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Saint Lawrence Freeze Up Date Outlook
National Weather Service Buffalo NY
945 AM EST Sun Nov 3 2024

...FREEZE-UP DATE OUTLOOK FOR THE SAINT LAWRENCE RIVER...

The date of the first freeze-up on the Saint Lawrence River near
Massena, NY is forecast to be January 5, 2025.

WATER TEMPERATURES...

Water temperatures have been running well above average across the
eastern basin of Lake Ontario and the Saint Lawrence River through
most of the fall. The water temperature across the Thousand Islands
region is 3 to 5 degrees above average for early November.

Water Temperatures November 3rd:

Alexandria Bay, NY   57F (normal 53F)

LAKE ONTARIO OUTFLOW...

The outflow from Lake Ontario has averaged just under 250,000 CFS
through the last week of October and first few days of November,
which is slightly above the long term average for this time of year.
Slightly above average outflow from Lake Ontario is expected to
continue through the month of November.

Above average outflow from Lake Ontario results in faster current in
the Saint Lawrence River, which can delay the onset of shore to
shore ice.

AIR TEMPERATURES...

Temperatures have been mild and above average on the whole through
the fall so far. September through the first few days of October
were consistently above average most of the time, resulting in much
warmer than normal water temperatures heading into mid fall.

October was more of a mixed bag, with an extended period of
temperatures near to below average during the second and third week
of the month. This trend turned around for the last 10 days of the
month, with several stretches of well above average temperatures,
including record warmth on the last two days of the month.

October Average Air Temperatures through October 31st:

Watertown, NY   50.1F (1.3F above normal)
Massena, NY     49.1F (1.6F above normal)

FORECAST FOR NOVEMBER...

There is moderate to high confidence that above normal temperatures
will continue for most, if not all of November. The persistent above
normal air temperatures will continue to support above normal water
temperatures leading into late fall and early winter.

A weak La Nina pattern is expected this winter. This pattern may
allow for other, more difficult to predict circulations to have more
influence on the winter pattern across central and eastern North
America. Overall, trends favor a continuation of above normal
temperatures into December, then colder and more typical
temperatures for January and February in the eastern Great Lakes and
Saint Lawrence Valley.

Given the above factors, and the overall trend in later onset of
ice cover over the past 15 years, the first freeze-up on the Saint
Lawrence River near Massena, NY is forecast to be January 5, 2025.
This date is around two weeks later than the long term average.

NOTE: Once the water temperature drops to the mid 30s, ice cover can
develop in just one very cold, calm night.

NOTE: This forecast is for the first shore to shore freeze-up of the
Saint Lawrence River near Massena, NY. The first permanent shore to
shore ice often occurs several weeks later.

$$

Hitchcock