Snowfall graphic from Chanhassen NWS from Saturday and Saturday night.
A large swath of Minnesota missed out on the Saturday snowfall. Lakes will ice over and the ice will thicken at different rates depending on the micro-climate. Snow covered lakes/ponds are likely to be insulated somewhat in southeast Minnesota and ice may be slow to thicken despite the cold temperatures.
Before venturing out on regional lakes please check for ice thickness with the DNR. Here's a link on ice safety.
Once again the moisture deprived region of from Redwood Falls to Ortonville missed out on Saturday's precipitation.
The snow to water ratio varied from the Twin Cities to Winona. Rochester received 3.4 inches of snow with 0.34 inches of liquid. In Chanhassen, the snowfall was 3.2 inches with liquid precipitation 0.16 inches. That difference in moisture content identifies the challenge of predicting snow amounts based on expected liquid precipitation.
A cold week is in store for the Great Lakes region. I'll avoid using the term "warm-up", but a moderation is expected on the weekend.
In other weather news, more heavy rain is on tap from Indiana into Kentucky and Ohio. Louisville, Kentucky has accumulated nearly 64 inches of moisture in 2011, 22 inches above normal for the year.
Here's a snap shot of the radar from early this morning.
Take a look at Lake Minnetonka today near the Weather Lab.
You can see the ice has formed in some of the protected bays, but it's still all open water on the main lake.
Wave action and a lack of clear calm nights with temps near zero have kept the big lakes open so far this season. It's not unusual to have some open water on December 1st on the bigger metro lakes, but I can remember many years in the 70s where we were skating and playing hockey as kids exactly where the above photo was taken on Thanksgiving weekend in the '70s.
Lake ice data from the Minnesota DNR and Freshwater Society founder Dick Gray shows that ice on Minnesota lakes is freezing about a week later and breaking up in spring about a week earlier on average than it did just 30 years ago. That's two weeks of extra open water on most Minnesota lakes. It also delays the dates that "safe ice" forms on our lakes early in the winter season.
Remember, you need at least 4" of ice to be considered safe for walking or ice fishing. We're just not there yet on lakes (and ponds!) around the metro, and in most of southern Minnesota. Since ice thickness can vary from spot to spot depending on springs and currents...there really is no "safe ice" according to some experts.
Take care on developing ice for a few more weeks. Next week looks cold enough to make some more ice around southern Minnesota.
Friday Clipper? (repost from AM...no changes in forecast thinking yet)
The forecast models are advertising the potential for our next snow maker Friday and Friday night. A clipper like system will slide east from Montana/Wyoming Friday, and will likely spread a shield of snow east as warm air tries to overrun our cold dome near the surface. It looks like all snow with this one...no pesky rain/snow line to deal with.
This colder system should feature a drier more powdery snow. The snow:water ratio could be 15:1 with this system...meaning it will take less water to pile up a few inches.
The forecast models are cranking out the potential for about .30" to .50" of liquid equivalent or so somewhere in southern Minnesota by Saturday morning. You can do the math to see that could be a "plowable" snow event. Somebody in southern Minnesota could see the potential for 3" to 6" with this system...but it's too early to say where (or if?) that may happen.
The forecast tracks of clippers are notoriously fickle, and precip amounts otften too high in early model runs. I'll have to see a few more model runs to see if the system tracks further south. The models have a tendency to steer these systems south over time. If it does...that could spell the difference between placing the heavier snow band in the metro...or along the I-90 corridor in southern Minnesota.
The "meteorologically responsible" thing to do at this point is to alert for the possibility of snow...and leave the "inches" forecast until a few more model runs (hopefully) agree on the storm track and precip output.
Stay tuned, but be prepared for the possibility of slick travel and "shovelable" snow Friday PM (& PM rush hour!) into Saturday morning.