Flash Flood Warning 114, NWS Las Vegas, NV

Area Forecast Discussion
National Weather Service Las Vegas NV
133 PM PDT Sun Aug 7 2022

.SYNOPSIS...After a couple of quiet days, monsoonal moisture is
expected to return in full force this week providing the fuel for
daily scattered thunderstorms. The flash flooding threat is expected
to increase once again as these storms will be capable of producing
very heavy rain. With the additional moisture and cloud cover,
temperatures will lower to around normal through the week.
&&

.SHORT TERM...Through Tuesday.

Quiet day across the region today with some leftover dust remaining
over portions of the lower Colorado River Valley. Visibilities are
still showing around 8-10 miles, but those are expected to improve
through the afternoon. We are starting to see a few storms develop
east of Mohave County, which is where the best instability is
located. Additional isolated storms are forecast to build over
portions of southern Mohave County and possibly as far west as the
Colorado River Valley, but instability is weaker and any storms that
do develop are not expected to last long, however, they could still
produce brief heavy rain and gusty winds.

Overnight and early Monday, the overall flow will become more
southeast allowing for ample moisture to start advecting into the
region. Precipitable water values are expected to increase from 0.5-
1 inch today to around 1-1.5 inches Monday. This moisture combined
with better instability will lead to more coverage of thunderstorms,
especially over the Spring Mountains and the mountains of eastern
San Bernardino County and central/southern Mohave County. Another
area to watch for thunderstorm development will be across the
eastern Sierra and White Mountains as added dynamics associated with
a deep low off the coast and pw's approaching 1 inch could lead to
some heavier rain, especially along the Sierra Crest north of
Independence. High temps will trend downward a few degrees with
increasing moisture.

.LONG TERM...Tuesday through Sunday.

Moisture will continue to increase through Tuesday in the convergent
broad southeast to southerly flow over our forecast area. In
addition, there will likely be some weak vorticity advection as the
easterly wave over northwest Mexico is entrained into the flow. The
NBM continues to indicate Tuesday will be quite active across our
entire forecast area with PoP values of 30-40 percent over the
valleys and deserts and 60-70 percent in Mohave County and the
southern Nevada mountains. A moist southerly flow persists Wednesday
through Sunday over most of southern Nevada/northwest Arizona and
eastern San Bernardino County and 20-40 percent chances of
thunderstorms will be in place the rest of the week. However, a
drier southwest flow is indicated after Wednesday over western San
Bernardino and Inyo counties as the West Coast Low moves inland over
the Pacific Northwest. This will lead to reduced chances for
thunderstorms for these areas the latter half of the week. This
weather pattern will also hold temperatures down a little below
normal for most sites.
&&

.AVIATION...For Harry Reid...Light winds gradually turning from the
northeast to southeast to southwest can be expected into this
evening.  Speeds should remain primarily below 10 kts through the
entire TAF period.  There is a non-zero chance of a thunderstorm
developing over the higher terrain south and west of the terminal
this afternoon, but none of this activity is expected to move into
the valley.  Any cloud cover will be FEW-SCT AOA 10kft into Monday.
Thunderstorm chances will increase some tomorrow, but not enough to
include them in the TAF package at this time.

For the rest of southern Nevada, northwest Arizona and southeast
California...Typical diurnal wind patterns will continue at area TAF
sites into tomorrow.  Speeds will generally remain 10kts or less,
although a few gusts to 20kts will be possible later this afternoon
and early evening at KBIH.  A few isolated thunderstorms are
possible over southeastern portions of the region this afternoon and
evening. Any of these will be capable of producing gusty outflows
that could cause briefly higher winds, mainly at the Colorado River
sites, into this evening. Otherwise, skies should be FEW-SCT AOA
10kft through the period.
&&

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

SHORT TERM...Gorelow
LONG TERM...Adair
AVIATION...Planz

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