Flood Potential Outlook
Issued by NWS Hastings, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6
000
FGUS73 KGID 292120 CCA
ESFGID
NEC129-NEC175-NEC077-NEC125-NEC163-NEC093-NEC019-NEC079-NEC019-
KSC147-KSC163-051800-

PROBABILISTIC HYDROLOGIC OUTLOOK...Corrected
NATIONAL WEATHER SERVICE Hastings NE
315 PM CST Thu Feb 29 2024

..2024 Spring Flood and Water Resources Outlook Number 2...

This outlook is for the Hastings Hydrologic Service Area (HSA).
In South Central Nebraska this outlook includes the
Platte...Loup...Little Blue...and Republican Rivers and their
tributaries. In North Central Kansas...the Solomon River and its
tributaries are included.

...The potential for spring flooding is generally below average to
near average across the majority of the area...

...Short Term Hydrologic Outlook...March 1st Through March 14th...

The thick river ice we accumulated in January has melted off or
broken up and moved out of the area. We do not expect enough
additional ice accumulation through late winter or early spring to
cause any additional ice jams this season. Therefore, the ice jam
threat has ended for the spring season. There is good confidence
that we will continue to see above normal temperatures through the
first half of March. The precipitation outlook through early March
is above normal, but given our dry soil conditions, it`s unlikely
that we will see enough precipitation to result in any flooding.


...Long Term Hydrologic Outlook...March 15th Through May 31st...

The overall potential for spring flooding is below average across
the majority of the area to near average in a few locations along
primarily the Loup River Basin.

Spring flood outlooks are routinely issued from February through
March to give advanced notice of possible flooding. They are based
on soil moisture, snowpack magnitude, stream flow conditions, and
the long range forecast of future precipitation patterns.

There are several primary factors leading to our below average
threat for spring flooding.
- The local snowpack is negligible to non-existent.
- The mountain snowpack in the Platte River Basin is near to below
normal.
- Lake McConaughy is at 63 percent capacity and has plenty of
storage space available.
- Soil moisture is drier than normal in many locations given the
ongoing moderate to severe drought. We do have some locations that
have come out of the drought, but even in these areas soil moisture
is just near normal at best.  Consequently, the soil is still
capable of absorbing plenty of moisture thus limiting spring flood
potential.
- Current streamflow on our biggest rivers is averaging near normal
to below normal.
- The March precipitation outlook is trending towards above normal
precipitation, but the longer range outlook of April through June
indicates equal chances with no strong indicators one way or the
other. A wetter than normal March may help our drought situation,
but is unlikely to have much impact on our short term flooding
threat due to the other factors listed above.

It is important to mention that isolated  or localized flooding is
still possible even in dry years and when the overall risk of
widespread flooding is low. Isolated heavy spring thunderstorms will
still be capable of producing localized areas of flooding.

For a graphical, more in-depth version of this assessment, please
refer to our PDF report that will be linked at:

https://www.weather.gov/media/gid/hydro/SpringFloodOutlook_2024.pdf


...Climatological Review (Recent/Winter 2023-24 Precipitation
Analysis...

In the previous issuance of this statement back on Feb. 15th, this
section included a precipitation recap/analysis for the full year of
2023 across our 30-county NWS Hastings coverage area (24 counties in
central/south central NE and six counties in north central KS).
Please refer back to that previous statement for 2023 details.

From this point forward, the focus here will be on more recent
precipitation trends over the past three months, specifically what
has transpired since the start of "meteorological winter" 2023-24
back on Dec. 1, 2023 (meteorological winter is defined as the three
full calendar months of Dec-Jan-Feb).

As evidenced in the data presented in the table below (and supported
by AHPS precipitation analysis), this meteorological winter featured
modestly above normal precipitation across nearly our entire
coverage area (despite the last three weeks actually being very
dry). More specifically, most of our area has received somewhere
between 2.00-4.00" of precipitation since Dec. 1st (including melted
snow). This equates to most of our receiving 100-200 percent of
normal for the season.

