571
FXUS65 KVEF 141646
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
945 AM PDT Tue May 14 2024

.SYNOPSIS...An upper low near Southern California will keep limited
moisture and instability over our region leading to isolated light
showers or sprinkles along with a few thunderstorms over the
mountains through Wednesday. A warm weather pattern will persist
with highs climbing around 10 degrees above normal by Friday. A
slight cooling trend with increasing southwest winds develops late
this weekend into early next week.
&&

.UPDATE...Recent satellite loops showed a band of mid level
moisture being pulled across Mohave County into Clark County by the
SoCal upper low which lead to a chaotic looking sky this morning
with fairly extensive virga detected in radar loops. The 12Z Las
Vegas sounding showed the moisture layer right around 500mb with a
very dry layer below. So, it will be difficult for any precipitation
to make it to the surface. Afternoon heating will lead to more
convection developing over the southern Great Basin and Sierra and
also northwest Arizona. The latest HREF indicates a 30-50 percent
probability of convective gusts over 35 mph confined over eastern
Lincoln County and far northeast Mohave County. These are the main
forecast issues today, but no immediate changes to the forecast
needed.
&&

.PREV DISCUSSION...206 AM PDT

.SHORT TERM...through Thursday Night.

In general, expecting low impact with the main story being the
warmer than normal temperatures the next couple of days. The area of
high pressure that was over the region yesterday and brought the
warmest day thus far to many locations across the area will be
shoved eastward as a weak low pressure system moves into southern
California. This will result in an area of convergence, which can
currently be seen on IR satellite as an area of clouds stretched
from the western Mojave Desert region into southwest Arizona. This
convergence zone will lift into the Southern Great Basin this
afternoon. where combined with weak instability could allow for some
showers and isolated thunderstorms to develop. With limited
moisture, precipitation will struggle to reach the ground and
impacts will be limited. Ensemble probabilities for more than 0.01
inches of rainfall total this afternoon is low outside of the
terrain where moderate probabilities around 60%-70% exist. However,
with this dry air, sudden gusty winds to 30mph or 40 mph will be
possible with any precipitation that develops, especially in Lincoln
County which hi-res models are consistently showing some outflows
developing this afternoon. Precipitation will diminish after sunset,
but a similar set up will be in place for Wednesday afternoon as the
low continues to shift inland. Will need to fine tune Wednesday`s
forecast based on how this afternoon plays out.

With the low moving into the region and bringing height falls and
cooler mid to upper level temperature- expecting high temperatures
today and Wednesday to be slightly cooler than yesterday`s high
temperatures. Temperatures will drop back about 5 degrees compared
to Monday, but this is still about 5 degrees above normal. Heat risk
today and tomorrow remains low in most locations outside of Death
Valley where moderate heat risk is expected and extra precaution
should be taken for anyone with outdoor plans or who are sensitive
to the heat.

By Thursday, the ridge builds back into the region behind the
exiting wave to the east. Temperatures will begin to climb again as
the area remains dry and clear skies prevail. While height rises
are modest on Thursday, moderate heat risk spreads into the valleys
of San Bernardino County as well as the southern Colorado River
Valley for Thursday afternoon, including Lake Mohave and Lake
Havasu.
&&

.LONG TERM...Friday through next Tuesday.

A growing ridge over the eastern Pacific will continue to grow over
the western United States late-week into the weekend. Temperatures
will remain 10 to 12 degrees above seasonal averages, with desert
valleys increasing to "Moderate" HeatRisk. Las Vegas has a 50%
chance of the first 100F of the year on Friday and a 30% chance on
Saturday.

There remains a fairly large temperature spread over the weekend and
into the start of next week (10 degrees between the 25th and the
75th percentiles) in the NBM. This is largely due to the approach of
a closed low in the southeastern Pacific which will lower heights
over the region as it pushes inland. Details regarding strength,
location, and timing will continue to be ironed out as we move
through the week.
&&

.AVIATION...For Harry Reid...South-southwest winds of under 10
knots will lighten and become variable after sunrise. This
afternoon, winds increase to over 10 knots out of the south to
southwest once again, decreasing to less than 10 knots after sunset.
Mid and upper level clouds with bases at or above 12kft will
continue to stream across the Las Vegas area through the forecast
period.

For the rest of southern Nevada, northwest Arizona and southeast
California...Winds increase out of the south to southwest with
speeds over 10 knots this afternoon in the Las Vegas Valley and the
Colorado River Valley. At KIFP and KEED, this will also include wind
gusts between 15 and 20 knots. At KBIH, winds follow a diurnal
pattern, but thunderstorms will also develop in the afternoon which
may cause sudden changes in wind direction and speed. Winds will
follow a diurnal pattern at KDAG with speeds reaching over 10 knots
in the evening. Mid and upper level clouds stream across the area
through the forecast period.
&&

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

$$

UPDATE...Adair
SHORT TERM...Nickerson
LONG TERM...Varian
AVIATION...Meltzer

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