Flood Potential Outlook
Issued by NWS Sioux Falls, SD

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000
FGUS73 KFSD 201400
ESFFSD
SDC005-011-027-035-061-067-079-083-087-099-101-111-125-127-135-
MNC033-063-081-083-101-105-117-133-NEC043-051-
IAC021-035-041-059-093-119-141-143-149-167-193-201200-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
800 AM CST THU FEB 20 2014

IN TABLE 1 BELOW...THE CURRENT (CS) AND HISTORICAL (HS) OR NORMAL
PROBABILITIES OF EXCEEDING MINOR...MODERATE...AND MAJOR FLOOD STAGES
ARE LISTED FOR THE VALID TIME PERIOD.

CS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY
BASED ON CURRENT CONDITIONS.

HS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY
BASED ON HISTORICAL OR NORMAL CONDITIONS.

WHEN THE VALUE OF CS IS MORE THAN HS...THE PROBABILITY OF
EXCEEDING THAT LEVEL IS HIGHER THAN NORMAL. WHEN THE VALUE OF CS IS
LESS THAN HS...THE PROBABILITY OF EXCEEDING THAT LEVEL IS LOWER
THAN NORMAL.


...TABLE 1--PROBABILITIES FOR MINOR...MODERATE AND MAJOR FLOODING...
                    VALID PERIOD:  2/22/2014 - 5/23/2014

                                       :    CURRENT AND HISTORICAL
                                       :     CHANCES OF EXCEEDING
                                       :       FLOOD CATEGORIES
                                       :      AS A PERCENTAGE (%)
                      CATEGORICAL      :
                   FLOOD STAGES (FT)   :   MINOR    MODERATE   MAJOR
LOCATION           MINOR   MOD   MAJOR :  CS   HS   CS   HS   CS   HS
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:FLOYD RIVER
SHELDON             12.0   14.0   16.0 :  10   35    9   23   <5   <5
ALTON               12.0   16.0   18.0 :  10   35    7   18   <5    5
LE MARS             20.0   21.0   24.0 :   7   18    5   14   <5   <5
:WEST BRANCH FLOYD
STRUBLE             14.0   15.0   16.0 :   5   13   <5    9   <5   <5
:FLOYD RIVER
MERRILL             12.0   14.0   16.0 :  <5   11   <5    8   <5    5
JAMES               26.0   30.0   34.0 :  <5    5   <5   <5   <5   <5
:LITTLE SIOUX RIVER
ABOVE SPENCER       10.0   13.0   15.0 :  19   55   <5   22   <5   7
AT SPENCER          10.0   14.0   16.0 :  36   74    5   22   <5   9
:OCHEYEDAN RIVER
SPENCER              8.0    9.5   10.5 :  16   47   10   21    5   11
:LITTLE SIOUX RIVER
LINN GROVE          18.0   19.5   21.0 :  27   63    7   36   <5   14
CHEROKEE            17.0   21.0   24.0 :   7   40   <5   18   <5    6
CORRECTIONVILLE     19.0   20.0   21.0 :   6   20   <5   17   <5   10
:WEST FORK DITCH
HORNICK             20.0   22.0   27.0 :  12   22    8   15   <5   <5
:PERRY CREEK
SIOUX CITY          24.0   26.0   28.0 :  <5   <5   <5   <5   <5   <5
:BIG SIOUX RIVER
BROOKINGS            9.0   10.5   12.0 :  51   48   31   36   15   25
DELL RAPIDS         12.0   14.0   15.0 :  28   34   11   22    8    9
SIOUX FALLS 60TH    12.0   14.0   16.0 :  27   33    9   22    5    8
:SKUNK CREEK
SIOUX FALLS         11.5   15.0   17.0 :  <5   10   <5    5   <5   <5
:BIG SIOUX RIVER
SIOUX FALLS NORTH   16.0   18.0   31.0 :  23   34   13   30   <5   <5
:SPLIT ROCK CREEK
CORSON               8.5   11.0   14.0 :  19   34   10   19    7    7
:ROCK RIVER
LUVERNE             10.0   12.0   14.0 :  17   16    7    7   <5   <5
ROCK RAPIDS         13.0   16.0   19.0 :  28   41   14   23   11   11
ROCK VALLEY         16.0   17.0   19.0 :  12   12    9   11    7    8
:BIG SIOUX RIVER
HAWARDEN            15.0   20.0   23.0 :  37   50   12   28    7   13
AKRON               16.0   18.0   20.0 :  35   54   27   45   14   30
SIOUX CITY          99.0  105.0  108.0 :   7   12   <5   <5   <5   <5
:JAMES RIVER
HURON               11.0   13.0   15.0 :  41   41   27   32   21   18
FORESTBURG          12.0   14.0   16.0 :  38   43   27   29   11   16
MITCHELL            17.0   20.0   22.0 :  40   49   21   33   12   19
:FIRESTEEL CREEK
MOUNT VERNON         8.0   13.0   15.0 :  16   36   <5   12   <5   <5
:JAMES RIVER
SCOTLAND            13.0   14.0   16.0 :  31   49   24   39   12   29
YANKTON             12.0   14.0   16.0 :  24   44   16   32   12   29
:WEST FORK VERMILLION RIVER
PARKER               9.0   10.0   11.0 :  <5   10   <5    6   <5   <5
:EAST FORK VERMILLION RIVER
PARKER              12.0   14.0   16.0 :   9   23   <5   11   <5   <5
:VERMILLION RIVER
DAVIS               11.0   13.0   15.0 :  31   39   13   31   <5    7
WAKONDA             14.0   15.5   17.0 :  28   40   22   34   14   31
VERMILLION          21.0   22.0   30.0 :  13   30    6   29   <5   <5
:REDWOOD RIVER
MARSHALL            14.0   15.0   16.5 :  15   13   13   10   13    7
:DES MOINES RIVER
JACKSON             12.0   14.0   16.0 :  12   21   <5   13   <5   <5

