Flood Potential Outlook
Issued by NWS Twin Cities, MN

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PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
110 PM CDT FRI APR 26 2019

..UPDATED LONG RANGE FLOOD OUTLOOK FOR THE MINNESOTA, UPPER
MISSISSIPPI, AND WESTERN WISCONSIN RIVER BASINS: THE PROBABILITY OF
SNOWMELT FLOODING FOR THIS SPRING HAS INCREASED...

Rivers continue to run high over the entire area as a result of the
spring snowmelt and April rain/snow events. Though rivers are
receding slowly, we remain vulnerable to heavy rainfall events in
the coming month.

Table 1 below lists the current (CS) and historical or normal (HS)
probabilities for exceeding minor, moderate, and major flood stages.

...TABLE 1--PROBABILITIES FOR MINOR...MODERATE AND MAJOR FLOODING...
                    VALID  PERIOD: 04/29/2019 - 07/28/2019

                                       :    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 :  47   10   <5   <5   <5   <5
:COTTONWOOD RIVER
NEW ULM             11.0   13.0   16.0 :  50   19   21   12   11   <5
:MINNESOTA RIVER
MONTEVIDEO          14.0   16.0   17.5 : >95   39   94   14   20    6
GRANITE FALLS      888.5  893.5  896.5 :  17   <5   <5   <5   <5   <5
MANKATO             22.0   25.0   30.0 :  24    6    9   <5   <5   <5
HENDERSON          732.0  736.0  739.5 :  46   12   12   <5   <5   <5
JORDAN              25.0   28.0   34.0 : >95   21   30    7   <5   <5
SAVAGE             702.0  710.0  712.0 : >95   50   37    7   19    5
:LONG PRAIRIE RIVER
LONG PRAIRIE         7.0    8.0   10.0 :  18   17    9    8   <5   <5
:SAUK RIVER
ST CLOUD             6.0    7.0    9.0 :  11   11   <5   <5   <5   <5
:SOUTH FORK CROW RIVER
MAYER               11.0   15.0   16.0 :  39   18    7   <5   <5   <5
DELANO              16.5   17.5   18.5 :  33    7   22   <5   14   <5
:CROW RIVER
ROCKFORD            10.0   12.0   14.0 :  40   13   28   <5   12   <5
:MISSISSIPPI RIVER
ST CLOUD             9.0   10.0   11.0 :  22   21   16    9    7   <5
ANOKA               12.0   14.0   17.0 :  17   <5   <5   <5   <5   <5
MINNEAPOLIS         16.0   16.5   17.0 :   8   <5    7   <5    6   <5
ST PAUL             14.0   15.0   17.0 :  85   15   42   11   26    7
HASTINGS L/D#2      15.0   17.0   18.0 : >95   30  >95   13   34    9
RED WING L/D#3     680.5  681.5  683.0 :  57   13   28    9   12   <5
RED WING            14.0   15.0   16.0 :  52    9   25    8   17   <5
:ST CROIX RIVER
STILLWATER          87.0   88.0   89.0 :  41   16   22   11   15    6
:EAU CLAIRE RIVER
FALL CREEK          11.0   14.0   17.0 :  13   11    8    6   <5   <5
:CHIPPEWA RIVER
EAU CLAIRE         773.0  776.0  778.0 :  12    5    5   <5   <5   <5
DURAND              13.0   15.5   17.0 :  34   20   11   <5   <5   <5


...TABLE 2--EXCEEDANCE PROBABILITIES...Shows the probabilities of
reaching various stages for each forecast point through July...

                              CHANCE OF EXCEEDING STAGES
                                 AT SPECIFIC LOCATIONS
                          VALID  PERIOD: 04/29/2019 - 07/28/2019
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:REDWOOD RIVER
REDWOOD FALLS         3.9    3.9    4.6    5.8    7.7    9.6   12.9
:COTTONWOOD RIVER
NEW ULM               6.9    6.9    7.6   11.1   12.6   16.1   18.2
:MINNESOTA RIVER
MONTEVIDEO           16.0   16.0   16.0   16.2   17.2   18.7   19.9
GRANITE FALLS       886.2  886.2  886.2  886.4  887.5  889.3  890.4
MANKATO              16.3   16.4   17.1   19.4   21.9   24.8   27.5
HENDERSON           730.3  730.4  730.6  731.8  734.0  736.3  738.4
JORDAN               25.1   25.1   25.3   26.3   28.4   30.8   33.2
SAVAGE              709.0  709.1  709.1  709.6  711.3  713.2  714.3
:LONG PRAIRIE RIVER
LONG PRAIRIE          5.1    5.1    5.1    5.8    6.7    7.9    9.0
:SAUK RIVER
ST CLOUD              4.8    4.8    4.8    4.9    5.6    6.0    6.9
:SOUTH FORK CROW RIVER
MAYER                 8.5    8.6    8.7    9.9   12.9   14.5   15.8
DELANO               13.7   13.7   13.8   14.4   17.0   18.7   19.2
:CROW RIVER
ROCKFORD              8.5    8.6    8.6    9.2   12.5   14.5   15.7
:MISSISSIPPI RIVER
ST CLOUD              7.7    7.7    7.8    8.2    9.0   10.3   11.7
ANOKA                 9.0    9.0    9.2    9.9   11.6   12.2   13.0
MINNEAPOLIS          10.6   10.6   10.7   11.2   13.9   15.7   17.6
ST PAUL              13.9   14.0   14.1   14.7   17.2   20.3   20.8
HASTINGS L/D#2       17.1   17.1   17.2   17.5   18.7   21.0   21.5
RED WING L/D#3      680.1  680.1  680.1  680.8  681.8  683.1  684.8
RED WING             13.5   13.5   13.6   14.1   15.0   17.2   18.8
:ST CROIX RIVER
STILLWATER           85.9   85.9   85.9   86.5   87.8   89.4   91.8
:EAU CLAIRE RIVER
FALL CREEK            5.2    5.2    5.6    6.8    9.0   12.6   14.6
:CHIPPEWA RIVER
EAU CLAIRE          766.1  766.1  766.2  767.1  769.6  773.6  776.0
DURAND               10.9   11.0   11.0   11.7   13.8   15.9   16.8


