Flood Potential Outlook
Issued by NWS Grand Forks, ND

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MNC005-007-027-029-051-057-069-077-087-089-107-111-113-
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PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE EASTERN NORTH DAKOTA/GRAND FORKS ND
0907 AM CDT Fri May 29 2015


...RED RIVER BASIN OUTLOOK FOR RIVER FLOOD POTENTIAL...

         This outlook covers the Red River of the North
         and its Minnesota and North Dakota tributaries.

  Probabilistic Hydrologic Outlooks now use 64 years (1949-2012)
    of past weather...temperature and precipitation...for the
    ensemble predictive hydrographs used in calculating the
    probabilities of exceeding a river level for the valid period
    of the outlook.

  Outlook Schedule - The National Weather Service in Grand Forks,
    North Dakota will be providing the Advanced Hydrologic
    Prediction Services (AHPS) Long-Range Probabilistic Hydrologic
    Outlooks for the Red River of the North and its Minnesota and
    North Dakota tributaries according to the following schedule:

    - near the end of the month throughout the year, except for...

    - The Spring Flood and Water Resources Outlooks that will be
       issued at least twice a month during the spring snow-melt
        season beginning in mid-to-late February or early-March.

  The following message has three river data sections...

    - The first (Table 1) gives the current and normal/historical
       chances of river locations reaching their Minor...Moderate
        and Major flood category.

    - The second (Table 2) gives the current chances of river
       locations rising above the river stages listed.

    - The third (Table 3) gives the current chances of river
       locations falling below the river stages listed.

.Red River Long-Range Probabilistic Outlook by Flood Category...
                     from  6/1/2015 to 8/30/2015

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:   6/1/2015 - 8/30/2015

                                         : Current and Historical
                                         :  Chances of Exceeding
                                         :    Flood Categories
                                         :   as s Percentage (%)
                         Categorical     :
                      Flood Stages (ft)  :  Minor   Moderate  Major
Location            Minor    Mod   Major :  CS HS    CS HS    CS HS
--------            ------ ------ ------ : --- ---  --- ---  --- ---
Red River of the North.....
  WAHPETON            11.0   13.0   15.0 :  44  47   10  18   <5  <5
  HICKSON             30.0   34.0   38.0 :   6   9   <5  <5   <5  <5
  FARGO               18.0   25.0   30.0 :  56  58   12  12   <5   7
  HALSTAD             26.0   32.0   37.5 :  <5   6   <5  <5   <5  <5
  GRAND FORKS         28.0   40.0   46.0 :  13  20   <5  <5   <5  <5
  OSLO                26.0   30.0   36.0 :  16  24    6  16   <5  <5
  DRAYTON             32.0   38.0   42.0 :  <5   6   <5   6   <5  <5
  PEMBINA             39.0   44.0   49.0 :   6  10   <5   6   <5  <5
Minnesota Tributaries.....
  SABIN               13.0   15.0   19.0 :  26  21   <5  <5   <5  <5
  HAWLEY               8.0    9.0   11.0 :  10  12    9   7   <5  <5
  DILWORTH            13.0   20.0   26.0 :  33  32   <5  <5   <5  <5
  TWIN VALLEY         10.0   12.0   14.0 :  <5  <5   <5  <5   <5  <5
  HENDRUM             20.0   28.0   32.0 :  10  18   <5  <5   <5  <5
  SHELLY              14.0   20.0   23.0 :  <5  <5   <5  <5   <5  <5
  CLIMAX              20.0   25.0   30.0 :  <5  <5   <5  <5   <5  <5
  HIGH LANDING        12.0   12.5   13.0 :  <5  <5   <5  <5   <5  <5
  CROOKSTON           15.0   23.0   25.0 :   9  23   <5  <5   <5  <5
  ABOVE WARREN        67.0   71.0   75.0 :  <5  <5   <5  <5   <5  <5
  ALVARADO           106.0  108.0  110.0 :  <5   7   <5  <5   <5  <5
  HALLOCK            802.0  806.0  810.0 :  21  21    9   7   <5  <5
  ROSEAU              16.0   18.0   19.0 :   7   7   <5  <5   <5  <5
North Dakota Tributaries.....
  ABERCROMBIE         10.0   12.0   18.0 :   9  13    6   9   <5  <5
  VALLEY CITY         15.0   16.0   17.0 :  <5  <5   <5  <5   <5  <5
  LISBON              15.0   17.0   19.0 :  <5  <5   <5  <5   <5  <5
  KINDRED             16.0   19.0   20.5 :  <5  <5   <5  <5   <5  <5
  WEST FARGO DVRSN    18.0   20.0   21.0 :  <5   6   <5  <5   <5  <5
  HARWOOD            884.0  886.0  891.0 :   7  <5   <5  <5   <5  <5
  ENDERLIN             9.5   12.0   14.0 :  <5   6   <5  <5   <5  <5
  MAPLETON           905.0  908.0  910.0 :  12  10   <5  <5   <5  <5
  HILLSBORO           10.0   13.0   16.0 :  <5  <5   <5  <5   <5  <5
  MINTO                6.0    8.0   11.0 :  <5  <5   <5  <5   <5  <5
  GRAFTON             12.0   13.5   14.5 :  <5  <5   <5  <5   <5  <5
  WALHALLA            11.0   16.0   18.0 :  <5  <5   <5  <5   <5  <5
  NECHE               18.0   19.0   20.5 :  <5   7   <5  <5   <5  <5

