139
FGUS73 KFGF 242146
ESFFGF
NDC005-027-071-281200-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE GRAND FORKS ND
446 PM CDT THU JUL 24 2025
..DEVILS LAKE OUTLOOK FOR FLOOD POTENTIAL
DEVILS AND STUMP LAKES
LONG-RANGE PROBABILISTIC OUTLOOK
THE NATIONAL WEATHER SERVICE PROVIDES LONG-RANGE PROBABILISTIC
HYDROLOGIC OUTLOOKS FOR DEVILS AND STUMP LAKES BETWEEN JANUARY
AND SEPTEMBER. THEY WILL NOT BE PROVIDED BETWEEN OCTOBER AND
DECEMBER. DEPENDING ON THE SEASON, THE HIGH OR LOW WATER
PROBABILITIES MAY BE OMITTED DUE TO THEIR APPLICABILITY TO
THE HYDROLOGIC SITUATION.
OUTLOOK SUMMARY
NOTE: THIS OUTLOOK INCORPORATES A DAILY AVERAGE OF 350 CFS WORTH OF
PUMPING OPERATIONS ON DEVILS LAKE FROM MAY 15TH THROUGH OCTOBER 30TH.
SUMMER PRECIPITATION THUS FAR (JUNE 1-CURRENT) REMAINS BELOW
AVERAGE...DRIEST ACROSS THE NORTHERN BASIN (2 TO 3 INCHES BELOW
NORMAL) WHILE AN INCH OR SO BELOW NORMAL ACROSS THE FAR SOUTH. DUE TO
THE PRECIPITATION DEFICIT THROUGHOUT THE FIRST HALF OF THE SUMMER,
MODERATE DROUGHT CONDITIONS (D1) ARE NOW DEPICTED ACROSS THE NORTHERN
HALF OF THE BASIN WITH ABNORMALLY DRY (D0) CONDITIONS ACROSS THE
SOUTH.
CLIMATE OUTLOOKS AT THIS TIME INDICATE ABOVE NORMAL PRECIPITATION
THROUGH THE END OF JULY AND FIRST HALF OF AUGUST ACROSS THE NORTHERN
PLAINS. IT REMAINS TO BE SEEN IF ANY PRECIPITATION RECEIVED WILL BE
ENOUGH TO PROVIDE ANY RELIEF FROM THE DROUGHT CONDITIONS ACROSS THE
AREA.
TODAY'S ISSUANCE OF EXCEEDANCE NUMBERS WILL BE THE LAST FOR THE
SEASON AND WILL RESUME IN JANUARY 2026. THE NEXT SET OF NON-
EXCEEDANCE NUMBERS OF THE SEASON WILL BE ISSUED ON THURSDAY, AUGUST
28, 2025.
CHANCES OF DEVILS AND STUMP LAKES RISING ABOVE GIVEN LAKE LEVELS
THE PROBABILITY OF EXCEEDING A GIVEN LAKE LEVEL IS THE PERCENTAGE
OF MAXIMUM LAKE LEVEL RISES THAT ARE ABOVE THAT LEVEL FOR ALL THE
YEARS (1949-2019) THAT WERE RUN THROUGH THE MODEL USING THE
PRECIPITATION AND TEMPERATURES FOR THOSE YEARS DURING THE VALID
PERIOD OF THE OUTLOOK.
INTERPRETATION AID: THERE IS A 50 PERCENT CHANCE THAT DEVILS
LAKE WILL RISE ABOVE 49.1 FEET DURING THE VALID PERIOD AND
A 5 PERCENT CHANCE THAT IT WILL RISE ABOVE 49.2 FEET.
NOTE: THE CURRENT GAGE ZERO DATUM OF THE DEVILS LAKE AT CREEL BAY
GAGE IS 1401.33 FEET NAVD88 OR 1400.00 FEET NGVD29. THE GAGE ZERO
DATUM OF THE STUMP LAKE AT EAST STUMP LAKE GAGE IS 1401.21 FEET
NAVD88 OR 1400.00 FEET NGVD29.
PROBABILITIES FOR EXCEEDING LISTED LAKE LEVELS
FROM JULY 21, 2025 TO SEPTEMBER 30, 2025
LOCATION 95% 90% 75% 50% 25% 10% 05%
-------- ------ ------ ------ ------ ------ ------ ------
DEVILS LAKE.....
CREEL BAY 49.1 49.1 49.1 49.1 49.1 49.1 49.2
STUMP LAKE.....
EAST STUMP LAKE 49.1 49.1 49.1 49.1 49.1 49.1 49.2
CURRENT AND PREVIOUS RECORD HIGH LAKE LEVELS
* THE CURRENT HEIGHT OF DEVILS LAKE IS 1449.0 FEET NGVD29.
* THE CURRENT HEIGHT OF STUMP LAKE IS 1449.0 FEET NGVD29.
