Flood Potential Outlook
Issued by NWS Grand Forks, ND

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FGUS73 KFGF 191928
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NDC005-027-071-301200-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE EASTERN NORTH DAKOTA/GRAND FORKS ND
130 PM CST THU FEB 19 2015

...Devils Lake Outlook for Spring Flood Potential...

                          Devils and Stump Lakes
                    Long-Range Probabilistic Outlook

  The National Weather Service is providing long-range probabilistic
   hydrologic outlooks for Devils and Stump lakes between January
    and September. They will not be provided between October and
     December.

  The AHPS graphics associated with this outlook will be on the web
   no later than 10:30 AM this Friday under the experimental
    long-range flood risk tab at...

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

  Depending on the season, the high or low water probabilities may
   be omitted due to their applicability to the hydrologic situation.
    Refer to the scheduling section farther on in this message.


. Outlook Discussion...

    There has been little change since the last outlook at the end
     of January...with below normal lake rises expected due to
      below normal springtime inflows.

   Fall and winter precipitation has been within the 20 to 50% of
    normal across the Devils Lake basin ranging from a bit above on
     the northwestern side and below normal on the eastern side.
      Snow water equivalents (SWEs) in the snowpack are modeled at
       0.85 inches compared to a typical 1.25 to 2.75 inches.

   The model was run with normal climatological precipitation and
    slightly above normal temperatures...and with the maximum 600
     cfs pumping capacity of the Devils Lake outlets from the 1st
      of June through the 10th of November. This produced the
       highest rising hydrograph member derived from the 60+ years
        of temperature and precipitation used in the model to peak
         at 1453.13 feet.


. Chances of Devils and Stump Lakes rising above given lake levels...

  The probability of exceeding a given lake level is the percentage
   of maximum lake level rises that are above that level for all the
    years that were run through the model using the precipitation
     and temperatures for those years during the valid period of the
      outlook.

  Interpretation Aid...There is a 50 percent chance that Devils
   Lake will rise above 1452.0 feet during the valid period and
    only a 5 percent chance that it will rise above 1452.3 feet.

           Probabilities for exceeding listed lake levels

             FROM FEBRUARY 16, 2015 TO SEPTEMBER 30, 2015

LOCATION              95%    90%    75%    50%    25%    10%    05%
--------            ------ ------ ------ ------ ------ ------ ------
DEVILS LAKE.....
  CREEL BAY         1451.8 1451.8 1451.9 1452.0 1452.1 1452.3 1452.6
STUMP LAKE.....
  EAST STUMP LAKE   1451.8 1451.8 1451.9 1452.0 1452.1 1452.3 1452.6


. Current and previous record high lake levels...

 *  The current height of Devils Lake at Creel Bay is 1451.6 feet
 *  The current height of  Stump Lake near Lakota  is 1451.5 feet

 *  The most recent USGS provisional record daily average height
    for Devils Lake at the Creel Bay gage:
                ...1454.30 feet on   June 27 of 2011
 *  Previous records:
                ...1452.05 feet on   June 27 of 2010
                ...1450.93 feet on   June 27 of 2009
                ...1449.20 feet on    May  9 of 2006
                ...1449.18 feet on   June 17 of 2004
                ...1449.17 feet on August  2 of 2005

 * For more high water marks...see the USGS flood tracking charts at:

         HTTP://ND.WATER.USGS.GOV/FLOODTRACKING


. Outlook Schedule...

 - Between January and May, only the high water exceedances will be
    provided with valid periods ending at the end of September.

 - For June and July, both high-water and low-water exceedances
    will be provided.

 - For August and September, only the low-water exceedances will be
    provided with valid periods ending at the end of November.

 - No probability of exceedance/non-exceedance information will be
    given from October through December, since lake freeze-up
     levels will be given in the fall outlooks previously issued.

. Additional Information...

Snowpack information provided by NWS National Operational Hydrologic
  Remote Sensing Center (NOHRSC) is on the web at:

           www.nohrsc.noaa.gov

Wind and Wave forecasts for Devils and Stump lakes are available for
  a seven day period when the lakes are sufficiently ice-free at:

           www.crh.noaa.gov/fgf/hydro/lake_Fcst.php

Additionally, 7 day lake evaporation forecasts are available
  during the growing season at:

           www.crh.noaa.gov/fgf/climate/farm_info.php

The long-range probabilistic outlook is based on high and low lake
  levels that were calculated for the valid period using multiple
   scenarios of temperature and precipitation from 1949 to 2012 and
    current conditions of the lake, snowcover (in winter), and soil
     moisture.

By providing the complete range of lake level probabilities, the
  amount of risk associated with long-range planning decisions can
   be determined. These probabilistic outlooks are part of Noah`s
    National Weather Service`s Advanced Hydrologic Prediction
     Services (AHPS).

This outlook is also presented as probability graphs of lake height
  for the full period as well as weekly probabilities. The outlook
    graphics and explanations that help in interpreting these
      outlooks are available from the NWS Grand Forks AHPS web page
        on the internet at:

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

Outlook graphics of the probabilities of exceeding various lake
  levels for Devils and Stump lakes are also on out web site. They
   should be available by 10:30 AM Friday. Monthly probabilistic
    outlooks are usually issued on the Thursday or Friday of the week
     following the first Thursday after the 15Th of the month,
usually
      the third or fourth week of the month.

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

$$
      weather.gov/fgf






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