LEGEND:
    CS  =  Conditional Simulation (Outlook for current conditions)
    HS  =  Historical  Simulation ( "       "  normal  conditions)
    ft  =  feet                   (above gage zero datum)


.Probabilities for Rising Above Listed River Stages...
                     from  6/1/2015 to 8/30/2015

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 at the location listed.

  Interpretation Aid...The flood stage for Wahpeton on the Red
   River of the North is 11 feet. There is a 50 percent chance
    that it will rise above 10.4 feet and only a 10 percent chance
     that it will rise above 13.1 feet.

...Table 2--Exceedance Probabilities...

                                 Chance of Exceeding Stages
                                   at Specific Locations
                            Valid Period:   6/1/2015 - 8/30/2015


LOCATION              95%    90%    75%    50%    25%    10%    05%
--------            ------ ------ ------ ------ ------ ------ ------
Red River of the North.....
  WAHPETON             6.5    6.5    7.6   10.4   12.0   13.1   14.4
  HICKSON             12.8   12.8   14.8   20.3   23.6   28.4   31.3
  FARGO               16.0   16.0   16.6   19.3   21.5   25.6   28.5
  HALSTAD             12.1   12.1   12.1   13.3   17.2   22.9   25.2
  GRAND FORKS         18.7   18.7   18.7   19.4   22.8   28.8   33.5
  OSLO                14.3   14.3   14.3   15.6   22.0   29.2   32.7
  DRAYTON             16.6   16.6   16.6   16.7   20.7   26.7   30.3
  PEMBINA             23.3   23.3   23.3   23.3   28.2   35.4   41.1


MINNESOTA TRIBS:      95%    90%    75%    50%    25%    10%    05%
--------            ------ ------ ------ ------ ------ ------ ------
South Fork Buffalo River.....
  SABIN                6.2    6.2    8.7   10.8   13.3   13.8   14.6
Buffalo River.....
  HAWLEY               3.8    3.9    4.4    4.9    5.7    9.0   10.1
  DILWORTH             4.7    4.8    6.8   10.6   14.9   17.5   19.9
Wild Rice River.....
  TWIN VALLEY          2.4    2.4    2.8    3.8    5.4    7.4    9.6
  HENDRUM              5.9    5.9    7.4   10.1   16.4   20.6   26.2
Marsh River.....
  SHELLY               4.6    4.6    4.6    5.5    8.6   10.2   11.8
Sand Hill River.....
  CLIMAX               4.9    5.5    6.4    7.5    9.7   12.2   15.4
Red Lake river.....
  HIGH LANDING         4.2    4.3    5.4    8.9    9.0    9.5   10.1
  CROOKSTON            6.5    7.0    7.3    8.9   11.3   15.2   16.5
Snake River.....
  ABOVE WARREN        60.2   60.3   60.9   61.9   63.0   63.9   66.9
  ALVARADO            96.2   96.2   96.3   97.5   99.5  101.9  106.8
Two Rivers River.....
  HALLOCK            796.8  796.8  797.2  798.1  801.2  805.5  808.2
Roseau River.....
  ROSEAU               6.4    6.4    6.4    7.6    9.8   14.2   17.2


