Flood Potential Outlook
Issued by NWS Twin Cities, MN

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PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
215 PM CST FRI MAR 2 2018

...Spring Flood Probabilities for the Minnesota, Upper Mississippi,
and St. Croix River Basins and Tributaries...

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.

...TABLE 1--PROBABILITIES FOR MINOR...MODERATE AND MAJOR FLOODING...
                   VALID  PERIOD: 03/11/2018 - 06/02/2018

                                       :    CURRENT AND HISTORICAL
                                       :     CHANCES OF EXCEEDING
                                       :       FLOOD CATERGORIES
                                       :      AS A PERCENTAGE (%)
                      CATEGORICAL      :
                   FLOOD STAGES (FT)   :   MINOR    MODERATE   MAJOR
LOCATION           MINOR   MOD   MAJOR :  CS   HS   CS   HS   CS   HS
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:REDWOOD RIVER
REDWOOD FALLS        6.0   15.0   16.0 :  57   24   <5   <5   <5   <5
:COTTONWOOD RIVER
NEW ULM             11.0   13.0   16.0 :  92   34   62   19   26   10
:MINNESOTA RIVER
MONTEVIDEO          14.0   16.0   17.5 :  61   44   33   26   14   16
GRANITE FALLS      888.5  893.5  896.5 :   9   10   <5   <5   <5   <5
MANKATO             22.0   25.0   30.0 :  36   16   17    7   <5   <5
HENDERSON          732.0  736.0  739.5 :  49   20   18    8   <5   <5
JORDAN              25.0   28.0   34.0 :  70   32   39   17   <5   <5
SAVAGE             702.0  710.0  712.0 :  91   61   35   14   15   10
:LONG PRAIRIE RIVER
LONG PRAIRIE         7.0    8.0   10.0 :  20   24    7    7   <5   <5
:SAUK RIVER
ST CLOUD             6.0    7.0    9.0 :  14   18   <5   10   <5   <5
:SOUTH FORK CROW RIVER
MAYER               11.0   15.0   16.0 :  59   28   17   11   11    9
DELANO              16.5   17.5   18.5 :  37   18   20   14   16   11
:CROW RIVER
ROCKFORD            10.0   12.0   14.0 :  53   23   33   14   18   10
:MISSISSIPPI RIVER
ST CLOUD             9.0   10.0   11.0 :  32   31   13   15    6    6
MINNEAPOLIS         16.0   16.5   17.0 :   8   10    7    9    6    8
ST PAUL             14.0   15.0   17.0 :  47   24   41   19   23   12
HASTINGS L/D#2      15.0   17.0   18.0 :  66   39   45   22   31   16
RED WING L/D#3     680.5  681.5  683.0 :  39   18   26   17   14    9
RED WING            14.0   15.0   16.0 :  36   18   23   15   16    9
:ST CROIX RIVER
STILLWATER          87.0   88.0   89.0 :  31   21   20   14   17   11
:EAU CLAIRE RIVER
FALL CREEK          11.0   14.0   17.0 :  38   27   19   16    7   <5
:CHIPPEWA RIVER
EAU CLAIRE         773.0  776.0  778.0 :  33   16   15    9    9    6
DURAND              13.0   15.5   17.0 :  68   48   28   13   10    6


LEGEND
CS = CONDITIONAL SIMULATION (CURRENT OUTLOOK)
HS = HISTORICAL SIMULATION ("NORMAL")
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: 03/11/2018 - 06/02/2018
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:REDWOOD RIVER
REDWOOD FALLS         3.3    4.0    4.8    6.3    7.8   11.1   13.6
:COTTONWOOD RIVER
NEW ULM               9.5   11.3   12.2   13.8   16.2   19.1   19.6
:MINNESOTA RIVER
MONTEVIDEO            8.9   10.5   12.9   15.0   16.8   17.8   19.0
GRANITE FALLS       882.9  883.4  884.2  885.4  887.2  888.4  889.6
MANKATO              12.5   14.1   16.7   19.6   23.0   26.2   27.7
HENDERSON           725.9  727.4  729.5  731.9  734.8  737.6  739.1
JORDAN               19.8   22.1   24.4   26.8   29.3   32.1   33.9
SAVAGE              699.5  702.3  705.6  708.7  710.8  713.7  715.6
:LONG PRAIRIE RIVER
LONG PRAIRIE          5.1    5.3    5.9    6.3    6.9    7.7    8.2
:SAUK RIVER
ST CLOUD              3.7    4.0    4.6    5.1    5.7    6.2    6.8
:SOUTH FORK CROW RIVER
MAYER                 6.9    7.6    9.4   11.5   13.9   16.1   18.1
DELANO               11.7   12.4   14.0   15.7   17.3   19.1   20.7
:CROW RIVER
ROCKFORD              5.8    6.9    8.4   10.2   13.2   15.6   17.9
:MISSISSIPPI RIVER
ST CLOUD              7.2    7.6    7.9    8.5    9.4   10.3   11.2
MINNEAPOLIS           8.9    9.9   10.4   11.7   13.9   15.7   18.2
ST PAUL               7.7    9.5   10.8   13.7   16.9   19.7   21.9
HASTINGS L/D#2       10.7   12.7   14.1   16.4   18.5   20.5   22.3
RED WING L/D#3      675.9  676.8  678.1  679.7  681.6  684.1  685.4
RED WING              9.1   10.1   11.2   13.1   14.8   18.3   19.3
:ST CROIX RIVER
STILLWATER           82.9   83.3   84.7   85.9   87.6   90.7   92.6
:EAU CLAIRE RIVER
FALL CREEK            7.2    7.7    8.1    9.5   12.5   15.2   17.5
:CHIPPEWA RIVER
EAU CLAIRE          766.5  766.9  768.4  771.5  774.0  777.3  783.3
DURAND               10.6   11.2   12.5   14.5   15.8   17.0   19.0

