Flood Potential Outlook
Issued by NWS Grand Rapids, MI

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FGUS73 KGRR 052247
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MIC005-015-025-035-037-045-057-065-067-073-075-077-081-085-
105-107-117-121-123-127-133-139-159-041800-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
545 PM EST THU MAR 05 2015

...SPRING FLOOD AND WATER RESOURCES OUTLOOK NUMBER 2...

This spring flood and water resources outlook is for the rivers in
Southwest Lower Michigan.


...Flood Outlook Highlights...

The risk of flooding from late winter into spring is generally near
normal. Rivers in Southwest Lower Michigan with the greatest risk for
at least minor flooding include the Grand, Thornapple, Looking Glass,
and Maple basins. The Muskegon and Chippewa basins feature a below
normal risk for flooding.

...Flood Terminology...

The term Minor Flooding is used to indicate minimal or no property
damage. However some public inconvenience is possible.

The term Moderate Flooding is used to indicate some inundations of
structures and roads near streams, some evacuations of people and/or
transfer of property to higher elevations.

The term Major Flooding is used to indicate extensive inundation of
structures and roads, significant evacuations of people and/or
transfer of property to higher elevations.

...Probabilistic Outlook...

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
temperatures and precipitation. By providing a range of
probabilities, the level of risk associated with the long-range
planning decisions can be determined. These probabilistic forecasts
are part of the National Weather Service`s Advanced Hydrologic
Prediction Service.

...Past Precipitation...

The precipitation so far this winter has been below normal.

...River Conditions...

Current flows are generally below normal across the region. Ice
coverage on area rivers is likely above normal based on the colder
than normal temperatures since November including the record cold
month of February for some areas.

...Soil Moisture and Frost Depths...

Soil moisture was generally below normal. Frost depths were deeper
than normal.

...Snow Cover and Liquid Water Content...

Snow cover ranged from 5 to 10 inches in the upper reaches and
tributaries of the rivers, to 15 to 20 inches in the lower reaches
near Lake Michigan. Snow cover and liquid water content were
generally below normal with values mostly in the 1 to 3 inch range.
Highest values were mostly in the lower reaches of the rivers, close
to Lake Michigan.

...Weather Outlook...

Little or no precipitation is forecasted through March 11th. A
warming trend will begin during this period, which will lead to snow
melt. The outlook for March 12th to 18th calls for an increased
chance for warmer than normal temperatures and equal chances for
above/below normal precipitation. The long range forecast for March
through May shows equal chances for above/below normal temperatures
and precipitation.

...Flood Outlook Summary...

This spring flood and water resources outlook is for the rivers in
Southwest Lower Michigan and calls for generally a near normal risk
for flooding. The Muskegon and Chippewa basins feature a lower risk
partially due to the less than normal water content of the snowpack.
The rivers with the highest risk for at least minor flooding include
the Grand, Thornapple, Looking Glass and Maple Rivers. With rivers
mostly ice covered and likely thicker than average ice, flooding from
ice jams remain a higher threat.


