014
FZUS81 KCLE 041825
ICEGL
GREAT LAKES FREEZE-UP OUTLOOK
NATIONAL WEATHER SERVICE CLEVELAND OH
126 PM EST THU DEC 4 2025
...GREAT LAKES ICE SEASON FOR 2025-2026 EXPECTED TO BE NEAR AVERAGE
ICE COVER...
FOR THIS ISSUANCE, WE WILL KEEP THE OUTLOOK AT NEAR AVERAGE FOR THE
SEASONAL ICE COVERAGE DESPITE THE RECENT COLD SNAP ACROSS ALL OF THE
GREAT LAKES.
OVER THE PAST COUPLE OF WEEKS, THE LONGWAVE PATTERN HAS SET UP SO
THAT COLDER AIRMASSES ARE EASILY AND FREQUENTLY DROPPING INTO THE
GREAT LAKES REGION WITH COLDER THAN NORMAL CONDITIONS AREA WIDE. IT
HAS ALSO BEEN CHARACTERISTIC OF INTENSE LOW PRESSURE SYSTEMS WITH
FREQUENT GALES FOR ALL OF THE GREAT LAKES, AND EVEN STORM CONDITIONS
AT TIMES FOR SOME OF THE LAKES AS WELL. DURING THESE EVENTS, SURFACE
WATER TEMPERATURES HAVE RESPONDED ACCORDINGLY TO THE MORE
ACTIVE/COLDER WEATHER AND WINDS IN TERMS OF HEAT REMOVAL, AND WE
WILL SEE THIS CONTINUE TONIGHT INTO DECEMBER 5TH IN THE WAKE OF AN
ARCTIC COLD FRONT AND ANOTHER REINFORCEMENT OF VERY COLD AIR. AS A
RESULT, EFFICIENT TEMPERATURE DROPS OVER ALL OF THE LAKE WATERS HAVE
BEEN OBSERVED AS WE HEAD INTO DECEMBER. GENERAL LAKE WATER
TEMPERATURES ARE IN THE 40S FOR ALL OF THE LAKES WITH COLDER WATERS
ALONG MUCH OF THE COASTLINES IN THE 30S. AREAS OF THE NORTHERN GREAT
LAKES ARE SHOWING THESE COASTLINES, SMALLER BAYS, AND SMALLER INLETS
WITH TEMPERATURES THAT ARE NOW SUPPORTIVE OF FREEZING WITH CONTINUED
COLD AIR OUTBREAKS. SATELLITE DATA IS SHOWING MINOR SHORELINE ICE
FORMATION IN BIG BAY/LITTLE BAY DE NOC AND DOWN INTO THE SOUTHERN
END OF GREEN BAY WITH THE MAJORITY OF WATER TEMPERATURES IN THE MID
30S. THE ST. MARYS RIVER ALSO SITS IN THE LOW TO MID 30S.
WITH THE COLDER PATTERN, THE LAKES ARE STILL TRENDING ABOVE AVERAGE
ON THE WHOLE FOR EARLY DECEMBER, WITH LAKES SUPERIOR AND MICHIGAN AT
2-3F ABOVE AVERAGE, WHILE LAKES HURON AND ERIE ARE AROUND 1F ABOVE
AVERAGE. SAGINAW BAY ON LAKE HURON IS ALSO DOWN INTO THE MID 30S,
AND THE SHALLOW WESTERN BASIN OF LAKE ERIE IS IN THE MID TO UPPER
30S. SANDUSKY BAY, A LARGE AND VERY SHALLOW AREA OF LAKE ERIE, IS
SHOWING SIGNS OF ICE FORMATION AS WELL ALONG THE SHORELINES.
OVER THE NEXT COUPLE OF WEEKS, THERE DOES NOT APPEAR TO BE MUCH IN
THE WAY OF CHANGES TO THE OVERALL WEATHER PATTERNS FOR THE GREAT
LAKES WITH THE COLDER TREND PERSISTING. LONG RANGE MODEL ENSEMBLES
ARE POINTING TO WEAK UPPER LEVEL RIDGING OVER THE
SOUTHWESTERN/SOUTHERN PACIFIC COAST OF THE UNITED STATES, PAIRING UP
WITH UPPER LEVEL TROUGHING OVER THE EASTERN THIRD OF THE CONTINENT.
