374
FXUS65 KVEF 020720
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1220 AM PDT Thu May 2 2024

.SYNOPSIS...Dry conditions with seasonably warm temperatures are
expected through Friday. Over the weekend, a strong trough will
move into the West Coast, bringing widespread strong winds to the
area on Saturday, with cooler temperatures and continued gusty
winds for Sunday. Some light mountain precipitation is also
possible. Improving conditions are expected early next week with
temperatures slowly moderating.


&&

.SHORT TERM...through Friday.

Dry and seasonably warm conditions will continue for the next
couple of days as a weak trough in the intermountain region moves
east and subtle surface ridge builds in. Lingering north-south
pressure gradients will foster continued north breezes down the
Colorado River Valley today, that will slack off in the late
afternoon hours. Elsewhere, typical westerly afternoon breezes can
be expected, with similar conditions expected again for Friday
afternoon.

.LONG TERM....Saturday through Wednesday.

At the start of the period, a rather anomalous (-2.5 sigma) closed
low is forecast to move into NorCal and Southern Oregon. Ahead of
the low, notable surface pressure falls will occur over the Great
Basin, driving strong south-southwest winds across pretty much the
entire CWA. Latest NBM guidance paints all but far SE San Bernardino
and S Mohave Counties with 50-90% chances of impactful winds on
Saturday. Chances of 55+ mph winds are largely confined to Inyo and
Western San Bernardino Counties, but localized hot spots like the
Spring Mountains and Desert Rock area are apparent as well. It`s
possible (if not likely) that wind speeds and the probability of
impacts increases as guidance comes into better agreement with the
closed low and high-res guidance begins to influence NBM output.
Winds remain strong into Sunday as the low traverses the Great
Basin, with a northwesterly wind shift pushing SE throughout the
day.

The other aspect of this system we`ll have to monitor is
precipitation potential. Ensemble guidance depicts a tongue of 150-
200% of normal PWATs feeding into our area ahead of the trough axis.
While not overly impressive moisture values when you consider normal
for early May is about 0.37", it`ll be enough to spur 30-60% PoPs in
Western Inyo and our northern counties. High snow levels should
prohibit any wintry impacts, but these areas could see beneficial
snow on the peaks and light rainfall below. The NBM the
percentile (reasonable worst-case scenario) keeps QPF values
generally below 0.50", except on the Sierra crest where it gets up
to 0.90". As such, rainfall impacts should be minimal (if any) in
these locations. The one caveat to this will be the development
of convection. The anomalous closed low will feature very cold air
aloft, with deterministic guidance showing 500mb temps less than
- 20C. If the low`s center can pass through during peak heating on
Sunday, we could see a thunderstorms in parts of the area.
Currently, best chances are over Lincoln County and the AZ Strip
with 10-15% probabilities.

As the weekend system pulls away on Monday, winds weaken, PoPs wane,
and temperatures quickly rebound. By mid-week, highs are forecast to
be within a few degrees of normal, far from the 10-15 degrees below
normal forecast for Sunday. Afternoon breezes will persist, but not
of the magnitude nor impact of this weekend`s winds.


&&

.AVIATION...For Harry Reid...Light north to northeast wind this
morning will become more easterly for several hours this afternoon.
By late afternoon, a southwesterly wind will spread across the
valley and continue through the night. VFR conditions will prevail
throughout the entire TAF period across the valley.

For the rest of southern Nevada, northwest Arizona and southeast
California...Strongest northerly winds this morning will stay
confined to the lower CRV, between KIFP and KEED. The north winds
will weaken by mid-day and quickly reverse to a southerly direction
by late afternoon. Surface winds during the forecast period will
favor a northwesterly direction around KBIH. Elsewhere, surface
winds will predominately be from the southwest to west across San
Bernardino County and Mohave County. VFR conditions will prevail
throughout the entire TAF period in all areas.

&&

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

&&

$$

SHORT TERM...Outler
LONG TERM...Woods
AVIATION...Pierce

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