Forecast models still on track for hefty snowfall totals and high winds

Phase 1 of our winter storm is the easy part.

Light snow continues across most of the southern half of Minnesota as of late Tuesday evening. So far this “easier” first wave of the storm is going about as expected. Snowfall totals range from around 1 to 3 inches as of early Tuesday evening.

Most forecast models continue the trend of mainly lighter snow overnight. NOAA’s NAM 3 km model shows the likely snowfall trends between 9 p.m. and 6 a.m Wednesday.

Rush hour lull

Many of us will likely catch a lull in snowfall Wednesday from morning rush hours into the midday hours.

But the storm won’t be over. The far more intense second wave will arrive with heavy snow and high winds Wednesday afternoon through Thursday morning.

Wave #2: Still on track

Tuesday night’s late (0Z) forecast model runs continue to show a powerful second storm wave. Most models forecast snow to spread north once again into southern Minnesota Wednesday morning, then increase into central Minnesota including the Twin Cities area Wednesday afternoon. The peak snowfall rates and wind intensity are still likely to occur Wednesday night through Thursday morning.

NOAA’s NAM 3 km model shows the main low-pressure wave driving an expanding snow shield across most of Minnesota between noon Wednesday and 6 p.m. Thursday.

The long duration of snow with the second storm wave and embedded intense snow bands will produce copious snowfall totals.

Forecast models coming in late Tuesday evening are still cranking out an additional 15 to 20 inches of snow across most of southern Minnesota through 6 pm Thursday.

Here’s the Canadian model snowfall output.

Here’s the American GFS model.

Here’s NOAA’s HRRR model snowfall output.

Blizzard and winter storm warnings remain in effect for most of central and southern Minnesota.

URGENT - WINTER WEATHER MESSAGE National Weather Service Twin Cities/Chanhassen MN 848 PM CST Tue Feb 21 2023

...HISTORIC WINTER STORM SHOULD LEAD TO IMPOSSIBLE TRAVEL BY WEDNESDAY NIGHT AND EARLY THURSDAY...

.Two primary rounds of snow are expected. The first will continue through tonight. Accumulations of 4 to 8 inches by Wednesday morning.

Round two is more widespread and continuous, and will begin Wednesday afternoon and continue into Thursday with an additional 8 to 18 inches expected. Total snow accumulations will range from 14 to 24 inches, with the best chance for the higher end totals along a west to east axis from southwest Minnesota through east central Minnesota and into west central Wisconsin.

This is expected to reach the top 5 heaviest snow storms for many locations.

The worst conditions will be Wednesday afternoon through Thursday morning, and a Blizzard Warning is in effect for areas south of I-94 and west of I-35. Heavy snow will combine with northeast wind gusts of 35 mph across the region, to around 45 mph in western and southern Minnesota. This will lead to significant blowing and drifting snow with whiteout conditions in open areas. Some drifts may be several feet deep, making travel nearly impossible.

Don’t be fooled by the easier first part of this storm, and by the lull in snowfall Wednesday morning into the midday hours. The worst part of the storm will crank up Wednesday afternoon through Thursday morning.

Stay tuned.