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124
FXUS65 KVEF 170247
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
747 PM PDT Mon Sep 16 2024

.SYNOPSIS...A large low pressure system will slowly move across
California and Nevada bringing widespread gusty south to southwest
winds to the region through this evening along with a significant
cooling trend. A second trough of low pressure will move across
the area midweek bringing a reinforcing shot of cool air along
with scattered showers.
&&

.UPDATE...
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Winds were decreasing this evening, so the Wind Advisory
and Lake Wind Advisory will expire on schedule. No other changes at
this time.
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&&

.PREV DISCUSSION...
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1259 PM PDT Mon Sep 16 2024

.SHORT TERM...The Rest of Today through Wednesday night.

Autumn-like weather is expected the next few days as an upper level
trough continues to influence our weather pattern.

The upper level low currently situated over northern California will
move through Nevada tonight. By Tuesday morning, the center of the
low will be moving into western Utah. Behind the system,
anticyclonic flow is expected to set up. Precipitation chances will
quickly drop behind the trough axis, with much of the area becoming
dry with little to no risk for precipitation by 10 PM tonight.
However- despite the typically dry flow with winds aloft turning
northwest, lingering moisture that was attached to the main system
will continue to sit over the Great Basin tonight and Tuesday. This
moisture will not be significant, however it may be enough for a few
showers to develop tonight and Tuesday. No impacts are expected if
precipitation can develop given the lack of dynamics. Probabilities
for impactful rainfall is zero so at most, could see a quick shower
tonight or Tuesday in northern Esmeralda and northern Lincoln
counties. The flow will turn west as the low lifts into the Northern
Plains Tuesday night which will scour out any left over moisture.
Precipitation is not expected Tuesday night or Wednesday.

Winds will decrease behind the exiting system as well as the pressure
gradient decreases. By late this evening, wind gusts should fall
below impactful levels as gusts fall below 40 MPH. Isolated gusts
over 40 MPH may linger into the early overnight in Mohave County as
well as the western Mojave Desert in California. Considered
extending the wind advisory for these ares past the current end time
of 7 PM tonight. However, NBM probabilities for wind gusts over 40
MPH fall to 30% in these areas after 7PM. HREF probabilities for 40
MPH do remain over 50% in the Western Mojave Desert through much of
the night, however the highest probabilities are anchored to the
terrain. Overall, wind impacts should drop off enough by tonight
that didnt see the need to extend the wind advisory past the current
end time. Some gusts over 40MPH could continue around the Barstow,
CA area overnight as west winds are enhanced through the terrain,
and later shifts should watch trends to see if the stronger HREF
solution verifies over the NBM which would mean wind impacts would
linger through the night in that area. By Tuesday morning, winds
will drop off and no wind impacts are expected through midweek.

Cooler temperatures than normal temperatures are likely (near 100%
probability) Tuesday and Wednesday as dry, northwest to west flow
remains over the region. High temperatures each day will run about
10-15 degrees below normal for this time of the year.

The next system will approach the region Wednesday night as it drops
down the West Coast into California. The trend with the system in
the latest model runs is slower than previously, which delays the
onset of precipitation. There is a low risk for precipitation in
Esmeralda County Wednesday night as forcing increases ahead of
the incoming system, however anything that develops with be light
and non impactful. The rest of the region will remain dry through
Wednesday night.

.LONG TERM...Thursday through Sunday.

The next low pressure system will continue to drop southeast from
the Pacific Northwest into California/Nevada on Thursday. One
impact from this system will be elevated southerly to southwesterly
winds as a tight pressure gradient passes overhead. There is not
a strong signal for widespread gusts over 40 mph at this time, but
will continue to monitor trends. A modest increase in moisture
associated with the low may bring another opportunity for
precipitation, particularly over the southern Great Basin where
forcing under the center of the low should be strongest. Lastly,
it should help maintain temperatures 10 to 15 degrees below
average through the rest of the workweek. One the trough exits to
the east, a ridge over the Pacific Ocean will expand into the
western United States, bringing rising heights and closer to
average temperatures over the weekend.
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&&

.AVIATION...Gusty southwesterly winds will continue
through the afternoon before becoming more west-southwesterly during
the early evening hours. Winds will fall back to the southwest
during the overnight hours with gusts gradually decreasing through
early Tuesday morning. Light winds following typical diurnal
directional trends are expected on Tuesday.

For the rest of southern Nevada, northwest Arizona and southeast
California...KHND and KVGT will follow similar trends to KLAS with
gusty southwesterly winds continuing through the evening hours. KHND
will continue to favor a more southerly to southwesterly direction
with guts decreasing throughout the overnight hours. KVGT will see
winds decrease and swing around to the northwest during the
overnight hours. KDAG will favor a westerly direction with 35 knot
wind gusts continuing into the overnight hours before decreasing
Tuesday morning. The Colorado River Valley TAF sites will see gusty
southerly winds continue into the overnight hours before wind gusts
drop off. Once wind gusts drop off KEED will become more
southwesterly, whereas KIFP will favor a more south-southeasterly
direction. KBIH will favor a more northerly direction with 20 to 25
knot wind gusts continuing into the evening hours. Showers and
thunderstorms will pop up in the higher terrain surrounding KBIH
with the potential for storms to move into the terminal area this
afternoon and early evening.
&&

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

$$

UPDATE...Morgan
SHORT TERM...Nickerson
LONG TERM...Meltzer
AVIATION...Stessman

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