Flash Flooding and High Wind in Arizona, November 8 to 9, 2022

Area Forecast Discussion
National Weather Service Las Vegas NV
720 PM PST Tue Nov 8 2022

.SYNOPSIS...An Pacific storm will move across our region through
early Wednesday. Significant snow accumulations will occur in the
mountains above 7000 feet while the lower elevations and the Mojave
Desert region will see widespread rain and strong winds with
temperatures decreasing 10 to 15 degrees. Dry weather will return
Thursday through the weekend.
&&

.UPDATE...Been monitoring narrow line of thunderstorms which
initially developed over southern Nye County in the late afternoon.
Currently, the line is crossing the Spring Mountains, between Las
Vegas and Pahrump. Rainfall rates likely between 0.25-0.50" under
these embedded thunderstorms. The rare thundersnow occurring in the
Spring Mountains where 3"/hour accumulations possible with the
convection. This will be the main show for southern Nevada over the
next 6 hours as the swath of precipitation slowly shift east. The
heavier threat of precipitation will linger longer for Lincoln and
Mohave Counties through 7-10 am PST when precipitation should start
tapering off.

Until now, high snow levels have kept much of the precipitation in
the Spring Mountains as liquid with Clark County ALERT stations in
upper Harris Springs reporting an impressive 3.82" and 2.01" over
the past 24 hours ending at 7 pm. Best estimates on snow as of 6 pm
are between 3-4" off of SNOTEL.

Will continue to monitor real-time gauge network for any additional
hydro related products this evening. Otherwise, forecast looks to be
in decent shape.
&&

.PREV DISCUSSION...1259 PM PST Tue Nov 8 2022
.SHORT TERM...The Rest of Today through Wednesday.

Continuing to track the incoming upper level system that will bring
varying impacts through the next 24 hours.

The first round of precipitation associated with a significant
moisture flux will continue to drift east through the afternoon and
early evening. The main focus with this first wave will be over
Lincoln County as well as the Spring Mountains and Sheep Range.
There should also be a fairly constant stream of precipitation
hitting the Sierra crest which should overtop the ridgeline this
afternoon, with precipitation spilling into portions of Inyo County.
Impactful precipitation is likely at times through this evening,
especially as moisture interacts with terrain is enhanced by
orographic lift. High probabilities for over 10yr 6 hourly ARIs are
noted on HREF in the Sierra north of Lone Pine, the terrain of Death
Valley, the Spring Mountains, and eastern Lincoln County. Negative
LIs and probabilities for lightning show convection potential
through Nye and Lincoln counties through about 02Z, which could add
to the rainfall totals and impact expectations. The WPC Excessive
Rainfall Outlook outlines an area of marginal risk for Clark,
eastern Nye, Lincoln, and parts of northern Mohave County and that
best captures where the highest impacts are expected.

Overnight, the main trough axis shift into southern Nevada. Strong
dynamics ahead of the trough will help push the moisture over the
Sierra and Inyo County eastward, allowing for another around of
precipitation to develop as it does so. Light to moderate
precipitation is likely, with pockets of heavy precipitation
possible at times through Lincoln and northern Mohave County (where
1in in 3hr PMMs are highlighting the highest potential). There could
also be heavy precipitation at times on the Spring Mountains and
Sheep Range. Snow levels overnight will fall quickly as the trough
drags in colder temperatures. Snow levels will drop to around 3500ft
in the Owens Valley after 10PM, though much of the precipitation
should be ending by this time so low level snow impacts are not
anticipated.  Elsewhere, snow levels will drop to around 5000ft
outside of Mohave County where snow levels through tonight should
remain at 6000ft in the northwest part of the county to 8000ft to
the southeast. This is notably colder than the previous forecasts.
However, not expecting the impacts to change other than in the
Spring Mountains where snow accumulations that may lead to minor to
low end moderate impacts between 6000ft and 7000ft.

Precipitation will end Wednesday morning and early afternoon from
west to east. Any precipitation on Wednesday will be lighter than
today's, thus lower impacts are expected. Snow is possible above
4000-5000ft. This would allow for snow to fall in a few impactful
spots, such as Mountains Pass and on US-93 north of Pioche, however
any snow on Wednesday will be light. Another inch or two is also
possible in the Spring Mountains through 10AM Wednesday. Wednesday
in general will be chilly with high temperatures expected to be
about 15 to 20 degrees below normal. Cold temperatures are likely
Wednesday night, though they have increased slightly from previous
forecasts so the risk for freezes in areas that have not experienced
freeze yet this season has decreased.

