Flood Potential Outlook
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
924
FGUS75 KBOU 132128
ESFBOU
COC001-005-013-014-019-031-035-039-047-049-057-059-069-073-075-087-
093-095-115-117-121-123-152130-
Water Supply Outlook
National Weather Service Denver CO
328 PM MDT Thu Mar 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 3...
This is the third 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 still early and snow
typically accumulates into April, therefore conditions may change
before the runoff begins.
Water supply forecasts issued in early March 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 slightly 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 near to slightly above 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.
For February an isolated swath of snow from southeastern Grand
county to northeastern Park and southwestern Jefferson counties made
the monthly precipitation well above normal for that area. The rest
of northeastern Colorado has spotty slightly above normal mixed with
slightly below normal precipitation. March has continued to be spotty
with areas of both above and below normal precipitation.
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. Temperatures for February have been well
below normal for the eastern plains and above normal for the
mountains. For the first part of March Temperatures have been above
normal for northeastern Colorado.
Basin snowpack conditions for the period
October 1 2024 to March 12 2025:
---------------------------------
(Snow is percent of Median)
(Total precipitation is percent of Average)
Basin Snow Precip
----- ---- ------
Upper Colorado 98 95
South Platte 101 100
Upper North Platte 98 100
Subbasin Snow Precip
-------- ---- ------
Colorado Headwaters 104 99
Blue 119 112
South Platte Headwaters 94 89
Clear Creek 112 110
St Vrain 99 103
Big Thompson 102 94
Cache La Poudre 103 102
North Platte Headwaters 101 102
Weather Outlook
---------------
The current ENSO pattern is La Nina and is forecast to remain
through the near-term. The chance of ENSO changing to neutral later
this spring reaches 60 to 70 percent.
The outlook through the rest of March favors slightly better chances
of above normal temperatures over the eastern plains with an equal
change of either above, below or normal for the mountains. A slight
chance of above normal precipitation over the mountains and along the
urban corridor with equal chances of either above, below or normal
precipitation over the far eastern plains.
Farther out, the March through May 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: 03/15/2025 - 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 : 17 5 16 <5 16 <5
Denver 11.0 13.0 15.0 : 5 <5 5 <5 <5 <5
Henderson 11.0 13.0 15.0 : 6 <5 5 <5 5 <5
Fort Lupton 11.0 13.0 15.0 : 9 5 6 <5 6 <5
Kersey 10.0 11.5 13.5 : 16 15 11 8 <5 <5
Weldona 10.0 11.0 12.0 : 13 14 10 9 8 7
Fort Morgan 17.5 19.5 21.5 : 14 13 10 10 8 7
Balzac 10.0 11.0 12.5 : 12 12 11 11 9 9
Atwood 11.5 13.0 14.5 : 11 11 9 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 : 7 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 : 14 17 9 13 7 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: 03/15/2025 - 09/30/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:South Platte River
Denver 3.9 4.0 4.7 5.2 5.7 6.4 11.9
Henderson 5.2 5.4 6.2 6.8 7.3 8.8 14.3
Fort Lupton 4.9 5.3 6.2 7.4 8.8 10.6 16.9