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: 03/11/2018 - 06/02/2018
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:REDWOOD RIVER
REDWOOD FALLS         2.0    2.0    2.0    1.9    1.9    1.8    1.8
:COTTONWOOD RIVER
NEW ULM               3.4    3.3    3.3    3.2    3.0    2.8    2.7
:MINNESOTA RIVER
MONTEVIDEO            4.9    4.8    4.3    3.9    3.8    3.4    3.3
GRANITE FALLS       881.6  881.6  881.4  881.2  881.1  881.0  880.9
MANKATO               3.9    3.8    3.8    3.7    3.4    3.2    3.2
HENDERSON           715.3  715.2  715.1  715.1  714.8  714.4  714.3
JORDAN                6.7    6.6    6.5    6.5    6.2    5.9    5.8
SAVAGE              687.6  687.6  687.6  687.5  687.5  687.5  687.5
:LONG PRAIRIE RIVER
LONG PRAIRIE          1.8    1.8    1.8    1.8    1.8    1.7    1.7
:SAUK RIVER
ST CLOUD              1.8    1.8    1.7    1.7    1.7    1.7    1.7
:SOUTH FORK CROW RIVER
MAYER                 2.4    2.2    2.1    2.1    2.1    2.0    1.9
DELANO                6.7    6.4    6.3    6.2    6.2    6.1    6.0
:CROW RIVER
ROCKFORD              3.0    2.9    2.9    2.9    2.9    2.8    2.8
:MISSISSIPPI RIVER
ST CLOUD              4.5    4.5    4.5    4.5    4.4    4.4    4.4
MINNEAPOLIS           4.7    4.6    4.6    4.6    4.6    4.5    4.5
ST PAUL               3.4    3.4    3.3    3.3    3.3    3.3    3.3
HASTINGS L/D#2        4.6    4.5    4.5    4.5    4.5    4.5    4.5
RED WING L/D#3      667.5  667.4  667.1  667.1  667.0  667.0  667.0
RED WING              2.5    2.4    2.2    2.2    2.1    2.1    2.0
:ST CROIX RIVER
STILLWATER           75.3   75.3   75.3   75.3   75.2   75.2   75.2
:EAU CLAIRE RIVER
FALL CREEK            1.7    1.7    1.4    1.2    1.1    1.0    0.9
:CHIPPEWA RIVER
EAU CLAIRE          759.4  759.2  759.1  759.1  758.9  758.9  758.8
DURAND                3.8    3.4    3.1    3.0    2.8    2.7    2.6


Spring flood factors will be based on past precipitation...soil
moisture...snowpack...snow water runoff...frost depth...and forecast
snow and rainfall amounts in the next couple of months.

Our snowpack is fairly close to normal over the region as of early
March; after a dry mid-winter, February saw nearly double the amount
of snow over central MN. Most of the area has from one to three
inches of snow water equivalent (SWE) on the ground, which is
nothing unusual. Soil moisture and frost depth are also very close
to what we would normally see in early March.

Therefore...the main flood threat will be determined by the
occurrences of heavy rain events in late March and April.

The next two weeks call for above normal precipitation over
Minnesota and western Wisconsin; we expect about an inch of water
early next week (in the form of snow north and mixed rain/snow
south). The March and April climate outlooks continue this
trend...so we will be watching for more rainfall events to
potentially trigger flooding.

Pay close attention to the 6-10 and 8-14 day outlooks from the
Climate Prediction Center, as well as NWS Twin Cities forecasts and
outlooks. Plan accordingly should heavy precipitation be
expected.

These long-range probablistic outlooks contain forecast values that
are calculated using multiple season scenarios from 30+ years of
climatological data, including current conditions and long range
outlooks. These probabilistic forecasts are part of the NWS Advanced
Hydrologic Prediction Service (AHPS). They are available in
graphical format at:

water.weather.gov/ahps2/index.php?wfo=mpx

The next outlook will be issued in late March.

$$



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