Boulder City, Nevada Weather Forecast Discussion

338
FXUS65 KVEF 170826
AFDVEF
Area Forecast Discussion
National Weather Service Las Vegas NV
126 AM PDT Wed Sep 17 2025
.KEY MESSAGES...
* Seasonably warm and dry conditions will persist today.
* Increasing moisture associated with the remnants of Mario will
  move into the region Thursday through Friday, bringing chances for
  showers and thunderstorms. Locally heavy rain and high rainfall
  rates will lead to an increased risk of flash flooding.
&&
.DISCUSSION...through Tuesday. The tropical moisture is knocking on
our southern door. Satellite loop showed cirrus outflow from the
remnants of Mario nearing our southern CWA border, and surface obs
showed dewpoints up 10-20F in the past 24 hours at sites including
KDAG, KNXP, and KBLH. On a positive note, recent model runs show
very little change from 24 hours ago with respect to precipitation
timing as well as the most probable amounts (25th to 75th percentile
range), which increases forecast confidence. That said, there is
still significant uncertainty in one very important regard - will
there be enough sunshine in between the clouds Thursday and/or
Friday to allow for destabilization and intense rainfall rates, or
will solidly overcast skies prevent instability from being realized,
resulting in less-hazardous stratiform rain? Because of that
uncertainty, will not issue a Flash Flood Watch at this time. Best
guess is that the best heavy rain potential will be along and west
of Highway 95 Thursday and Thursday night. Best forcing exits by
Friday night, leaving more of a low-grade monsoon pattern in place
for Saturday and possibly Sunday. Not much confidence in Monday or
Tuesday, but the overall pattern favors mostly dry weather with
temperatures climbing back above normal for late September.
&&
.AVIATION...For Harry Reid...For the 06Z Forecast Package...Winds
will follow typical diurnal directional patterns with sustained
speeds of 10 knots or less. Southwesterly winds will become light
and variable during the early morning hours. These light and
variable winds will continue into the late morning when winds will
settle in from a more easterly direction through the afternoon
and into the early evening. High clouds will begin to push into
southern Nevada overnight tonight, with mid-level clouds moving in
tomorrow evening. Temperatures are not expect to reach 100
degrees, but will climb to the upper 90s between 21 and 01z.
For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package... High clouds will
push into the area from the south overnight and throughout the day
tomorrow. Mid-level clouds will begin to increase late tomorrow
afternoon/early tomorrow evening. There is a low chance that
showers will begin to push into the area as early as tomorrow
evening. However, chances for showers will increase during the
overnight hours as moisture moves into the area. Confidence
regarding whether or not any of these showers will impact
terminals is low at this time. Outside of influence from any
showers, which may result in erratic gusty winds, winds across the
region will follow typical diurnal directional trends with speeds
of 12 knots or less. The one exception to this will be the
western Mojave Desert tomorrow night when breezy southwesterly
winds will pick up.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
DISCUSSION...Morgan
AVIATION...Stessman
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NWS VEF Office Area Forecast Discussion