Great Lakes Freeze-Up Outlook

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

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FZUS81 KCLE 010827

ICEFBO

GREAT LAKES FREEZE-UP OUTLOOK

NATIONAL WEATHER SERVICE CLEVELAND OH

427 AM EDT TUE NOV 1 2016

GREAT LAKES ICE SEASON FOR 2016-2017 WILL LIKELY TREND CLOSER

TO NORMAL AS A LA NINA WATCH HAS BEEN ISSUED.

A LA NINA WATCH HAS BEEN REISSUED AS WATER TEMPERATURES AND

ATMOSPHERIC CONDITIONS HAVE BEEN TRENDING TOWARD A LA NINA

OVER THE LAST SEVERAL WEEKS.

THE LATEST LONG RANGE OUTLOOK IS CALLING FOR TEMPERATURES TO BE

BELOW NORMAL...ESPECIALLY IN THE WESTERN GREAT LAKES THROUGH

THE WINTER MONTHS.  LONG RANGE PRECIPITATION FORECASTS ARE CALLING

FOR ABOVE NORMAL PRECIPITATION IN THE GREAT LAKES REGION.

THE CURRENT FORECAST TRENDS DURING A LA NINA WINTER ARE IN LINE

WITH PAST LA NINA WINTERS WHERE TEMPERATURES WERE BELOW NORMAL

AND PRECIPITATION WAS ABOVE NORMAL IN THE GREAT LAKES.

LA NINAS WILL DEVELOP A BLOCKING HIGH PRESSURE CENTER OVER THE

GULF OF ALASKA FORCING THE JET STREAM TO TRACK EAST ACROSS

CENTRAL ALASKA AND THEN SOUTHEAST THROUGH ALBERTA CANADA INTO

THE OHIO VALLEY.  THIS TRACK IS VARIABLE THROUGH THE WINTER

BUT FAVORS COLDER AIR ACROSS THE GREAT LAKES REGION. THIS TRACK

ALSO FAVORS THE INTERACTION OF THE COLD ARCTIC AIR FROM CANADA

WITH THE WARM MOIST AIR FROM THE GULF OF MEXICO.  HENCE...THIS

SCENARIO FAVORS GREATER CHANCES FOR PRECIPITATION ACROSS THE

LOWER GREAT LAKES REGION.

DURING YEARS IN WHICH THERE WERE MODERATE LA NINAS...THE ICE ON

THE GREAT LAKES WAS NOT OVERLY SIGNIFICANT.  ICE COMPLETELY

COVERED LAKE ERIE...GREEN BAY...THE BAYS DE NOC...SAGINAW BAY...

AND ALONG THE IMMEDIATE LAKE SHORE OF LAKE SUPERIOR. THE OTHER

FACTOR DURING LA NINA WINTERS IS THE TIME PERIOD IN WHICH ICE

BEGINS TO FORM. TYPICALLY ICE BEGAN TO CAUSE PROBLEMS FOR

SHIPPING DURING THE FIRST WEEK OF JANUARY...ESPECIALLY IN THE

WESTERN BASIN OF LAKE ERIE.

RELATIVELY LOW ICE FORMATION ON THE GREAT LAKES WILL LEAD TO

THE POTENTIAL FOR THE COMBINATION OF INCREASED STORM ACTIVITY

AND SIGNIFICANT LAKE EFFECT SNOW ACCUMULATION DURING THE COLD

AIR OUTBREAKS.

DURING THE NEXT TWO WEEKS...THE NORTH ATLANTIC OSCILLATION AND

THE ARCTIC OSCILLATION ARE EXPECTED TO BE IN THE STRONG NEGATIVE

PHASE. THIS TREND USUALLY RESULTS IN BELOW NORMAL TEMPERATURES

ACROSS THE GREAT LAKES REGION. HOWEVER...THE NEXT 6 TO 10 DAYS

ARE EXPECTED TO REMAIN ABOVE NORMAL IN TEMPERATURES AND

PRECIPITATION WILL BE NEAR NORMAL.  THE OVERALL PATTERN DURING

THE NEXT COUPLE WEEKS IS FAVORING A STRONGER MORE ZONAL FLOW

ACROSS THE ENTIRE UNITED STATES.  SINCE THE ARCTIC OSCILLATION

AND NORTH ATLANTIC OSCILLATION ARE IN THE STRONG NEGATIVE

PHASE...THE POTENTIAL EXISTS FOR THE EVOLUTION OF THE FIRST

POLAR VORTEX OF THE SEASON TO STRIKE THE UNITED STATES.

HOWEVER...THE POLAR VORTEXES HAVE BEEN SLIDING SOUTH ACROSS

RUSSIA AND NOT INTO CANADA. THEREFORE...THE GREAT LAKES WILL

CONTINUE TO SEE MILD FALL TEMPERATURES.

THE WATER TEMPERATURES ON THE GREAT LAKES ARE RUNNING WELL

ABOVE NORMAL AT THIS TIME. A LARGE PART OF THIS IS THE FACT

THAT THE GREAT LAKES REGION HAS BEEN SO MILD OVER THE LAST

COUPLE MONTHS. THE LAKE WATER TEMPERATURES COULD QUICKLY

RETURN BACK TO NORMAL LEVELS AFTER THE FIRST COLD AIR

OUTBREAK HITS THE REGION ALONG WITH STORM SYSTEMS THAT

PRODUCE CONSIDERABLE WIND ON THE LAKES. THE STORMINESS

HELPS TO MIX THE WATER AND RELEASE THE HEAT FASTER.

KEEP IN MIND THAT ICE COULD DEVELOP EARLIER OR LATER SINCE ICE

DEVELOPMENT IS HIGHLY DEPENDENT ON THE OCCURRENCE OF COLD AIR

OUTBREAKS AND WARM PERIODS ACROSS THE GREAT LAKES DURING THE NEXT

TWO MONTHS.

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 LAKES THERMAL STRUCTURE OVER SHORT PERIODS

OF TIME.

THE LATEST HARBOR WATER TEMPERATURES COMPARED TO PREVIOUS YEARS:

                 2016 2015 2014 2013 2012 2011 2010 2009 2008  NORMAL

DULUTH            52   53   44   48   43   50   48   50   44     44

SAULT STE MARIE   58   53   46   50   52   54   47   48   50     47

CHICAGO           60   55   48   54   57   54   54   50   53     53

ALPENA            58   53   50   50   52   53   45   52   50     48

DETROIT           56   53   49   48   58   53   47   51   50     52

CLEVELAND         62   58   53   57   51   55   51   53   52     56

BUFFALO           60   54   52   55   52   55   51   53   52     54

WATER TEMPERATURES FROM THE MID-LAKE BUOYS COMPARED TO PREVIOUS

YEARS:

LAKE SUPERIOR

WEST              49   43   43   46   41   47   44   45   46     47

CENTRAL           47   45   42   44   44   46   46   43   44     47

EAST              52   45   42   MM   41   44   47   44   45     48

LAKE MICHIGAN

NORTH             59   51   47   53   45   MM   50   47   49     54

SOUTH             61   54   46   54   48   55   48   48   53     56

LAKE HURON

NORTH             56   53   48   49   48   46   49   46   48     53

SOUTH             57   54   49   56   48   54   53   51   52     55

LAKE ERIE

WEST              61   51   51   54   45   54   49   53   52     56

CENTRAL           62   58   53   57   46   55   53   53   54     58

EAST              59   56   52   54   48   55   52   53   54     57

THE NEXT FREEZE UP OUTLOOK WILL BE ISSUED IN APPROXIMATELY TWO WEEKS.

$$

LOMBARDY