Flood Potential Outlook
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
Versions:
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FGUS75 KBOU 132114
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COC001-005-013-014-019-031-035-039-047-049-057-059-069-073-075-087-
093-095-115-117-121-123-152115-
Water Supply Outlook
National Weather Service Denver CO
214 PM MST Thu Feb 13 2025
...SPRING FLOOD AND WATER RESOURCES OUTLOOK FOR NORTH CENTRAL AND
NORTHEAST COLORADO...
...Spring Flood and Water Resources Outlook for North Central and
Northeast Colorado Issuance Number 1...
This is the initial 2025 spring runoff outlook for North Central and
Northeast Colorado covering all or portions of the Upper North
Platte...Upper South Platte and Upper Colorado River Basins.
Flood and Water Supply Outlook Summary
--------------------------------------
Spring flood potential is near to slightly below normal at this
time for the South Platte River Basin, the Upper North Platte
River Basin and the far Upper Colorado River Basin. Any
widespread, significant flooding is not likely due to snowmelt
alone. It should be emphasized that it is very early and snow
typically accumulates into April, therefore conditions may change
before the runoff begins.
Water supply forecasts issued in early February by the National
Weather Service project generally near to slightly below average
April through July runoff volumes for the Upper Colorado Basin and
slightly below to below normal for the South Platte Basins and the
Upper North Platte basin.
Appreciable mountain snowmelt runoff in a normal year starts in
late April to early May. Mountain snowmelt generally peaks in
mid-May to mid-June. It is still very early to make long range
predictions on the magnitude of flooding from mountain snowmelt
runoff. Heavy rainfall, a cold spring, or unseasonably warm
temperatures during the snowmelt season can affect total runoff
volume and peak flow, increasing the threat of flooding.
Observed Precipitation...Snowpack and Temperatures
--------------------------------------------------
The average higher elevation total water year precipitation for
the Upper Colorado, Upper South Platte and Upper North Platte Basins
are near to below normal.
For the water year the percent of normal precipitation is still
below normal for the central and northern part of the Denver metro
area and becomes worse, well below normal, extending northward and
northeastward. Above normal to well above normal precipitation fell
south of a line extending from southern Park and Jefferson counties
northeast to southern Morgan and central Washington counties. The
North Central Mountains also had slightly below to below normal
precipitation.
Precipitation in October was well below normal for most of
Northeastern Colorado. November had an increase in precipitation with
most areas near normal to well above normal, Although November
normals are on the dry side. The lack of moisture came back for
December with all areas well below normal. Thankfully, On the Plains
and foothills January ranged from near normal to well above normal.
Unfortunately the mountains remained dryer than normal for January.
Temperatures on average since the beginning of the water year
through the first part of February have above normal. October and
December both had well above normal temperatures. November had a mix
of above and below normal and January was well below normal. So far
for February the mountains have been above normal with the Urban
Corridor also above normal. The far eastern plains had slightly below
normal temperatures.
Basin snowpack conditions for the period
October 1 2024 to February 12 2025:
---------------------------------
(Snow is percent of Median)
(Total precipitation is percent of Average)
Basin Snow Precip
----- ---- ------
Upper Colorado 88 89
South Platte 97 95
Upper North Platte 90 93
Subbasin Snow Precip
-------- ---- ------
Colorado Headwaters 92 91
Blue 109 106
South Platte Headwaters 93 87
Clear Creek 95 97
St Vrain 105 102
Big Thompson 98 91
Cache La Poudre 99 96
North Platte Headwaters 92 96
Weather Outlook
---------------
The current ENSO pattern is La Nina and is forecast to remain
through the February through April time range. The chance of ENSO
changing to neutral later this spring reaches 60 percent.
The outlook through the rest of February favors slightly better
chances of above normal temperatures with a slight chance of below
normal precipitation over the mountains and along the urban corridor
with equal chances of either above, below or normal precipitation on
the Palmer Divide.
Farther out, the February through April seasonal outlook favors
equal chances of either above or below normal temperatures and
better chances of below normal precipitation over northeastern
Colorado.
