914
FXUS65 KVEF 262116
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
216 PM PDT Sat Sep 26 2026

.KEY MESSAGES...

* An incoming weather system will bring increased chances for
  showers and thunderstorms to the region Monday and Tuesday along
  with cooler temperatures.

* Remnant tropical moisture will make for favorable conditions for
  flash flooding early in the week across Northwest Arizona.

&&

.DISCUSSION...through Saturday.

Fairly tranquil conditions persist across the region this
afternoon though breezy surface winds will continue through the
evening beneath a southwesterly flow aloft. However, changes to
the weather pattern are on the way which will bring more unsettled
conditions to the region through midweek. The first hint of this
change will occur tomorrow as mid and upper level moisture from
Hurricane Odalys in the eastern Pacific begins to stream northward
into the Mojave Desert and Northwest Arizona. This will begin to
moisten our atmosphere from the top down Sunday, mainly across
areas south and east of I-15. The low levels will remain rather
dry, but some sprinkles will be possible across Northwest Arizona
by the early afternoon. Then, on Monday, a fairly deep low will
drop south into central California and interact with some of this
tropical moisture from both Odalys and Polo off the west coast of
Mexico, while also dynamically forcing convection as the mid-
levels cool. There remains considerable uncertainty in
precipitation coverage outside of Northwest Arizona Monday and
Tuesday, but given the amount of forcing moving in with the low
and some anomalous moisture in play, we do anticipate at least
scattered storm coverage across much of the area.

Highest confidence in this event is across Northwest Arizona which
will be favorably positioned downstream of the tropical systems
and in advance of the incoming low to see numerous rounds of
locally heavy rainfall. Strong southwesterly flow through a deep
layer of the atmosphere will also be favorable for training
thunderstorms which could produce localized intense rainfall
amounts. The Weather Prediction Center has coordinated a Moderate
Risk of Flash Flooding across much of the Four Corners region on
Monday, which extends west into Mohave County as well. Risks of
this category usually only happen once every couple years in our
region. With this in mind, went ahead and issued a Flash Flood
Watch for parts of Mohave County Monday and Tuesday, and the
potential exists for this watch to be expanded if we see forecast
guidance trend wetter for areas further north and west.

The low will begin to shift eastward into Arizona on Tuesday with
some wrap around rainfall possible mainly across our eastern areas
through the day, though locally heavy rainfall will remain a
concern across Mohave County. Drier conditions will resume midweek
onward as weak high pressure builds back across the southwest with
seasonably warm temps expected.

&&

.AVIATION...For Harry Reid...For the 18Z Forecast Package...Breezy
southwesterly winds will increase through the remainder of the
morning hours and continue thru the early evening. Gusts will
subside overnight before returning Sunday afternoon. Mid and high
clouds will increase overnight, but remain generally AOA 12kft AGL.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...Gusty south-
southwesterly winds expected across the Las Vegas Valley and
Colorado River Valley thru the afternoon with speeds between 20 and
25 kts. KBIH will gust from the south-southeast to 25 kts and KDAG
will gust from the west to 25 kts. Increasing mid and high clouds
expected overnight...mainly across the Mojave Desert and northwest
Arizona. &&

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

&&

$$

DISCUSSION/AVIATION...Outler


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