LEGEND
CS = CONDITIONAL SIMULATION (CURRENT OUTLOOK)
HS = HISTORICAL SIMULATION
FT = FEET

IN TABLE 2 BELOW...THE 95 THROUGH 5 PERCENT COLUMNS INDICATE THE
PROBABILITY OF EXCEEDING THE LISTED STAGE LEVELS (FT) FOR THE VALID
TIME PERIOD.

...TABLE 2--EXCEEDANCE PROBABILITIES...

                               CHANCE OF EXCEEDING STAGES
                                  AT SPECIFIC LOCATIONS
                          VALID PERIOD: 2/22/2014 - 5/23/2014
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:FLOYD RIVER
SHELDON               5.7    5.8    6.0    6.9    8.9   12.1   14.8
ALTON                 6.1    6.2    6.6    7.2    8.8   12.8   16.3
LE MARS              10.8   10.9   11.4   11.9   13.6   18.0   20.9
:WEST BRANCH FLOYD
STRUBLE               4.3    4.5    5.0    5.3    6.9   11.7   14.0
:FLOYD RIVER
MERRILL               0.3    0.5    1.1    1.5    3.4    8.2   10.1
JAMES                 9.6    9.7   10.1   10.5   12.1   16.6   18.4
:LITTLE SIOUX RIVER
ABOVE SPENCER         5.5    5.5    5.8    6.8    9.5   10.9   12.4
AT SPENCER            5.7    5.8    6.6    7.8   10.7   12.4   13.9
:OCHEYEDAN RIVER
SPENCER               2.5    2.6    2.9    3.5    6.3    9.4   10.6
:LITTLE SIOUX RIVER
LINN GROVE           15.9   16.0   16.1   16.4   18.1   19.1   20.6
CHEROKEE              5.2    5.6    6.0    8.0   13.7   16.5   19.2
CORRECTIONVILLE       6.1    6.3    6.9    7.8   12.3   15.6   19.3
:WEST FORK DITCH
HORNICK               6.7    7.3    8.0   10.1   14.5   20.4   23.7
:PERRY CREEK
SIOUX CITY            7.1    7.1    7.5    7.9    8.7   13.6   17.3
:BIG SIOUX RIVER
BROOKINGS             4.5    5.2    7.1    9.1   10.9   12.2   13.0
DELL RAPIDS           5.8    6.1    7.5    9.6   13.1   14.2   16.0
SIOUX FALLS 60TH      3.7    4.1    5.8    8.1   12.5   13.6   16.0
:SKUNK CREEK
SIOUX FALLS           4.3    4.8    5.3    5.8    6.8    7.5    8.9
:BIG SIOUX RIVER
SIOUX FALLS NORTH     7.8    8.5    9.9   11.6   15.6   18.9   23.1
:SPLIT ROCK CREEK
CORSON                3.4    3.7    4.2    4.8    7.1   10.1   14.5
:ROCK RIVER
LUVERNE               3.9    4.0    4.2    4.8    8.2   11.8   12.5
ROCK RAPIDS           8.4    8.5    8.9   10.0   13.3   19.4   23.3
ROCK VALLEY           5.3    5.6    6.2    8.2   11.4   16.8   20.4
:BIG SIOUX RIVER
HAWARDEN              8.8    9.4   11.5   13.2   17.0   20.8   24.7
AKRON                 8.8    9.3   11.2   13.3   18.9   21.3   23.6
SIOUX CITY           85.4   85.6   86.5   87.2   92.0   94.6  101.9
:JAMES RIVER
HURON                 9.4    9.5    9.7   10.7   14.3   16.9   19.3
FORESTBURG            5.1    5.5    6.5   11.1   14.3   16.4   18.2
MITCHELL             10.3   11.0   12.4   15.5   19.7   23.0   24.2
:FIRESTEEL CREEK
MOUNT VERNON          2.2    2.2    2.2    3.8    6.2   10.7   12.7
:JAMES RIVER
SCOTLAND              4.8    5.1    5.8    9.3   13.7   17.5   19.1
YANKTON               2.0    2.4    3.9    6.3   11.4   18.8   21.9
:WEST FORK VERMILLION RIVER
PARKER                1.5    1.6    1.9    2.6    3.4    6.3    8.0
:EAST FORK VERMILLION RIVER
PARKER                4.9    5.2    6.0    8.3   10.8   11.8   13.8
:VERMILLION RIVER
DAVIS                 4.6    5.1    6.2    8.4   11.6   13.2   14.6
WAKONDA               5.0    5.3    6.5    9.0   14.7   17.4   17.5
VERMILLION            4.3    4.8    6.0    8.7   14.7   21.4   24.1
:REDWOOD RIVER
MARSHALL              8.0    8.1    8.5    9.4   11.0   18.1   22.0
:DES MOINES RIVER
JACKSON               5.6    5.8    6.2    7.0    9.8   12.3   13.3