Numerical River Outlooks
------------------------
In Table 1 below, the current (CS) and historical (HS) or normal
probabilities of exceeding minor...moderate...and major flood stage
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: 02/15/2025 - 09/30/2025
: 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 8.5 9.5 : <5 5 <5 <5 <5 <5
Denver 11.0 13.0 15.0 : <5 <5 <5 <5 <5 <5
Henderson 11.0 13.0 15.0 : <5 <5 <5 <5 <5 <5
Fort Lupton 11.0 13.0 15.0 : <5 5 <5 <5 <5 <5
Kersey 10.0 11.5 13.5 : 12 15 11 8 <5 <5
Weldona 10.0 11.0 12.0 : 14 14 10 9 8 7
Fort Morgan 17.5 19.5 21.5 : 12 13 11 10 8 7
Balzac 10.0 11.0 12.5 : 12 12 11 11 10 9
Atwood 11.5 13.0 14.5 : 11 11 10 10 <5 <5
Julesburg 10.0 11.0 12.5 : 10 10 <5 <5 <5 <5
:Plum Creek
Sedalia 8.0 10.0 12.0 : <5 <5 <5 <5 <5 <5
:Bear Creek
Morrison 9.0 10.0 10.5 : <5 <5 <5 <5 <5 <5
Sheridan 8.0 10.0 10.5 : <5 <5 <5 <5 <5 <5
:Clear Creek
Golden 8.5 9.5 10.5 : <5 <5 <5 <5 <5 <5
Derby 10.5 11.5 12.5 : <5 <5 <5 <5 <5 <5
:N Fk Big Thompson River
Drake 5.5 6.0 7.0 : <5 <5 <5 <5 <5 <5
:Cache la Poudre River
Fort Collins 9NW 7.5 9.0 10.5 : <5 10 <5 6 <5 <5
Fort Collins 10.5 11.5 13.0 : <5 <5 <5 <5 <5 <5
Greeley 8.0 9.5 10.5 : 11 17 8 13 5 10
:North Platte River
Northgate 8.0 9.5 11.0 : <5 12 <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: 02/15/2025 - 09/30/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:South Platte River
South Platte 3.8 3.9 4.0 4.3 4.6 5.1 5.9
Denver 3.9 4.0 4.6 5.0 5.6 6.0 6.5
Henderson 5.0 5.2 6.1 6.5 7.0 7.8 8.8
Fort Lupton 4.6 4.9 6.2 7.1 8.2 8.9 10.5
Kersey 3.5 3.9 5.5 6.8 7.7 12.0 12.9
Weldona 3.0 3.3 4.7 6.1 7.4 11.1 13.0
Fort Morgan 10.2 10.3 11.2 12.6 14.5 20.0 22.1
Balzac 3.1 3.2 4.3 6.3 7.4 12.2 13.4
Atwood 3.8 4.0 5.0 7.2 8.1 12.9 13.9
Julesburg 6.0 6.1 6.6 7.9 8.3 10.1 10.4
:Plum Creek
Sedalia 3.6 3.7 3.8 4.1 4.6 5.4 6.2
:Bear Creek
Morrison 6.4 6.5 6.7 7.0 7.2 7.5 7.6
Sheridan 3.0 3.1 3.3 3.4 3.9 4.0 4.2
:Clear Creek
Golden 4.5 5.0 5.5 6.0 6.4 6.8 7.2
Derby 4.7 4.8 5.2 6.0 6.5 7.0 7.4
:N Fk Big Thompson River
Drake 2.7 2.8 2.9 3.2 3.7 3.9 4.5
:Cache la Poudre River
Fort Collins 9NW 4.0 4.1 4.6 5.0 5.7 6.7 7.2
Fort Collins 3.4 3.4 3.7 4.1 4.8 5.8 6.8
Greeley 1.9 2.0 2.8 4.0 5.5 8.4 10.5
:North Platte River
Northgate 3.2 3.5 4.6 5.5 6.3 7.0 7.9
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: 02/15/2025 - 09/30/2025
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:South Platte River
South Platte 2.9 2.9 2.8 2.8 2.7 2.7 2.7
Denver 2.8 2.7 2.7 2.7 2.7 2.6 2.6
Henderson 3.5 3.5 3.5 3.5 3.5 3.5 3.5
Fort Lupton 3.2 3.1 3.1 3.1 3.0 3.0 3.0
Kersey 2.1 2.0 2.0 1.9 1.9 1.8 1.7
Weldona 2.0 1.9 1.7 1.5 1.1 1.1 1.0
Fort Morgan 8.4 8.4 8.4 8.4 8.4 8.4 8.3
Balzac 1.5 1.1 0.6 0.6 0.6 0.6 0.6
