the Southern Plains/Ozarks northeast into the Mid Atlantic. Based on what they have on that site, looking at the composite of all charts...the 5% outline has reasonable skill in projecting severe weather regions in the week one timeframe.

So, I am a litle intrigued by the potential. The models generally agree on a western trough and southwest flow which is a generally favorable flow pattern for severe weather, but I'll also agree with Jordan here that to bet on a monster yet would be jumping out on an unstable limb a bit.

I will classify this event as "being watched with interest" for now.

 

[Jordan Gerth]

The GFS has been fairly consistent in ejecting a system into the Upper Midwest, but take Madison, for example, the forecast sounding profile is different every six hours.

Not to mention the ECMWF suppresses this system.

 

[Alex Lamers]

Ok, one day later, the models still eject a cyclone through the North-Central US and most bring it pretty close to Chicago. I'm getting increasing confidence that someone in my general area will see something of note in the way of snowfall. Meanwhile, SPC analogs continue to indicate possible severe weather south across S IA/WC IL/MO.

Encouraging signs are the cP airmass that will be surging into the Northern Plains and the Gulf opening up about 36-48 hours before the cyclone passes through my area. Lots of cold air and moisture leads me to believe there will be heavy snow somewhere. Pegging down the location with any skill would be pretty hard to do this far out.

Not a whole lot of consistency yet. We'll see where we are by tomorrow.

 

[Jason McIntosh]

Yeah, the SDS is getting at me a bit. I still like the potential for a good snowstorm out of this first system on Wednesday. Maybe not the "monster" i saw at first but the models are showing some consistency of a SW flow developing with ample moisture from the gulf and cold air racing in from Canada. Looks like MSP and LSE are looking to get the brunt of the first storm. We haven't had a big snowstorm in Madison in quite some time now. I hope we are gonna get buried!

 

[Robert Dewey]

I'm still waiting for the clash... Latest NAM starting to line up with the other models, and indicates an icing event with 1 to 1.25 inches of accumulation. My luck, it will end up being a very cold, rainy, nasty day. I really hope we can get SOMETHING to help the SDS out a bit.

 

[Alex Lamers]

I'm forecasting heavy snow for S WI Thursday...signfiicant enough to qualify as a winter storm and throw things into a slippery mess. Too early to tell if we will get into the "WOW" storm range (what I like to think as double digit snows or 8 inches or more with strong winds)...but it should be close in some part of the area. 00Z NAM really came around.

 

[Robert Dewey]

I'd really watch this system up in WI... GFS has 850MB temps hanging around -10C, indicating high snow ratios. In addition, I wouldn't be surprised to see a heavy snow band develop well ahead of this thing, creating a one-two punch.

Either way, GFS outputs nearly 1.15 inches across WI in air that would support ratios as high as 20 to 1.

GFS isn't so supportive of an ice storm near my area though, SFC T's too warm. Still several days for things to change though.

 

[Jason McIntosh]

The model runs are now starting to look more consistent. The clash is going to happen, except it looks like Winter will win this battle and drop the northern 1/3 of the country into the arctic circle. Damn Groundhog!
Anyhow, I am starting to think my 6 inch prediction for Madison is looking good. The way the GFS is predicting this i may have to double that.
We are due up here; it was 50 degress in January for crying out loud.
My regards to the NE U.S. with that monster Noreaster last weekend!
We'll try and even it out on Thursday so you people don't fall into the ocean.

 

[Robert Dewey]

12Z NAM is actually a hair further southeast. The SFC low passes south of my area, leaving us with a LONG ENE to NE fetch of cool dry air. Td's remain AOB freezing during the heaviest precipitation bursts.

The first burst appears to be associated with a slug of mid level WAA WED night and THU morning, with 0.50 to 0.75 inches of QPF, falling into a subfreezing SFC layer. Drizzle and freezing drizzle should persist through THU evening before the next slug of moisture comes through. After 00Z THU, we're looking at yet another 0.75 to 1.00 inch of liquid precipitation falling into a subfreezing SFC layer. The NAM solution would be quite icy, with most of central/southern lower MI experiencing at least 1.00 inch of total ice, possibly as much as 1.50 inches when all is said and done.

To top it off, winds kick up with gusts in the range of +40MPH... Not to mention the deep freeze after the event to make any ice accumulation solid...

I guess we will have to wait and see what the GFS says.

 

[Robert Dewey]

GFS did make a small wobble to the southeast, and is less wrapped up. I actually think something along the lines of the NAM is possible, or maybe in between.

With such a tight baroclinic zone (850MB 15C temp gradient in 75 miles, or roughly 0.2C per mile) - the EXACT track will be crucial for the RN/ZR/SN lines. Either way, it does look like someone in lower MI will get a severe ice storm with windy conditions following.