IN TABLE 3 BELOW...THE 95 THROUGH 5 PERCENT COLUMNS INDICATE THE
PROBABILITY OF FALLING BELOW THE LISTED STAGE LEVELS (FT) FOR THE
VALID TIME PERIOD.

...TABLE 3--NONEXCEEDANCE PROBABILITIES...

                            CHANCE OF FALLING BELOW STAGES
                                 AT SPECIFIC LOCATIONS
                          VALID PERIOD: 2/22/2014 - 5/23/2014
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:REDWOOD RIVER
MARSHALL              7.0    7.0    7.0    6.9    6.8    6.8    6.7
:DES MOINES RIVER
JACKSON               3.6    3.6    3.5    3.5    3.5    3.4    3.4

SUMMARY OF THE PROBABILISTIC OUTLOOKS...
THE CONDITIONAL SIMULATIONS BASED ON THE CURRENT CONDITIONS INDICATE
THAT THERE IS A LOWER THAN NORMAL CHANCE OF SEEING MINOR...
MODERATE...OR MAJOR FLOODING FOR NEARLY THE ENTIRE REGION. THE ONLY
EXCEPTIONS ARE NEAR NORMAL CHANCES OF MINOR AND MODERATE FLOODING ON
THE MIDDLE PORTIONS OF THE JAMES RIVER BETWEEN HURON AND MITCHELL...
AND FOR THE UPPER PORTIONS OF THE BIG SIOUX RIVER AROUND AND
UPSTREAM OF BROOKINGS. ALSO...NEAR NORMAL CHANCES FOR MINOR FLOODING
ARE INDICATED ON PARTS OF THE ROCK RIVER. NORMAL CHANCES FOR
MINOR...MODERATE...OR MAJOR FLOODING ARE INDICATED AS WELL AS THE
REDWOOD RIVER IN SOUTHWESTERN MINNESOTA.

CURRENT SNOW CONDITIONS...
AREAS SOUTH OF A LINE FROM HURON TO SIOUX FALLS TO SPENCER IOWA HAVE
LITTLE TO NO SNOW REMAINING ON THE GROUND. NORTH OF THAT LINE...SNOW
DEPTHS ARE STILL IN THE 4 TO 8 INCH RANGE...WITH POCKETS OF 10 TO 14
INCHES REMAINING AROUND FLANDREAU AND PIPESTONE...AS WELL AS NORTH
OF BROOKINGS COUNTY IN THE UPPER BIG SIOUX BASIN. THE WATER CONTENT
OF THE REMAINING SNOW PACK IS GENERALLY IN THE 1 TO 3 INCH RANGE.
THE SNOW PACK DENSITY IS GENERALLY 15 TO 25 PERCENT. SIGNIFICANT
MELTING AND RUNOFF WILL OCCUR WHEN THE SNOW DENSITY GETS OVER 30 TO
40 PERCENT.

