Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 160952

Area Forecast Discussion
National Weather Service Reno NV
252 AM PDT Sun Jul 16 2017


Isolated thunderstorms remain possible today with the best
chances in the eastern Sierra and central Nevada. Low pressure
approaching the west coast will increase winds Monday and Tuesday,
leading to critical conditions for rapid fire spread. Winds will
decrease a little each afternoon with hot temperatures expected
for the balance of the week.



Weak upper level wave moving through the area this morning is
keeping high level clouds draped over the region with a few light
showers possible. No thunderstorms have have popped up yet, but
an isolated storm or two will remain possible the next few hours.

Ridge of high pressure over the area is flattening in response to
an incoming trough moving through the Pacific Northwest. This
will have a few implications for our weather the next few days
including pushing thunderstorm activity out of the region and
increasing dry southwest winds. It will also cool afternoon high
temperatures starting Monday, albeit only by a few degrees.

Today should be the last day of thunderstorms in the area this
week with storms expected to be limited today mainly to Mono,
Mineral, and southern Lyon counties.

Winds will begin to pick up today with the windiest day of the
week expected to be Monday and only a slight decrease in wind
speeds Tuesday. A Red Flag Warning is in effect for Monday with a
Fire Weather Watch out for Tuesday. See the Fire Weather Section
below for more on the critical fire weather conditions expected
for the start of the week. -Zach

.LONG TERM...Wednesday onward...

More "typical" summer conditions are anticipated Wednesday into the
start of next weekend with warm and mainly dry conditions. While
wind speeds will begin to decrease by midweek compared to Monday and
Tuesday, afternoon westerly zephyr winds of 10-15 mph with gusts
to 25 mph can still be expected.

Thunderstorm chances will be limited to southern and eastern Nevada
for much of the work week due to the drier and more stable air mass
across the region. The high pressure center begins to weaken and
shift eastward heading into the weekend, allowing for moisture to
slowly creep northward and bring the return of thunderstorms to the
region. As we get toward the latter part of the weekend and into the
start of next week there are indications in the ensemble guidance
that a monsoon surge may work northward. This has the potential to
bring greater thunderstorm coverage to the area, but will also be
battling a trough just off the Pacific Northwest coast. If this wave
arrives slightly further south, the increasing dry southwesterly flow
would push thunderstorm chances farther south. Based on the pattern
so far this summer, we definitely can`t count troughs out! -Dawn



Mid and high level clouds are moving across the the Sierra and
northern Nevada early this morning, but latest radar signatures
suggest there is hardly any rain associated with them. Otherwise,
widespread VFR conditions early this morning with chances for
thunderstorms this afternoon and evening. Storms are anticipated
mainly south of Highway 50 and will be fairly isolated in coverage.
Isolated storms are possible for KMMH, KHTH, KNFL, and KBAN, but
with chances small of a terminal having a storm pass directly over,
will leave the mention of TS out of the TAF this morning. Outflow
wind gusts of 40 kts and lightning are a possibility with any storm
that does form. Storm bases are likely to be fairly high, leading to
a low risk of terrain obscuration. Chances for storms are near
zero Monday and Tuesday.

Fairly typical westerly winds of 10-15 kts gusting up to 25 kts can
be expected this afternoon and early evening. Stronger winds with
gusts up to 35 kts are likely on Monday, with winds increasing
earlier in the day than usual, around noon local. Breezy
conditions will linger into Tuesday. -Dawn



A weak passing wave overnight brought an increase in clouds across
the Sierra and northwestern Nevada, but latest radar trends indicate
little if any rain is reaching the ground. Instability is lacking
and therefore do not think we will see thunderstorm activity now
through morning.

Thunderstorm coverage today looks similar to what we saw Saturday.
Storms should be mainly confined to Mono, southern Lyon, and
Mineral counties and be isolated in coverage. Storms are likely to
be a hybrid of wet and dry as relatively fast storm motions will
limit precipitation totals outside of the main rain core. Dry
lightning strikes could potentially ignite new fires across the
region ahead of Monday`s critical conditions.

Increasing winds on Monday will combine with a significant dry slot
leading to critical fire weather conditions. Winds are expected to
gust 30-40 mph along with single digit to low teen minimum humidity
values for portions of northeast California and northwest Nevada and
Red Flag Warnings continue to be in effect. Winds will remain breezy
on Tuesday with a very dry air mass still over the region. While not
as clear cut of a critical fire weather day compared to Monday, the
continuous and heavy grass crop this year has proven to carry fires
in even typical afternoon winds. With Tuesday`s winds being
stronger than usual, a Fire Weather Watch was issued during the
day shift and will remain in effect for Tuesday afternoon and
early evening.

The dry slot will also lead to poor humidity recovery both Monday
and Tuesday nights, especially for midslopes and ridges. Winds will
remain breezy overnight across ridges Monday night as well.

More "typical" afternoon winds will continue through the week with
afternoon gusts up to 25 mph. -Dawn


.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from noon to 8 PM PDT Monday NVZ450-453-458-459.

     Fire Weather Watch from Tuesday afternoon through Tuesday
     evening NVZ450-453-458-459.

CA...Red Flag Warning from noon to 8 PM PDT Monday CAZ270-271-278.

     Fire Weather Watch from Tuesday afternoon through Tuesday
     evening CAZ270-271-278.



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