901
FXUS63 KLBF 092015
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
315 PM CDT Fri May 9 2025

.KEY MESSAGES...

- Isolated weak thunderstorms are possible this afternoon and
  early evening, mainly for portions of the Sandhills, with
  infrequent lightning and gusty winds the main concerns.

- Fire weather concerns increase in the coming days as forecast temperatures
  increase and winds become strong, peaking Sunday and Monday
  for western Nebraska. Later forecasts may require Fire Weather
  headlines if current forecasts hold.

- Rain and thunderstorm chances return around the middle of next
  week but recent trends have shifted much of the potential for
  measurable rain north of the area.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 314 PM CDT Fri May 9 2025

Mild and mostly dry conditions are expected through this evening
with dry conditions returning for Saturday. Late this afternoon and
evening, a weak cool front continues to move south into northwest
Nebraska. This is allowing for afternoon cumulus to blossom over the
western Sandhills where forecast soundings depict convective
temperatures being breached this afternoon. While lift is meager at
best, the frontal boundary and low-level convergence may be enough
to produce a few isolated showers and general thunderstorms. Lapse
rates aloft remain modest but enough to support MLCAPE values
nearing 250-500 j/kg. Given little to no deep-layer shear,
expectation is for a few showers and thunderstorms to develop and
slowly list south and east before dissipating this evening with loss
of daytime heating. Can`t rule out a few cloud to ground lightning
strikes and in areas that have yet to see much in the way of
moisture in recent weeks, am somewhat concerned about lightning
start fires. While HREF ensemble max QPF values paint fairly spotty
but appreciable rainfall amounts, probability-matched mean values
depict little in the way of measurable rain and given dry air in the
low levels to the tune of 35-45F dew point depressions believe the
dry air will win out. This dry air will also support some gusty
erratic winds in close vicinity to this activity, but magnitudes
should safely remain below 40 mph. For tonight, as precipitation
wanes through the evening hours we should see skies become mostly
clear through the early morning hours on Saturday. Overnight lows
should hold onto the 40s to low 50s.

Saturday/Saturday night...temperatures will again moderate during
the daytime where we should see a 3-6 degF increase from Friday`s
values for all locations in western Nebraska. Southerly winds will
increase through the afternoon as a northern stream disturbance
deepens and the local surface pressure gradient constricts with high
pressure over the northern Mississippi Valley. These winds may just
begin to increase late enough to prevent overly strong winds during
the day. As a result, the strongest wind gusts appear to favor the
late evening into the overnight hours. This will help keep
temperatures mild with only a fall into the 50s from the widespread
middle to upper 80s during the daytime.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 314 PM CDT Fri May 9 2025

Sunday through Tuesday...Broad upper-ridging will slowly translate
east heading into the early period of next week. This leaves the
area upstream of the ridge axis and well within gradual ridge
breakdown. Further upstream, broad troughing will begin moving
onshore the Pacific Northwest and it`s this feature that`ll be our
mid-week disturbance to watch for rain and thunderstorm chances.
While the brunt of the positive height anomalies will settle east
quickly towards the Great Lakes by late Sunday into Monday, the area
will still be caught under the influence of strong thermal ridging.
Daytime highs for the forecast period will peak Sunday through
Tuesday as a result with values well into the 80s and even
threatening the 90s for a select few. The Gulf Coast system, though
beginning to slide north and east, will still act as a road block
for more appreciable low-level moisture with PWATs settling around
climatological values but low-level moisture characterized by
specific humidity towards the bottom of NAEFS climatology suggesting
fairly dry low-level air. This increases fire weather concerns with
more details to follow in the Fire Weather discussion below. As lee
troughing increases and a Northern Plains disturbance takes shape,
strong southerly winds will develop Sunday and Monday. Forecast
gusts suggest widespread 30 to 40 mph gusts Sunday with more
localized 25 to 35 mph gusts for Monday. BUFKIT soundings show a
notable decrease in momentum transfer day-over-day and similarly
NBM probabilities of exceeding 30 knot gusts, albeit at 10-m
heights, falls from 70-90% to generally 50-70% for the start of the
new week. This supports the idea that winds will be strongest on
Sunday, as illustrated in ensemble guidance, with weakening expected
for Monday. ECWMF Extreme Forecast Index does show greater positive
anomalies for our northern zones on Sunday as opposed to Monday even
though magnitudes in the ensemble mean remain fairly steady. Height
falls increase heading into Tuesday as the parent trough across the
Western CONUS begins to dig into the Great Basin and lift north and
east into the Central and Northern Rockies. Guidance varies on
placement/evolution of main upper-level dynamics and as a result,
varies on timing and placement of greatest precipitation potential.
What does appear fairly likely is that the brunt of any
precipitation shield will likely remain north and west of the
forecast area. In fact, latest ensemble probabilities of exceeding
0.10" QPF in any 24-hour period has fallen to less than 50% for any
location within the forecast area. This is pointing towards less QPF
and much drier conditions, especially for folks along and south of
Highway 2. Utilizing the NBM solution has maintained Chance (< 50%
PoPs) and so no reason to deviate from these. Believe subsequent
forecasts should see a decrease in our southern zones but again will
allow trends to handle this instead of making wholesale changes for
one package.