Gusty winds this afternoon and evening will slowly diminish
overnight from west to east as the trough pushes into the region.
Strongest winds will be through the early evening outside of where
precipitation is falling. By Wednesday, winds drop off
significantly compared to today, with most areas seeing gust fall
below 25 MPH by midmorning Wednesday.

.LONG TERM...Thursday through Monday.

Much less impact expected in the long term as the early week weather
maker system exits the area to the east and at least briefly, allows
for some H5 ridging to build into the region. Continued northerly
surface flow will likely keep temperatures from recovering too much,
but a slight warm up is expected heading into the weekend.

Quite a bit of uncertainty exists in the long range ensembles in
regards to early next week. 12Z cluster analysis shows generally two
schools of thought: another Pacific trough, but much less
significant compared to this week's, or continued ridging over the
western CONUS. The latter outcome is obviously the less impactful to
the region, and is about a 55/45 advantage among the totality of the
ensemble membership. Current long range NBM has very little PoP/QPF
as of the 01Z population
&&

.AVIATION...For Harry Reid...Low ceilings, strong winds, and off and
on precipitation will lead to moderate impacts for the terminal
through the next 12-18 hours. Precip this afternoon will be largely
off and on, with southerly wind gusts in the 35-40kt range during
the afternoon and evening hours. Precipitation will complicate the
wind forecast for the terminal, both due to variable directions, but
also periods of much lighter winds when precip is ongoing. Wind
directions could shift from 140-200 through much of the afternoon,
complicating configuration planning, but generally out of a
southerly direction. Ceilings could fall to MVFR briefly during
precipitation periods as well. Conditions are not expected to
significantly improve until tomorrow morning, around 12Z.

For the rest of southern Nevada, northwest Arizona and southeast
California...Poor flying conditions expected region-wide due to a
significant storm system bringing strong gusty winds and
precipitation to all terminals through early tomorrow morning. Gusts
as high as 40+ kts will be possible at sites such as KDAG, as well
as ceilings falling to around 3kft and MVFR conditions for periods
of time through at least 12Z tomorrow morning. Overall improvement
is not expected until 12-18Z tomorrow morning as this system moves
to the east.
&&

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

UPDATE...Pierce

SHORT TERM...Nickerson
LONG TERM/AVIATION...TB3

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
355 PM PST TUE NOV 8 2022

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

1216 PM     FLASH FLOOD      JOSHUA TREE             34.14N 116.32W
11/08/2022                   SAN BERNARDINO     CA   LAW ENFORCEMENT

            CALIFORNIA HIGHWAY PATROL REPORTS ROADWAY
            FLOODING ON CHOLLITA ROAD IN JOSHUA TREE
            CALIFORNIA.

&&

MS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
624 PM PST TUE NOV 8 2022

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

0330 PM     NON-TSTM WND GST 3 W YUCCA VALLEY        34.12N 116.49W
11/08/2022  M61 MPH          SAN BERNARDINO     CA   MESONET

            AT 230 PM PST THE YUCCA VALLEY SENSOR BEGAN
            GUSTING IN EXCESS OF 58 MPH. THESE GUSTS
            CONTINUED UNTIL 440 PM PST. THE PEAK GUST
            WAS 61 MPH AND OCCURRED AT 1530.

&&

MS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
942 PM PST TUE NOV 8 2022

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

0320 PM     SNOW             10 NE BIG PINE          37.27N 118.15W
11/08/2022  E5.0 INCH        INYO               CA   LAW ENFORCEMENT

            CALIFORNIA HIGHWAY PATROL REPORTS 4 TO 5
            INCHES OF SNOW ON STATE ROUTE 168 IN
            WESTGARD PASS. STATE ROUTE 168 HAS BEEN
            CLOSED FROM DEATH VALLEY ROAD NEAR BIG PINE
            TO DEEP SPRINGS RANCH ROAD DUE A BIG RIG
            THAT GOT STUCK IN THE SNOW.

&&

MS