121
FXUS65 KVEF 132250
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
250 PM PST Sat Dec 13 2025

.KEY MESSAGES...

* Mild conditions with light breezes continue across the region
  through the upcoming week.

* A disturbance will bring a 10-25% chance for precipitation to
  portions of Inyo County, mainly the Sierra Crest, late week.

&&

.DISCUSSION...

The unseasonably mild weather continues across the region the
next several days, thanks to persistent ridging over the western
CONUS. Latest water vapor imagery and RUC 500 hPa analysis
indicates a subtle disturbance near the California/Baja border
that will undercut the ridge and translate eastward toward the
Four Corners Region through Monday. Locally, the only impacts from
this will be an uptick in mid-level and high clouds, with winds
expected to generally remain light. Heading into midweek, the
first of a series of disturbances will translate across the
northern tier of the CONUS, acting to flatten the ridge and
produce zonal flow over southeastern California, southern Nevada,
and northwestern Arizona. This zonal flow will persist thereafter,
having little impact on the persistent mild conditions across the
area, with temperatures only expected to cool a few degrees
through the end of the week, with the cooldown most pronounced
across the southern Great Basin.

The aforementioned transition to zonal flow will displace the
ridge southward and allow for a subtle uptick in moisture across
the Sierra. Precipitation chances begin increasing to the north
of the area midweek, with low-order PoPs (10-25%) returning to the
Sierra Crest late week into the weekend when another trough
pushes into the Pacific Northwest. Currently, QPF remains very low
(ranging from a trace to around a quarter of an inch along the
crest) with only light snow accumulations expected at this time,
mainly above 9000 feet. Elsewhere, dry conditions continue through
the forecast period and beyond, with cluster analyses and
ensembles indicating a more substantial pattern shift possible in
time for the Christmas holiday. Stay tuned.

&&

.AVIATION...For Harry Reid...For the 00Z Forecast Package...Winds
will follow typical diurnal directional patterns through the
forecast period, remaining light with speeds under 8KT. Ceilings
will gradually become SCT-BKN with bases 12-15kft and above,
improving late in the period. Operational impacts are not
anticipated with VFR conditions prevailing.


For the rest of southern Nevada, northwest Arizona and southeast
California...For the 00Z Forecast Package...Across the region,
winds will generally remain light, following typical terrain-
driven and diurnal directional patterns. The exception will be
along portions of the Lower Colorado River Valley near IFP, where
channeling of winds will result in gusts to 20-30KT early in the
period, with another round of gusty winds expected on Sunday.
VFR conditions otherwise prevail with increasing mid and high
clouds at or above 12kft this evening onward.

&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.

&&

$$

DISCUSSION/AVIATION...Phillipson


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