The Great Lakes, as you may  know, are very big: hundreds of miles long, tens of miles wide, and hundreds of feet deep, so it’s not likely they’ll all entirely freeze over for any significant amount of time, although it is, on rare occasion, possible that they’ll mostly freeze over, like during the very cold winters of 1976-1977, 1977-1978, and 1978-1979.  Most years, though, most locales on the lakes don’t get a break and get inundated with lake snow all winter long.

In several areas, though: far western New York, northwestern Pennsylvania, and northern Ohio, folks do get a break!  During the coldest months of the winter; it’s typical during many winters, the shallowest of all the lakes, Lake Erie, will nearly entirely freeze over and this nearly closes down the heavy snow machine along its shoreline.

February 8, 2011 Lake Erie Ice Cover, Image: NOAA

In the latest February image of Lake Erie taken via satellite above, you can see  there’s lots of white over the lake.  That’s actually a sheet of ice.  The darker black area, in fact, is the area of the lake that has been left uncovered and unfrozen. By far, there’s more ice than water.   Therefore, it’s tough to get much more than lake-effect flurries going.  Earlier in the season, though, before it really gets cold, it’s a totally different story.

January 11, 2011 Lake Erie Ice Cover, Image: NOAA

In the satellite photo above, you can see just a month ago, before the long duration of cold… the lake is wide open with plenty of water and water vapor to work with!  This is the season where we see the blizzards along the lake shore.

To check out the forecast in places affected by the lake  freeze-over lull, take a look at Cleveland and Buffalo.

On a side note, take a look at the imagery again and focus on the upper right.  That’s Lake Ontario.  It’s over 10 times deeper than Lake Erie.  You can see, between both photos, there’s not much change in the amount of white on the lake.  Lake Ontario, since its much deeper and contains a larger volume of water, has a much harder time cooling off and, therefore, has a much harder time freezing.  In places like Rochester and Watertown, New York, there’s nary a respite from the lake snow onslaught.

Lake Effect Snow Event, Image: NOAA

The National Weather Service is predicting heavy snow from Upstate New York to Ohio as a cold artic airmass continues to descend across the country.

See my previous post on lake effect snow.

A quiet weather pattern will remain in place across portions of the Central Plains and Mid-Atlantic region until Saturday.

Expect heavy rain along the Gulf Coast this Friday into Saturday.

Along the West Coast, another storm system will be a rain event for the Bay Area and Los Angeles, a snow event for the Sierra.

-Dawn Brown

Southeast US Radar, Image: NOAA (Image is OLD!)

Click for the latest radar image.

Thunderstorms are delaying travel in the Miami-Ft. Lauderdale area this Wednesday morning. The FAA’s website has all the latest travel delays across the country. Check it before you go to the airport. If the sphere on the map is green where you are flying, you are good to go. If not, click on the yellow or orange sphere, and it will tell you the amount of the delay and the reason for it.

Currently, there are also weather delays in New York, New Jersey, Philadelphia and D.C..

No delays in the Midwest so far, but with an arctic air mass advancing toward the Great Lakes region over the next two days, minor accumulations of lake effect snow are a possibility.

The previous link shows you another awesome graphic from USA Today explaining lake effect snow.

Lake Effect Snow Explainer, Image: NOAA

As you can see, it takes a delicate combination of cold air near the surface, a cold, straight wind blowing across a warmer body of water, and some high ground on the leeward side of the lake for lake effect snow to occur.

Forecasters in northern Michigan, and parts of Illinois, Ohio, Pennsylvania and New York will be in for some interesting weather this holiday weekend. Go to the GET YOUR LOCAL TV FORECAST! link on the right hand menu bar, find the city your in, or where you are traveling, and follow their forecast.

I hope you and your family have a Happy Thanksgiving.

-Dawn Brown