292
FXUS65 KVEF 110754
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1254 AM PDT Thu Jul 11 2024

.SYNOPSIS...Intense, long-duration heatwave will finally come to
and end over the weekend as increasing monsoonal moisture moves
into the region. In the meantime, record heat remains a concern
through Friday. Thunderstorms over the weekend may bring pockets
of heavy rain, strong winds, and dangerous lightning to the area,
with a few dry thunderstorms further west over the Sierra.
Temperatures will moderate from Saturday onward but remain several
degrees above normal.

&&

.SHORT TERM...through Friday.

Another couple days of record heat remain, but there is relief on
the horizon as monsoonal moisture makes a gradual return to the
region. Indications of some very modest moisture increases are
already evident with current satellite imagery depicting some
trapped midlevel moisture circulating around the high over
southern Utah and western Arizona. Intense surface heating today
will once again spark a few high based thunderstorms across the
Coconino Plateau which may drift into eastern Mohave County this
evening, with locally gusty winds and minimal rainfall. Elsewhere,
it will just be hot - with afternoon highs topping out near or
above record values once again.

Monsoonal moisture will continue to tick upwards Friday ahead of
a deeper surge of moisture pushing northward from the Gulf of
California. This should encourage better convective coverage
across Northwest Arizona during the afternoon and evening hours.
Meanwhile, the high pressure center responsible for the ongoing
historic heat wave will shift east into Utah, allowing the flow
aloft to become more easterly. This will direct convection forming
in Mohave County westward towards the Colorado River Valley in the
evening with a risk for strong outflow winds as storms slowly
weaken as they outrun the deeper instability gradient.

Outside of the convective potential - the obvious headline will be
the continued heat. Temperatures will remain at similar values to
the past couple days, which have been hovering near or above
record values. By Friday, temperatures will tick downward 2-4
degrees across our eastern zones, while remaining fairly steady
across our western zones. This will be the beginning of the end of
our intense heat wave as increasing moisture works to cool off
temps and the center of the ridge axis shifts eastward.

.LONG TERM...Saturday through Thursday.

It is looking more and more favorable for scattered showers and
thunderstorms to develop over much of Mohave, Clark and San
Bernardino and Inyo counties Saturday as moisture quickly gets
pulled up from northern Mexico/southern Arizona between the closed
high migrating over the Four Corners and an elongated trough just of
the California Coast. NBM pop values have increased and now indicate
30-50 percent probability of measurable precipitation across the
aforementioned areas, including the southern and western parts of
the Las Vegas Valley. This would support all the typical monsoon
hazards (flash flooding, gusty outflow winds, dust, and lightning)
over the southern half of our area...from Clark County southward
where PWAT values of 1-1.5 inches can be expected. Farther
northwest, where low-level moisture will be more limited, flooding
is less of a concern and dry lightning potential increases. A fire
weather watch is in effect for the Eastern Sierra for Saturday and
Sunday. Fuels are very dry, especially after this heat wave, and the
latest NBM thunder chances are 20-30% while wetting rain potential
is less than 10%.

Moisture expands across south central Nevada Sunday for another
potentially active day of convection across most of our forecast
area. The coastal trough is forecast to lift inland across northern
California Monday which should turn the flow a little more
southwesterly and the NBM and model ensembles indicate modest drying
trend Monday through Thursday with a slight drying trend and chances
of thunderstorms confined mainly to Mohave County Tuesday through
Thursday. Temperatures will decrease several degrees with the
increasing moisture, cloud cover and storm influences although highs
will still be in the 105-100 degree range across most of the desert
zones.

&&

.AVIATION...For Harry Reid...Southwesterly winds of less than 10
knots early this morning become variable later in the morning,
remaining variable for most of the day. Winds pick up out of the
west to southwest in the late afternoon with gusts up to around 15
knots possible. By the late evening, winds should decrease but
maintain a southwesterly direction. FEW mid level clouds move over
the area throughout the forecast period.

For the rest of southern Nevada, northwest Arizona and southeast
California...Winds follow a diurnal pattern this morning. Speeds
should be less than 10 knots with the exception of KDAG, and KEED,
where speeds at or slightly above 10 knots are possible this
morning. A push of elevated westerly to southwesterly winds arrives
in the late afternoon and evening for the Las Vegas Valley, Owens
Valley including KBIH, and KDAG. Peak gusts should remain less than
20 knots except for KDAG where gusts over 20 knots may develop.
Winds should weaken later in the night and resume a diurnal pattern.
Outflow winds from convection in Mohave County may reach KEED and
KIFP tonight, causing temporary changes in wind speed and direction.
FEW-SCT mid and high level clouds move across the forecast area
today and tonight.

&&

.FIRE WEATHER...Increasing mid-level monsoonal moisture will result in
isolated dry thunderstorms across eastern Mohave County today and
Friday which may also produce locally strong wind gusts.
Thunderstorms will become increasingly wet over the weekend with
chances spreading west. Across the Sierra, low levels will
struggle to moisten and dry thunderstorms will be possible
Saturday and Sunday, where a Fire Weather Watch remains in effect.

&&

.CLIMATE...Numerous climate locations have a forecast high
temperature and/or forecast warm low temperature within 3 degrees of
the daily record.

The table below shows the daily record maximum temperature and the
year the record was last set. An asterisk (*) denotes which records
are in jeopardy (within 3 degrees of the forecast).

MAX   THU, JUL 11   FRI, JUL 12
  Record(Yr)    RECORD (Yr)

Las Vegas     116(1959)*   114(2003)*
Bishop        109(2021)*   108(2020)*
Needles       120(2020)*   124(1925)
Daggett       117(2021)*   115(2021)*
Kingman       110(1961)*   111(2020)*
Desert Rock   114(2021)*   112(2021)*
Death Valley  129(1913)*   130(1913)

The table below shows the daily record warm minimum temperature
and the year the record was last set. An asterisk (*) denotes
which records are in jeopardy (within 3 degrees of the
forecast).

WARM MIN      THU, JUL 11  FRIDAY, JUL 12
              Record(Yr)   RECORD (Yr)

Las Vegas     91(2012)*     94(2020)*
Bishop        70(2013)      69(1990)*
Needles       96(2021)      96(2021)
Daggett       90(2021)      87(2012)*
Kingman       81(2021)*     80(2021)*
Desert Rock   87(2021)      83(2023)*
Death Valley  105(1920)     107(2012)


&&

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

&&

$$

SHORT TERM...Outler
LONG TERM...Adair
FIRE WEATHER...Outler
AVIATION...Meltzer

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