US and Great Lakes Snowfall Recap Thus Far

Snowfall across northern Ohio started out impressive in late November. More than 60"+ inches of snow fell in parts of the snowbelt. The most in parts of eastern Lake and the northern 2/3rds of Ashtabula county since the record setting lake effect event in November of 1996.

Photo: NWS Cleveland

Snow across northern Ohio and the Great Lakes started out with a bang in November and December. Here are some great images from Meteorologist Ben Noll showing snowfall vs normal by November 22 around the Great Lakes and nationally.

Snowfall vs Normal through November 22

After the big snow at the end of the month, snowfall recovered fast. Blue and Purple areas indicated WELL ABOVE seasonal snow.

Nationally through December 10:

Here is the snowfall vs normal map through December 18th:

Now snowfall vs normal through January 1st.  Notice how the departures began to drop around the Great Lakes snowbelt areas. Below normal snowfall the latter half of December.  The November snow kept the overall seasonal totals above normal.

National snowfall numbers also started to drop.

The snowfall decline accelerated in January. The snowbelts still had spots with seasonal snow above normal driven by the late November snows. Snowfall was well below normal since January. Much of the interior regions were running well below normal snowfall by early February.

The middle of the US, upper mid-west and most of the Ohio Valley was well below normal by early February.

By March 1st, the seasonal snow across the Great Lakes was almost back to normal. Snowbelt of northern Ohio, PA and western New York only slightly above due to the late November snowfall.

Seasonal snowfall across the US east of the Rocky Mountains through March 1 is characterized like this:

• Well below normal snowfall in the central US, upper mid-west, Ohio Valley including Pennsylvania, New Jersey and parts of New England.

• Slightly above normal snowfall in the Great Lakes snowbelts due to early season snow. Below normal snowfall since January 1st.

• Above normal snowfall in the south from southern Missouri, Arkansas, Kentucky and Tennessee.

• Above normal snowfall along the gulf coast due to the late January record snowfall:

Ohio and Pennsylvania snow depth animation from November 20 through March 3:

My next post will dive into northern Ohio snowfall further comparing this year to years similar

Lake Erie Ice Cover History UPDATE (1972-Present)

Click to enlarge each image to show the daily ice coverage for NOVEMBER, DECEMBER, JANUARY AND FEBRUARY (THROUGH FEB 4, 2025) each month dating back to 1972

Sure, January Is Supposed To Be Cold. Why Is This Year Different?

When I derive long range outlooks especially in winter, the responses are usually something like "January is Supposed to be cold. What's the big deal?".  The cold this month is much different.  Usually we don't get into serious, longer stretches of cold until the third week of the month. Historically, the cold to starts to January typically are accompanied with small breaks with temperatures in the 40s. 

Here are the high temperatures for each day through the 15th over the last 20 years in January.

Almost every year had some break from colder periods. The last cold period to start the year was in 2018. That only lasted 6 days.  The longest "colder" period was in 2010 and 2011.  Even in those years we had a few days above 40 degrees. It's looking like we won't have a day above 35 degrees until after January 15th!

Overall High Temperature Forecast for Cleveland, Ohio Through January 18th

Back on December 7th, the signals were strongly pointing to long stretches of cold to arrive around the 1st of the year. Notice the cold air draining south from the Arctic Circle with no breaks across the eastern half of the US.

Again, this cold has staying power. The pattern across the continent is locked in through the middle of the month. Here is a look at the number of days below normal for the first half of January over the last 25 years. The years on the right side are 13 of the top 25 coldest January years on record for comparison. I also differentiated between the number of days below normal and the number of days 10 degrees, 20 degrees and 30 degrees below normal.

A few things to note: 

* The last time we had a first half of January with more days below than above normal was 2018

* The period between 2009 and 2018 featured more days below normal than 2018 through 2024

* Only three years had EVERY DAY below normal between January 1 and January 15th:

                                                        1981, 1977, 1970

* We average about 5 days below normal in the first half of January over the last 10 years

What about the second half of January?

