160
FXUS65 KVEF 161535
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
835 AM PDT Thu May 16 2024

.SYNOPSIS...Warm and dry conditions are expected the rest of the
work week, with heat peaking on Friday before a system to the
north knocks temperatures backs lightly for this weekend. Gradual
cooling and increasing winds will continue into next week as low
pressure develops over the region.
&&

.UPDATE...No showers or storms today, but otherwise it`s
shaping up to be relatively similar to yesterday. Temperatures
remain several degrees above normal with light afternoon breezes.
Temperatures peak tomorrow afternoon as an area of high pressure
moves overhead. Chances of Las Vegas reaching 100 appear to have
dropped slightly (now ~30%), but regardless, it`s going to be the
warmest day so far this year. Over the weekend and into next week,
two areas of low pressure move into the region, resulting in a
gradual return to seasonal temperatures and increased winds. With
most of the moisture staying to our south, dry conditions will
largely prevail through next week. Only 10-20% rain chances exist in
our far northern areas on Monday.
&&

.SHORT TERM...Through Friday Night.

Weak ridging will build into the region today and Friday which will
bring modest height rises as the area remains in a transition zone
between an area of high pressure to the south and a low pressure
system over the northwest US. This will result in dry conditions,
afternoon breezes, and warming temperatures. The ridge is not overly
strong with only slightly above normal 500mb height rises over the
region, however we can still expected above normal temperatures in
most locations. Today`s high temperatures will be a degree or two
warmer than yesterday, and Friday temperatures will climb a few more
degrees from there as better mixing with afternoon gusts of 15 to 25
MPH allows for temperatures to efficiently warm. Latest NBM
probabilities of reaching 100 degrees has dropped back to 30% and
Death Valley has a 20% chance of reaching 110. However, with
prolonged above normal temperatures, heat risk climbs to moderate
levels by Friday for many valley locations; including Death Valley,
Las Vegas, and Daggett...as well as in the Colorado River Valley and
the Lake Mead Recreation area. Heat of that level could affect
anyone outdoors for a prolonged period of time who are not prepared,
anyone who is not used to desert heat, as well as heat sensitive
individuals.

.LONG TERM...Saturday through next Thursday.

A longwave trough will dive southward through the central United
States this weekend, effectively squashing our eastern Pacific ridge
and altering the synoptic pattern for the western United States. A
shortwave trough will push into the Pacific Northwest on Saturday as
it rides along this longwave, which will further reduce heights over
the Desert Southwest. As the weekend progresses, the central US
trough will dive southwestward into the Great Basin with a 100kt
250mb jet.

Meanwhile, a weak closed low will push inland into the northern
Baja, ushering modest moisture into the region. The trough axes
associated with both systems are expected to pass through the Desert
Southwest on Monday. There remains uncertainty regarding how much
(if at all) these two systems phase with one another. If the closed
low completely phases with the longwave trough, the Desert Southwest
will be breezy. If the closed low holds onto its independent center
of circulation, we could get a repeat of the last two days` weather
(isolated convection and showery activity). Regardless, we can
expect temperatures to moderate. That said, as mentioned in the
previous discussion, the NBM4.2 maintains a robust temperature
difference between the 25th and 75th percentile for high temps next
week, which highlight the synoptic uncertainty. Details including to
what degree temperatures moderate will become more clear as we
progress through the remainder of this week.
&&

.AVIATION...For Harry Reid...Quieter day across the region as any
threat of convection remains well outside of our area and there is
no threat of outflow boundaries. Overall winds will generally remain
diurnal with light northeast winds late morning and afternoon up to
7 knots, becoming light southwest after sunset. Skies will remain
mainly clear.

For the rest of southern Nevada, northwest Arizona and southeast
California...High pressure building over the region will keep winds
over most TAF sites under 10 knots along with any threat of
convection and associated outflow boundaries outside of the forecast
area. Light winds and just a few clouds around 12k feet expected
through the end of the week.

&&

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

&&

$$

UPDATE...Woods
SHORT TERM...Nickerson
LONG TERM...Varian
AVIATION...Gorelow

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