Subscribe by RSS
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
1020 AM CST THU FEB 21 2013
…SPRING FLOOD AND WATER RESOURCES OUTLOOK…
THIS IS THE ANNUAL SPRING FLOOD AND WATER RESOURCES OUTLOOK FOR THE
MISSOURI AND JAMES RIVER BASINS OF WESTERN AND CENTRAL NORTH
DAKOTA…COVERING THE TIME PERIOD OF 22 FEBRUARY TO 23 MAY 2013. THE
SIGNIFICANCE OF THIS ISSUANCE IS IN THE TIMING WHICH ENCOMPASSES THE
VAST MAJORITY OF THE SPRING MELT SEASON ACROSS THE NATION WHILE
HAVING ENOUGH OF THE SNOW ACCUMULATION SEASON BEHIND US TO GIVE THE
MODELS A GOOD BASIS FOR DETERMINING THE LIKELIHOOD OF FLOODING
RELATED TO THE SPRING THAW.
THE FOLLOWING MESSAGE HAS THREE SECTIONS…THE FIRST PROVIDES
HIGHLIGHTS OF THIS PRODUCT AND CONDITIONS AFFECTING LOCAL HYDROLOGY.
THE SECOND GIVES THE CURRENT AND NORMAL/HISTORICAL CHANCES OF RIVER
LOCATIONS REACHING THEIR MINOR…MODERATE…AND MAJOR FLOOD
CATEGORY. THE FINAL SECTION GIVES THE CURRENT CHANCES OF RIVER
LOCATIONS RISING ABOVE LISTED RIVER STAGES.
…FLOOD OUTLOOK OVERVIEW HIGHLIGHTS…
IN THE MOST GENERAL OF TERMS AND BASED ON CURRENT CONDITIONS…THE
MISSOURI AND JAMES RIVER BASINS OF NORTH DAKOTA ARE BELOW THE
HISTORICAL (NORMAL) RISKS FOR FLOODING THIS COMING SPRING. WHILE
BELOW NORMAL…APPLE CREEK NEAR MENOKEN AND THE CANNONBALL RIVER
NEAR BREIEN STILL HAVE OVER A 30 PERCENT PROBABILITY OF AT LEAST
MINOR FLOODING. SIMILARLY…THE SNOW ACCUMULATION SEASON STILL HAS
ENOUGH TIME LEFT FOR PLACES LIKE THE UPPER JAMES RIVER
BASIN…BEAVER CREEK NEAR LINTON…AND THE LITTLE MUDDY CREEK NEAR
WILLISTON TO ACCUMULATE A GREATER THAN NORMAL SNOWPACK BEFORE THE
SPRING MELT.
IMPORTANTLY…THE BELOW LISTED PROBABILITIES FOR FLOODING DO NOT
INCORPORATE RISKS ASSOCIATED WITH ICE JAMS…NOR DO THEY INCLUDE
RISKS ASSOCIATED WITH LOCALIZED OVERLAND FLOODING. ICE JAMS DO NOT
LEND THEMSELVES TO MATHEMATICAL MODELS. RIVER MEANDERS AND BRIDGES
THAT RESTRICT THE EASY PASSAGE OF ICE…OR CHANGE FLOW
DIRECTION…ARE THE MOST LIKELY LOCATIONS FOR AN ICE JAM. DESPITE
HAVING MODEST PROBABILITIES FOR RIVER FLOODING…SOME AREAS SUCH AS
THE SOUTHERN JAMES RIVER BASIN IN NORTH DAKOTA HAVE ENOUGH WATER
EQUIVALENT ON THE GROUND TO CREATE OVERLAND FLOODING. THE POTENTIAL
IN THOSE AREAS FOR OVERLAND FLOODING CAN EASILY BE ENHANCED BY A
HEAVY RAIN ON TOP OF THE SPRING MELT.
…CURRENT CONDITIONS…
RESERVOIRS WITH FLOOD CONTROL AS ONE OF THE PURPOSES ARE ALL AT OR
BELOW THEIR NORMAL DRAWDOWN LEVELS. MOST RIVERS AND STREAMS HAVE AT
LEAST ENOUGH WATER EQUIVALENT SITTING ON THE GROUND TO ENSURE
ADEQUATE STREAMFLOW THIS SPRING. THE SNOWPACK IN GENERAL IS BELOW
NORMAL SOUTH AND WEST OF THE MISSOURI RIVER AND TRANSITIONS TO A
MORE NORMAL…TO SLIGHTLY ABOVE NORMAL WATER CONTENT SOUTH OF
JAMESTOWN. MOUNTAIN SNOWPACK FOR THE MISSOURI RIVER ITSELF IS NEAR
NORMAL FOR THIS TIME OF YEAR…ALTHOUGH ROUGHLY ONE THIRD OF ITS
SNOW ACCUMULATION SEASON REMAINS.