Kersey 4.3 4.8 5.7 7.5 8.9 12.2 12.9
Weldona 3.7 4.1 5.0 6.6 8.1 11.2 13.1
Fort Morgan 10.5 10.6 11.6 13.1 15.2 19.6 22.3
Balzac 3.2 3.5 4.7 6.3 7.7 11.7 13.5
Atwood 3.9 4.2 5.4 7.1 8.5 12.6 14.0
Julesburg 3.3 3.6 6.7 7.9 8.5 10.0 10.4
:Plum Creek
Sedalia 4.5 4.6 4.7 5.0 5.2 6.7 7.8
:Bear Creek
Morrison 6.4 6.5 6.7 6.9 7.2 7.5 7.5
Sheridan 3.1 3.1 3.3 3.6 3.9 4.1 4.2
:Clear Creek
Golden 4.8 5.2 5.7 6.1 6.6 6.9 7.3
Derby 4.9 5.0 5.5 6.1 6.7 7.2 7.5
:N Fk Big Thompson River
Drake 2.7 2.9 3.0 3.3 3.7 3.9 4.5
:Cache la Poudre River
Fort Collins 9NW 4.0 4.1 4.6 5.1 5.7 6.1 7.6
Fort Collins 3.4 3.4 3.7 4.2 4.7 6.4 7.3
Greeley 1.7 1.9 2.8 4.0 5.4 8.8 11.0
:North Platte River
Northgate 3.4 3.8 4.8 5.7 6.4 7.3 7.8
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: 03/15/2025 - 09/30/2025
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:South Platte River
South Platte 3.0 3.0 3.0 3.0 3.0 3.0 3.0
Denver 3.0 3.0 3.0 3.0 2.9 2.9 2.9
Henderson 3.6 3.6 3.6 3.5 3.5 3.5 3.5
Fort Lupton 3.3 3.1 3.1 3.1 3.0 3.0 3.0
Kersey 2.8 2.7 2.6 2.5 2.5 2.4 2.4
Weldona 1.7 1.7 1.7 1.6 1.5 1.5 1.5
Fort Morgan 9.3 9.2 9.0 8.9 8.6 8.5 8.4
Balzac 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Atwood 2.1 1.5 1.5 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 3.2 3.2 3.2 3.2 3.1 3.1 3.1
:Bear Creek
Morrison 5.3 5.3 5.3 5.3 5.3 5.3 5.2
Sheridan 2.5 2.5 2.5 2.5 2.5 2.5 2.4
:Clear Creek
Golden 3.4 3.4 3.4 3.3 3.3 3.2 3.2
Derby 2.7 2.6 2.6 2.5 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 2.7 2.7 2.7 2.7 2.7 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 2.6 2.6 2.5 2.5 2.5 2.3 2.2
These long-range probabilistic outlooks contain forecast values that
are calculated using multiple season scenarios from 30 or more years
of 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.
...Table 4--ESP Mean Daily Peak Flow Forecasts as of March 12, 2025
The Upper Colorado River Basin
Daily ESP Mean Daily Peak Flow Forecasts in CFS as of March 12, 2025
LOCATION FLOOD FORECAST FLOWS
FLOW 90% 75% 50% 25% 10%
----------------------------------------------------------------------
WILLIAMS FORK - MOUTH, AT -99 960 1250 1450 1600 2100
SNAKE - MONTEZUMA, NR 2195 310 340 380 450 540
TENMILE CK - FRISCO, N TE 2005 580 620 710 770 900
STRAIGHT CK - LASKEY GULC 299 75 80 95 110 140
...Table 5--Water Supply forecasts Mar 1, 2025...
Following are the forecasts for selected locations:
Median Forecast
Volume Percent
Stream and Station Period 1000 AF of Med
__________________ ______ _______ _______
South Platte River
Antero Reservoir inflow Apr-Sep 12 99
Spinney Mtn Res inflow Apr-Sep 36 88
11-Mile Canyon Res inflow Apr-Sep 38 95
Cheesman Lake inflow Apr-Sep 66 76
South Platte Apr-Sep 141 76
Bear Creek
Morrison Apr-Sep 15 78
Clear Creek
Golden Apr-Sep 110 87
Saint Vrain Creek
Lyons Apr-Sep 84 82
Boulder Creek
Orodell Apr-Sep 53 104
South Boulder Creek
Eldorado Springs Apr-Sep 31 82
Cache La Poudre River
Canyon Mouth Apr-Sep 206 107
North Platte River
Northgate Apr-Sep 250 93
Colorado River
Granby Apr-Jul 215 98
Willow Creek
Willow Creek Res Apr-Jul 45 94
Fraser River
Winter Park Apr-Jul 21 110
Williams Fork River
Williams Fork Reservoir Apr-Jul 93 103
Blue River
Dillon Res Apr-Jul 163 99
Green Mtn Res Apr-Jul 285 106
Muddy Creek
Wolford Mtn Res Blw Apr-Jul 46 90
Colorado River
Kremmling Apr-Jul 855 104
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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