Flood Potential Outlook
Issued by NWS Bismarck, ND

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FGUS73 KBIS 291954
ESFBIS
NDC009-013-023-049-061-069-075-079-101-302200-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
150 PM CST FRI JAN 29 2016

...Flood and Water Resources Outlook...

This probablistic flood outlook is for the Souris (Mouse) River basin
of North Dakota and covers the period of late January through
late April.

The following message has four sections. The first provides some text
on the highlights of this outlook and conditions affecting the local
hydrology. The second section gives the current and normal/historical
risks of flooding as determined by the Ensemble Streamflow Forecast
model of the National Weather Service. The third section gives the
current probabilities for reaching flood stage at the listed forecast
locations. And finally, the fourth section covers the risk of the
river sites falling below the listed stages.

...Flood Outlook Highlights...
In general, risks presented below tend to reflect a well below normal
probability of widespread flooding. This is consistent with the
warmer and somewhat drier than normal winter the region has enjoyed
thus far. However, while expectations for a continuation of the below
normal moisture and above normal temperatures, recent history would
suggest that one should not discount the risks of heavy spring rains.

...Current Conditions...
Most rivers and streams tend to be low and iced over, which is
normal for this time of year. Reservoirs are all within their
seasonally normal range and if not already there, they are on track
to meet their designated drawdown levels well ahead of the onset of
the spring flood season. Frost thickness in the soil is a little over
two feet on average, which is less than normal for this time of
year and not considered something that will enhance flood risk going
forward. Snow cover, depth, and water equivalent in existing snowpack
are all considered below normal for this time of year.

...Weather Outlook...
The one-month, and three-month climate outlooks tend to favor a
continuation of the below normal precipitation and above normal
temperatures the region has experienced thus far. Again, this is
consistent with the El Nino in place and is expected to last well
into spring.

...Important Note On Substantive Changes... Beginning January 1st of
2016, the National Weather Service began converting all river
gage data in the Souris River basin of North Dakota to feet above
Mean Sea Level using the North American Vertical Datum of 1988.
This will included raises in flood stage definitions by up to one
foot at individual locations in order to continue working with
whole numbers. More information on this can be found on our website,
or by contacting Service Hydrologist Allen Schlag at 701-250-4495.

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 of the model
predicting a rise to 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: 01/31/2016 - 04/30/2016

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
Des Lacs River
  Foxholm         1651.0 1653.0 1654.0    <5   <5   <5   <5   <5   <5
Souris River
  Sherwood        1623.0 1625.0 1630.0    <5   11   <5   <5   <5   <5
  Foxholm         1573.0 1576.0 1578.0     6   33   <5   13   <5   <5
  Minot 4NW       1562.0 1565.0 1570.0    <5   11   <5    6   <5   <5
  Minot Brwy Brdg 1551.0 1553.0 1557.0    <5    5   <5   <5   <5   <5
  Logan           1536.0 1538.0 1540.0     5   17   <5    5   <5   <5
  Sawyer          1524.0 1526.0 1528.0    <5    7   <5   <5   <5   <5
  Velva           1507.0 1512.0 1517.0    <5   15   <5   <5   <5   <5
Wintering River
  Karlsruhe       1509.0 1511.0 1512.0    <5    6   <5   <5   <5   <5
Souris River
  Towner          1454.0 1456.0 1458.0    14   52    6   21   <5   <5
  Bantry          1440.0 1441.0 1443.0    13   49    7   31   <5   <5
Willow Creek
  Willow City     1442.0 1446.0 1448.0    NA   NA   NA   NA   NA   NA
Souris River
  Westhope        1414.0 1418.0 1420.0    15   40   <5   20   <5   14

Legend
CS = Conditional Simulation (Current Outlook)
HS = Historical Simulation
FT = Feet
NA = Not available due to the datum change but is expected to be below
     normal and will be included in future outlooks.

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: 01/31/2016 - 04/30/2016
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Des/ Lacs River
Foxholm             1639.8 1640.1 1640.5 1641.1 1641.9 1643.1 1650.7
:Souris River
Sherwood            1609.3 1609.5 1610.7 1613.0 1616.3 1619.5 1620.9
Foxholm             1568.9 1569.2 1569.8 1570.9 1571.0 1571.4 1573.8
Minot 4NW           1552.0 1552.4 1552.9 1554.0 1554.2 1554.9 1561.8
Minot Brwy Brdg     1542.0 1542.3 1542.6 1543.1 1543.2 1543.5 1547.3
Logan               1523.0 1523.7 1524.6 1526.5 1527.0 1528.4 1536.1
Sawyer              1509.2 1509.8 1510.4 1512.0 1512.6 1514.5 1521.9
Velva               1492.6 1493.0 1493.3 1496.0 1496.7 1499.1 1506.7
:Wintering River
Karlsruhe           1504.1 1504.2 1504.3 1504.6 1505.0 1507.2 1508.0
:Souris River
Towner              1446.5 1446.5 1449.3 1452.1 1453.1 1454.6 1456.6
Bantry              1432.0 1432.1 1434.6 1437.4 1438.8 1440.4 1441.8
:Willow Creek
Willow City             NA     NA     NA     NA     NA     NA     NA
:Souris River
Westhope           1411.0 1411.1 1411.5 1412.6 1413.5 1414.7 1416.1

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: 01/31/2016 - 04/30/2016
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
Des Lacs River
  Foxholm           1638.8 1638.8 1638.8 1638.6 1638.6 1638.6 1638.6
Souris River
  Sherwood          1605.8 1605.7 1605.7 1605.7 1605.7 1605.7 1605.7
  Foxholm           1566.5 1566.5 1566.5 1566.5 1566.5 1566.5 1566.5
  Minot 4NW         1551.1 1551.0 1551.0 1550.9 1550.9 1550.8 1550.6
  Minot Brwy Brdg   1538.2 1538.1 1537.7 1537.4 1537.0 1536.7 1533.5
  Logan             1519.9 1519.9 1519.9 1519.9 1519.8 1519.8 1519.8
  Sawyer            1506.6 1506.6 1506.6 1506.6 1506.5 1506.5 1506.5
  Velva             1490.2 1490.2 1490.2 1490.2 1490.2 1490.2 1490.2
Wintering River
  Karlsruhe         1502.8 1502.8 1502.8 1502.8 1502.8 1502.8 1502.8
Souris River
  Towner            1444.4 1444.4 1444.4 1444.4 1444.4 1444.4 1444.4
  Bantry            1429.9 1429.9 1429.9 1429.9 1429.9 1429.9 1429.9
Willow Creek
  Willow City           NA     NA     NA     NA     NA     NA     NA
Souris River
  Westhope         1409.1 1409.1 1409.1 1409.1 1408.9 1408.7 1408.7

These long-range probabilistic outlooks contain forecast values that
are calculated using historical conditions from 30 or more years of
climatological data...and 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/bis for more weather and water
information.

The next outlook will be issued toward the end of next month.

$$
ajs


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