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Flood Potential Outlook
Issued by NWS Denver/Boulder, CO
Issued by NWS Denver/Boulder, CO
000
FGUS75 KBOU 142137
ESFBOU
COC001-005-013-014-019-031-035-039-047-049-057-059-069-073-075-
087-093-095-115-117-121-123-162145-
Water Supply Outlook
National Weather Service Denver CO
337 PM MDT Thu Mar 14 2024
...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 2024 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 snow typically accumulates into April, therefore
conditions may change before the runoff begins.
Water supply forecasts issued by the National Weather Service in
early March have slightly increases from the mid-February
forecasts and project generally near to just slightly below
average April through July runoff volumes for Upper Colorado and
South Platte Basins. The Upper North Platte basin, and the Fraser
River Basin continue to show a slightly above average runoff
volume if current conditions persist.
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 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 the Upper North Platte
Basins are near to slightly below normal with and Cache La Poudre
Basin 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 extending out into most of the northeastern plains. The
exception with along the north Weld county border and most of
Sedgwick and Phillips counties with near normal precipitation.
Southern part of the Denver metro area into the Palmer Divide and
adjacent foothills are near to slightly above normal.
Precipitation in October through November was well below normal
for most of Northeastern Colorado including the eastern plains,
the urban corridor and mountains. In December the far eastern
plains over to the Palmer Divide and into the foothills had above
normal precipitation for the month. The northern part of the metro
area east and north had much less than normal precipitation. Weld
and Morgan counties had the least precipitation. January
continued the dry trend over most of the eastern plains and Denver
metro area. The Palmer Divide and portions of the mountains
received some much needed moisture and spotty areas above normal
for the month.
The very end of January and through February brought much needed
precipitation to the area. The eastern plains and into the
foothills have received well over normal precipitation for the
month of February. The mountains also received much needed snow
and increased the snowpack to near to slightly below normal for
the water year.
The first part of March has well above normal precipitation for
the far northeastern plains and over the northern Front Range
Mountains. The central plains and urban corridor were dryer than
normal. A current storm will bring additional moisture to the
urban areas into the foothills and Front Range Mountains.
Temperatures on average since the beginning of the water year have
been above normal. In January temperatures were below normal.
February temperatures have been above normal with the exception of
the northern Gore and southern Park Ranges.
The northern part of the Front Range mountains has had less snow
and precipitation than normal although the last month saw slight
improvements, including the St Vrain, Big Thompson, and Cache La
Poudre Basins.
Basin snowpack conditions for the period
October 1 2023 to March 13 2024:
---------------------------------
(Snow is percent of Median)
(Total precipitation is percent of Average)
Basin Snow Precip
----- ---- ------
Upper Colorado 105 104
South Platte 98 94
Upper North Platte 109 110
Subbasin Snow Precip
-------- ---- ------
Colorado Headwaters 107 106
Blue 109 102
South Platte Headwaters 106 98
Clear Creek 103 105
St Vrain 93 92
Big Thompson 94 91
Cache La Poudre 94 89
North Platte Headwaters 100 98
Climate Outlook
---------------
The current ENSO pattern is El Nino and is forecast to transition
to the neutral phase later this spring. The chance of ENSO
changing to neutral later this spring reaches 79 percent.
The outlook for March favors equal chances of either above, below
or normal temperatures with a better chance of above normal
precipitation over the mountains and along the urban corridor with
a slightly smaller chance of above normal precipitation on the
far eastern plains.