NORTH DAKOTA TRIBS:   95%    90%    75%    50%    25%    10%    05%
--------            ------ ------ ------ ------ ------ ------ ------
Wild Rice River.....
  ABERCROMBIE          1.5    1.5    1.5    2.7    4.5   10.0   13.9
Sheyenne River.....
  VALLEY CITY          5.7    5.7    5.7    6.5    8.2   10.6   11.6
  LISBON               5.0    5.0    5.0    5.6    7.6   10.7   12.3
  KINDRED              6.8    6.8    6.8    6.8   10.2   13.2   15.2
  WEST FARGO DVRSN    14.2   14.2   14.2   14.2   14.4   16.5   17.9
  HARWOOD            876.2  876.2  876.2  876.2  876.4  881.9  885.7
Maple River.....
  ENDERLIN             2.7    2.7    2.7    2.7    3.5    7.8   10.3
  MAPLETON           897.3  897.3  897.3  897.3  899.5  905.8  907.6
Goose River.....
  HILLSBORO            1.9    1.9    1.9    2.2    3.4    5.0    7.6
Forest River.....
  MINTO                1.7    1.7    1.7    2.0    2.8    4.7    5.8
Park River.....
  GRAFTON              7.5    7.5    7.5    7.8    8.3    9.4   10.6
Pembina River.....
  WALHALLA             2.9    2.9    2.9    3.2    4.6    6.2    8.6
  NECHE                4.7    4.7    4.7    5.3    7.9   10.3   16.4

.Probabilities for Falling Below Listed River Stages...
                     from  6/1/2015 to 8/30/2015

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 at the location listed.

  Interpretation Aid...The flood stage for Wahpeton on the Red
   River of the North is 11 feet. There is a 50 percent chance
    that it will fall below 4.3 feet and only a 10 percent chance
     that it will fall below 3.5 feet.

...Table 3--Non-Exceedance Probabilities...

                               Chance of Not Exceeding Stages
                                   at Specific Locations
                            Valid Period:   6/1/2015 - 8/30/2015


LOCATION              95%    50%    75%    50%    25%    10%    05%
--------            ------ ------ ------ ------ ------ ------ ------
Red River of the North.....
  WAHPETON             5.2    5.1    4.8    4.3    3.9    3.5    3.5
  HICKSON             11.4   11.3   10.9   10.4   10.0    9.6    9.6
  FARGO               15.0   15.0   14.7   14.4   14.1   13.8   13.8
  HALSTAD              6.3    5.8    5.0    4.3    3.8    3.2    3.0
  GRAND FORKS         16.5   16.3   16.1   15.8   15.6   15.4   15.2
  OSLO                 8.3    7.9    7.4    6.9    6.6    5.6    4.9
  DRAYTON             12.0   11.7   11.4   11.1   10.9   10.7   10.6
  PEMBINA             12.9   11.9   11.0    9.5    8.6    7.3    7.0


MINNESOTA TRIBS:      95%    90%    75%    50%    25%    10%    05%
--------            ------ ------ ------ ------ ------ ------ ------
South Fork Buffalo River.....
  SABIN                5.2    5.0    4.9    4.7    4.5    4.3    4.3
Buffalo River.....
  HAWLEY               3.4    3.4    3.3    3.2    3.1    3.0    3.0
  DILWORTH             3.8    3.7    3.3    3.0    2.9    2.7    2.6
Wild Rice River.....
  TWIN VALLEY          2.2    2.1    1.9    1.1    0.9    0.9    0.9
  HENDRUM              2.1    2.1    1.9    1.8    1.6    1.6    1.6
Marsh River.....
  SHELLY               4.0    3.9    3.8    3.8    3.7    3.7    3.7
Sand Hill River.....
  CLIMAX               3.9    3.8    3.6    3.4    3.4    3.4    3.4
Red Lake river.....
  HIGH LANDING         3.3    3.3    3.2    3.2    3.2    0.5    0.5
  CROOKSTON            4.9    4.8    4.6    4.5    4.4    3.0    2.8
Snake River.....
  ABOVE WARREN        60.2   60.2   60.2   60.2   60.2   60.2   60.2
  ALVARADO            95.7   95.4   94.8   94.8   94.8   94.8   94.8
Two Rivers River.....
  HALLOCK            794.9  794.4  793.9  793.5  793.3  793.2  793.1
Roseau River.....
  ROSEAU               5.9    5.8    5.6    5.2    5.0    4.8    4.8