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:  3/9/2015 - 6/7/2015

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:Red Cedar River
Williamston          9.0   10.0   10.5 :  <5   <5   <5   <5   <5   <5
East Lansing         7.0   10.0   13.0 :  32   23   <5   <5   <5   <5
:Sycamore Creek
Holt                 8.0    9.0   10.0 :  44   32   <5   <5   <5   <5
:Looking Glass River
Eagle                7.0    9.0   11.0 :  66   53   12    7   <5   <5
:Maple River
Maple Rapids         9.0   11.0   13.0 :  40   36   <5   <5   <5   <5
:Thornapple River
Hastings             7.0    9.0   10.0 :  44   30   <5   <5   <5   <5
Caledonia           10.0   12.0   14.0 :   7   15   <5   <5   <5   <5
:Rogue River
Rockford             8.0   10.0   11.0 :   6   13   <5   <5   <5   <5
:Flat River
Smyrna               8.5    9.5   10.5 :  <5   <5   <5   <5   <5   <5
:Grand River
Jackson             14.0   15.0   16.0 :  32   30   12   12   <5    9
Eaton Rapids         6.0    8.0    9.0 :  <5   <5   <5   <5   <5   <5
Dimondale           13.0   14.0   16.0 :  <5   <5   <5   <5   <5   <5
Lansing             11.0   13.0   15.0 :   9   10   <5   <5   <5   <5
Grand Ledge         11.0   13.0   15.0 :  <5   <5   <5   <5   <5   <5
Portland            12.0   14.0   16.0 :  <5   <5   <5   <5   <5   <5
Ionia               21.0   23.0   25.0 :   7   15   <5   <5   <5   <5
Lowell              15.0   18.0   20.0 :  10   21   <5   <5   <5   <5
Ada                 20.0   22.0   25.0 :  <5   10   <5   <5   <5   <5
Grand Rapids        18.0   21.0   23.0 :  <5   13   <5   <5   <5   <5
:Muskegon River
Evart               12.0   13.0   14.0 :  <5   23   <5    7   <5   <5
:Little Muskegon River
Morley               6.0    7.0    8.0 :  <5   <5   <5   <5   <5   <5
:Muskegon River
Croton               9.0   11.0   12.0 :  16   33   <5   <5   <5   <5
:White River
Whitehall            6.0    7.0    8.0 :   6   <5   <5   <5   <5   <5
:Pere Marquette River
Scottville           5.5    6.5    7.0 :  <5   <5   <5   <5   <5   <5
:Battle Creek
Battle Creek         4.0    5.0    6.0 :  <5   <5   <5   <5   <5   <5
:Kalamazoo River
Marshall             8.0    9.0   10.0 :  <5   12   <5    9   <5    7
Battle Creek         9.0   10.0   11.0 :  <5   <5   <5   <5   <5   <5
Comstock             9.0   10.0   11.0 :  <5    7   <5   <5   <5   <5
New Richmond        17.0   19.0   21.0 :  <5    7   <5   <5   <5   <5
:St Joseph River
Burlington           6.5    9.0   11.0 :  <5   10   <5   <5   <5   <5
:Portage River
Vicksburg            5.0    7.0    8.0 :  27   33   <5   <5   <5   <5
:Chippewa River
Mt Pleasant          8.0   11.0   13.0 :  <5   13   <5   <5   <5   <5
:Pine River
Alma                 8.0   10.0   12.0 :  <5    9   <5   <5   <5   <5

Legend
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: 3/9/2015 - 6/7/2015
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Red Cedar River
Williamston           7.0    7.2    7.4    7.7    8.1    8.6    8.8
East Lansing          5.7    6.0    6.3    6.7    7.1    7.8    8.2
:Sycamore Creek
Holt                  7.1    7.2    7.5    7.8    8.3    8.8    8.9
:Looking Glass River
Eagle                 6.2    6.5    6.9    7.6    8.4    9.2    9.6
:Maple River
Maple Rapids          8.5    8.6    8.8    8.9    9.3    9.6    9.6
:Thornapple River
Hastings              5.7    6.1    6.4    7.0    7.5    8.0    8.6
Caledonia             6.8    7.3    7.7    8.5    9.2    9.9   10.7
:Rogue River
Rockford              5.5    5.6    6.1    6.5    7.0    7.9    8.3
:Flat River
Smyrna                4.8    5.0    5.3    5.6    6.2    6.9    7.4
:Grand River
Jackson              11.5   12.2   12.6   13.4   14.3   15.2   15.7
Eaton Rapids          4.1    4.2    4.4    4.6    5.0    5.4    5.5
Dimondale             6.9    7.1    7.8    8.3    9.0   10.0   10.2
Lansing               6.6    7.2    7.8    8.7    9.5   11.0   11.3
Grand Ledge           6.8    7.1    7.4    7.9    8.4    9.2    9.4
Portland              8.5    8.9    9.2    9.9   10.5   11.1   11.5
Ionia                15.3   16.7   17.3   18.3   19.6   20.9   21.3
Lowell                9.5   10.4   11.0   12.1   13.5   15.3   15.8
Ada                  13.7   14.9   15.6   16.6   18.0   19.5   20.1
Grand Rapids         10.1   11.7   12.8   14.2   15.6   17.6   18.1
:Muskegon River
Evart                 9.4    9.5    9.9   10.3   10.9   11.5   11.9
:Little Muskegon River
Morley                3.0    3.1    3.3    3.7    4.1    4.7    4.8
:Muskegon River
Croton                7.1    7.4    7.7    8.1    8.7    9.2    9.6
:White River
Whitehall             3.8    4.0    4.2    4.8    5.4    5.8    6.1
:Pere Marquette River
Scottville            3.4    3.6    3.8    4.2    4.5    5.0    5.3
:Battle Creek
Battle Creek          1.7    1.7    1.8    2.0    2.2    2.5    2.6
:Kalamazoo River
Marshall              5.0    5.1    5.2    5.8    6.3    6.7    7.4
Battle Creek          4.1    4.1    4.3    4.5    5.1    5.7    5.8
Comstock              5.1    5.3    5.6    5.9    6.6    7.5    7.8
New Richmond         13.7   13.9   14.2   14.6   15.2   15.9   16.2
:St Joseph River
Burlington            4.7    4.9    5.1    5.4    5.8    5.9    6.4
:Portage River
Vicksburg             4.4    4.4    4.6    4.8    5.0    5.2    5.3
:Chippewa River
Mt Pleasant           4.7    4.9    5.1    5.4    6.2    6.9    7.3
:Pine River
Alma                  4.5    4.6    4.9    5.4    6.2    7.4    7.5

