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Saint Lawrence Freeze Up Date Outlook

National Weather Service Buffalo NY

241 PM EST Tue Jan 2 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 8, 2024.



WATER TEMPERATURES...



Water temperatures were running near average through the first few

weeks of December, but then fell very little during the second

half of the month. This leaves water temperatures well above 

average to start January.



Water Temperatures January 2nd:



Alexandria Bay, NY   41F (normal 37F) 



LAKE ONTARIO OUTFLOW...



The outflow from Lake Ontario has averaged about 261,000 CFS through 

the last week of December, which is above the long term average. 

Above average outflow from Lake Ontario is expected to continue 

through the early portion of January.



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 through the month of November averaged slightly below

normal. Temperatures had a much more typical range through the 

month than the big temperature swings of October, with just a few 

brief periods of well above or well below normal temperatures.



Temperatures through the month of December have been well above

normal, with the greatest positive departures from normal coming

during the last 8 days of the month. December 2023 ranked as the

2nd warmest December on record at Watertown.  



December Average Air Temperatures through December 31st: 



Watertown, NY   36.5F (9.2F above normal) 

Massena, NY     30.9F (7.1F above normal)



FORECAST FOR JANUARY...



Air temperatures are forecast to be above normal most days through

the first week to 10 days of January, although departures from 

normal will be much smaller than in December. A trend towards

more consistent winter cold is expected by mid January, although

temperatures may still run slightly above average. 



A moderate to strong El Nino pattern will continue through the 

winter, which favors increased odds of above normal temperatures 

for the winter on a whole in the eastern Great Lakes and Saint 

Lawrence Valley as we continue through the winter months.



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 8, 2024. 

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.



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HITCHCOCK