Hoosier

Here it is for anyone too lazy to go read it .AVIATION... For the 18Z TAFs... Numerous aviation weather concerns during the upcoming TAF period including: * Strong and gusty SSW winds this afternoon but easing a bit with time * Expanding -SHRA this afternoon and evening, IFR vsbys expected this evening * FROPA with a north to northeast wind shift late this evening * Rain transitioning to a brief wintry mix and eventually all snow tonight and Thursday morning. Developing potential INVOF the Chicago-area sites for a brief burst of heavier snow roughly 9-13z. * Notable break in precipitation chances Thursday morning with the next round of snow developing through the afternoon. IFR/LIFR vsbys anticipated. Gusty south-southwesterly winds generally from a 210 to 220 direction will continue this afternoon but will be gradually easing with time. Showers will expand in coverage through the late afternoon hours and will become widespread this evening. Vsbys will likely drop into IFR for a time this evening. Colder air will push into the region in the wake a cold front which will bring a north and north-northeast wind shift to the terminals after 03-04z or so. Profiles will begin to support a wintry mix at RFD first as early as about 04-05z, and then into the Chicago-area sites a few hours later. It appears the window for FZRA and PL may be fairly brief, and have continued to reflect these within quick TEMPO groups. Snow is expected to become the dominant p-type after about 07z at RFD, and 09/10z at the Chicago-area terminals. There is a developing signal in model guidance that could support a brief period of heavy snowfall, mainly INVOF DPA, ORD, and MDW very early Thursday morning. Confidence was not high enough to TEMPO LIFR vsbys at this time, but did coordinate a PROB30 mention for 3/4SM snow between 9 and 13z to account for this potential. Thereafter, snow is expected to gradually push south and east of the terminals, likely ending entirely through mid-morning at all sites (perhaps lightly snowing through the morning at GYY). The next system pushes in rapidly through Thursday afternoon. There is still some uncertainty regarding the northwestern terminus of the heavier snow potential with this next system, but confidence was high enough to prevail IFR and LIFR vsbys at ORD and MDW, respectively. TEMPOs have been added to highlight a window supporting heavy snowfall rates in excess of 1 inch per hour. Vsbys to 1/4 sm on a temporary basis are possible. While snow to liquid ratios will start on the wetter side near 10:1 as snow starts late Thursday morning/early afternoon, these are expected to increase to above 15:1 through Thursday afternoon. Combined with strong gusty north winds (gusting potentially above 30 kts), BLSN appears probable and a mention has been added to the 18z TAFs. Carlaw

The new LOT aviation disco addresses the potential burst of snow tomorrow morning.

Higher I actually feel fairly confident in pulling 6" here, especially with a little contribution from the lake. And I don't really care much about what the 12z Euro comes in with haha. How much over 6", I don't know.

Once again, problems already show up earlier on in the run with unrealistic totals in N IL by early tomorrow morning.

Really think LOT needs to expand the flood watch into our area. If anything there's better qpf progged here tonight than in the current flood watch area.

This is getting a little ridiculous now. Main part of storm only a day and a half away.

00z Euro is a little underwhelming.

Appreciate the post, RC.

A lot of turds, a lot of spread, or both to have numbers that low.

Pulled this NAM forecast sounding for northwest Indiana on Thursday afternoon. This is some pretty impressive stuff. The pink bars on the left are omega, and there is a lot extending through a deep portion of the atmosphere. Also note a layer of steeper lapse rates aloft. All this in the presence of pwats in excess of 0.7", which is excellent for a snow system. All of this should add up to the potential for a period of 1-2" per hour snowfall rates, if not briefly/locally a tad higher in heaviest banding.

Obviously how quickly it changes over remains to be seen, but even putting 1-3" in the bank would be a nice little start given the uncertainty after that.

Those weird initial fake snows are showing up on various guidance.

Actually retains good totals in Chi metro though.

Really nails the city with the rain tomorrow into early Thursday.

Updated WSW from LOT mentioned an axis of higher totals possible.

Some of this model output is almost hard to believe. About an inch of rain and a little ice/sleet followed by a foot+ of snow and arguably a blizzard on both NAMs and the HRRR around here. But still have many models/runs left to go.

This will come off as an imby weenie post, but think some of the worst conditions could be somewhere nearby where there is an overlap between the higher snow amounts and some enhanced gustiness downwind of Lake Michigan.

Even got the B word thrown out as one scenario. One thing I'm wondering about is how they mention it being wet snow. I wonder how wet it will actually be. The relative warmth aloft will hurt ratios but I would think it would make it more of a dense snow but not necessarily wet. A denser type of snow should still be capable of blowing around quite a bit given the expected winds.

LOT got the storm part of the afd out. Worth a read.

Got the link?

That run is unrealistic even early on in the storm. It already has several inches around Chicago by 12z Thursday.

I'm actually surprised that 10 minutes went by after my post about the RAP.

There's our more amped RAP run.

Still gotta think we will eventually get a north bump from the Euro, even if it's 25-50 miles. I refuse to believe that the NAM/GFS could have blown THAT badly

Clicking around on various WSW texts, it's basically 3-7" or 4-6" in the main band. Hopefully these numbers are playing it conservative due to the uncertainty in placement and will bump up in time. Would be a shame if that's all this managed to be.