Although much of this precipitation fell as snow during January,
quite a bit of it actually fell as rain during December and early
February. Although not a large/significant difference, the overall-
wettest locations have mainly favored eastern/southern portions of
our area, with the overall-driest locations mainly concentrated in
western/northern counties. In fact, of mainly our far western
coverage area (including Furnas County) actually received slightly
below normal winter precipitation. Per official NWS cooperative
observer and airport stations, a few of the wettest locations in our
area from Dec-Feb included: Plainville KS 4WNW (5.17"), Smith Center
KS (5.03") and Hebron (4.42"). In fact, this ended up being the 2nd-
wettest winter on record at both the Plainville and Smith Center
stations. Meanwhile, a few of the driest official observation sites
in our area this winter ended up being: Cambridge (1.51"), Edison
(1.97") and Greeley (2.04").


-- Winter-to-date Drought Recap (per weekly updates by the U.S.
Drought Monitor/USDM):

Thanks to the aforementioned above normal precipitation this winter
(and in particular the fact that much of it fell as rain and
efficiently soaked into the soil), there was an unusually-
significant improvement in drought categories across much of our
coverage area from Dec-Feb. At the start of December, 64% of our
coverage area was under drought categories ranging from Moderate
(D1) to Exceptional (D4), including 36% of the area in worst-off
D3+D4 (primarily focused east of Highway 281 in Nebraska and also in
parts of north central Kansas). However, the winter months only
brought gradual improvement, and as of the very latest USDM issued
today (Feb. 29), our entire coverage area is void of all Extreme
(D3) and Exceptional (D4) Drought categories. That being said, half
of our area remains under Moderate (D1) or Severe (D2) drought, with
D2 dominating most local Nebraska counties along/east of Highway
281. In the "best news of all" department, 31% of our coverage area
is currently indicated to be void of all drought categories
whatsoever (even Abnormally Dry D0), including large parts of
several counties mainly west of the Highway 281 corridor. Despite
this overall-good news, we will need some beneficial precipitation
soon given how dry it has been over the most recent three weeks, or
drought categories could perhaps start going back the other
direction again.

The next table below highlights precipitation totals and departures
from normal/percent of normal for meteorological winter 2023-24,
covering Dec. 1 - Feb. 29. Data is shown for just a small sampling
of official NWS cooperative observers representing various parts of
our area, along with a few primary airport sites.


  Location          Precip      Departure    Percent of
North Central KS  Dec 1-Feb 29  from Normal    Normal
---------------    --------       ------      ---------
Beloit               4.03         +1.49          159
Phillipsburg         3.07         +0.79          134
Plainville 4WNW      5.17         +2.75          214
Smith Center         5.03         +2.95          242


  Location          Precip      Departure    Percent of
South Central NE  Dec 1-Feb 29  from Normal    Normal
---------------    --------       ------      ---------
Cambridge            1.51         -0.21           88
Elwood 8S            2.06         +0.39          123
Grand Island Arpt    3.50         +1.31          160
Hastings Airport     3.28         +1.12          152
Hebron               4.42         +1.75          166
Holdrege             2.80         +0.84          143
Kearney Airport      2.51         +0.73          141
Lexington 6SSE       2.24         +0.70          145
Ord                  2.93         +0.95          148
Osceola              3.78         +1.25          149
Superior             3.61         +1.07          142
St. Paul             2.33         +0.22          110
York 3N              3.59         +0.82          130



...Weather/Climatological Outlook For The Next Week Through The Next
Three Months...

It`s now time to switch gears and look ahead to expected weather
conditions over the next several days and expected climate trends
over the next several months:

The next week (through March 7):
According to our latest official 7-day forecast, at least the vast
majority of this week should (unfortunately) remain dry, with only
very slight chances for light precipitation during the Sunday night-
Tuesday time frame (March 3-5). Although still of low confidence,
there might actually be a slightly better chance of rain toward the
Thursday-Friday time frame (March 7-8). Temperature-wise,
unseasonably-warm highs in the 60s-70s will prevail through Sunday
(March 3), before a modest cool-down occurs for Monday onward with
highs easing back more so into the 50s.

Two weeks out (March 8-14):
Looking out just a bit farther in time, the latest 8-14 day outlook
from the Climate Prediction Center (CPC) strongly leans toward a
high probability of overall above normal temperatures across our
entire coverage area, and also calls for a modest lean toward above
normal precipitation.

