Flood Potential Outlook
Issued by NWS Denver/Boulder, CO

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093-095-115-117-121-123-021200-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
310 PM MST THU MAR 03 2016

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

...Average Snowmelt Flood Potential this Spring...

This outlook is for the Upper Colorado and North Platte River Basins
in North Central Colorado and South Platte Basin which also extends
across Northeast Colorado.

Temperatures continue slowly melting snowpack in the Front Range
Foothills. This combined with near normal mountain snowpack...near
normal subsurface soil moisture and diminished frozen ground have
decreased the risk of significant spring snowmelt flooding.

Snow typically accumulates into April in North Central Colorado and
conditions may change before the runoff begins. An extended period
of much above normal temperatures or heavy rainfall during the melt
will cause or exacerbate flooding problems while below normal future
precipitation and gradual or intermittent freezing and thawing will
decrease the magnitude of the current assessment. Near average risk
suggests that locations which typically experience minor spring time
flooding may flood again this year. Those locations that do not
normally experience flooding are not projected to flood this year.

...Current Hydrologic Conditions...
The March 3rd mountain snowpack was around 100 percent of average in
the South Platte and Upper Colorado River Basins and 93 percent of
average in the North Platte Basin. Liquid water in the mountain
snowpack generally ranged from 5 to 28 inches. With temperatures
generally 6 to 10 degrees above average and only spotty and light
precipitation below 6000 feet the past several weeks...there is no
snow cover at lower elevations. The ground at lower elevations is
also free of frost. Soil moisture is mostly in thenormal range.

Basin reservoir storage continued holding steady at 105 to 110
percent of average and 72 to 77 percent of capacity at the end of
February.

On March 3rd 56 percent of U.S. Geological Survey stream gages had
normal flows...32 percent had above normal to high flows and 12
percent had below normal to low flows in North Central Colorado.

On the U.S. Drought Monitor abnormally dry conditions (D0) continued
in Washington and Southwest Lincoln Counties on the Eastern Colorado
Plains.

...Climate Summary...
Temperatures the past 2 weeks continued to be 6 to 11 degrees above
normal in the South Platte Basin and 1 to 8 degrees in the Upper
Colorado and North Platte River Basins. Precipitation the past 14
days ranged from below average west of the Continental Divide and
the Eastern Colorado Plains to above average in areas of the Front
Range Foothills. Precipitation since October 1st has varied from
near to slightly below average in the Upper Colorado and North
Platte River Basins to near to above average in the South Platte
Basin.

...Weather Outlooks...
Temperatures are expected to be above average and precipitation
below average through mid-March. The outlooks are trending toward
wetter conditions with temperatures a bit closer to normal in latter
March.

Above-average sea-surface temperatures in the east-central
equatorial Pacific...referred to as El Nino conditions...are
predicted to weaken through 2016. Most models suggest a transition
to ENSO-neutral by this summer with the possibility of La Nina
conditions this fall. This is consistent with the historical
tendency for strong El Nino events to be followed by a La Nina.

...Numerical River Outlooks...
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 greater 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:  3/05/2016 - 6/03/2016