Wednesday and beyond...As the disturbance lifts north and east,
a Pacific cool front will shift south into western and central
Nebraska. This will help cool things down with a return to more
seasonable temperatures to round out the week. This translates
to highs in the 60s and 70s. Though precipitation chances may
linger through the end of the forecast period, overall signals
point to little in the way of beneficial rain potential.
Ensemble solutions remain muted through Day 7-8 but point to a
more active period around Day 10 as modest troughing becomes
reestablished across the west. Being at such a long range,
details are low confidence. It is promising to see the signal
exist in both major ensemble suites and as a result, the NBM so
stay tuned.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1232 PM CDT Fri May 9 2025

VFR conditions are expected through the forecast period.

Afternoon diurnal cumulus was increasing in coverage mainly for
cetnral Nebraska and this activity should remain east of the LBF
terminal. Elsewhere, a modest cool front will settling south out
of South Dakota. This boundary will serve as the focus for
isolated shallow convection across the Sandhills. Activity
should largely remain west of VTN but will monitor trends for
inclusion. Winds remain light and variable for the bulk of the
period before taking a prevailing southerly direction towards
midday Saturday.

&&

.FIRE WEATHER...
Issued at 314 PM CDT Fri May 9 2025

Elevated fire weather conditions will exist this afternoon and again
on Saturday, largely owing to dry air but marginal winds. For Sunday
through the middle of next week, elevated to near-critical
conditions appear probable. Confidence at this time remains too low
to issue Fire Weather headlines but should the current forecast
remain on track, this may be necessary with later forecasts.

As surface high pressure settles east to start the new week, upper
level ridging will peak on Sunday and gradually shift east into
Monday. This will support a strong thermal ridge nosing into the
Northern Plains where temperatures off the surface will tip the
scale to the 90th percentile or higher. This translates to well
above normal temperatures for the region with highs in the middle to
upper 80s each day or roughly 15 to 20F above normal for early to
mid-May. As the next disturbance approaches from the west, ridge
breakdown will begin and peak late Sunday into Monday. As a result
of deepening lee troughing along the Front Range, strong southerly
winds will develop with probabilities of exceeding 30 mph reach 75-
100% on Sunday and generally reach similar though slightly less
expansive probabilities on Monday. This, with well above normal
temperatures, and only seasonable environmental moisture should
support the elevated to near-critical conditions. Though dew points
climb into the upper 30s to lower 40s, the temperature anomalies
should still allow for humidity minimums to fall into the 15-25%
range or within 5% of criteria for Red Flag Warnings.

With recent updates regarding fuel status, concern is high that
conditions would allow for rapid spread and erratic behavior of any
fire starts. Do favor erring on the side of caution owing to the
magnitude of winds but will hold off on headline issuance at this
time to monitor trends and evaluate conditions later as forecast
confidence increases.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...NMJ
FIRE WEATHER...NMJ