Atwood 2.1 2.0 1.6 1.5 1.5 1.5 1.5
Julesburg 3.3 3.3 3.3 3.3 3.3 3.3 3.3
:Plum Creek
Sedalia 3.0 3.0 3.0 3.0 3.0 3.0 3.0
:Bear Creek
Morrison 5.4 5.4 5.3 5.3 5.3 5.3 5.2
Sheridan 2.5 2.5 2.5 2.5 2.0 1.8 1.7
:Clear Creek
Golden 3.4 3.4 3.3 3.3 3.2 3.2 3.2
Derby 2.4 2.0 2.0 2.0 2.0 2.0 2.0
:N Fk Big Thompson River
Drake 2.0 2.0 2.0 2.0 2.0 2.0 2.0
:Cache la Poudre River
Fort Collins 9NW 2.6 2.6 2.6 2.6 2.6 2.6 2.6
Fort Collins 2.4 2.3 2.3 2.3 2.3 2.3 2.3
Greeley 0.6 0.6 0.6 0.6 0.6 0.6 0.6
:North Platte River
Northgate 2.3 2.3 2.3 2.3 2.3 2.2 2.1
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 National
Water Prediction Service.
Following are the forecasts for selected locations:
Median Forecast
Volume Percent
Stream and Station Period 1000 AF of Avg
__________________ ______ _______ _______
South Platte River
Antero Reservoir inflow Apr-Sep 14 99
Spinney Mtn Res inflow Apr-Sep 39 87
11-Mile Canyon Res inflow Apr-Sep 41 82
Cheesman Lake inflow Apr-Sep 72 77
South Platte Apr-Sep 136 66
Bear Creek
Morrison Apr-Sep 14 54
Clear Creek
Golden Apr-Sep 96 73
Saint Vrain Creek
Lyons Apr-Sep 82 75
Boulder Creek
Orodell Apr-Sep 51 98
South Boulder Creek
Eldorado Springs Apr-Sep 31 78
Cache La Poudre River
Canyon Mouth Apr-Sep 187 89
North Platte River
Northgate Apr-Sep 229 77
Colorado River
Granby Apr-Jul 200 89
Willow Creek
Willow Creek Res Apr-Jul 42 84
Fraser River
Winter Park Apr-Jul 20 108
Williams Fork River
Williams Fork Reservoir Apr-Jul 42 84
Blue River
Dillon Res Apr-Jul 155 93
Green Mtn Res Apr-Jul 270 96
Muddy Creek
Wolford Mtn Res Blw Apr-Jul 44 85
Colorado River
Kremmling Apr-Jul 800 92
These forecasts reflect natural flow only. Actual observed flow will
likely be affected by upstream water management.
It should be emphasized that snow accumulation and snow pack
conditions could change before the runoff begins.
Changing hydrometeorological conditions can have a significant
impact on water supply forecasts. Additional products will be
issued as conditions evolve.
Additional supportive information
---------------------------------
- Visit the Missouri Basin RFC information webpage for water supply
forecasts east of the divide at weather.gov/mbrfc/water.
- Visit the Colorado Basin RFC for water supply forecasts west of
the divide at cbrfc.noaa.gov/lmap/lmap.php?interface=wsup.
- Visit our website at weather.gov/bou for additional local
weather and stream information.
- Long range precipitation and temperature outlooks are available at
www.cpc.ncep.noaa.gov/products/predictions/.
- Snowpack and reservoir data are available from the Natural
Resources Conservation Service at www.wcc.nrcs.usda.gov/snow/.
$$
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