…WEATHER OUTLOOK…
NO REAL STRONG INDICATOR IS IN PLACE FOR THE ONE MONTH OR THREE
MONTH CLIMATE OUTLOOKS WHICH GENERALLY FIND NORTH DAKOTA IN THE
EQUAL CHANCES CATEGORY FOR ABOVE NORMAL…NORMAL…OR BELOW NORMAL
TEMPERATURE AND PRECIPITATION. IN THE SHORTER 6 TO 10 AND 8 TO 14
DAY OUTLOOKS…THE GENERAL TREND IS FOR NORMAL TO ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL TO NORMAL PRECIPITATION.
IMPORTANTLY…NO INDICATORS EXIST THAT SUGGEST A REPEAT OF THE VERY
WET SPRING OF 2011.
…SUMMARY OF HYDROLOGIC CONDITIONS…
RIVER…ICE…AND SNOWPACK CONDITIONS SUGGEST THAT WHILE ENOUGH
WATER WILL BE AVAILABLE FOR ADEQUATE STREAMFLOW THROUGH
SPRING…SPRING RAINS WILL LIKELY BE THE DRIVING FORCE BEHIND ANY
FLOODING.
…LONG-RANGE PROBABILISTIC RIVER OUTLOOK BY FLOOD CATEGORY…
THE TABLE BELOW GIVES BOTH THE CURRENT CHANCES (CS) AND THE
NORMAL/HISTORICAL CHANCES (HS) FOR EXCEEDING THE MINOR…MODERATE
AND MAJOR FLOOD STAGES AT THE RIVER FORECAST POINT LOCATIONS DURING
THE VALID PERIOD OF THIS OUTLOOK.
JAMES AND MISSOURI RIVER BASINS
LONG-RANGE PROBABILISTIC OUTLOOK
PROBABILITIES FOR MINOR…MODERATE AND MAJOR FLOODING
FROM 2/22/2013 TO 5/23/2013 Z
TABLE 1 : CURRENT AND HISTORICAL
: CHANCES OF EXCEEDING FLOOD
: CATEGORY IN PERCENT (%)
CATEGORICAL :
FLOOD STAGES (FT) : MINOR MODERATE MAJOR
LOCATION MINOR MOD MAJOR : CS HS CS HS CS HS
——– —— —— —— : — — — — — —
LITTLE MUDDY CREEK…..
WILLISTON 10.0 12.0 14.0 : 16 63 5 28 5 10
LITTLE MISSOURI RIVER…..
MARMARTH 18.0 23.0 30.0 : 5 5 5 5 5 5
MEDORA 15.0 18.0 20.0 : 5 7 5 6 5 5
WATFORD CITY 20.0 24.0 30.0 : 5 5 5 5 5 5
KNIFE RIVER…..
MANNING 15.0 17.0 20.0 : 5 21 5 5 5 5
SPRING CREEK…..
ZAP 14.0 18.0 20.0 : 6 22 5 7 5 5
KNIFE RIVER…..
HAZEN 21.0 24.0 25.0 : 6 29 5 14 5 8
HEART RIVER…..
MANDAN 17.0 23.0 28.0 : 5 6 5 5 5 5
APPLE CREEK…..
MENOKEN 15.0 16.0 17.0 : 35 55 13 47 5 25
CANNONBALL RIVER…..
REGENT 22.0 24.0 26.0 : 5 5 5 5 5 5
CEDAR CREEK…..
RALEIGH 12.0 14.0 16.0 : 5 5 5 5 5 5
CANNONBALL RIVER…..
BREIEN 10.0 20.0 23.0 : 30 41 5 5 5 5
BEAVER CREEK…..
LINTON 9.0 11.0 13.0 : 15 38 9 29 5 24
JAMES RIVER…..
GRACE CITY 12.0 14.0 15.0 : 5 10 5 6 5 5
PIPESTEM CREEK…..
PINGREE 9.0 11.0 13.0 : 7 11 5 6 5 5
JAMES RIVER…..
LAMOURE 14.0 16.0 18.0 : 5 9 5 5 5 5
LEGEND:
CS CONDITIONAL SIMULATION (OUTLOOK FOR CURRENT CONDITIONS)
HS HISTORICAL SIMULATION ( ” ” NORMAL CONDITIONS)
FT FEET ABOVE GAGE ZERO DATUM
…LONG-RANGE PROBABILISTIC OUTLOOK BY RIVER STAGE…
THE TABLE BELOW GIVES THE CURRENT 95 THROUGH 5 PERCENT CHANCES FOR
EXCEEDING RIVER STAGES AT THE RIVER FORECAST POINT LOCATIONS DURING
THE VALID PERIOD OF THIS OUTLOOK.