NORTH DAKOTA TRIBS:   95%    90%    75%    50%    25%    10%    05%
--------            ------ ------ ------ ------ ------ ------ ------
Wild Rice River.....
  ABERCROMBIE          0.4    0.3    0.1   -0.4   -0.4   -0.4   -0.4
Sheyenne River.....
  VALLEY CITY          4.4    4.4    4.2    4.1    4.0    4.0    4.0
  LISBON               3.2    3.1    2.9    2.8    2.7    2.7    2.7
  KINDRED              3.3    3.2    3.0    2.9    2.8    2.8    2.8
  WEST FARGO DVRSN    10.1   10.0    9.9    9.8    9.8    9.8    9.7
  HARWOOD            869.0  868.5  868.1  867.7  867.5  867.4  867.4
Maple River.....
  ENDERLIN             2.1    2.1    2.0    1.9    1.9    1.9    1.9
  MAPLETON           894.9  894.8  894.8  894.6  894.6  894.6  894.6
Goose River.....
  HILLSBORO            1.8    1.7    1.6    1.6    1.6    1.6    1.6
Forest River.....
  MINTO                1.5    1.4    1.3    1.3    1.3    1.3    1.3
Park River.....
  GRAFTON              7.2    7.1    7.1    7.1    7.1    7.1    7.1
Pembina River.....
  WALHALLA             2.0    1.9    1.6    1.3    1.0    1.0    1.0
  NECHE                3.0    2.8    2.4    1.9    1.6    1.6    1.6



.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 Community Hydrologic Prediction System (CHPS). The model
 is run for multiple scenarios starting at current river, low and
 soil conditions and using over 60 years of past precipitation and
 temperature conditions that were experienced for those past years
 during the time-frame of the outlook period. These crests can then
 be ranked from lowest to highest, and then be 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).

 A YouTube video on "How to Interpret River Outlook Products" is at:

         www.youtube.com/watchv?=pSoEgvsnpv4

The probabilities can be used for risk management by using them 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
 contributing to the area`s 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).

This outlook was produced using precipitation and temperatures
 for the years 1949 through 2012.


.ADDITIONAL INFORMATION SOURCES...

The AHPS long-range Probabilistic Hydrologic Outlooks are issued
 each month typically between the first and second Friday after
 mid-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 Grand Forks AHPS web
 page on the internet at:

        www.weather.gov/grandforks or weather.gov/fgf

 then click on the "Rivers and Lakes" on the tab above the map.

Current river conditions for all river forecast points in the Red
 River of the North and Devils/Stump Lake conditions are also
 available on our web site, as well as the 7-day forecasts when
 the river at the forecast point is in or near flood.

If you have any questions, contact the NWS at 701-772-0720.

A new, point specific flood briefing web page is available at:

   www.crh.noaa.gov/fgf/briefing/floodbriefing.php

Also, 7-day deterministic forecasts will be issued at least once a
 day when the river forecast locations will be at flood during that
 period.

Probabilistic Hydrologic Outlooks will be issued monthly throughout
 the rest of the year during the later part of the month or as
 conditions warrant.

Refer to the separate Devils Lake Probabilistic Hydrologic Outlook
 for Devils and Stump Lakes probability of exceedance levels and
 low-water non-exceedance levels.

You can follow us on Facebook at: www.facebook.com/NWSGrandForks
 and on Twitter at: @NWSGrandForks.

$$
     weather.gov/fgf
NNNN






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