* USGS DAILY AVERAGE HEIGHT RECORDS FOR DEVILS LAKE AT THE CREEL
BAY GAGE:
...1454.30 FEET ON JUNE 27, 2011
...1452.05 FEET ON JUNE 27, 2010
...1450.93 FEET ON JUNE 27, 2009
...1449.20 FEET ON MAY 9, 2006
...1449.18 FEET ON JUNE 17, 2004
...1449.17 FEET ON AUGUST 2, 2005
NOTE: ALL PREVIOUS RECORDS ARE RECORDED IN NGVD29.
CHANCES OF DEVILS AND STUMP LAKES FALLING BELOW GIVEN LAKE LEVELS
THE PROBABILITY OF NOT EXCEEDING A GIVEN LAKE LEVEL IS THE
PERCENTAGE OF LAKE LEVEL FALLS THAT ARE BELOW THAT LEVEL FOR
ALL THE YEARS (1949-2019) THAT WERE RUN THROUGH THE MODEL USING
THE PRECIPITATION AND TEMPERATURES FOR THOSE YEARS DURING THE
VALID PERIOD OF THE OUTLOOK.
INTERPRETATION AID: THERE IS A 50 PERCENT CHANCE THAT DEVILS
LAKE WILL FALL BELOW 47.8 FEET DURING THE VALID PERIOD AND
A 5 PERCENT CHANCE THAT IT WILL FALL BELOW 47.5 FEET.
PROBABILITIES FOR FALLING BELOW LISTED LAKE LEVELS
FROM SEPTEMBER 01, 2025 TO NOVEMBER 30, 2025
LOCATION 95% 90% 75% 50% 25% 10% 05%
-------- ------ ------ ------ ------ ------ ------ ------
DEVILS LAKE.....
CREEL BAY 48.2 48.1 47.9 47.8 47.6 47.5 47.5
STUMP LAKE.....
EAST STUMP LAKE 48.2 48.1 47.9 47.8 47.6 47.5 47.5
THE NON-EXCEEDANCE VALUE FOR A LISTED PERCENTAGE IS THE VALUE
WHERE THAT PERCENTAGE OF ALL MODEL CASES RUN WERE BELOW THAT
LAKE LEVEL FOR THE SPECIFIED VALID PERIOD OF THE OUTLOOK.
OUTLOOK SCHEDULE
- BETWEEN JANUARY AND MAY, ONLY THE HIGH WATER EXCEEDANCES WILL BE
PROVIDED WITH VALID PERIODS ENDING AT THE END OF SEPTEMBER.
- SPECIAL SPRING FLOOD AND WATER RESOURCES OUTLOOKS WILL BE ISSUED
FROM MID-FEBRUARY THROUGH MID-MARCH.
- FOR JUNE AND JULY, BOTH HIGH-WATER AND LOW-WATER EXCEEDANCES WILL
BE PROVIDED.
- FOR AUGUST AND SEPTEMBER, ONLY THE LOW-WATER EXCEEDANCES WILL BE
PROVIDED WITH VALID PERIODS ENDING AT THE END OF NOVEMBER.
- NO PROBABILITY INFORMATION WILL BE PROVIDED FROM OCTOBER THROUGH
DECEMBER.
ADDITIONAL INFORMATION
THESE LAKE LEVEL PROBABILITIES CAN BE USED FOR RISK MANAGEMENT AS AN
INDICATION OF THE RANGE OF LAKE LEVELS THAT MAY BE POSSIBLE DURING
THE VALID PERIOD OF THE OUTLOOK. HOWEVER, NOTE THAT IT IS POSSIBLE
THAT LAKE LEVELS MAY STILL REACH ABOVE/FALL BELOW THE 95TH AND 5TH
PERCENTILE VALUES.
THIS OUTLOOK IS ALSO PRESENTED AS GRAPHS OF THE POTENTIAL LAKE
LEVELS FOR THE FULL OUTLOOK PERIOD AS WELL AS WEEKLY PROBABILITIES.
THESE GRAPHICS, AND EXPLANATIONS THAT HELP IN INTERPRETING THEM,
CAN BE FOUND ON THE NWS GRAND FORKS NWPS WEB PAGE BY CLICKING ON
"RIVERS AND LAKES" ABOVE THE MAP AT WWW.WEATHER.GOV/FGF.
WIND AND WAVE FORECASTS FOR DEVILS AND STUMP LAKES ARE AVAILABLE FOR
A 7-DAY PERIOD WHEN THE LAKES ARE SUFFICIENTLY ICE-FREE AT
WWW.WEATHER.GOV/FGF/LAKE_INFO.
IF YOU HAVE ANY QUESTIONS, PLEASE CONTACT THE NWS AT 701-772-0720.
YOU CAN FOLLOW US ON FACEBOOK AT WWW.FACEBOOK.COM/NWSGRANDFORKS
AND ON X AT @NWSGRANDFORKS.
WEATHER.GOV/FGF
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