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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
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