Area Forecast Discussion
Issued by NWS Las Vegas, NV

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000
FXUS65 KVEF 211037
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
337 AM PDT Fri Jul 21 2017

.SYNOPSIS...
Retreating moisture will allow most areas to remain dry for much
of the weekend except for eastern Lincoln County and Mohave
County where isolated showers and storms will be possible each
day. Temperatures will warm slightly each afternoon through
Sunday when a shift in the weather pattern is expected to open to
the door to increasing chances of showers and storms across the
region as moisture spreads back northward.

&&

.SHORT TERM...Today through Sunday

Drier air shifts eastward today and Saturday across southern Nevada
and southeastern California, confining chances for isolated to
scattered showers and thunderstorms to Mohave and eastern Lincoln
counties where medium-grade monsoonal moisture will still be
present. On Sunday the weather pattern will begin to shift as low
pressure approaches the northern California coast. This could
pull a bit of extra moisture across southern Nevada and southeast
California and trigger a few isolated showers/storms across the
southern Great Basin and Sierra in addition to continued chances
across northwest Arizona. Warming trend continues through the
weekend with increasing sunshine and prevailing south to
southwesterly flow leaving max temps slightly above seasonal
norms.

The Detwiler fire in Mariposa County California continues to burn
just to the northwest of Inyo county and have continued the
mention of areas of smoke along the Sierra, White Mountains, and
Owens Valley today. Tonight a spreading of this smoke looks to be
possible with the forecast flow pattern across much of the
remainder of Inyo County as well as San Bernardino and Esmeralda
counties. These areas could see periods of smoke throughout the
upcoming weekend.

.LONG TERM...Monday through Friday.

A favorable pattern appears to be shaping up Monday and Tuesday for
an influx of a broad moisture plume which may spread over our entire
forecast area, especially by Tuesday. A closed low is forecast to be
spinning near the northern California Coast Monday morning while a
close high becomes centered near the Four Corners. The resulting
moderate to strong southeast-southerly flow between the two
circulations will quickly pull moisture from southern Arizona and
northwest Mexico across almost all of southeast California, southern
Nevada and northwest Arizona. The GFS and ECMWF solutions are in
quite good agreement with this pattern and both indicate an inverted
trough near the Gulf of California will get pulled up across
southeast California and southern Nevada. Also, a 60-70 knot jet on
the east side of the aforementioned closed low will work its way
across Inyo County and central Nevada Monday into Tuesday. So, there
should be some broad upward forcing to work on the increasingly
moist and unstable air. This looks like the first good opportunity
this season for the potential of heavy rain producing storms to
develop over the southern Sierra and other parts of Inyo County.

A drying trend is then indicated Wednesday through Friday as the
NorCal low moves inland and a southwest flow pushes the moisture
away leading to a gradually reduction in chances for showers and
thunderstorms each day, especially Thursday and Friday. Temperatures
were lowered Tuesday based on the latest guidance which accounts for
the increased moisture and cloud cover. Otherwise, near normal
temperatures can be expected the rest of the week.

&&

.FIRE WEATHER...
Monsoonal moisture shifts eastward for the weekend with lingering
moisture allowing for isolated showers and storms across eastern
Lincoln and Mohave counties. Critical RH values will be likely
each afternoon this weekend across Inyo, Esmeralda, Nye, and San
Bernardino counties but with no significant wind expected fire
danger concern remains low. Increasing chances for showers and
storms is expected next week as a shift in the weather pattern
allows for moisture to stream northward across the region.

&&

.HYDROLOGY...
Creeks, streams and rivers in northern Inyo County have shown
decreasing flows over the last day and a half. However, some road
closures continue in the area. Bishop Creek Bypass and Big Pine
Creek Bypass continue to be utilized to minimize flows through
Bishop and Big Pine. Remember, never drive through flooded
roadways or around barricades. Also, pastureland or farmland
adjacent to creeks, streams or rivers could experience areas of
standing water.

&&

.AVIATION...For McCarran...A weak circulation over southern Nevada
will keep mid and high clouds over Las Vegas today, but no
thunderstorms are expected in the terminal area. Isolated
thunderstorms will occur in the Peach Springs corridor this
afternoon and early evening. A prevailing south wind up to 10 knots
will persist today then a southwest component will develop
tonight.

For the rest of southern Nevada, northwest Arizona and southeast
California...Isolated to scattered thunderstorms will be confined to
northwest Arizona this afternoon and early evening. The rest of the
region will see VFR conditions with clouds generally above 14Kft MSL
and south to southwest winds of 5 to 15 knots. Areas of dense smoke
can be expected over west central Nevada this morning then near the
southern Sierra and the western Mojave Desert this afternoon and
evening.

&&

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

$$

SHORT TERM/FIRE WEATHER...Guillet
LONG TERM/AVIATION....Adair

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