Great Lakes Ice Forecasts - Text

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Great Lakes Ice Outlook (CLEICELIO)

Issued Monday Wednesday Friday (product only valid when ice is present on the Great Lakes)

Freeze-Up/Break-Up Outlook (NWS CLE)

Typically only issued in Nov/Dec. Otherwise, below text will be blank.

    
                        
189
FZUS81 KCLE 181556
ICEGL

GREAT LAKES FREEZE-UP OUTLOOK
NATIONAL WEATHER SERVICE CLEVELAND OH
1056 AM EST Wed Dec 18 2024

...Great Lakes Ice Season for 2024-2025 Expected to Have Below
Average Ice Cover...

Periodic colder weather has cycled through the Great Lakes over the
past couple of weeks/first half of December with some relative
consistency in temperatures remaining at or below freezing across
the northern tier. While the lakes overall remain above average,
especially Lakes Huron and Michigan, the smaller bays/inlets and
some of the shoreline area water temperatures have come down into
the mid 30s, and some ice formation has occurred. It is interesting
to note that the open waters of the lakes remain on the warmer side
despite an active period of weather the past two weeks with higher
frequencies of gales during that time.

In the near term forecast, a late week Alberta Clipper system will
track down into the Great Lakes from the Canadian Prairies,
reinforcing the colder air across the Great Lakes, especially for
the upcoming weekend - December 21st/22nd. 6 to 10 and 8 to 14 day
outlooks are exhibiting strong signals for above normal temperatures
for the Great Lakes (and even much of the continental US) as we head
through next week, which should continue to delay the significant
ice formation processes through the end of the month. It appears
that it will be into the first part January before the next
potential shot of sustained Arctic air comes into play, but the
confidence for this right now remains low.

Water temperatures across the Great Lakes on the whole continue to
run above average as stated above. Outside of the aforementioned
lakeshore areas and shallower protected bays and inlets, and the
western basin of Lake Erie, 40 plus degree water temperatures in the
open waters are still holding on. Lake Superior is getting close to
the 40F mark, averaging just under 41F on the whole for the lake.
South through the St Marys River, water temperatures are near
freezing and the Straits of Mackinac are near 40F. Lakes Michigan
and Huron open waters continue to be in the mid 40s while Big/Little
Bays de Noc and Saginaw Bay are in the 30s. Green Bay is one
location with significant ice formation at the time of this
issuance, and could see some growth through the weekend with the
effects of the Alberta Clipper system pushing through the region.
Down into the St Clair River and Detroit River, low 40s are
prominent, but Lake St Clair is running slightly cooler in the upper
30s. Lake Erie is near freezing in the western basin, and in the
upper 30s to lower 40s for the central and eastern basins.

Water temperatures down to around 35F tend to set the stage for
freezing/ice formation.

Ice formation is determined by two factors: The amount of heat
stored in the water from the summer and how fast that heat can be
removed by arctic outbreaks of Polar air and high winds. Long range
outlooks do not consider the "storminess" factor which can
significantly alter the thermal structure of the lake over short
periods of time.



FREEZING DEGREE DAY ACCUMULATIONS AT SELECTED STATIONS
COMPARED TO NORMAL CALCULATED ON Tue Dec 17:

LOCATION           DATE   NORMAL CURRENT
----------------------------------------

   DULUTH,   MN  DEC   16  292  312
MARQUETTE,   MI  DEC   16  224  209
SAU_S_MAR,   MI  DEC   16  102  108
 GREENBAY,   WI  DEC   16   88  119
MILWAUKEE,   WI  DEC   16   14   49
  CHICAGO,   IL  DEC   16    7   61
 MUSKEGON,   MI  DEC   16    0   22
   ALPENA,   MI  DEC   16   51   59
  DETROIT,   MI  DEC   16    2   14
CLEVELAND,   OH  DEC   16    0    0
  BUFFALO,   NY  DEC   16    1   19



          Freezing Degree Day Accumulation Forecast

 Location   12/19   12/20   12/21   12/22   12/23   12/24

Duluth      344     372     395     427     445     453
Marquette   222     231     245     260     269     272
GreenBay    129     136     151     183     215     247
Milwaukee   55      57      67      76      80      79
Chicago     62      62      69      76      80      77
Muskegon    25      28      34      43      48      47
Alpena      67      74      89      104     114     116
Detroit     16      16      24      36      44      44
Cleveland   0       0       3       10      18      18
Buffalo      21      23      33      49      61      64


This is the last Freeze-Up Outlook, and we will be transitioning to
the Great Lakes Ice Outlook products which will be issued Monday,
Wednesday, and Friday around 5PM EST at the point when significant
ice begins to form on the lakes.

$$

Marsalek