Flood Potential Outlook
Issued by NWS Duluth, MN

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7

FGUS73 KDLH 170012 CCA

Probabilistic Hydrologic Outlook...UPDATED
National Weather Service Duluth MN
610 PM CST Thu Feb 16 2017

...Spring Flood and Water Resources Outlook...

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:  02/19/2017 - 05/20/2017

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:Prairie River
Taconite            10.0   12.0   13.0 :   8   <5   <5   <5   <5   <5
:Mississippi River
Aitkin              13.0   15.0   18.0 :  87   48   62   35   25    9
Fort Ripley         10.0   12.5   26.0 :  92   48   31   18   <5   <5
:Snake River
Pine City            9.0   10.0   11.0 :  <5    8   <5   <5   <5   <5
:St. Louis River
Scanlon             10.5   11.0   13.0 :  12    7    7    6   <5   <5

CS = Conditional Simulation (Current Outlook)
HS = Historical Simulation
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: 02/19/2017 - 05/20/2017
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Prairie River
Taconite              6.8    7.1    7.9    8.5    9.1    9.8   10.5
:Mississippi River
Aitkin               11.6   12.3   14.1   15.8   18.0   19.7   21.1
Fort Ripley           9.7   10.2   10.5   11.6   13.3   14.7   15.4
:Snake River
Pine City             5.5    5.7    6.0    6.2    7.3    8.3    9.0
:St. Louis River
Scanlon               6.9    7.2    7.9    8.9    9.5   10.7   11.6

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: 02/19/2017 - 05/20/2017
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Prairie River
Taconite              3.0    3.0    3.0    2.9    2.8    2.7    2.6
:Mississippi River
Aitkin                6.7    6.7    5.6    4.6    3.4    2.6    2.4
Fort Ripley           5.1    5.1    5.1    5.1    4.8    4.4    4.1
:Snake River
Pine City             3.6    3.6    3.5    3.3    3.2    3.2    3.2
:St. Louis River
Scanlon               3.6    3.6    3.6    3.5    3.4    3.3    3.2

These long-range probabilistic outlooks contain forecast values that
are calculated using multiple season scenarios from 30 or more years
of climatological data, including 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.

The snowpack varies from south to north across the Northland with
the highest values occurring in the north. Water content across the
Rainy River Valley is in the 4 to 6 inch range. Much of the
Minnesota arrowhead east of a Two Harbors to Ely line is also in the
4 to 6 inch range with embedded areas of 6 to 8 inches north of
Silver Bay and north of Grand Marais. Water content across much of
the remainder of northeastern Minnesota is in the 2 to 4 inch range
with pockets of 4 to 6 inches seen along the Iron Range and up the
US 53 corridor. The area of 2 to 4 inches runs to about Minnesota
highway 210 before dropping to 1 to 2 inches to the south. Water
content drops to a trace to 1 inch near Lake Mille Lacs and along
Interstate 35 from Moose Lake southward. In Wisconsin, water content
of a trace to 2 inches was observed roughly west of a Winter to
Hayward to Port Wing line. The remainder of northwest Wisconsin has
2 to 4 inches with lower pockets of a trace to 2 inches just south
of Ashland, near Winter, and just west of Phillips. The snow pack
across Minnesota has gradually built up since just prior to
Thanksgiving 2016 with some melting between storms. Northwest
Wisconsin has seen more mixed precipitation events, limiting snow
pack there.

Actual snow cover is in the 15 to 25 inch range from roughly the
Iron Range northward with pockets of 25 to 35 inches north of Grand
Marais. Snowfall decreases south of the Iron Range to 4 to 12 inches
and even further to a trace to 4 inches south of Minnesota Highway
210. Across northwest Wisconsin, snow cover is generally from 4 to
10 inches with slightly higher amounts to 12 to 16 inches near
Ironwood and closer to a trace around Grantsburg. For more
information on snow pack and water equivalent, visit

Precipitation since mid-November has been above normal across the
entire area. However, it has not been an even distribution. The
winter season started out on the wet side but has turned drier as of
late, especially across northwest Wisconsin. While still running
above normal for the season, northwest Wisconsin is running below
normal over the past month with the St. Croix and Montreal River
Valley seeing this deficit stretch back into mid- December. Given
the lack of significant snow pack across Wisconsin and the warmer
temperatures expected over at least the next week, snowmelt flooding
is mitigated across this area. The story is different across
Minnesota. Precipitation totals are running 2 to 4 inches above
normal across much of Minnesota, with southeast Lake and all of Cook
Counties seeing totals up to 8 inches above normal. Much of this
fell prior to mid-January, but up until the last week the total has
been above normal. It has only been over the last week where a drier
trend has started to take over. However, the outlook over the next
two weeks shows a return to above normal precipitation. This
combined with warmer temperatures may lead to some flooding concerns
if frozen rivers are slow to open up. The overall threat appears low
at this time.

The 8 to 14 day outlook for the period February 24th to March 2nd is
for greater chances for above normal temperatures for Wisconsin and
the southeast half of Minnesota. The northwest half of Minnesota is
expected to have normal temperatures. There is a higher chance for
above normal precipitation for the entire Northland during this
period. There are equal chances for above, below, and normal
temperatures and precipitation for the month of March.

Visit our website www.weather.gov/dlh for more weather and water

For additional information on stream flow conditions for USGS
locations please visit:

for Minnesota - https://waterdata.usgs.gov/mn/nwis/rt
for Wisconsin - https://waterdata.usgs.gov/wi/nwis/rt

For additional information on stream flow conditions at MN DNR
locations, please visit:

www.dnr.state.mn.us/waters/csg/index.html   -or-

For more information on climate outlooks please visit:

The next outlook will be issued March 2, 2017


WFO Duluth

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.