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: 3/9/2015 - 6/7/2015
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Red Cedar River
Williamston           3.1    3.1    3.1    3.0    3.0    3.0    3.0
East Lansing          3.3    3.2    3.2    3.2    3.2    3.2    3.2
:Sycamore Creek
Holt                  3.6    3.5    3.4    3.4    3.4    3.4    3.3
:Looking Glass River
Eagle                 2.6    2.6    2.5    2.5    2.5    2.5    2.5
:Maple River
Maple Rapids          3.9    3.8    3.7    3.7    3.6    3.4    3.3
:Thornapple River
Hastings              2.9    2.9    2.9    2.9    2.9    2.9    2.9
Caledonia             3.3    3.2    3.2    3.2    3.2    3.2    3.2
:Rogue River
Rockford              3.9    3.9    3.9    3.9    3.9    3.9    3.9
:Flat River
Smyrna                3.5    3.5    3.4    3.4    3.4    3.4    3.4
:Grand River
Jackson               9.2    9.0    8.9    8.8    8.8    8.8    8.8
Eaton Rapids          3.6    3.6    3.6    3.6    3.6    3.6    3.6
Dimondale             4.6    4.6    4.6    4.5    4.5    4.5    4.5
Lansing               2.7    2.7    2.7    2.6    2.6    2.6    2.6
Grand Ledge           4.9    4.9    4.8    4.8    4.8    4.8    4.8
Portland              5.7    5.6    5.6    5.5    5.5    5.5    5.5
Ionia                 8.3    8.3    8.3    8.2    8.2    8.2    8.2
Lowell                5.0    5.0    5.0    5.0    5.0    4.9    4.9
Ada                   6.1    6.0    6.0    6.0    6.0    6.0    6.0
Grand Rapids          3.2    3.2    3.2    3.2    3.2    3.2    3.2
:Muskegon River
Evart                 7.3    7.2    7.2    7.2    7.2    7.1    7.0
:Little Muskegon River
Morley                2.2    2.2    2.2    2.2    2.2    2.2    2.2
:Muskegon River
Croton                5.0    4.9    4.9    4.9    4.9    4.8    4.7
:White River
Whitehall             1.7    1.7    1.7    1.7    1.7    1.6    1.5
:Pere Marquette River
Scottville            1.6    1.6    1.6    1.6    1.5    1.4    1.4
:Battle Creek
Battle Creek          0.9    0.8    0.8    0.8    0.8    0.8    0.8
:Kalamazoo River
Marshall              4.1    4.0    3.2    3.2    3.2    3.2    3.2
Battle Creek          3.1    3.0    3.0    3.0    3.0    3.0    2.9
Comstock              4.0    4.0    4.0    4.0    3.9    3.9    3.9
New Richmond         10.5   10.4   10.3   10.3   10.3   10.2   10.0
:St Joseph River
Burlington            3.7    3.6    3.6    3.6    3.6    3.5    3.5
:Portage River
Vicksburg             3.6    3.6    3.5    3.5    3.5    3.5    3.5
:Chippewa River
Mt Pleasant           3.0    3.0    3.0    3.0    3.0    3.0    3.0
:Pine River
Alma                  1.2    1.1    1.1    1.1    1.1    1.1    1.1

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.

Visit our web site weather.gov/grr for more weather and water
information.

This is the last scheduled hydrologic outlook for 2015.

$$







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