...TABLE 3--NONEXCEEDANCE PROBABILITIES...shows the probabilities of
falling below various stages through July...

                            CHANCE OF FALLING BELOW STAGES
                                 AT SPECIFIC LOCATIONS
                          VALID  PERIOD: 04/29/2019 - 07/28/2019
LOCATION              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:REDWOOD RIVER
REDWOOD FALLS         2.7    2.5    2.3    2.1    2.1    2.0    2.0
:COTTONWOOD RIVER
NEW ULM               4.4    4.0    3.4    3.1    2.9    2.6    2.5
:MINNESOTA RIVER
MONTEVIDEO           10.1    9.9    9.7    6.5    5.7    5.4    5.1
GRANITE FALLS       882.6  882.5  882.5  881.4  881.1  881.0  880.9
MANKATO              10.0    7.9    6.9    6.0    4.7    4.2    4.1
HENDERSON           723.5  721.2  719.9  718.6  716.9  715.9  715.5
JORDAN               15.5   12.6   10.9    9.5    7.8    7.0    6.6
SAVAGE              696.2  693.7  691.1  689.0  688.3  687.8  687.7
:LONG PRAIRIE RIVER
LONG PRAIRIE          4.1    3.8    3.2    2.6    2.3    2.1    2.1
:SAUK RIVER
ST CLOUD              3.5    2.9    2.4    1.9    1.7    1.6    1.6
:SOUTH FORK CROW RIVER
MAYER                 4.3    3.9    3.5    2.8    2.2    1.9    1.6
DELANO                9.0    8.5    8.0    7.0    6.4    6.0    5.8
:CROW RIVER
ROCKFORD              4.8    4.5    4.1    3.6    3.3    3.1    3.0
:MISSISSIPPI RIVER
ST CLOUD              6.2    6.0    5.5    5.3    5.0    4.7    4.6
ANOKA                 5.7    5.4    5.1    4.8    4.6    4.5    4.5
MINNEAPOLIS           7.1    6.6    6.0    5.6    5.2    4.9    4.8
ST PAUL               6.0    5.3    4.4    3.9    3.6    3.5    3.4
HASTINGS L/D#2        8.7    7.9    6.9    6.0    5.3    5.0    4.7
RED WING L/D#3      673.0  672.3  671.7  670.2  669.3  668.8  668.6
RED WING              7.0    6.4    5.6    4.3    3.6    2.9    2.7
:ST CROIX RIVER
STILLWATER           78.4   77.6   76.7   75.6   74.7   73.6   73.1
:EAU CLAIRE RIVER
FALL CREEK            1.5    1.2    1.1    0.9    0.7    0.5    0.5
:CHIPPEWA RIVER
EAU CLAIRE          760.2  759.7  759.3  759.1  759.0  758.8  758.7
DURAND                4.2    3.8    3.1    2.9    2.6    2.3    2.2

The timing and severity of late spring flooding will now be largely
dependent whether we receive a period of very heavy rainfall during
the month of May. With river levels remaining high and soil moisture
also remaining high, we are more susceptible to flooding from heavy
rain events, particularly thunderstorms with torrential rainfall
rates (such as 1-2 inches per hour over several hours).  Rivers
would rise faster than normal and reach higher levels than normal in
this case. Keep an eye on the forecasts at weather.gov to be ready
to take action should we see these types of storms on the horizon.

These long-range probabilistic outlooks are calculated using
multiple season scenarios from 30 or more years of climatological
data, and include current streamflow, soil moisture, snowpack, and
30 to 90 day long range outlooks of temperature and precipitation.

Graphical versions of the long range flood potential are available
at: water.weather.gov/ahps/long_range.php

Updated weather forecasts are located at: weather.gov/twincities

The next outlook will be issued as conditions warrant; appropriate
statements, watches, and warnings will be issued as needed if the
threat becomes imminent.

$$


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