CURRENT SOIL MOISTURE/FROST CONDITIONS...
THE LATEST MODELED SOIL MOISTURE SHOWS -2 TO -4 INCH ANOMALIES
ACROSS SOUTHWESTERN MINNESOTA...EXTREME NORTHEASTERN NEBRASKA AND
NORTHWESTERN IOWA...AND +1 TO -2 INCH ANOMALIES IN SOUTH-CENTRAL AND
SOUTHEASTERN SOUTH DAKOTA. FROST DEPTHS IN THE SOILS ACROSS THE
REGION STILL RANGE FROM AROUND 20 INCHES IN THE SOUTH TO 40 INCHES
IN THE NORTH. SOME OF THE SOUTHERN AREAS HAVE SEEN THE TOP FEW
INCHES OF THE SOILS START TO THAW WITH THE WARM TEMPERATURES AND
SNOW MELT EARLIER THIS WEEK.

CURRENT RIVER/ICE CONDITIONS...
A FEW OF THE MOST SOUTHERN PORTIONS OF THE MAIN RIVERS...AND SEVERAL
OF THE SMALLER STREAMS AND TRIBUTARIES...HAVE STARTED TO SEE SOME
VERY MINIMAL RUNOFF FROM SNOW MELT OVER THE LAST FEW DAYS. MOST OF
THE REST OF THE RECENT SNOWMELT IS EITHER BEING ABSORBED BY THE TOP
FEW INCHES OF THAWED SOILS...OR IS SIMPLY PONDING UP IN FIELDS AND
DITCHES WAITING FOR THE SOILS TO BEGIN THAWING. CURRENT STREAMFLOWS
ARE NEAR NORMAL TO SLIGHTLY ABOVE NORMAL ACROSS NORTHWEST IOWA. THE
REST OF THE REGION STILL HAS COMPLETELY ICE COVERED RIVERS AND
STREAMS. ICE THICKNESSES ARE ESTIMATED TO STILL BE AT LEAST ONE TO
TWO FEET ACROSS ALL OF SOUTHWESTERN MINNESOTA AND EASTERN SOUTH
DAKOTA. DUE TO THIS THICK ICE...ICE JAMS WILL BE A VERY REAL THREAT
AS WE HEAD INTO THE MELT/BREAKUP PERIOD OVER THE NEXT SEVERAL
WEEKS.

TEMPERATURE/PRECIPITATION OUTLOOKS...
FOR THE NEXT 2 WEEKS...TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL
WITH BELOW NORMAL PRECIPITATION. THE LATEST 30 DAY OUTLOOK FOR MARCH
SHOWS THE BEST CHANCES FOR BELOW NORMAL TEMPERATURES ACROSS THE
AREA...WITH EQUAL CHANCES OF ABOVE...NORMAL...OR BELOW
PRECIPITATION. THE 90 DAY OUTLOOK FOR MARCH THROUGH MAY SHOWS
INCREASED CHANCES FOR BELOW NORMAL TEMPERATURES FOR MOST OF THE
AREA...AND EQUAL CHANCES FOR ABOVE...NORMAL...OR BELOW
PRECIPITATION.

THESE LONG-RANGE PROBABILISTIC OUTLOOKS CONTAIN FORECAST VALUES THAT
ARE CALCULATED USING MULTIPLE SEASON SCENARIOS FROM 30 OR MORE YEARS
OF CLIMATOLOGICAL DATA...INCLUDING CURRENT CONDITIONS OF THE
RIVER...SOIL MOISTURE...SNOW COVER...AND 30 TO 90 DAY LONG-RANGE
OUTLOOKS OF TEMPERATURE AND PRECIPITATION. BY PROVIDING A RANGE OF
PROBABILITIES...THE LEVEL OF RISK ASSOCIATED WITH LONG-RANGE PLANNING
DECISIONS CAN BE DETERMINED. THESE PROBABILISTIC FORECASTS ARE PART
OF THE NATIONAL WEATHER SERVICE`S ADVANCED HYDROLOGIC PREDICTION
SERVICE.

VISIT OUR WEB SITE WEATHER.GOV/FSD FOR MORE WEATHER AND WATER
INFORMATION.

THE NEXT OUTLOOK WILL BE ISSUED ON THURSDAY MARCH 6.

$$

MG









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