mimillman

Loving the ensemble look.

Clearly going to be a monster for someone and would say most of this forum is still in play with the exception of the OV crew (sorry)

Issued at 221 PM CST Sun Dec 18 2022 Tuesday through Sunday... All eyes in the long term period are on the late week cyclone and intrusion of bitterly cold air along with dangerous wind chills late this week into the weekend. Confidence continues to steadily increase that a potentially crippling blizzard could impact portions of the region later this week, the timing of which couldn`t be worse for holiday travel. If, and how severely, our forecast area (CWA) will be impacted depend on the exact track of the cyclone and to some extent the magnitude and timing of the forecast rapid deepening. Medium range guidance has been advertising a powerful cyclone spinning up over the Great Lakes or northeast U.S. for days now, with a pretty sizable spread in where the storm will develop/track. There was a cluster of guidance favoring a Great Lakes target region, which would increase chances for major impacts in our CWA, with a second cluster favoring the New England resulting in disruptive, but far less extreme winter weather locally. Trend in ensemble guidance over the past 48 hours has been decidedly away from a New England cyclone and toward cyclogenesis farther west over the Great Lakes with recent runs of the GFS/GEFS making the significant shift west. While track guidance has shown (pretty typical) variability, the theme of rapid, and potentially explosive, deepening of the cyclone has been a fairly consistent theme in guidance for days now. The expected intensity of the cyclone combined with the very strong arctic high (>1040mb) over the northern and central Plains leads to high confidence in a noteworthy high wind event with this system. The eventual track of the cyclone and timing of rapid/explosive deepening will determine where the very high impact winter weather/potential blizzard will set up. Given recent model and ensemble trends, our CWA lies very solidly within the potential threat region. The incipient wave that is forecast to spawn this system is still located north of Alaska across the Beaufort Sea, so it still has a lot of distance to cover with plenty of time for shifts in guidance. It isn`t uncommon for models to make leftward adjustments to the track of powerful cyclones like this, so it is important not to get locked in on a forecast track yet. At this distance, it is also advisable not to focus on individual operational runs of models, as operational runs will likely exhibit variability in the strength and especially track over the next couple or days. This run to run variability in operational runs is often not an actual "trend" but rather "noise" in the range of possibilities at this distance. Rather than focusing on noise level changes in operational runs, focusing on trends in ensemble data the next couple of days should prove more meaningful as we look to hone in on location and magnitude of the threat. In addition to producing blizzard conditions, the high winds will likely cause lakeshore flooding (which shore depends on track of cyclone) and dangerous wind chills well below zero. Currently, most guidance strongly supports advisory level wind chills (-20 to -30F) Friday into at least the first half of the Christmas weekend, with some potential for even a period of warning level (colder than -30F) wind chills as actual air temperatures plummet below zero. All indications are that our high temp Christmas Day will be the coldest since the mid 90s and possibly one of the top five coldest on record. Any power outages resulting from the strong winds greatly increase potential danger of the cold spell. We strongly urge everyone to pay close attention to later forecasts, particularly if you have holiday travel planned. - Izzi

Just wish wasn’t 100 hours away, but it’s a strong signal for somewhere in the region nonetheless.

Cautiously optimistic but cognizant there’s still 72 hours to go before this is better defined.

Pretty big difference between neighborhoods and downtown on my way to work this AM. Downtown is rain/snow mix, Wicker Park was all snow beginning to accumulate on side roads.

LOT radar is filling in not dissimilar to what the euro has been advertising

Trip to the UP in 10 days looking golden

Seems fair

Real deal

Can confirm…death band

Yea I see that…

I’m at ORD. Flight boards in 10. Wish me luck

It was ok around here

I haven’t been as invested in this one because of travel plans etc, but yea, GFS was garbage. First epic failure of the season for that model, it was bound to happen

Would you believe it if I said orientation change? (Actually)

RAP or bust.

Thursday night flight trending towards a Friday morning panic lift

I would be selling significant ice accretion at advertised precipitation rates especially if temps the day before approach 50 and the ground is wet from heavy rain.

Flight to Mexico at 6pm on Thursday. Damn

Tragic

Can’t wait for the RAP to verify again

Rainer