THIS SET UP IN THE PATTERN ALOFT WILL CONTINUE TO ALLOW COLDER
AIRMASSES TO SPILL INTO THE GREAT LAKES HEADING INTO MID DECEMBER.
OPPORTUNITIES FOR HOLDING BACK ADDITIONAL SURFACE WATER COOLING WILL
BE FEW AND FAR BETWEEN, MEANING MILD SPELLS ARE NOT ANTICIPATED, AND
IF THEY DO OCCUR IN THE NEXT COUPLE OF WEEKS, THEY WILL BE VERY
SHORT LIVED. OVERALL, SIGNIFICANT ICE FORMATION OUTSIDE OF THE BAYS
AND INLETS AND ST. MARYS RIVER IS NOT EXPECTED AS WATER TEMPERATURES
IN THE OPEN WATERS ARE STILL TOO WARM FOR NOW. OTHERWISE, EXPECT
SHORELINE ICE TO INCREASE, AND SMALLER BAYS AND INLETS WILL LIKELY
START TO FREEZE WITH SUBFREEZING WEATHER.
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/ARCTIC AIR AND HIGH WINDS. LONG
RANGE OUTLOOKS DO NOT CONSIDER THE "STORMINESS" FACTOR WHICH CAN
SIGNIFICANTLY ALTER THE THERMAL STRUCTURE OF THE LAKES OVER SHORT
PERIODS OF TIME.
TEMPERATURE FORECASTS FOR SELECTED CITIES
LOCATION 12/04 12/05 12/06 12/07 12/08 12/09
DULUTH -4 15 10 26 5 14 1 14 5 19 10 23
MARQUETTE 10 19 12 28 17 23 12 21 12 24 17 26
GREENBAY -1 12 5 24 12 23 8 21 8 23 14 26
MILWAUKEE 1 14 6 24 17 26 14 26 14 26 17 32
CHICAGO 8 19 8 28 21 30 23 30 19 28 23 33
MUSKEGON 17 28 17 32 26 32 19 28 15 30 21 32
ALPENA 12 21 14 28 21 30 14 23 12 26 17 28
DETROIT 17 23 10 26 19 33 19 28 15 28 17 30
TOLEDO 17 23 6 24 19 30 19 28 15 26 15 30
CLEVELAND 23 30 12 32 23 35 26 33 23 30 19 33
BUFFALO 21 28 12 32 24 35 21 28 14 26 15 30
FREEZING DEGREE DAY ACCUMULATIONS AT SELECTED STATIONS
COMPARED TO NORMAL CALCULATED ON TUE DEC 2:
LOCATION DATE NORMAL CURRENT
----------------------------------------
DULUTH, MN DEC 1 93 79
MARQUETTE, MI DEC 1 68 55
SAU_S_MAR, MI NOV 28 6 10
GREENBAY, WI DEC 1 6 42
MILWAUKEE, WI DEC 1 0 22
CHICAGO, IL DEC 1 0 19
MUSKEGON, MI DEC 1 0 12
ALPENA, MI NOV 28 0 6
DETROIT, MI DEC 1 0 10
TOLEDO, OH DEC 1 0 19
CLEVELAND, OH DEC 1 0 7
BUFFALO, NY DEC 1 0 7
FREEZING DEGREE DAY ACCUMULATION FORECAST
LOCATION 12/04 12/05 12/06 12/07 12/08 12/09
DULUTH 106 120 152 184 209 241
MARQUETTE 73 85 97 113 127 138
GREENBAY 74 104 119 140 172 189
MILWAUKEE 54 83 95 107 119 130
CHICAGO 51 79 87 93 101 108
MUSKEGON 22 30 33 42 52 58
ALPENA 22 33 40 54 67 77
DETROIT 22 36 42 51 62 71
TOLEDO 31 63 95 127 159 191
CLEVELAND 13 23 26 29 35 41
BUFFALO 15 25 28 36 48 58
THE NEXT FREEZE-UP OUTLOOK WILL BE ISSUED IN APPROXIMATELY TWO WEEKS.
MARSALEK
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