Sargent, Nebraska Weather Forecast Discussion

710
FXUS63 KLBF 162028
AFDLBF
Area Forecast Discussion
National Weather Service North Platte NE
328 PM CDT Tue Sep 16 2025
.KEY MESSAGES...
- Thunderstorm development is likely later this afternoon into
  the evening hours in advance of an approaching cold front.
  There is a slight risk (level 2 of 5) for severe
  thunderstorms. Main severe modes are large hail, damaging
  winds and heavy rain. A tornado or two cannot be ruled out
  initially if discrete cells develop downstream of the
  approaching front.
- The threat for rainfall will continue through the first half
  of Friday as an upper level low meanders across the central
  to northern High Plains.
- Conditions will dry out late friday into the weekend. The
  threat for precipitation early next week is more uncertain.
&&
.SYNOPSIS...
Issued at 328 PM CDT Tue Sep 16 2025
H5 analysis this morning had an area of low pressure over
northwestern Wyoming. A trough of low pressure extended south of
this feature into southeastern Utah. Upstream of this feature,
a highly amplified ridge of high pressure extended from northern
California into northern portions of British Columbia and
northern Alberta. East of the trough, a secondary shortwave
trough was located over central Manitoba with another shortwave
noted over northern Saskatchewan. Further east, high pressure
was noted over the central Great Lakes with ridging into eastern
Ontario and southern Quebec. Southeast of this feature, low
pressure was present over the Carolinas. At the surface, a cold
front extended from near Mullen to Ogallala to west of Imperial.
Another outflow boundary extended east of the front from south
of Valentine to south of O`Neill. Currently severe storms were
firing post frontal in the western and NW Sandhills, as well
INVOF a warm front over far SW Nebraska. Temperatures as of 3 PM
CDT ranged from 56 degrees at Gordon to 86 degrees at Imperial
and Thedford.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 328 PM CDT Tue Sep 16 2025
As mentioned in the key messages above, thunderstorm chances
and the severe threat for tonight is the main forecast
challenge. Later on, the threat for showers/embedded
thunderstorms will be a secondary threat Wednesday into
Wednesday night. A couple of areas we continue to watch this
afternoon for storm initiation are over far SW Nebraska INVOF a
warm front and along an approaching cold front and surface
trough. Along and east of the surface trough and INVOF the warm
front will be the most favored areas for severe storms this
evening. Already as of 2 PM this afternoon, a corridor of 2000
to 4000 SB CAPES exists east of the frontal boundary and surface
trough. As of 2 PM CT, this line is roughly east of a line from
Chappell to Butte. So far, deep layer shear is greatest from
north central Nebraska into the Panhandle. This area is post
frontal. Deep layer shear is expected to continue to increase
over the next 1 to 3 hours, as a strong mid level shortwave
enters the panhandle. This, along with the already steep mid
level lapse rates (H5-H7) will be very favorable for severe
storms. Current thinking is that the main tornado threat will be
over SW Nebraska INVOF the warm front where low level winds are
backed. The main hail threat appears to lie over the western
Sandhills into the southern Panhandle where mid level lapse
rates are maximized. Into the early evening hours, convection is
expected to morph into a line with the main severe threat
shifting to gusty winds. Once the line develops, believe the
threat for large hail will decrease significantly. This is due
to 4 to 6 KM storm relative winds expected to lie parallel to
the cold front and expected thunderstorm line. This will lead to
increased competition for hail embryos and a diminished threat
for large hail. The threat for winds will carry over into the
mid to late evening hours as the line tracks east. With respect
to the heavy rain threat tonight: A couple of things stand out
with today`s setup which are favorable for heavy rain. First,
surface dew points in advance of the cold front, are running in
the middle 60sF. This is well above the 90th% ile and approaches
max climatology value for North Platte for this date (per SPC
sounding climatology). PWATS this afternoon for KLBF also also
nearing the 90th percentile for today per SPC sounding
climatology. One final aspect which makes a case for heavy
rainfall tonight is that within the expected line of storms this
evening, steering winds (4-6KM) will be parallel or nearly
parallel to the line. This will promote longer residence times
for thunderstorms over a given area. As for expected location of
heaviest rainfall, the latest NBM guidance has the heaviest
rainfall over the southern Sandhills tonight. This is also
supported by the REFS and NBM ensembles. The REFS 24 hr QPF
probabilities have a 70 to 90 percent threat for 1+ inch of QPF
centered along highway 92 from Tryon east to Arnold. The WPC
probabilities are slightly less, however the location is similar
to the REFS. With this location in peak expected QPF, believe
the flash flood threat will be minimized being over the southern
Sandhills. ATTM, do not feel confident enough to issue a flood
watch for tonight given the forecast area of highest QPF being
over the southern Sandhills.
Overnight, in the wake of the exiting line of convection, there will
be a continued threat for light rainfall. Further southwest, where
the threat for rainfall decreases overnight, time sections are
indicating some mid level drying and fog formation into Wednesday
morning. ATTM, the signal for dense fog appears week and will limit
mention to patchy. The leading shortwave, responsible for convection
and pushing the cold front across Nebraska, will lift into South
Dakota Wednesday. The main low will "dumbbell" into Wyoming, then
western Nebraska Wednesday afternoon. Precipitation chances will
increase across the area, with the greatest threat for rainfall over
northern into eastern sections of the forecast area. Across
southwestern Nebraska, precipitation is more in doubt given mid
level westerly winds and drying. Wednesday night another shortwave
within the H5 trough will approach western Kansas with another
round of light precipitation traversing the area.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 328 PM CDT Tue Sep 16 2025
Conditions will begin to dry out Thursday night as the pattern
de-amplifies across the central and northern plains. This will
lead to warmer temperatures in the 80s this weekend then above
normal temps in the mid to upper 70s to begin next week.
Conditions are expected to be dry during the period beyond
Thursday night.
&&
.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1253 PM CDT Tue Sep 16 2025
The threat for thunderstorms will increase significantly toward
the later half of this afternoon. By 23z, expect occasional
thunderstorms at both terminals with the threat lasting through
05-08z this evening. The greatest threat for strong to severe
storms is from 22z through 04z this evening. Wind gusts up to 45
KTS will be the main threat along with heavy rain. Some hail
cannot be ruled out as well. After late evening, ceilings will
fall to MVFR, then IFR overnight as light rain showers develop.
Low ceilings will carry over into mid to late morning Wednesday
with overcast sky coverage continuing.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...Buttler

NWS LBF Office Area Forecast Discussion