171
FGUS73 KFGF 281943
ESFFGF
NDC005-027-071-281200-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE GRAND FORKS ND
243 PM CDT THU AUG 28 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.
WITH MINIMAL TO NO PRECIPITATION THROUGH THE END OF AUGUST, SUMMER
PRECIPITATION (JUNE, JULY, AND AUGUST) WILL BE RECORDED AS BELOW
NORMAL ACROSS THE BASIN. NORTHERN PORTIONS OF THE BASIN WERE THE
DRIEST DURING THIS PERIOD COMING IN 2 TO 4 INCHES BELOW NORMAL WHILE
SOUTHERN PORTIONS WERE 1 TO 2 INCHES BELOW NORMAL. WITH THAT SAID,
RECENT PRECIPITATION HAS BROUGHT SOME IMPROVEMENT TO THE
PRECIPITATION DEFICIT ACROSS THE BASIN. THIS HAS RESULTED IN VAST
IMPROVEMENT IN DROUGHT CONDITIONS WITH ONLY THE FAR NORTHEASTERN
CORNER OF THE STATE STILL EXPERIENCING ABNORMALLY DRY (D0)
CONDITIONS.
CLIMATE OUTLOOKS POINT TOWARDS A COOLER THAN NORMAL START TO THE FALL
THROUGH THE FIRST WEEK OR TWO OF SEPTEMBER. THEREAFTER, ABOVE NORMAL
TEMPERATURES ARE EXPECTED TO RETURN FOR THE LATTER HALF OF THE MONTH
BEFORE EQUAL CHANCES OF ABOVE, BELOW, OR NEAR NORMAL TEMPERATURES
(AND PRECIPITATION) RETURN FOR THE REMAINDER OF THE FALL SEASON.
NO EXCEEDANCE NUMBERS ARE ISSUED WITH THIS OUTLOOK BUT WILL RESUME IN
JANUARY 2026. THE NEXT (AND FINAL) SET OF NON-EXCEEDANCE NUMBERS OF
THE SEASON WILL BE ISSUED ON THURSDAY, SEPTEMBER 25, 2025.
CURRENT AND PREVIOUS RECORD HIGH LAKE LEVELS
* THE CURRENT HEIGHT OF DEVILS LAKE IS 1448.6 FEET NGVD29.
* THE CURRENT HEIGHT OF STUMP LAKE IS 1446.6 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 47.6 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 48.0 47.8 47.7 47.6 47.6
STUMP LAKE.....
EAST STUMP LAKE 48.2 48.1 48.0 47.8 47.7 47.6 47.6
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.
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.
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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