High Wind in Arizona, December 25, 2025

Area Forecast Discussion
National Weather Service Las Vegas NV
902 PM PST Wed Dec 24 2025

.KEY MESSAGES...

* Widespread rainfall and isolated flash flooding expected to
  continue across the area through tonight, with high elevation
  snow and gusty winds adversely impacting Christmas travel.

* Several feet of heavy snow expected in the highest elevations of
  the Sierra and White Mountains through the end of the week, with
  another round of rain and mountain snow on Friday that will
  result in light accumulations in the Spring Mountains.

* Gradual drying trend over the weekend, with cooler temperatures
  and another round of rain and mountain snow possible midweek
  next week.

&&

.DISCUSSION...

Today's anticipated Atmospheric River (AR) event is underway, with
the initial round of rainfall having moved across the region this
morning, with lingering scattered light to moderate
showers across the area early this afternoon. The next more
substantial round is still on target to arrive later this
afternoon and gradually shift eastward through tonight. The
southerly to south- southwesterly trajectory of the AR's
associated moisture plume is favorable for impactful rainfall
across the region, evidenced by the record precipitable water
value of 1.04" sampled by the 18Z NWS Las Vegas special sounding.
The previous record for December 24th was 0.71", and the prior
record for the month of December was 1.00". This amounts to
precipitable water values roughly 300-400% of normal, yielding
efficient rainfall producing showers and significant wet snows at
higher elevations. Flash flooding has already been observed in
Death Valley, with additional flooding and flash flooding expected
across sensitive basins, desert watersheds, and vulnerable areas
through tonight as additional rain moves through the area.
Overall, rainfall amounts on the order of 0.25"- 1.25" are
expected across the lower elevations through tonight, with locally
higher amounts possible where any convective elements materialize
(with MUCAPE around 100-300 J/kg), and higher amounts up to
1.50"-3.00" across the highest elevations, with snow levels
generally above 8500 feet. Thus, the Flood Watch and Winter Storm
Warnings that are in effect are in good shape. Additionally, gusty
southerly winds are expected on at least an intermittent basis
(and especially during lulls in rainfall), resulting in hazardous
travel conditions on east-west oriented roadways, including
portions of I- 15 and I-40.

As mentioned, the snow levels of 8500 feet and above through this
evening will keep accumulating snow at the highest elevations of
the Sierra and White Mountains, though as cooler air filters into
the region, snow levels gradually fall through Christmas Day. By
Christmas morning, snow levels will range from around 6500 feet
across western areas to around 7000-7500 feet in the mountains of
southern Nevada, yielding potential for accumulating snow at lower
elevations. These decreasing snow levels will however be battling
against an overall decrease in moisture as the primary plume
associated with the AR shifts eastward overnight. Thus, while
multiple feet of snow are expected across the peaks of the Sierra
and White Mountains through tonight, significantly lower
accumulations are expected elsewhere. Lingering rain and snow
chances will persist through Christmas Day and into Friday, when
ensembles indicate a secondary - but much weaker - surge of
moisture will move into the area. Given lower snow levels on
Friday, there will be a better chance for accumulations in Lee
Canyon and Mount Charleston, though amounts are expected to remain
fairly light. Otherwise, showery conditions persist, though the
threat for flooding will be less with this second round.

A drying trend will get underway Saturday, with mainly dry
conditions expected Sunday through early next week. The main story
for this time frame will be the cooler temperatures in the wake of
the departing system, as highs drop closer to normal for the end
of December. There are some indications that the next system to
impact the area will arrive in time for the New Year, but for now,
the details that far out are uncertain, so stay tuned.

&&

.AVIATION...For Harry Reid...For the 06Z Forecast Package...Most of
the rain has moved east of the Las Vegas Valley and overall
conditions will start to improve. We may see a few light showers
overnight, but those are not expected to last long and will not
impact visibilities. CIGS around 4-5k feet will rise to around 6-8k
feet after 07Z and remain through sunrise. Skies will generally be
partly cloudy Christmas Day with FEW-SCT050 and SCT-BKN080-100.
Mountain obscurations are likely through mid morning, but improving
by afternoon.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Most of the rain
activity has pushed east and will mainly impact Mohave County
through the remainder of the overnight period before those showers
push east of the county after sunrise. CIGS will also improve as the
showers push east with most areas seeing CIGS around 5-7k feet, but
increasing overnight. Surface visibilities are not expected to be
much of an issue, but some isolated areas of 5SM or less is possible
overnight. Mountain obscurations are likely through mid morning, but
improving by afternoon.

&&

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

&&

DISCUSSION...Phillipson
AVIATION...Gorelow

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