EXAMPLE: DURING THE VALID TIME OF THIS OUTLOOK…THERE IS A
95 PERCENT CHANCE FOR THE LITTLE MUDDY CREEK AT
WILLISTON TO RISE ABOVE 5.1 FEET AND ONLY A 10 PERCENT
CHANCE THAT IT WILL RISE ABOVE 10.4 FEET.
JAMES AND MISSOURI RIVER BASINS
LONG-RANGE PROBABILISTIC OUTLOOK
PROBABILITIES FOR EXCEEDING LISTED RIVER STAGES
FROM 2/22/2013 TO 5/23/2013
TABLE 2
LOCATION 95% 90% 75% 50% 25% 10% 05%
——– —— —— —— —— —— —— ——
LITTLE MUDDY CREEK…..
WILLISTON 5.1 5.2 6.2 7.5 8.9 10.4 10.8
LITTLE MISSOURI RIVER…..
MARMARTH 1.8 1.8 2.1 3.0 4.0 6.8 10.3
MEDORA 1.9 2.0 2.4 3.7 4.7 7.7 10.6
WATFORD CITY -0.9 -0.3 0.5 1.6 3.1 5.0 6.5
KNIFE RIVER…..
MANNING 6.2 6.2 6.5 8.1 9.3 10.4 10.8
SPRING CREEK…..
ZAP 5.2 5.3 5.8 7.0 9.8 11.6 15.0
KNIFE RIVER…..
HAZEN 1.3 1.7 4.7 8.3 10.8 16.1 22.0
HEART RIVER…..
MANDAN 1.1 1.4 2.5 3.4 6.5 7.1 8.2
APPLE CREEK…..
MENOKEN 5.4 5.7 6.5 10.7 15.6 16.2 16.9
CANNONBALL RIVER…..
REGENT 4.4 4.5 6.3 7.2 8.7 9.9 10.7
CEDAR CREEK…..
RALEIGH 3.2 3.4 4.0 4.6 5.8 7.2 7.8
CANNONBALL RIVER…..
BREIEN 6.5 6.5 7.1 8.0 10.2 13.2 14.2
BEAVER CREEK…..
LINTON 5.4 5.5 6.1 7.0 7.9 10.7 12.5
JAMES RIVER…..
GRACE CITY 3.8 3.8 4.3 4.8 5.4 7.1 9.2
PIPESTEM CREEK…..
PINGREE 4.8 4.8 5.0 5.4 5.8 6.6 10.4
JAMES RIVER…..
LAMOURE 6.8 6.9 7.1 7.3 7.9 9.6 12.7
…THE OUTLOOK PRODUCTION PROCESS…
THIS LONG RANGE PROBABILISTIC OUTLOOK IS BASED ON A SERIES OF PEAK
RIVER LEVELS OR CRESTS TAKEN FROM THE FORECAST HYDROGRAPH RESULTS
OF THE NWS ENSEMBLE STREAMFLOW PREDICTION MODEL (ESP). THE MODEL
IS RUN FOR MULTIPLE SCENARIOS STARTING AT CURRENT RIVER…SNOW AND
SOIL CONDITIONS AND USING 25 OR MORE YEARS OF PAST PRECIPITATION AND
TEMPERATURE CONDITIONS IN THE HISTORICAL RECORD. THESE CRESTS CAN
THEN BE RANKED FROM LOWEST TO HIGHEST…AND ASSIGNED AN
EXCEEDANCE PROBABILITY. FOR EXAMPLE…FOR A SERIES OF 50 YEARS…
THE LOWEST RANKED CREST HAS 49 CRESTS ABOVE IT AND SINCE 95 PERCENT
OF THE CRESTS ARE ABOVE IT… IT IS ASSIGNED A 95 PERCENT
PROBABILITY OF EXCEEDANCE (POE).
THE PROBABILITIES CAN BE USED FOR RISK MANAGEMENT BY COMPARING THIS
YEARS CURRENT TEMPERATURE AND PRECIPITATION OUTLOOKS WITH
THOSE OF PAST YEARS USED IN THE HYDRO OUTLOOK. THEY CAN ALSO BE
USED AS AN INDICATION OF THE RANGE OF CRESTS THAT MAY BE EXPECTED
DURING THE VALID PERIOD OF THE OUTLOOK.