Below normal days in the second half are more numerous since 2018 versus the first half of the month. Extreme cold days are also more frequent even in the historically cold years in the 1970s and 1980s

How Often Do Conditions Develop To Produce Lake Effect Snow?

One of the many variables to produce lake effect snow is a significant enough difference between the water temperature and the temperature 5000 feet off the ground. Typically you need a difference of at least 13 degrees Celsius. So if the water temperatures is say 50 degrees F (10 Celsius) and the air temperature at 5000 feet is 27 degrees (-3 Celsius) that would be the lowest difference to allow evaporation and eventually the condensation of water vapor to occur as the colder air moves over the warmer lake.  The greater the difference, the faster the air rises and the more unstable the lake effect snow becomes.

This satellite image shows the uniform bands of lake effect cloud cover off every Great Lakes with a strong northwest wind. Notice the lack of cloud cover on the windward (western) side of each lake. The condensation of the water vapor occurs more than 20 miles offshore as the warm water vapor rises into the colder air aloft. 

How often does a difference of 13 degrees Celsius occur in northern Ohio in the prime lake effect snow time of the year?

I cross referenced the Lake Erie water temperature and the temperature at 5000 feet for five straight winters (Nov 2014 through January 2019). Each instance where the difference meets of exceeds 13 degrees Celsius I shaded that day in blue.

We average about four instances where the Lake Erie/5000 foot temperature difference exceeded 13 degrees (high enough for lake effect snow) each winter between 2014 and 2019.  How many of these produced significant snow?  More on that later.

What Happened to the "Warm" Lake Erie?

It was only a little over 3 weeks ago (November 18) when Lake Erie was the warmest ever at this point in November. Satellite water temperatures go back to the mid 1990s. This was undoubtedly in response to the very warm early November.

The warmth started in October across the central US and Great Lakes.

When you look at just the first 3 weeks of November the warmest expanded and intensified.

November 14 through the 19th warmth continued to move into the Midwest.

Once we moved past Thanksgiving, the overall pattern became dominantly colder across areas that were breaking record high temperatures. Here is the progression of the cold from central Canada starting in late November. Each image is a 10 day period. First image starts November 19th.

The first half of December has been below normal overall across much of the Great Lakes even after the core of the cold retreated back north.

The graph below illustrates the Lake Erie water temperature each year (1995 through 2024) starting on November 28 and ending December 17. Notice how this year was the warmest 3 weeks ago. Look how the Lake Erie water temperatures responded to the below normal temperatures. Compared to the last 30 years, the water temperature now is near average. A huge drop of roughly 10 degrees in almost 3 weeks!

Given the 2-3 day period of cold this weekend then the warmer pattern between Christmas and New Years, the water temperature drop will probably slow.  Look at the new Canadian long range model output for early January. Ridge development near Greenland, Gulf of Alaska/Aleutian island low shifts west. Ridge/warmth over the central US shifts west. Trough/cold settles into the Great Lakes/eastern US the first week of January. (This setup was highlighted on the the FOX 8 Morning Newscast December 9). If this verifies, Lake Erie water temperature will continue to drop. Good bet we will have some ice coverage by the second week of January.

First San Francisco Tornado Warning Ever!

Tornadoes in California are a rarity but not unprecedented. 

 Here is the short list of tornado warnings issued by the NWS office in San Francisco since 1989:

Composite map showing all 9 tornado warnings since 1986.

Each tornado warning and the radar composite for each event:

December 14, 2024

The warning went out before 6am Saturday and ended at 6:15am. Damage assessments from the NWS said the tornado had peak winds of 90 mph

A team from the National Weather Service San Francisco Bay Area conducted a storm survey in Scotts Valley. The team identified a swath of tornadic damage that began near the intersection of Mount Hermon Rd and Lockewood Ln and continued southeast along Mount Hermon Rd until just short of Kings Village Rd. A wide range of damage was observed including: downed trees, downed power poles, trees stripped of branches, numerous overturned vehicles, and damaged street signs. Based on these damage indicators the survey team assessed a maximum wind speed of 90 mph, which is a weak EF1 tornado.

March 2, 2024

March 18, 2011

January 20, 2010

January 23, 2010

September 18, 1989