217
FXUS65 KVEF 192020
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
120 PM PDT Sun Oct 19 2025

.KEY MESSAGES...

* Dry conditions and near normal temperatures continue through
  Tuesday.

* A weak storm system Tuesday night and Wednesday will bring
  slightly cooler temperatures along with an increase in wind and
  slight chances for rain for portions of the area.

* Quiet weather is expected Thursday and Friday, and then another
  storm system could bring windy conditions over the weekend.
&&

.DISCUSSION...through Sunday. Midday satellite loop showed a narrow
band of cirrus across the middle of the CWA with clear skies farther
north and south. Surface obs showed mostly light winds and
temperatures slightly warmer than 24 hours ago.

Very little change in reasoning from 12 or 24 hours ago. Large-scale
subsidence will remain in place through Tuesday, keeping our region
dry with little day to day change in temperatures.

There is still excellent agreement among the ensembles showing the
cutoff low which was near 28N 125W early this afternoon getting
kicked northeast beginning Monday night as deep low pressure comes
through the Gulf of Alaska. Ahead of the low, a plume of slightly
higher precipitable water of 0.5-0.6 inch is expected to get pulled
up into our area, with slight chances for light rain beginning as
early as Tuesday night at the higher elevations. As the low moves in
on Wednesday, slight chances for rain become more expansive, mainly
north of Las Vegas, and chances end by Thursday morning as the low
accelerates away to the east. If anything, the models are maybe 3 to
6 hours slower with everything versus 24 hours ago. The passing low
will also help stir up some breezy winds, and the increased clouds
will likely hold temperatures down just a bit Wednesday versus
Tuesday.

After the low moves out, quiet weather should return Thursday and
Friday. There is still good model agreement on the existence of a
big low pressure system in the Gulf of Alaska thereafter, with
typical disagreement on exact placement, depth, and forecast track.
At this time, the most likely outcome looks like increased winds
over the weekend and slightly cooler temperatures, with
precipitation chances (if any) limited to the Sierra and the higher
terrain of the southern Great Basin. That said, timing and track are
still uncertain, so details will likely change as we get closer.
&&

.AVIATION...For Harry Reid...For the 18Z Forecast Package...Light
easterly winds are expected into the afternoon. The next concern is
whether winds will shift to the south or southwest before sunset or
not. Some of the guidance is suggesting it will, but there is a
history of easterly winds persisting longer than the guidance
depicts. Have pushed back the timing of the wind shift to 23Z, and
could see it occurring even later. When it does occur, speeds should
increase to near 10 knots with a chance of a few gusts up to 15
knots. Winds then become light and variable overnight through Monday
morning. VFR conditions will prevail.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...Wind gusts of less than
20 knots expected areawide through Monday morning, except across the
Sierra crest and in northern Lincoln County, where southwesterly to
westerly winds gusting 20 to 25 knots can be expected for a period
this afternoon. VFR conditions will prevail with passing high clouds
around 25kft.
&&

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

$$

DISCUSSION...Phillipson
AVIATION...Morgan

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NWS Flagstaff Office