Meteorological Spring (March-May):
Turning to the upcoming meteorological spring months of March-April-
May as a whole, the latest Climate Prediction Center (CPC) three-
month outlook (issued Feb. 15th) indicates a slight lean toward
above normal precipitation (primarily driven by expectations of a
somewhat-wet March), along with "Equal chances" for temperatures to
be above normal, below normal or near normal. This means that there
are no clear signals in current longer-range forecast data to lean
toward one of these outcomes over another. Based on 30-year normals,
total March-May precipitation across the NWS Hastings coverage area
typically ranges from 7-10", with the lowest amounts generally west
of Highway 183 and highest amounts near the Highway 81 corridor.

U.S. Seasonal Drought Outlook (issued by CPC on Feb. 15th and valid
through the end of May):
Going hand in hand with the aforementioned slight lean toward above
normal precipitation this spring, this outlook indicates that those
parts of our coverage area currently under any drought category
(Moderate Drought D1 or worse), will either see some improvement or
perhaps have drought removed altogether.

(The longer range forecasts issued by CPC and referenced in the
preceding paragraphs are based on output from various forecast
models, as well as forecaster expertise, and take into consideration
ongoing global/tropical atmospheric and oceanic states, recent
trends in observed data, soil moisture conditions, etc. More
information about these longer-range forecasts can be obtained from
the CPC web site at: https://www.cpc.ncep.noaa.gov)


...Long Range Probabilistic 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 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:  03/02/2024  - 05/31/2024

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:Little Blue River
Deweese             10.0   16.0   17.0 :  20   34   <5    6   <5    5
:North Fork Solomon
Glade               11.0   16.0   18.0 :   6   15   <5    8   <5   <5
:Bow Creek
Stockton             9.0   12.0   13.6 :   8   24   <5    7   <5   <5
:Platte River
Darr                11.5   12.5   13.0 :  21   27   15   23   12   13
Overton              7.5   12.0   14.0 :  16   26   <5   <5   <5   <5
Kearney              7.0    8.0    9.0 :  12   15   <5    5   <5   <5
:Wood River
Gibbon              15.0   16.0   16.5 :  21   32   18   26   16   21
Alda                10.0   11.0   12.2 :  31   41   29   33   19   25
Wood River Divers   19.5   20.5   21.5 :   9   20    8   10    6    8
:Platte River
Grand Island         6.5    7.0    7.5 :  21   29   18   21   13   14
:South Loup River
Ravenna              5.0    8.0   10.0 :  39   37    8   11    5    8
:Mud Creek
Sweetwater          16.5   18.0   21.0 :  13   27    6   10   <5   <5
:South Loup River
Saint Michael        9.5   14.0   17.0 :  13   19    5    8   <5   <5
:Middle Loup River
Saint Paul           8.0   10.0   12.0 :   5    9   <5    7   <5    5
:North Loup River
Saint Paul           7.0   10.0   12.0 :  <5    6   <5   <5   <5   <5
:Cedar River
Fullerton            9.0   15.0   18.0 :  <5    9   <5   <5   <5   <5
:Loup River
Genoa               10.5   12.0   13.0 :   6   11   <5    6   <5    5
:Beaver Creek
Genoa               15.0   17.0   19.0 :   8   21    5    9   <5    7

