Dalfy

I've been in 20-25dbz returns for the last hour or so, I'll take a short walk to get sense of depth. Visibility slightly under a mile I want to say. Temp is 17.

First flakes just starting to fall in the STL metro area. It's incredible to see the precip shield of the two waves on one map, there's rain and snow falling from the US-mex border all the way to maine.

Radar looks so juicy

Second wave at LSX's doorstep, hoping for 4-8''to pad the 2'' from this morning.

We're officially all snow, at 12z, ~4-8 hours earlier than short term guidance forecasted [RGEM, RAP, HRRR] up until 1 or 2 last night. I'm really looking forward to the afd as they also went with short term in suggesting changeover would occur sometime in mid morning through early afternoon.

Here's a webcam from near forest park in St. Louis for those interested: https://fox2now.com/webcams/chess-club-hall-of-fame-in-the-central-west-end/

Wow, I looked outside and it's currently sleet/snow with trace accumulation on grass. Temp is 31.

30 with snow/rain mix in STL

Don't take my word for it but I think it'll be in the next 2-3 hours max. Current wetbulb temps; check the time trend on spc:

Maples' rough estimate of changeover- Jefferson, MO and metro. 1-4am sounds right and earlier than Canadian guidance by 10-12 critical hours. I don't think I'll be able to sleep monitoring this haha: .AVIATION... (For the 06z TAFs through 06z Wednesday Night) Issued at 1040 PM CST Tue Feb 1 2022 A high impact winter storm is imminent with a broad area of precipitation stretching from central Illinois southwestward through a large portion Missouri. Rain transitioned to all snow at KUIN around 02z this evening with the transition affecting KCOU between 03z and 04z. Following shortly behind will be KJEF around the release of this update. Metro terminals will likely follow between 07z and 10z.

For those in LSX: 000 FXUS63 KLSX 020254 AFDLSX Area Forecast Discussion...Updated National Weather Service Saint Louis MO 854 PM CST Tue Feb 1 2022 .UPDATE... Issued at 830 PM CST Tue Feb 1 2022 A broad area of precipitation stretches from interior sections of central Illinois to southwest Missouri this evening. Coverage and arrival time of the precipitation is in good agreement with expectations so far. Automated surface observations show sub-freezing air making progress into portions of northeast Missouri and west-central Illinois. Rain transitioned to a brief period of freezing rain/sleet around Quincy before changing to all snow around the 02z hour. Reports of all snow in Hannibal also provide ground truth to the advancing cold air. What has been evident over the last 3-4 hours is that the cold air has run about 20-25 miles further southeast than hourly forecast trends previously depicted. Updates have been made to reflect this trend with the potential that FZRA/PL could be 1-2 hours ahead of schedule, should this trend win out. The only question remains the warm nose aloft and how long it holds/erodes tonight into the morning period. This trend will need to be monitored through the night, as any deviation will have the greatest impact on accumulations near the transition zone (southeast MO/southwest IL). Maples && Current rain snow line:

16'' downtown STL lol, crazy.

It seems MBY continues to be at a real battleground with respect to warm layer. 18z RGEM and 12z GGEM maintain warm layer aloft well into Thursday which keeps us mixed for most of the event; NAM, EURO, GFS have trended toward warm layer cooling by late Wednesday night/00z Thursday which keeps us snow for precip thrust from the main low which is resulting in these boosted forecast totals. I'm liking my chances especially given the new 00z guidance, we'll see how RGEM and GGEM trend tonight. EDIT: RGEM came in slightly cooler, with changeover around 6z Thursday.

ILX is going to get shellacked. It seems like track is relatively consistent, I'm just hoping the warm nose erodes fast enough for us in St. Louis.

This includes sleet correct? Going by sim radar St. Louis doesn't changeover to snow until ~hr 87. QPF after is ~.4. 9.7'' seems high.

<6'' STL for both events. I'm hoping GHDIII puts an end to the northern monopoly. STL-DTW axis lets go #1982

It's a small user base but we do post here.

3'' of largely sleet on that run for St. Louis, reminds me of V. day 2007 when I was back in the DC burbs.

Please don't post porn in this thread.

100% correct. Bring on the southern track baby.

Fantastic written guide by the NWS https://www.weather.gov/jetstream/matrix

Ending with a very slushy 1.5-2'' imby, eyeballed. Totals from the forecasting area through 7am: MISSOURI 4 Springfield WFO/ASOS / 0. Kirksville 7.0 Princeton 6.5 Spickard 6.0 Trenton 4.2 Steffenville 4.1 Shelbina 4.1 Mexico 4.0 Hannibal 4.0 Green City 4.0 Chillicothe 4.0 Waverly 3.5 Saverton LD 22 TW 3.0 Salisbury 3.0 Marshall 3.0 Canton LD 20 TW 3.0 U of M Columbia 2.5 Lockwood 2.0 Freedom 2.0 Carrollton 2.0 Rosebud 1.7 St Peters 1.6 St Louis ASOS 1.5 Ash Grove 1.5 Richmond 1.2 Morrisville 1.0 Jefferson City 1.0 Harvester I 1.0 De Soto 1.0 Concordia 1.0 Clarksville 24 TW 1.0 Bowling Green 1E 1.0 St Charles 7SSW 0.7 Columbia ASOS 0.7 Chesterfield 0.7 Sweet Springs 0.6 NWS WFO 0.6 Cap Au Gris LD 25 0.2 West Plains 0.0 Iberia 0.0 CENTRAL AND SOUTHERN ILLINOIS Gladstone 5.0 Canton 4.0 Prairie City 3.5 Jerseyville 2SW 3.5 Galesburg 3.5 White Hall 1E 3.2 Avon 3.0 Jacksonville 1.7 Quincy L & D 21 1.5 Morton 1.5 Normal 1.0 Ramsey 0.7 Taylorville 0.6 Tuscola 0.5 Roanoke 0.5 Pana 0.5 Ogden 0.4 Buffalo 0.4 Windsor 0.3 Casey 0.3 Urbana 0.2 Steelville 0.0 Olney 0.0 Alton LD 26 TW 0.0

Transitioned over to snow maybe 30 minutes ago, temp 33.

I think we may be in for a surprise. Mid 30s on ground in St. Louis and current sounding is suggestive of snow, which would imply the entire event is snow, a much colder scenario than modeled. QPF for short range guidance HRRR and RAP is around 0.5. Assuming sub 10:1 rates, the 3-5'' call seems like it would be accurate with amounts on the higher end of the range. I hope I'm interpreting this right.

LSX AFD mentioned they expect a changeover around 02-04z [8-10pm] in St. Louis, which seems a few hours earlier than most guidance. They're basing it on some AMDAR soundings out of lambert that showed a weak warm layer extending to 850mb [<1C], which they feel will be rapidly washed away as heavy precip pulls cold air down. They're sticking with 3-5'' call, which is very bullish to me. I'm hoping they're right, we'll see how it plays out