775
FXUS63 KLBF 082109
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
409 PM CDT Tue Oct 8 2024

.KEY MESSAGES...

- Elevated to near critical fire weather conditions, mainly due to
very low humidity, through Thursday as above normal to near record
temperatures continue

- Haze, and potentially some smoke impacts, from Western US
wildfires through tomorrow

- A couple cool front passages to round out the week, resulting
  in below normal highs Sunday and Monday and the potential for
  a widespread freeze

&&

.SYNOPSIS...
Issued at 407 PM CDT Tue Oct 8 2024

The anomalous upper ridge holding over the Western US has broadened
over the Plains a bit more, with the axis lining up the High Plains.
The ridge is bounded by a deep low near the southern tip of the
Hudson Bay and an incoming trough for the Pacific Northwest. Upper
steering flow has also directed the atmospheric smoke from western
wildfires into the Sandhills. At the surface, a broad high remains
near the mid-Mississippi Valley, while a weak low near the Black
Hills stretches a trough southward through the Neb panhandle. These
features combined for another cloudless day with generally light
southerly flow and temperatures in the lower 80s.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 407 PM CDT Tue Oct 8 2024

This evening into tonight... A weak mid-level low and shortwave drop
south from the Dakotas, while the surface low and trough push into
the Sandhills. Despite the increased forcing associated with the
features, moisture content (in the low levels) remains very limited.
The surface trough will divide dew points in the 20s in the
panhandle from the lower 40s in central Neb. Also preceding the
trough will likely be a 25-30 kt low level jet. Forecast soundings
suggest a rather strong inversion holding through the night and
little if any of the jet being able to mix down. Used a blend of
NBM50 and Cons for speeds, which maintains ~5 kts at the surface.
Guidance suggests negligible to very weak warm air advection
overnight, roughly 1-2C rises at H85. With this in mind, nudged min
temp forecast up a degree or two, but kept values toward the lower
end of the NBM envelope to account for boundary layer decoupling and
very dry air. Forecast ranges from the mid 30s in the panhandle to
mid 40s central Neb.

Tomorrow... The upper ridge spreads eastward to cover the entire
Plains and part of the Midwest, although a subtle low will park over
northeast Nebraska. Little change in the surface pattern is expected
with the trough bisecting the Sandhills and the dominant high
centered near the Miss/Ohio R confluence. The day begins in
downsloping west winds before a gradual transition to northerly low
level flow takes place. Regardless, weak warm air advection
continues with much of the CWA achieving 20C at H85. The NBM
envelope spread is small (3-4F quartile range) for max temps,
centered around the mid 80s. These values also line up with the
milder MOS guidance (MET, ECS), but fall short of the aggressively
warm MAV. While clear skies and the dry airmass would support warmer
guidance, was hesitant to blend in 90s for highs given thicker haze
and the weaker nature of WAA. HRRR smoke also suggests increased
surface impacts, especially for the western CWA. Left forecast
values in the mid 80s for now. The vicinity of the surface trough
and the lack of strong low/mid level flow behind the low will keep
winds relatively light during the day. While widespread critically
low humidity values (

NWS LBF Office Area Forecast Discussion