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: 03/02/2024  - 05/31/2024
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Little Blue River
Deweese               3.0    3.6    4.5    6.8    9.3   12.3   14.0
:North Fork Solomon
Glade                 2.8    2.8    2.8    5.3    7.9    9.8   13.3
:Bow Creek
Stockton              4.2    4.2    4.2    5.0    7.2    8.2   11.0
:Platte River
Darr                  6.2    6.4    7.5    9.6   10.9   13.6   14.8
Overton               4.0    4.0    4.0    4.9    6.5    9.1   10.2
Kearney               3.4    3.4    3.4    4.1    5.4    7.3    7.8
:Wood River
Gibbon                4.3    4.3    4.9    8.7   13.4   17.1   18.5
Alda                  4.6    4.6    4.8    7.4   11.4   12.8   13.4
Wood River Divers    11.1   11.1   11.7   14.1   16.6   18.7   22.0
:Platte River
Grand Island          4.1    4.1    4.1    5.0    6.0    7.8    8.7
:South Loup River
Ravenna               2.9    3.0    3.6    4.8    5.4    6.4   10.3
:Mud Creek
Sweetwater            5.6    5.6    8.2   11.8   14.9   17.0   18.4
:South Loup River
Saint Michael         2.4    2.5    3.4    6.6    8.0   11.4   13.6
:Middle Loup River
Saint Paul            1.4    1.4    2.0    3.5    4.5    6.2    8.2
:North Loup River
Saint Paul            2.8    2.9    3.7    4.1    4.6    5.3    6.0
:Cedar River
Fullerton             2.1    2.3    3.2    4.9    6.4    7.4    8.2
:Loup River
Genoa                 4.5    4.5    5.6    6.6    8.0    9.5   10.8
:Beaver Creek
Genoa                 3.7    3.9    5.8    8.8   12.7   14.4   17.0

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: 03/02/2024  - 05/31/2024
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Little Blue River
Deweese               2.2    2.2    2.2    2.1    2.0    2.0    2.0
:North Fork Solomon
Glade                 2.2    2.2    2.1    2.1    2.0    0.1    0.0
:Bow Creek
Stockton              4.2    4.1    4.1    4.0    3.9    3.8    3.8
:Platte River
Darr                  4.4    3.0    3.0    3.0    3.0    3.0    3.0
Overton               3.1    3.1    2.5    2.5    2.5    2.5    2.5
Kearney               3.1    3.0    2.3    2.2    2.1    2.1    2.1
:Wood River
Gibbon                4.2    4.1    4.1    4.1    4.1    4.1    4.1
Alda                  4.5    4.4    4.4    4.4    4.3    4.3    4.3
Wood River Divers    10.9   10.8   10.8   10.8   10.7   10.7   10.7
:Platte River
Grand Island          4.0    3.9    3.4    3.2    3.2    3.2    3.2
:South Loup River
Ravenna               2.8    2.8    2.7    2.7    2.6    2.6    2.6
:Mud Creek
Sweetwater            5.5    5.5    5.5    5.4    5.3    5.2    5.2
:South Loup River
Saint Michael         2.3    2.2    2.2    2.1    2.0    1.9    1.8
:Middle Loup River
Saint Paul            1.0    0.9    0.7    0.6    0.2    0.0    0.0
:North Loup River
Saint Paul            2.7    2.7    2.6    2.4    2.3    2.2    2.2
:Cedar River
Fullerton             1.8    1.8    1.7    1.7    1.6    1.6    1.5
:Loup River
Genoa                 3.9    3.9    3.9    3.9    3.9    3.9    3.9
:Beaver Creek
Genoa                 3.2    3.2    3.2    3.1    3.0    3.0    2.9

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.


...Future Outlooks...

The next/final spring flood outlook will be issued Thursday, March
14th.

&&

Visit our local NWS office website for current weather/hydrological
and climate information for South Central Nebraska and North Central
Kansas at:
https://www.weather.gov/hastings

Additional climate information for the region can be obtained
from the High Plains Regional Climate Center: https://hprcc.unl.edu

Additional information on climatological outlooks can be found
from the Climate Prediction Center: https://www.cpc.ncep.noaa.gov

Further information on drought conditions can be obtained at:
https://droughtmonitor.unl.edu
https://www.drought.gov
https://drought.unl.edu

Information on mountain snowpack can be found at:
https://www.nrcs.usda.gov/resources/data-and-reports/snow-and-water-
interactive-map

NWS AHPS precipitation analysis maps can be found at:
https://water.weather.gov/precip

National snow analysis page can be found at:
https://www.nohrsc.noaa.gov

Soil Moisture:
https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring

Reservoir Levels:
www.usbr.gov/gp/hydromet/curres_google.htm

For training on NWS river forecast graphics:
www.youtube.com/watch?v=psIByj8EZY0

$$

Wesely/Pfannkuch


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.