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097
FXUS65 KVEF 211827
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1128 AM PDT Fri Jun 21 2024

.SYNOPSIS...We are looking for temperatures to increase well into
next week as we start knocking off the final days of June.
Temperatures will climb to around 5-8 degrees above normal
through the weekend with further warming expected next week. An
initial surge of moisture associated with the North American
Monsoon reaches Mohave County today and expands west and north
over the weekend. The surge is due to the remnants of a tropical
cyclone passing well south of the area. The result will be
increasing showers and thunderstorms, mainly over Mohave County
but potentially reaching areas further north and west over the
weekend.

&&

.UPDATE...
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Current satellite imagery shows an upper-level trough
moving through the Great Basin region. As the trough axis swings
through, it will kick off convection across northern Arizona and
southwestern Utah. Convection in our forecast area will be limited
to the Arizona Strip. Any convection that does form in this area
will be high based with the potential to produce gusty outflow
winds. Dry lightning is another threat that is on the table as dry
low-levels will make it difficult for precipitation to reach the
ground. Outside of the Arizona Strip, hot and dry conditions will
continue with afternoon high temperatures topping out around 3 to 5
degrees hotter than yesterday. This heating trend will continue into
the weekend with temperatures plateauing briefly before taking back
off early next week. Moisture will increase over the weekend across
the southern and eastern portions of our forecast area. Eastern San
Bernardino and southern Clark counties will see an increased chance
for isolated showers and thunderstorms on Sunday afternoon and
evening. Otherwise, precipitation chances will be limited to Mohave
County each afternoon through early next week.
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&&
.DISCUSSION...Through Monday.

The remnant tropical cyclone formally known as Alberto has reached
the western Mexico coastline tonight and is progged to continue
moving west into the eastern Pacific ocean. Weak troughing to our
west and high pressure to our east is and will continue drawing
moisture northward along the Gulf of California into the Desert
Southwest. Satellite imagery at midnight already shows a pool of
moisture residing over southern Arizona with precipitable water
values in excess of 1.25 inches in the Phoenix area. 0.80 to 1
inch PWATs are forecast over Mohave County this afternoon where
shower and thunderstorm chances increase. Model QPF output
suggests mainly light rain amounts primarily confined to the
Arizona Strip, making the threat for dry lightning possible.
Elsewhere, we expect dry conditions with mostly clear skies and
afternoon breezes.

Late Friday night into Saturday, a moisture surge is underway
with 1-1.50 inch PWATs extending from our southern CWA border into
far southern Nevada, reaching as far north as northern Clark
County and as far west as Barstow. 850 dewpoint temps of 8-12
degrees Celsius suggests storms will be capable of producing
heavy rain. Shower and storm coverage is generally limited to
Mohave County on Saturday. On Sunday, showers and storms are
again forecast over Mohave County but there is a slight chance of
shower development over southern and eastern San Bernardino County
in the afternoon. Showers chances retreat to areas mainly in
eastern Mohave County.

Temperatures are forecast to be 6-9 degrees above normal today
through Monday and will be within 2 or 3 degrees of daily records
Sunday and Monday. Excessive heat concerns are minimal through
Sunday with moderate heat risk indicated for most areas. Monday,
we begin to see major heat risk sprinkled in over a more
widespread part of the CWA. It may not justify a watch but does
signal an increase in excessively hot conditions to come in the
following days.

Tuesday through Thursday.

Overall, this period is looking very hot as high pressure
dominates. Residual moisture in Mohave County will keep a slight
chance of showers/storms near the eastern county border Tuesday
and Wednesday. The primary forecast concern shifts back to heat
with the potential for excessively hot conditions becoming more
widespread across our area Tuesday and Wednesday. The current
forecast has high temperatures generally 9-10 degrees above normal
both days which means they are forecast to be within a few
degrees of daily high temperature records. Currently, Wednesday is
day to watch in Las Vegas will probabilities giving a 50% chance
of tying an all time daily record of 114 degrees. Overnight warm
low temperature records could be in play as well. Coverage of
major Heat Risk notably expands on Tuesday with spatterings of
extreme heat risk thrown in. It becomes even more pronounced on
Wednesday when temperatures are forecast to peak. The overall
coverage of major heat risk is forecast to shrink on Thursday but
still remains fairly widespread.

&&

.AVIATION...For Harry Reid...Winds start off variable this
morning, increasing to over 10 knots and becoming gusty out of the
south to southwest in the afternoon and evening. Peak gusts between
15 and 18 knots are possible. Southwesterly winds decrease to under
10 knots overnight and eventually become variable. Clear skies
persist aside from FEW cloud development over the Spring Mountains
in the afternoon.

For the rest of southern Nevada, northwest Arizona and southeast
California...Generally diurnal winds are expected today with an
increase in winds in the afternoon and evening. Wind speeds will
reach 10 knots or greater and gusts between 15 and 18 knots are
possible in the Las Vegas Valley and Colorado River Valley. At KDAG,
winds increase out of the west in the evening with gusts to around
20 knots are possible. Clear skies persist through the forecast
period besides FEW cloud development over area mountain peaks,
including the Sierra and Spring Mountains.

&&

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

&&

$$

UPDATE...Stessman
DISCUSSION...Salmen
AVIATION...Meltzer

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