785
FXUS63 KLBF 241111
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
511 AM CST Tue Dec 24 2024

.KEY MESSAGES...

- Dense fog persists for areas east of Highway 183 through late
  this morning. Another round of patchy fog is possible tonight
  for areas near and east of Highway 83 and south of Highway
  20.

- The threat for accumulating precipitation continues to wane
  across much of the area Thursday and Friday.

- A return of above average temperatures (50s) and dry
  conditions is expected for the weekend, and could lead to
  increasing fire weather concerns.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 355 AM CST Tue Dec 24 2024

Currently, dense fog persists for areas near the Highway 281
corridor, behind a backdoor cool front laid across central Nebraska.
Aloft, the area remains situated between shortwave ridging over the
Upper Midwest and a trough axis crossing the Rockies.

For today, expect a gradual erosion of low stratus and fog by late
this morning, as southerly flow increases and shunts the shallow
colder airmass east of the area. Aloft, the aforementioned
trough axis swings across the area through the early afternoon.
An associated weak H85 low pushes across northern Nebraska late
this morning, dragging a weak elevated front into the Sandhills.
This allows for a west to northwest wind shift, and promotes
increasing warm advection. This boosts H85 temps back to ~5-7C
this afternoon, or around the 75th percentile climo. As with
previous days, as mixing occurs highs this afternoon climb back
to well above average, in the upper 40s to middle 50s.

Lows tonight fall into the 20s, with southerly flow increasing
through the night as lee cyclogenesis begins across eastern WY/CO.
This is a response to an upper low beginning to eject out of the
Four Corners across the Rockies. The approach of this wave also
brings increasing upper level moisture and high clouds stream into
the area overnight. As moisture streams northward overnight, some
guidance points towards a period of advection fog tomorrow morning.
Both the westward extent and any threat for dense fog remains low
confidence at this time, and trends will need to be monitored. This
is especially true given holiday travel, and future dense fog
advisories may be needed.

Christmas Day looks to be a slightly cooler day than today, as
persistent southwest flow aloft promotes a cloudy day across the
area. Any fog should erode by late morning as southerly flow/warm
advection increases, and this helps to offset the cloudiness
somewhat. Highs climb into the middle to upper 40s, which is still
some 10-15 degrees above average. As surface pressures continue to
deepen across the lee of the Rockies, the surface pressure gradient
constricts locally and allows for southerly wind gusts approaching
30 miles per hour tomorrow afternoon. The upper low finally begins
to eject across the southern Plains tomorrow night, with some threat
of precipitation for areas south of I-80 as this occurs. That said,
confidence continues to wane in little if any accumulating
precipitation across southwest Nebraska, with probabilities of
even 0.01" continuing to decrease (10-25%). Have maintained
slight chances (15-20%) for rain near/south of I-80 with this
package, though this might end up too optimistic. It appears the
appreciable forcing will remain well south of the area and
largely keep the area dry into Thursday morning.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 355 AM CST Tue Dec 24 2024

The upper low then ejects into the Mid-Mississippi Valley into
Thursday night, with a trough axis quickly following in its wake
across the Rockies. This second trough does deepen somewhat as it
ejects northeast into the Upper Midwest, though again only looks to
provide a glancing blow of forcing as it begins to pull away from
the area by Friday night. As with the first system, it appears
little in the way of beneficial precipitation accumulations can be
expected across the area. Better chances (>50% of 0.01"+) remain
across eastern Nebraska, and these quickly decrease along and west
of the HWY 281 corridor.

Downslope westerly flow establishes behind a surface trough pushing
across the area Friday afternoon, and this begins a period of above
average temperatures yet again. This looks to persist into the
weekend, as upper riding remains established across the western
CONUS. Will have to also monitor this period for increasing fire
concerns again, especially with the continued dryness in the
lead up to the return of mild temperatures. Sunday looks to be
the warmest day of the weekend, with an increasing signal in EFI
guidance for anomalous temperatures for late December. This
also coincides with ridge breakdown into Monday, and could
overlap with a period of increasing winds.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 515 AM CST Tue Dec 24 2024

Low stratus and fog will continue to lead to LIFR conditions for
terminals east of Highway 183 through late this morning, with
improvements to VFR this afternoon. VFR conditions are then
expected to prevail for all area terminals into tonight. By
early tomorrow morning, low stratus begins to increase again
from east to west, though timing of any impacts to KLBF remains
uncertain. That said, a period of MVFR/IFR looks probable for
southwest and central Nebraska terminals near and after the end
of the valid period tomorrow morning. Future inclusion at KLBF
may be needed.

Winds remain southerly today and tonight, generally around 5 to
10kts.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 10 AM CST this morning for NEZ007-010-
028-029.

&&

$$

SHORT TERM...Brown
LONG TERM...Brown
AVIATION...Brown