Damaging Wind and Lightning Strike in Nevada, September 10, 2021

Area Forecast Discussion
National Weather Service Las Vegas NV
108 PM PDT Fri Sep 10 2021

.SYNOPSIS...Isolated to scattered thunderstorms remain possible
through this evening with a brief pulse of monsoonal moisture.
Drier conditions expected tomorrow along with a continuation of
slightly above normal temperatures through much of next week.

&&

.SHORT TERM...through Saturday night.

Shower and thunderstorm activity picking up this afternoon, mainly
in Clark county and to a lesser extent eastern San Bern and
Lincoln counties. This activity has formed along a corridor of
enhanced mid- level moisture extending from Baja California
northward into southern Nevada. Thus far, precipitation amounts
have been fairly light, largely thanks to the swift storm motion,
and wind gusts have been sub-50 mph. However, DCAPE remains fairly
impressive (1500-2000 j/kg) so suspect as storms grow more robust
in the next couple hours, the potential for stronger wind gusts
will be realized.

Storm activity should peak in the late afternoon and gradually
wane in the evening hours, and especially with the loss of daytime
heating. Drier air will work in from the west tonight as the flow
aloft shifts more southwesterly, advecting drier and more stable
air into the region. Any shower activity Saturday will be in the
far northern panhandle of lincoln county and should be quite
light.

.LONG TERM...Sunday through Saturday.

High temperatures in the Colorado River Valley will be around 110F
on Sunday and Monday. As such Excessive Heat Warning for the
Colorado River Valley will go into effect Sunday morning and will
continue through 8 pm PDT/MST.

A weak shortwave moving through north of the forecast area may
result in breezy afternoons on Sunday and Monday. Moisture will
continue to clear out of the area Sunday evening into the early
hours of Monday morning. Precipitable water values will return to
the normal range for mid-September and will remain that way through
the end of the week. This decreasing moisture will result in clear
skies and strong daytime heating all week. Above average high
temperatures will persist through Saturday with triple digits
forecast to remain in the Colorado River Valley and Las Vegas metro
area through Thursday. Outside of the Excessive Heat Warning no
impactful weather is expected through the end of the week.

Heading into next weekend, some GEFS members are hinting at moisture
increasing. However, confidence in this is very low as it is at the
end of the forecast period, and there is no clear consensus amongst
ensemble models and their individual members.
&&

.AVIATION...For McCarran...Best chance of thunderstorms impacting
the Las Vegas Valley will be from 19Z to 00Z. With storms expected
both in and around Las Vegas, erratic, gusty winds from the
direction of these storms could reach 30 kts at times. In between
storms, the prevailing wind direction will be from the south-
southwest, with southwest winds from 210 to 240 expected after
sunset. CIGs could drop to 8 to 10 kft through the afternoon with
area storms. Quiet conditions expected through the weekend.

For the rest of southern Nevada, northwest Arizona and southeast
California...Thunderstorms are expected this afternoon, primarily
impacting the Las Vegas Valley TAF sites, KBIH and KDAG between 19Z
and 00Z. These storms will kick off gusty, erratic winds from the
direction of the storms with gusts to 30 kts. CIGs could get down to
8 to 10 kft with area storms. Winds will die down after sunset, with
quiet conditions expected through the weekend.

&&

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

SHORT TERM...Outler
LONG TERM...Stessman
AVIATION...Varian

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