757
FXUS63 KLBF 222325
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
525 PM CST Fri Nov 22 2024

.KEY MESSAGES...

- Mild and dry conditions on Saturday ahead of a cold front
  moving in Sunday bringing much cooler temperatures, breezy
  winds, and a threat for light snow across portions of
  northwest Nebraska.

- Benign weather Monday and Tuesday before an even colder
  airmass settles into the central US by the middle to end of
  next week with a threat for wintry precipitation, potentially
  impacting Thanksgiving holiday travel. Though uncertainties
  remain in regards to snow accumulations, greater confidence
  exists in seeing the most significant cold air outbreak of the
  season thus far heading into the start of December.

&&

.SYNOPSIS...
Issued at 235 PM CST Fri Nov 22 2024

Recent GOES-16 WV imagery and RAP 500-mb analysis showed three
strong low pressure systems. The first system was centered over the
mid-Atlantic with a trough extending south into the
northeastern portion of the Gulf of Mexico. Further to the west,
the third system continues to spin, just off the coast of
Washington State with a trough extending southwest into the
eastern Pacific. The third upper-level low was noted across
northern Manitoba. An upper-level ridge expands across the
Intermountain West into the Plains. At the surface, high
pressure extended along the Plains. A warm front extended south
from an area of low pressure centered over southwest South
Dakota. Outside of some high clouds, mostly clear skies prevail
across western and north central Nebraska with temperatures at
2 PM CT ranging from 51 degrees at O`Neill to 65 degrees at
Ogallala.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 235 PM CST Fri Nov 22 2024

Tonight`s lows falling into the 20s will moderate back into the 40s
and 50s on Saturday as broad warm air advection (WAA) continues. The
upper-level ridge axis will slide east into the northern Plains
through the day on Saturday. An upper-level shortwave will eject
from the main system centered off the coast of the Pacific Northwest
into the northern Rockies late Saturday. As this shortwave moves
eastward into the northern Plains, a cold front will be forced
southward, moving through the area late Saturday night into Sunday
morning. Northwest/north winds will strengthen behind the front with
3 to 4mb/3 hour pressure rises and robust cold air advection (CAA)
increased across western and north central Nebraska. Widespread
gusts in excess of 20 mph will be common during the day on Sunday
with the strongest gusts of 30 to 35 mph expected across northern
Nebraska. This frontal passage will bring the first of a series of
cold air intrusions expected through next week with temperatures
falling into the below normal range for Monday and beyond. As for
Sunday`s highs, a range of temperatures will set up across the area,
ranging from the upper-30s across northern Nebraska to the mid-50s
across southwest Nebraska. Divergence will increase under the left
exit region of a  250-mb jet streak moving through western Nebraska
Sunday night, downstream of the upper-level trough. This area of
divergence will be parallel to a band of moderate mid-level (700 to
500 mb) frontogenetical forcing that develops as well. Increased
moisture and mid-level forcing will present a threat for light
snow/flurries across northwest Nebraska Sunday night. Little to no
accumulation is expected as current NBM Probabilities of 24 Hour
Snowfall > 1" remains at 20% or less for northwest Nebraska. At this
time, any winter weather impacts appear low, though this will lead
to much colder temperatures as we head into Monday.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 235 PM CST Fri Nov 22 2024

Benign weather will mark the start of the long term period on Monday
and Tuesday as the flow aloft becomes zonal and surface high
pressure builds southward out of Canada. CAA will continue across
the region with temperatures falling into the 30s to low-40s on
Monday. Temperatures moderate back into the 40s as the upper-level
ridge flattens over the northern Plains on Tuesday. Though near-
normal for most locations, chilly overnight lows in the teens will
be felt Monday night and Tuesday night.

Attention then turns to the next system ejecting out of the
Rockies mid-week, potentially impacting Thanksgiving holiday
travel. The deterministic ECMWF, GFS, and Canadian continue to
have run-to-run differences that have significant implications
on potential impacts for Thanksgiving holiday travel across our
area. When comparing the deterministic GFS vs ECMWF, the GFS is
dry while the ECMWF highlights light snow/flurries across
western and north central Nebraska. Despite this, the GFS
Ensemble does show some ensemble members hinting at the
potential for snow across the area. Although uncertainties
remain, with such cold air in place, the threat for
accumulating snow is non-zero across the area. Thanksgiving
travelers should continue to stay up to date on the latest
forecast and be prepared to make adjustments to your plans if
needed.

One thing appears more certain with this system is the northern
Plains seeing the most significant cold air outbreak of the
season thus far. Ensemble guidance shows a ridge developing
over Alaska and northern Pacific, favoring surface high pressure
to build southward into the central CONUS by late next weekend,
continuing into the 7 o 10 day range. Just how cold it will get
remains uncertain at this time, however, confidence continues
to increase in a period of sub-freezing and perhaps well-below
freezing temperatures to be felt across the region as we head
into the first part of December.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 524 PM CST Fri Nov 22 2024

Over the next 24 hours VFR conditions will prevail. Winds will
remain light and mostly variable with wind speeds generally
around 5 kts or less.

&&

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

&&

$$

SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...Gomez