Spring Valley, Nevada 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

688
FXUS65 KVEF 280008
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
508 PM PDT Tue May 27 2025

.SYNOPSIS...Hot and dry conditions are expected as temperatures soar
10 to 15 degrees above seasonal normals late in the week. The
hottest temperatures will be Friday and Saturday, and an Extreme
Heat Watch has been issued for portions of the deserts. Cooler and
unsettled weather returns late this weekend into early next week,
but there is low confidence in the details and associated potential
impacts.
&&


.SHORT TERM...through Thursday night. Midday satellite loop showed
scattered cumulus and cirrus, with the greatest coverage and
vertical development of the cumulus over northern Mohave and
northern Lincoln counties. Surface obs showed lighter winds than
yesterday, and temperatures near to slightly below those of 24 hours
ago. Very little change to forecast reasoning through Thursday
night. The weak trough overhead will slowly vanish as low pressure
which was near 32N 135W early this afternoon digs down to near the
Baja Spur and cuts off while high pressure builds over the western
US. This will keep dry weather in place with light winds and
temperatures climbing a couple of degrees per day, leading into the
heat concerns in the long term period.

.LONG TERM...Friday through early next week.

Heat will be the main weather story Friday and Saturday thanks to
the large and dominant ridge that will stretch broadly across much
of the Western US.  Abundant sunshine and above normal heights will
result in temperatures climbing 10 to 15 degrees above normal. The
greatest temperatures anomalies look favored across our central and
northern zones, while heights are slightly lower further south in
closer proximity to the weak low spinning over the northern Baja.
Given the magnitude of the incoming heat spell, and the early season
nature of the heat, major heat risk is advertised across much of the
Mojave Desert and Colorado River Valley for Friday and Saturday.
With high confidence for extreme heat and the potential heat related
impacts, issued an Extreme Heat Watch in the areas where major heat
risk is highlighted. Major heat risk implies a level of heat that
impacts most of the population, especially those who without
adequate access to cooling or hydration sources or those who do not
take proper heat precautions. To quantify the heat to a value, the
latest NBM has a probability of LAS reaching 105F or greater at 75%
Friday and Saturday, with a nearly 20% chance of reaching 110F on
Saturday. Per official records- it has never reached 110F in Las
Vegas in May. Meanwhile, Death Valley stands 75%+ chances of
reaching 115+ both days and a 20% chance of reaching 120+ on
Saturday.

By Sunday onward, the low spinning over the northwest Baja Peninsula
will begin to lift north into the Mojave Desert as it`s nudged by a
large trough approaching the West Coast upstream. At the very least,
this low will bring the onset of a cooling trend thanks to
decreasing heights and an increase in regional cloud cover. What is
less certain is how it interacts with an anticipated tropical
disturbance in the Eastern Pacific.  NHC retains high probabilities
for this tropical system to develop and would be named Alvin as it
would be the first topical system of the eastern Pacific season.
Ensembles remain insistent at a slug of mid and high level moisture
from this tropical feature being ingested into the Baja low and
spreading it across the Mojave and Sonoran Deserts Sunday and
Monday. It`s a bit too early speculate on how this may manifest in
our area. as it could be as little as a modest increase in cloud
cover and spotty sprinkles, or more significant shower and
thunderstorm activity, but it remains an evolving focus of the
longer term forecast period.  With the low levels remaining fairly
dry at least early on, dry lightning could be a concern as well.
Once this low ejects inland, it will be followed by a larger Western
US trough bringing a return of mostly dry but cooler and gustier
conditions.
&&


.AVIATION...For Harry Reid...For the 00Z Forecast Package... Expect
continued southeasterly gusts of 15 to 20 knots this afternoon.
Winds should decrease and become more southerly late this evening.
Similar wind concerns are likely on Wednesday. VFR conditions
through the period.

For the rest of southern Nevada, northwestern Arizona and
southeastern California...For the 00Z Forecast Package...South to
southwest winds are expected today and Wednesday, with isolated
gusts of 20 to 25 knots most likely over the mountains. The
exception will be in spots with well established day/night wind
cycles, such as Barstow with easterly winds in the afternoon
shifting to westerly in the evening and overnight. VFR conditions
through the period.
&&


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

$$

SHORT TERM...Morgan
LONG TERM...Outler
AVIATION...Soulat

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