542
FXUS65 KVEF 110924
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
224 AM PDT Sun Aug 11 2024

.SYNOPSIS...Monsoonal moisture will continue to provide fuel
for thunderstorms across southern Nevada, northwest Arizona and
eastern San Bernardino County through Monday. Above normal
temperatures will continue as high pressure persists over the
southwestern states. Drier air is forecast to push into the region
Tuesday and much of the coming week, reducing thunderstorm chances
and bringing more normal August temperatures to the region.

&&

.SHORT TERM...through tonight.

Isolated showers and thunderstorms continuing at this hour across
northern Mohave County. One specific storm has become anchored to
the Virgin Mountains southeast of Mesquite and is dumping heavy rain
which has prompted the issuance of a flood advisory. Radar
estimating between 1"-1.40".

Large scale features remain unchanged from yesterday. Weak inverted
trough to our south over the lower CRV/Baja Peninsula will remain
sandwiched between high pressure centered over the eastern Pacific
and the other over New Mexico/Texas. Flow around these features is
producing a region of deformation over the Mojave Desert/southern
Nevada. Guidance shows best instability across eastern Lincoln and
northern Mohave Counties this afternoon where CAPE values are
projected to range between 1000J/kg-1500J/kg. This area will also
lie under an area of more favorable divergence aloft associated with
the deformation zone. Precipitable water values across southern
Nevada and northwest Arizona will be running up to 175% of normal.
We`ll see how the airmass recovers from yesterday`s late
afternoon/evening storms over Mohave County but given what happened
yesterday a few storms will be capable of producing heavy rain
leading to localized flooding.

The western half of the forecast area will remain dry,hot and breezy
as south to southwest breezes increase in the western Mojave Desert,
Death Valley NP and Nye County.

.LONG TERM...Monday through Saturday.

Increasing southwesterly flow aloft will bring a drying and cooling
trend to the region as troughing develops across the West. This will
mark another extended break period from the monsoon, with moisture
becoming confined to Northwest Arizona. In fact, by Wednesday and
Thursday, even most of Northwest Arizona will likely be mostly dry.
Meanwhile, temperatures will respond with a gradual cooling trend,
falling closer to mid-August normals and complimented by
southwesterly afternoon breezes.

Forecast confidence decreases Friday onward as some ensemble members
suggest the western US trough shifting westward and allowing the
monsoon high to build back towards the Four Corners. This would
allow for a more southerly flow pattern and potentially draw some
monsoonal moisture back into our eastern zones. Alternatively, other
guidance maintains a general troughing pattern over the region and
keeps dry air locked into the area. Ensemble members are roughly
split on the two options, so for now a modest increase in storm
chances return to mainly northwest Arizona Friday and Saturday, with
temperatures remaining near seasonal normals.

&&

.AVIATION...For Harry Reid...Outside of any convective influence,
expecting southerly breezes to persist through the TAF period.
Speeds in the morning and overnight hours in the 6-10 knot range,
while increasing to 10-15 knots in the afternoon with gusts 20-30
knots. While there is potential for convection in/around the valley,
the threat is not as high as it was yesterday. Latest guidance
suggests a 20-30% chance of a storm and gusty outflow in the valley.
FEW-SCT clouds at or above 10kft.

For the rest of southern Nevada, northwest Arizona and southeast
California...The threat of storms and gusty outflow at the area TAF
sites looks to be notably lower than yesterday, with 20-30% chances
in the Las Vegas Valley and 10-20% chances in the Colorado River
Valley. Outside of any convective influences, expect breezy south
winds to persist at these sites. Farther west at KDAG and KBIH,
mostly typical diurnal wind patterns are forecast. FEW-SCT clouds at
or above 10kft.

&&

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

$$

SHORT TERM...Pierce
LONG TERM...Outler
AVIATION...Woods

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