411
FXUS65 KVEF 072011
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
111 PM PDT Tue Oct 7 2025

.KEY MESSAGES...

* Dry conditions and a warming trend will continue today and
  Wednesday as high pressure builds across the region.

* Increasing confidence for showers and thunderstorms Thursday
  through Saturday as moisture from Hurricane Priscilla moves into
  the Desert Southwest.

* Pockets of very heavy rainfall and localized flooding are
  possible across parts of Northwest Arizona and Colorado River
  Valley late Thursday through Saturday.


&&

.DISCUSSION...through early next week.

Mostly clear skies dominate the region this afternoon as high
pressure builds across the Southwest. Northerly breezes persist
along the Colorado River Valley thanks to a 1022mb high across the
Eastern Great Basin setting up a north to south pressure gradient
across the region, which funnels down the Colorado River Valley,
but generally light winds exist elsewhere. Meanwhile,
temperatures remain seasonable today, before climbing a few
degrees above normal for Wednesday under continued sunshine and
rising heights.

Changes remain are in store Thursday onward as increasing
moisture from Hurricane Priscilla is advected northward ahead of a
deepening trough off the West Coast. Increasing cloud cover will
spread northward Thursday morning and by Thursday afternoon,
precipitable water anomalies of 250-300% of normal or greater
will encompass most of the Mojave Desert and southern Great
Basin. This deep subtropical moisture will remain in place through
Saturday morning before gradually drying out from west to east
through Sunday as the trough axis sweeps through.

This highly anomalous moisture advection interacting with the
approaching trough and favorable jet dynamics will result in
several periods of shower and thunderstorm activity late in the
week. Forecast guidance seems to be hinting at an axis of
precipitation developing on the western edge of the deeper
moisture collocated with the right entrance region of an upper
level jet by Thursday evening. This precipitation axis sets up
roughly along the I-15 corridor, with additional pockets of
precipitation developing across Northwest Arizona and the Colorado
River Valley into Friday. What remains somewhat uncertain is how
much of the precipitation late this week will be stratiform versus
convective, but given the near record precipitatable water values
that will be in play, along with synoptic enhancement from the
approaching trough, heavier downpours could certainly pose a
flood risk. Stay tuned to the forecast as we further hone in on
the details and areas of greatest risk for locally heavier
rainfall and flash flooding.

&&

.AVIATION...For Harry Reid...For the 18Z Forecast Package...Light
northeast winds will persist into the early evening before turning
southwest around sunset. While wind speeds will generally remain
below 8 knots, a few gusts to around 15 knots will be possible
through 00Z. Light and variable winds will continue overnight before
turning southeast tomorrow afternoon.  VFR conditions will prevail
through tomorrow afternoon under mainly clear skies.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...Most areas will
experience winds of less than 8 knots through today, with the
exception of the Colorado River Valley, where north winds gusting to
around 20 knots are likely into the early afternoon before
diminishing. All areas will see light winds overnight, followed by
increasing southeast winds by tomorrow afternoon. VFR conditions
will prevail through tomorrow afternoon under mainly clear skies.

&&

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

&&

$$

DISCUSSION...Outler
AVIATION...Planz

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