BY PROVIDING A RANGE OF PEAK RIVER LEVEL PROBABILITIES..THE NWS IS
IS CONTRIBUTING TO THE AREAS DECISION SUPPORT SERVICES THAT HELP
WITH LONG RANGE FLOOD PLANNING AND RESPONSE READINESS. THIS OUTLOOK
IS A PART OF NOAA/S NATIONAL WEATHER SERVICE/S AHPS (ADVANCED
HYDROLOGIC PREDICTION SERVICES).
. ADDITIONAL INFORMATION SOURCES…
THE AHPS LONG RANGE PROBABILISTIC HYDROLOGIC OUTLOOKS ARE ISSUED
NEAR THE END OF EACH MONTH. HOWEVER…SPRING FLOOD AND WATER
RESOURCES OUTLOOKS ARE ISSUED SEVERAL TIMES DURING THE CRITICAL
SPRING MELT PERIOD…USUALLY ON THURSDAYS BEGINNING IN LATE
FEBRUARY OR EARLY MARCH AND ENDING IN EARLY APRIL…DEPENDING ON
THE SPRING FLOODING CONDITIONS.
THIS OUTLOOK IS ALSO PRESENTED AS GRAPHS OF THE PROBABILITY OF STAGE
EXCEEDANCE FOR THE FULL PERIOD AND FOR WEEKLY INTERVALS DURING THE
PERIOD. THESE GRAPHS…TOGETHER WITH EXPLANATIONS THAT HELP IN
INTERPRETING THEM ARE AVAILABLE FROM THE NWS BISMARCK AHPS WEB
PAGE ON THE INTERNET AT:
WWW.WEATHER.GOV/BISMARCK OR WEATHER.GOV/BIS
THEN CLICK ON THE “RIVERS AND LAKES AHPS”ON THE TAB ABOVE THE MAP
…OR ON THE LINK IN THE BLUE-LEFT-HAND BANNER.
CURRENT RIVER CONDITIONS FOR ALL FORECAST POINTS WITHIN THE SOURIS
RIVER BASIN ARE AVAILABLE ON OUR WEB SITE…AS WELL AS THE FORECASTS
WHEN THE RIVER AT THE FORECAST POINT IS IN OR NEAR FLOOD.
IF YOU HAVE ANY QUESTIONS…CONTACT THE NWS AT 701-250-4495.
PROBABILISTIC HYDROLOGIC OUTLOOKS WILL BE ISSUED MONTHLY THROUGHOUT
THE REST OF THE YEAR DURING THE LATER PART OF THE MONTH OR AS
CONDITIONS WARRANT.
Jamestown, ND (KCSi-T.V. News Feb 21, 2013) — The National Weather Service says the risk of major flooding on the Sheyenne River is low so far, less than 30 percent for minor flooding or greater in Valley City, Lisbon, Enderlin and Hillsboro.
Snowpack moisture in the James River Valley is low so far, but are increasing, with present snow melt amounts expected to be controlled by Pipestem and Jamestown Dams.
The anticipated flood outlook as of Februay 21,, 2013 is roughly 10 percent for minor flooding of 12 feet, 6 percent for moderate flooding of 14 feet and 5 percent for minor flooding of 15 feet along the James River at Grace City.
The outlook includes 11 percent for minor flooding of 9 feet, 6 percent for moderate flooding of 11 feet and less than 5 percent for major flooding of 13 feet along Pipestem Creek at Pingree.
Calculations do not include any flooding caused by ice jams and assume normal levels of precipitation through the next three months.
Flooding below the Jamestown and Pipestem dams, measured at LaMoure, is also low with a 9 percent chance of minor flooding of 14 feet, 5 percent chance of moderate flooding of 16 feet and less than 5 percent chance of major flooding of 18 feet.
Overland flooding depends on the amount and timing of spring rains, and snow melt, plus the amount of frost in the ground, relative to run off amounts.
The National Weather Service has dramatically bumped up the chances of major flooding on the Red River near Fargo, but city officials say it should have minimal impact on residents.
Weather service meteorologist Greg Gust says the chance of major flooding in North Dakota’s largest city has increased from 6 percent a month ago to 79 percent, based mainly on water content in the snowpack.
Major flood stage in Fargo is 30 feet. There’s a 50 percent chance the river will reach 33.2 feet, a 25 percent chance it will hit 35.1 feet and a 5 percent chance of 37.8 feet.
Fargo officials say the city has taken steps to handle major flooding since a record crest in 2009.
The next flood outlook will be released March 7.
Comments are closed
Sorry, but you cannot leave a comment for this post.