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:South Platte River
South Platte         7.0    9.0   11.0 :  <5   <5   <5   <5   <5   <5
Denver              11.0   12.5   14.0 :  <5   <5   <5   <5   <5   <5
Henderson           10.0   11.0   15.0 :   8    8   <5  <5   <5   <5
Kersey              10.0   11.5   12.0 :  12   13   11   8    9    7
Weldona             10.0   11.0   13.0 :  10    9    9   8   <5   <5
Balzac              10.0   11.0   13.0 :  10   10    7   6   <5   <5
Julesburg           10.0   11.0   12.0 :   7    6   <5   <5   <5   <5
:Plum Creek
Sedalia              8.0   10.0   12.0 :   6   <5   <5   <5   <5   <5
:Bear Creek
Morrison             9.0   10.0   11.0 :  <5   <5   <5   <5   <5   <5
Sheridan             8.0   10.0   11.0 :  <5   <5   <5   <5   <5   <5
:Clear Creek
Golden              10.0   13.0   14.0 :  <5   <5   <5   <5   <5   <5
Derby                9.0   10.5   11.5 :  <5   <5   <5   <5   <5   <5
:N Fk Big Thompson River
Drake                6.0    7.0    8.0 :  <5   <5   <5   <5   <5   <5
:Cache la Poudre River
Fort Collins 9NW     7.5    9.0   10.5 :  <5   <5   <5   <5   <5   <5
Fort Collins        10.5   11.5   13.0 :  <5   <5   <5   <5   <5   <5
Greeley              8.0    9.5   11.0 :   5   <5   <5   <5   <5   <5
:North Platte River
Northgate            8.0    9.5   11.0 :  <5   <5   <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:  3/05/2016 - 6/03/2016
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:South Platte River
South Platte          3.7    3.8    4.0    4.3    4.9    5.7    6.0
Denver                4.1    4.2    4.6    5.3    6.0    6.8    7.5
Henderson             5.8    5.9    6.5    7.2    8.4    9.5   10.9
Kersey                4.5    5.0    6.0    7.2    8.6   11.7   14.2
Weldona               3.0    3.2    4.2    5.4    7.3    9.9   12.4
Balzac                3.1    3.4    4.0    5.4    7.7    9.8   12.1
Julesburg             1.0    1.0    4.3    6.4    7.6    8.7   10.5
:Plum Creek
Sedalia               3.7    3.7    4.0    4.3    5.1    6.8    8.8
:Bear Creek
Morrison              6.3    6.4    6.6    6.7    7.0    7.4    7.8
Sheridan              2.8    2.9    3.2    3.4    4.1    4.5    5.0
:Clear Creek
Golden                4.8    5.0    5.1    5.4    5.7    6.1    6.7
Derby                 2.6    2.7    3.0    3.2    3.9    4.5    5.5
:N Fk Big Thompson River
Drake                 4.1    4.1    4.2    4.3    4.4    4.6    4.8
:Cache la Poudre River
Fort Collins 9NW      3.8    4.0    4.1    4.4    4.8    5.4    6.0
Fort Collins          1.9    2.1    2.5    3.3    3.9    5.4    6.8
Greeley               2.6    2.8    3.1    4.9    6.0    7.4    8.2
:North Platte River
Northgate             3.7    4.0    4.3    5.0    5.9    6.6    6.7

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:  3/05/2016 - 6/03/2016
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:South Platte River
South Platte          2.3    2.3    2.3    2.3    2.3    2.3    2.3
Denver                3.1    3.1    3.0    3.0    3.0    2.9    2.9
Henderson             4.7    4.6    4.5    4.4    4.4    4.4    4.4
Kersey                3.9    3.6    3.1    3.0    2.9    2.8    2.8
Weldona               1.0    0.1    0.1    0.1    0.1    0.1    0.1
Balzac                2.3    2.1    1.8    1.8    1.8    1.8    1.8
Julesburg             1.0    1.0    1.0    1.0    1.0    1.0    1.0
:Plum Creek
Sedalia               3.3    3.2    3.1    3.1    3.1    3.1    3.1
:Bear Creek
Morrison              6.1    6.0    6.0    6.0    5.9    5.9    5.9
Sheridan              2.6    2.5    2.5    2.4    2.3    2.3    2.2
:Clear Creek
Golden                3.7    3.7    3.7    3.7    3.6    3.6    3.6
Derby                 1.3    1.0    1.0    1.0    1.0    1.0    1.0
:N Fk Big Thompson River
Drake                 3.7    3.7    3.7    3.7    3.7    3.7    3.7
:Cache la Poudre River
Fort Collins 9NW      2.9    2.9    2.9    2.8    2.8    2.8    2.8
Fort Collins          1.2    0.8    0.4    0.0    0.0    0.0    0.0
Greeley               1.8    1.3    1.2    1.2    1.2    1.2    1.2
:North Platte River
Northgate             2.4    2.4    2.4    2.4    2.4    2.4    2.4

These long-range probabilistic outlooks above 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.

Following are the streamflow forecasts for selected locations west
of the Continental Divide:
                              Most Probable Forecast
                                      Volume      Percent
Stream and Station         Period     1000 AF      of Avg
__________________         ______     _______     _______
Colorado River
Lake Granby                Apr-Jul     175          80

Willow Creek
 Willow Creek Res          Apr-Jul      43          91

Fraser River
 Winter Park               Apr-Jul      18          93

Williams Fork River
 Williams Fork Res         Apr-Jul      85          89

Blue River
 Dillon Res                Apr-Jul     145          89
 Green Mtn Res             Apr-Jul     245          89

Muddy Creek
 Wolford Mtn Res Blw       Apr-Jul      48          89

Colorado River
 Kremmling                 Apr-Jul     740          86

The streamflow forecasts above reflect natural flow only. Actual
observed flow will likely be affected by upstream water management.

This is the last spring flood outlook planned for 2016. Water supply
outlooks are issued near the middle of each month through June. Long-
range probabilistic outlooks are issued toward the end of the month
throughout the year. Visit our web site at weather.gov/denver for
more weather and water information including graphs of probabilistic
river outlooks.

$$
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