969
FGUS73 KFGF 251336
ESFFGF
NDC005-027-071-281200-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE GRAND FORKS ND
0828 AM CDT THU JUL 25 2024
..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.
PRECIPITATION HAS CONTINUED TO RUN ABOVE NORMAL SINCE THE LAST
OUTLOOK ISSUANCE. ABOVE NORMAL SPRING PRECIPITATION HAS CARRIED INTO
THE SUMMER.
CLIMATE OUTLOOKS INDICATE A STRONG SIGNAL FOR ABOVE NORMAL
TEMPERATURES THROUGH THE FIRST HALF OF AUGUST, WITH A WEAK SIGNAL FOR
BELOW NORMAL PRECIPITATION DURING THIS PERIOD.
THROUGH THE END OF OCTOBER, CLIMATE OUTLOOKS INDICATE NO SIGNAL
EITHER WAY FOR ABOVE, BELOW, OR NEAR NORMAL TEMPERATURE AND
PRECIPITATION.
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 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 1450.1 FEET DURING THE VALID PERIOD AND
ONLY A 5 PERCENT CHANCE THAT IT WILL RISE ABOVE 1450.2 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 22, 2024 TO SEPTEMBER 30, 2024
LOCATION 95% 90% 75% 50% 25% 10% 05%
-------- ------ ------ ------ ------ ------ ------ ------
DEVILS LAKE.....
CREEL BAY 50.1 50.1 50.1 50.1 50.1 50.2 50.2
STUMP LAKE.....
EAST STUMP LAKE 50.1 50.1 50.1 50.1 50.1 50.2 50.2
CURRENT AND PREVIOUS RECORD HIGH LAKE LEVELS
* THE CURRENT HEIGHT OF DEVILS LAKE IS 1450.14 FEET NGVD29.
* THE CURRENT HEIGHT OF STUMP LAKE IS 1450.05 FEET NGVD29.
* THE MOST RECENT USGS PROVISIONAL RECORD DAILY AVERAGE HEIGHT
FOR DEVILS LAKE AT THE CREEL BAY GAGE:
...1454.30 FEET ON JUNE 27 OF 2011
* PREVIOUS RECORDS:
...1452.05 FEET ON JUNE 27 OF 2010
...1450.93 FEET ON JUNE 27 OF 2009
...1449.20 FEET ON MAY 9 OF 2006
...1449.18 FEET ON JUNE 17 OF 2004
...1449.17 FEET ON AUGUST 2 OF 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 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 1449.1 FEET DURING THE VALID PERIOD AND
ONLY A 5 PERCENT CHANCE THAT IT WILL FALL BELOW 1448.8 FEET.
PROBABILITIES FOR NON-EXCEEDING LISTED LAKE LEVELS
FROM SEPTEMBER 01, 2024 TO NOVEMBER 30, 2024
LOCATION 95% 90% 75% 50% 25% 10% 05%
-------- ------ ------ ------ ------ ------ ------ ------
DEVILS LAKE.....
CREEL BAY 49.6 49.4 49.2 49.1 48.9 48.8 48.8
STUMP LAKE.....
EAST STUMP LAKE 49.6 49.4 49.2 49.1 48.9 48.8 48.8
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 NATIONAL WATER PREDICTION SERVICE
(NWPS).
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 NWPS WEB PAGE AT:
WWW.WATER.NOAA.GOV/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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