228  
FGUS73 KFGF 221635  
ESFFGF  
 
NDC005-027-071-281200-  
 
PROBABILISTIC HYDROLOGIC OUTLOOK  
NATIONAL WEATHER SERVICE GRAND FORKS ND  
1134 AM CDT THU SEP 22 2022  
   
..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 JUNE 1ST THROUGH NOVEMBER  
10TH.  
 
LAKE LEVELS CONTINUE TO FALL FOLLOWING THEIR SUMMER PEAK WITH  
READINGS CURRENTLY HOVERING AROUND THE 1449.7 FT MARK. PRECIPITATION  
HAS CONTINUED TO BE WELL BELOW NORMAL ACROSS THE MAJORITY OF THE  
BASIN WITH THE EXCEPTION OF THE FAR NORTHERN REACHES. THE DRY  
CONDITIONS THROUGHOUT THE SECOND HALF OF THE SUMMER AND INTO THE FALL  
CONTINUE TO AID IN THE RECESSION OF LAKE LEVELS.  
 
CLIMATE OUTLOOKS INDICATE BETTER CHANCES FOR ABOVE NORMAL  
TEMPERATURES AND BELOW NORMAL PRECIPITATION THROUGH OCTOBER. THERE  
ARE EQUAL CHANCES FOR ABOVE, BELOW, OR NORMAL PRECIPITATION AND  
TEMPERATURES HEADING INTO THE WINTER. EVEN DRIER CONDITIONS THAN  
EXPECTED WOULD LEAD TO MORE OF A DECLINE IN LAKE LEVELS (I.E., 5-10%  
PROBABILITIES).  
 
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 1401.15 FEET  
NAVD88 OR 1400.00 FEET NGVD29.  
 
   
CHANCES OF DEVILS AND STUMP LAKES RISING ABOVE GIVEN LAKE LEVELS
 
 
EXCEEDANCE INFORMATION IS NOT PUBLISHED IN SEPTEMBER.  
 
   
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 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 49.5 FEET DURING THE VALID PERIOD AND  
ONLY A 5 PERCENT CHANCE THAT IT WILL FALL BELOW 49.3 FEET.  
 
PROBABILITIES FOR NON-EXCEEDING LISTED LAKE LEVELS  
 
FROM SEPTEMBER 19, 2022 TO DECEMBER 25, 2022  
 
LOCATION 95% 90% 75% 50% 25% 10% 05%  
-------- ------ ------ ------ ------ ------ ------ ------  
DEVILS LAKE.....  
CREEL BAY 49.8 49.7 49.6 49.5 49.4 49.3 49.3  
STUMP LAKE.....  
EAST STUMP LAKE 49.8 49.7 49.6 49.5 49.4 49.3 49.3  
 
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 MANAGEMENT OUTLOOKS WILL BE ISSUED  
IN LATE FEBRUARY AND EARLY 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 OF EXCEEDANCE/NON-EXCEEDANCE INFORMATION WILL BE  
GIVEN FROM OCTOBER THROUGH DECEMBER, SINCE LAKE FREEZE-UP  
LEVELS WILL BE GIVEN IN THE FALL OUTLOOKS PREVIOUSLY ISSUED.  
   
ADDITIONAL INFORMATION
 
 
THE LONG-RANGE PROBABILISTIC OUTLOOK IS BASED ON HIGH AND LOW LAKE  
LEVELS THAT WERE CALCULATED FOR THE VALID PERIOD USING MULTIPLE  
SCENARIOS OF TEMPERATURE AND PRECIPITATION FROM 1949 TO 2018 AND  
CURRENT CONDITIONS OF THE LAKE, SNOWCOVER (IN WINTER), AND SOIL  
MOISTURE.  
 
BY PROVIDING THE COMPLETE RANGE OF LAKE LEVEL PROBABILITIES, THE  
AMOUNT OF RISK ASSOCIATED WITH LONG-RANGE PLANNING DECISIONS CAN  
BE DETERMINED. THESE PROBABILISTIC OUTLOOKS ARE PART OF NOAA'S  
NATIONAL WEATHER SERVICE'S ADVANCED HYDROLOGIC PREDICTION  
SERVICES (AHPS).  
 
A YOUTUBE VIDEO ON "HOW TO INTERPRET RIVER OUTLOOK PRODUCTS" IS AT:  
 
WWW.YOUTUBE.COM/WATCH?V=PSOEGVSNPV4  
 
THIS OUTLOOK IS ALSO PRESENTED AS PROBABILITY GRAPHS OF LAKE HEIGHT  
FOR THE FULL PERIOD AS WELL AS WEEKLY PROBABILITIES. THE OUTLOOK  
GRAPHICS AND EXPLANATIONS THAT HELP IN INTERPRETING THESE OUTLOOKS  
ARE AVAILABLE ON THE NWS GRAND FORKS AHPS WEB PAGE AT:  
 
WATER.WEATHER.GOV/AHPS2/INDEX.PHP?WFO=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, CONTACT THE NWS AT 701-772-0720.  
 
YOU CAN FOLLOW US ON FACEBOOK AT WWW.FACEBOOK.COM/NWSGRANDFORKS  
AND ON TWITTER AT @NWSGRANDFORKS.  
 

 
WEATHER.GOV/FGF  
NNNN  
 
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