Farther out, the March through May seasonal outlook favors equal
chances of either above, below or normal temperatures and equal
chances of either above, below or normal precipitation for
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: 03/16/2024 - 09/30/2024
: 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 : 6 5 <5 <5 <5 <5
Kersey 10.0 11.5 13.5 : 24 15 12 8 <5 <5
Weldona 10.0 11.0 12.0 : 16 9 10 8 8 6
Fort Morgan 17.5 19.5 21.5 : 17 13 13 10 9 7
Balzac 10.0 11.0 12.5 : 16 12 13 11 11 9
Atwood 11.5 13.0 14.5 : 14 11 11 10 5 <5
Julesburg 10.0 11.0 12.5 : 12 10 <5 <5 <5 <5
:Plum Creek
Sedalia 8.0 10.0 12.0 : 14 <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 : 12 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 : 18 17 11 12 6 7
:North Platte River
Northgate 8.0 9.5 11.0 : 6 13 <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: 03/16/2024 - 09/30/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:South Platte River
South Platte 3.9 4.1 4.3 4.8 4.9 5.7 7.1
Denver 4.9 5.1 5.5 6.1 6.6 7.5 8.1
Henderson 5.5 5.9 6.8 7.4 8.1 9.0 9.3
Fort Lupton 5.4 6.0 7.2 8.1 9.3 10.8 11.5
Kersey 4.6 5.0 6.9 7.9 9.6 12.4 13.4
Weldona 3.9 4.2 5.9 6.7 8.4 10.9 14.0
Fort Morgan 10.8 10.9 12.6 13.8 16.4 21.1 23.1
Balzac 4.3 4.3 6.0 6.9 8.9 13.1 14.1
Atwood 5.1 5.1 6.7 7.8 9.5 13.7 14.6
Julesburg 6.6 6.7 7.8 8.1 8.8 10.5 10.9
:Plum Creek
Sedalia 4.5 4.7 5.0 5.5 6.4 8.2 10.0
:Bear Creek
Morrison 6.5 6.7 6.9 7.1 7.4 7.6 7.7
Sheridan 3.3 3.5 3.8 4.3 4.9 5.3 5.3
:Clear Creek
Golden 5.0 5.3 5.9 6.2 6.8 7.1 7.4
Derby 5.0 5.2 5.6 6.4 6.9 7.2 7.6
:N Fk Big Thompson River
Drake 3.0 3.1 3.2 3.5 3.9 4.1 4.7
:Cache la Poudre River
Fort Collins 9NW 4.2 4.3 5.0 5.6 6.3 8.2 9.0
Fort Collins 2.5 2.9 4.2 5.3 6.2 8.8 10.3
Greeley 2.1 2.2 4.6 6.1 7.5 9.7 11.5
:North Platte River
Northgate 4.4 4.8 5.9 6.5 7.2 7.8 8.4
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: 03/16/2024 - 09/30/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:South Platte River
South Platte 2.8 2.8 2.8 2.8 2.8 2.8 2.8
Denver 3.2 3.1 3.1 3.0 3.0 3.0 3.0
Henderson 4.0 4.0 3.9 3.9 3.8 3.6 3.6
Fort Lupton 3.8 3.7 3.7 3.5 3.3 3.2 3.2
Kersey 3.2 2.5 2.3 2.2 2.1 2.0 2.0
Weldona 2.7 2.5 2.2 2.2 2.1 2.1 2.0
Fort Morgan 9.4 9.1 8.6 8.5 8.4 8.4 8.4
Balzac 2.8 2.5 2.1 2.0 1.6 1.6 1.6
Atwood 3.4 3.1 2.4 2.2 1.7 1.7 1.6
Julesburg 3.3 3.3 3.3 3.3 3.3 3.3 3.3
:Plum Creek
Sedalia 3.7 3.7 3.7 3.6 3.6 3.5 3.5
:Bear Creek
Morrison 5.7 5.7 5.7 5.7 5.7 5.6 5.4
Sheridan 2.5 2.5 2.5 2.4 2.2 2.0 2.0
:Clear Creek
Golden 3.3 3.3 3.3 3.3 3.3 3.3 3.3
Derby 3.0 2.9 2.7 2.7 2.7 2.7 2.7
:N Fk Big Thompson River
Drake 2.4 2.4 2.4 2.4 2.4 2.4 2.4
:Cache la Poudre River
Fort Collins 9NW 3.0 3.0 2.9 2.8 2.8 2.7 2.7
Fort Collins 0.1 0.1 0.0 0.0 0.0 0.0 0.0
Greeley 0.9 0.8 0.8 0.7 0.7 0.7 0.7
:North Platte River
Northgate 2.4 2.4 2.4 2.4 2.4 2.4 2.3
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.
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 13 91
Spinney Mtn Res inflow Apr-Sep 48 106
11-Mile Canyon Res inflow Apr-Sep 52 104
Cheesman Lake inflow Apr-Sep 94 101
South Platte Apr-Sep 182 89
Bear Creek
Morrison Apr-Sep 20 75
Clear Creek
Golden Apr-Sep 111 85
South Boulder Creek
Eldorado Springs Apr-Sep 38 96
Boulder Creek
Orodell Apr-Sep 56 108
Saint Vrain Creek
Lyons Apr-Sep 80 73
Cache La Poudre River
Canyon Mouth Apr-Sep 229 109
North Platte River
Northgate Apr-Sep 374 127
Colorado River
Granby Apr-Jul 196 87
Willow Creek
Willow Creek Res Apr-Jul 51 102
Fraser River
Winter Park Apr-Jul 21 113
Williams Fork River
Williams Fork Reservoir Apr-Jul 86 89
Blue River
Dillon Res Apr-Jul 152 91
Green Mtn Res Apr-Jul 268 96
Muddy Creek
Wolford Mtn Res Blw Apr-Jul 54 103
Colorado River
Kremmling Apr-Jul 835 96
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...climate 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/.
$$
as
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- Page last modified: Sep 19th, 2023 19:10 UTC