180
FXUS65 KVEF 081629
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
918 AM PDT Mon Jul 8 2024

.SYNOPSIS...Historic heatwave will persist over the region
for much of the week with numerous long-standing records set
to be challenged or broken. Very gradual cooling is expected
over the weekend as modest monsoonal moisture returns with
increasing cloud cover and isolated thunderstorms mainly across
northwest Arizona and the eastern Mojave Desert.
&&


.UPDATE...Several daily and even some all-time temperature records
were shattered yesterday. This trend will continue through the week
as afternoon high temperatures range from 10 to 15 degrees above
seasonal averages. The only update is the inclusion of potential
convection over northern Inyo County into Esmeralda County today.
Yesterday, the southern Sierra observed 20 lightning strikes from
afternoon convection. A repeat is possible today, with largest
impacts being strong gusty winds and frequent lightning from their
direction. With bone-dry conditions, this would increase the fire
threat for these areas. Otherwise, no changes made to the forecast
this morning.
&&

.PREVIOUS DISCUSSION...114 AM PDT Mon Jul 8 2024/


.SHORT TERM...through Friday.

Dangerously hot conditions will continue through the week as a
strong high pressure ridge remains anchored over the interior
Southwest. Yesterday`s heat broke many long standing temperature
records including setting a new all-time record high in Las Vegas of
120 degrees, breaking the previous record by 3 whole degrees.
Meanwhile, as of this writing at 1am, the temperature at Harry
Reid Airport remained above 100 degrees. The high pressure center
responsible for this intense heat will move little today, though it
will weaken *very* slightly and the northerly flow around its
eastern periphery will allow for some extremely subtle low level
cooling. The end result will be another very hot day today, though
afternoon highs are expected to fall 1-3 degrees from their Sunday
benchmarks.

Today will be the exception not the rule, however, as the high
pressure ridge slowly shifts back to the east Tuesday through
Thursday, positioning itself pretty squarely over southern Nevada.
While doing so, it will also intensify very slightly, sending
temperatures back to soaring levels similar to Sunday. So
unfortunately, we are nowhere near finished with the intense heat.

One fly in the ointment is fire activity which has been
increasing across Utah, and numerous large smoke plumes developed
yesterday evening which blew into northern Arizona. With the flow
aloft shifting more northeasterly today and Tuesday, some of that
smoke may drift into northwest Arizona and southern Nevada. It won`t
be enough to significantly alter our high temps, but may cost us a
degree or two if the smoke were thick enough. Not something we are
anticipating at the moment, but something to keep an eye on.

By Friday, the high pressure ridge will finally begin to nudge
east into Utah and towards the Four Corners region, setting the
stage for a possible moisture return and a gradual cooling trend
slated for the weekend. However, it will remain hot through Friday
as the moisture will be slow to move north and heights will remain
very high through Friday night.

.LONG TERM...Saturday through Monday.

By next weekend, ensemble guidance shows the aforementioned 500mb
high drifting towards the Four Corners area, a more-typical location
for the monsoon season. SSE winds within the anti-cyclonic flow
around the high are expected to advect at least some moisture back
into our area. The better quality moisture will likely be confined
to locations along and south of I-15, where 1" PWAT probabilities
range from 30-60%. As moisture increases, so too do PoPs. Latest NBM
paints eastern Mohave County with 20-50% rain chances on Saturday
and Sunday, with 20-30% chances on the Spring Mountains. Given the
setup, tempted to believe these numbers are somewhat inflated by
climatology influences in the NBM, but regardless, the trend of
increasing PoPs stands for next weekend. The magnitude and northward
extent of moisture return will largely dictate whether or not we see
a subtle reprieve from the historic heat.
&&


.AVIATION...For Harry Reid...Variable morning winds will become
northeast after 16z 7-9 knots with occasional gusts to 15 knots.
These northeast winds are forecast to persist through 23z before
becoming light and variable through 04z. After 04z, winds will
become southwest around 6-7 knots and persist through much of the
evening and overnight period. Temperatures are expected to be at or
above 100 degrees from 16z-07z and peak around 115 degrees
between 22z-02z.

For the rest of southern Nevada, northwest Arizona and southeast
California...No significant winds through the day with most TAF
sites seeing winds under 10 knots. At KDAG, west winds will increase
after 01Z with speeds between 15-25 knots. A few clouds near KBIH,
otherwise clear skies. Very hot temperatures today and tomorrow with
most areas seeing highs between 110 and 120 degrees. Tomorrow`s
highs in the Colorado River Valley may exceed 120 degrees.
&&


.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       MON, JUL 8   TUE, JUL 9  WED, JUL 10  THU, JUL 11
             Record(Yr)   Record(Yr)  Record(Yr)   Record(Yr)

Las Vegas     114(2021)*  116(2021)*  117(2021)*    116(1959)*
Bishop        109(2021)*  108(2021)*  111(2021)*    109(2021)*
Needles       120(2017)*  120(2021)*  122(2021)*    120(2020)*
Daggett       114(2021)*  113(2021)*  118(2021)*    117(2021)*
Kingman       108(2017)*  111(2021)*  111(2021)*    110(1961)*
Desert Rock   108(2017)*  111(2021)*  111(2021)*    114(2021)*
Death Valley  128(1913)*  130(2021)*  134(1913)     129(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      MON, JUL 8  TUE, JUL 9  WED, JUL 10  THU, JUL 11
              Record(Yr)  Record(Yr)  Record(Yr)   Record(Yr)

Las Vegas     92(2017)*   93(2021)*   94(2021)    91(2012)*
Bishop        70(1991)    72(1975)    71(1985)    70(2013)
Needles       95(2018)    95(2021)    98(2021)    96(2021)
Daggett       84(2021)*   85(2017)*   88(2021)    90(2021)
Kingman       84(2014)    82(2017)    79(1913)*   81(2021)
Desert Rock   81(2021)*   86(1985)    82(2021)*   87(2021)
Death Valley  105(1921)   104(2021)   100(1927)*  105(1920)
&&


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

&&

$$

UPDATE...Soulat
SHORT TERM...Outler
LONG TERM...Woods
AVIATION...Gorelow

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