Dust Storm Warning 4, NWS Las Vegas, NV

Area Forecast Discussion
National Weather Service Las Vegas NV
353 AM PDT Tue Sep 8 2020

.SYNOPSIS...A strong cold front will push through the area this
morning bringing with it a stark drop in temperatures, temporarily
clear skies and gusty northerly winds. Winds will linger down the
Colorado River Valley into Wednesday before a ridge of high pressure
crawls back over the Desert Southwest and gradually brings
temperatures back to above average territory.
&&

.DISCUSSION...Today through Monday.

The closed low and associated cold front we've all been waiting for
is finally here. The cold front will push southward through our
forecast area this morning and afternoon, bringing with it 2 pros
and a con.

Pro 1: Cooler temperatures! Forecast high temperatures will not only
drop into the double-digits, but will drop into the low 80s across
the lower elevations (including Las Vegas) today and struggle to
reach the 80s on Wednesday. Most areas will see a 20-30 degree
temperature drop between Labor Day weekend and Wednesday afternoon.

Pro 2: Brief reprieve of smokey skies! The cold front will
effectively push all of the smoke southward out of the Desert
Southwest today. Unfortunately, due to the ongoing wildfires across
the western CONUS, the smoke is expected to fill back into the area
toward the end of the work week.

Con: Wind! Behind the cold front is a very dense cold air mass which
will help the forward propagation of this front. Building off of its
own momentum, northerly winds will blast through the area,
predominantly this morning and this afternoon areawide. As a result,
we have a Wind Advisory that will go into effect at 6am. With the
overnight forecast package, we opted to add the Owens Valley as well
as the Western Mojave Desert zones to the Wind Advisory, resulting
in coverage of the entire forecast area with the exception of the
Eastern Sierra Slopes and White Mountains of Inyo County,
California. People are advised to tie down or secure loose objects
such as trampolines, patio furniture and trash bins. Northerly winds
will amplify down the Colorado River Valley due to a tunnel-effect,
which will make boating conditions very hazardous. Wave heights 2 to
4 feet are forecast along Lake Mead, Lake Mohave and Lake Havasu
today. Additionally, those who are recreating in the lakes and using
floatation devices such as pool toys may find themselves pushed over
deep waters due to the strong winds. As a result of the elevated
winds in these areas, the lake zones will be under an elevated wind
headline - a High Wind Warning. Winds will die down overnight
tonight, but will linger down the Colorado River Valley. For this
reason, a Wind Advisory will remain in effect for the lake zones on
Wednesday as well, with wave heights from 2 to 3 feet possible.

With strong winds and critically dry conditions come an increased
wildfire danger. Sparks from things such as grills, shotgun
practice, campfires, etc. have the potential to start and/or spread
wildfires rapidly under these conditions. We have a Red Flag Warning
in effect for the entire forecast area today as well to highlight
these hazards. Heed all fire restrictions to do your part to prevent
wildfires in your area. This Red Flag Warning will expire tonight
with the exception of along the Colorado River Valley, where it will
continue through Wednesday.

The closed low that will bring all of these impacts continues to
slow with every new model run. This slowing and brief retrograde is
the reason for both the elevated wind speeds and the cooler
temperatures now lasting through Wednesday. Thursday, though, the
low will begin to meander eastward, allowing the ridge of high
pressure over the Pacific to inch back over our area. Temperatures
will climb back into the 90s by the end of the work week, returning
to triple-digits by next weekend.
&&

.FIRE WEATHER...Elevated fire concerns will continue through the day
today for the entire forecast area, extending through Wednesday
night for the lake zones (NV zone 466, CA zone 229, AZ zone 101) as
northerly winds enhance through the day. Gusts today will peak
during the morning and afternoon hours with speeds 35 to 45 mph
expected areawide, and gusts 50 to 60 mph expected in the higher
elevations and along the Colorado River Valley. Though relative
humidity values will not appreciably recover, wind speeds will
decrease tonight and dip below criteria areawide by Wednesday
night.
&&

.AVIATION...For McCarran...An approaching cold front will result in
an early transition to north winds today which will become quite
gusty by mid-morning. Gusts of 30-40 knots will be possible from
late morning through the mid-afternoon before wind speeds begin to
trend downward, though northerly breezes will continue overnight.
Smoke will clear from the region with the passage of the front
with mostly clear skies expected.

For the rest of southern Nevada, northwest Arizona and southeast
California...Gusty north winds will prevail today, with the
strongest winds expected along the Colorado River near KEED and KIFP
where gusts over 45 knots are possible. Smoke will clear from north
to south early this morning with the passage of the cold front, with
mostly clear skies expected.
&&

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

DISCUSSION...Varian
AVIATION...Outler

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
659 AM PDT TUE SEP 8 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 AM     NON-TSTM WND GST 15 NNW AMARGOSA VALLEY  36.85N 116.47W
09/08/2020  M66 MPH          NYE                NV   MESONET

            YUCCA MOUNTAIN ARL SORD SENSOR OYMAB
            MEASURED A GUST OF 66 MPH AT 445AM.

0541 AM     NON-TSTM WND GST 12 SW ELGIN             37.25N 114.71W
09/08/2020  M59 MPH          LINCOLN            NV   MESONET

            KANE SPRINGS RAWS SENSOR KNSN2 MEASURED A
            GUST OF 59 MPH AT 541AM.

&&

VARIAN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
709 AM PDT TUE SEP 8 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0651 AM     NON-TSTM WND DMG 2 NW THE STRIP          36.13N 115.19W
09/08/2020                   CLARK              NV   FIRE DEPT/RESCUE

            LAS VEGAS FIRE RESCUE REPORTED A TREE DOWN
            ON A POWER BOX ON S. VALLEY VIEW AND SIRIUS
            AT 0651AM.

0651 AM     NON-TSTM WND DMG 1 WSW NORTH LAS VEGAS A 36.21N 115.21W
09/08/2020                   CLARK              NV   FIRE DEPT/RESCUE

            LAS VEGAS FIRE RESCUE REPORTED A POWER POLE
            ARCING AND A POWER OUTAGE ON EL CASTANO AVE
            AT 0651AM.

&&

VARIAN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
811 AM PDT TUE SEP 8 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0706 AM     NON-TSTM WND DMG 4 N SPRING VALLEY       36.16N 115.23W
09/08/2020                   CLARK              NV   BROADCAST MEDIA

            DOWNED POWER LINES REPORTEDLY CAUSED A WATER
            HEATER TO EXPLODE AT A RESIDENCE IN THE WEST
            CENTRAL LAS VEGAS VALLEY.

&&

JA