Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 292056
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
156 PM PDT MON AUG 29 2016

.SYNOPSIS...
Low pressure will set up near the West Coast this week with breezy
conditions expected Tuesday through Thursday. The trough will
slowly move inland Friday into the weekend with cooler
temperatures and lighter winds.

&&

.DISCUSSION...
The overall thinking remains the same with the trough along the
coast the main player into the weekend. Several short waves will
move through the parent trough as it slowly moves eastward.

The first will move through Tuesday morning and increase the
winds aloft with a decent jet streak. There is some instability
associated with this wave, but we expect any threat of
thunderstorms to remain near and west of I-5, not to affect NE
California.

Another short wave moves through Wednesday morning and it also
has some instability, but this time further east so added a slight
chance of thunder 12-18Z Wed north of a Portola-Gerlach line. A
third wave moves through Thursday, but by then the instability
will have moved north and east of us.

Winds are the other concern with each short wave. They become
breezy with gusts up to 35 mph possible north of Highway 50 both
Tuesday and Wednesday. Thursday`s winds may be stronger as the
main cold front finally pushes through and the timing of the wave
aloft is better. Still, it is hard to pin down exactly which day
is worst, but all are potential fire weather issues, see below.
Some blowing dust is expected as well, especially near the Smoke
Creek and Black Rock Deserts.

After the main front moves through, temps will cool Friday to
below average values for early September. The final short wave
with the trough axis will move through late Saturday, but winds do
not look to be that strong with it. However, temps aloft cool even
more, especially on the GFS and there could be a shower or two
near the Oregon Border. The EC is quite a bit warmer, but its
ensemble, as well as the GEFS support the GFS ideas. Have trended
temps down toward the GFS for the weekend. Still, I didn`t go
nearly as cool as it could be.

&&

.AVIATION...
VFR conditions through Wednesday with only a slight chance of a
thunderstorm 12-18Z Wed north of KRTS. Otherwise, main concern is
winds with southwest winds gusting around 30 kts near/north of
KTVL/KCXP 20-02Z Tues/Wed/Thurs. With good mixing during the
afternoon LLWS is not expected, but expect turbulence near the
mountains.

&&

.FIRE WEATHER...

Several days of enhanced winds across the region combined with low
humidity will bring a risk of critical fire weather Tuesday through
Thursday. This is the primary fire weather forecast hazard, though
confidence is only medium due to varying simulations on wind
intensity and timing of the strongest wind days. Gusts around 30 mph
are likely Tuesday and Wednesday afternoons, with further enhancement
Thursday where more widespread gusts 35+ mph are possible. For
messaging we`ve posted fire weather watches for zones 450,458,270,278
Tuesday-Thursday where we feel the highest risk of hitting critical
conditions is. Depending on how Tuesday shakes out or tonight`s
simulations go, upgrades to Red Flag Warning are possible. Overall
this summer model guidance for winds has struggled a bit in our
region, mainly over-predicting. The NAM (MET MOS) has done the best
so our wind forecast leans heavily in that direction. Friday could
still be breezy but confidence is low.

The other more localized fire weather concern is potential for
isolated dry thunderstorms between 3-9 AM Wednesday morning over the
northern Sierra and far NE California. Roughly Portola-Cedarville
line. Recent simulations show low pressure moving into N Cal with
moderate levels of instability and moisture aloft. If storms form,
dry cells are likely due to high bases and swift storm motions.
This could enhance risk of new fire starts over NE Cal.

The coming weekend is looking cooler, less windy, and with a
little better humidity recovery compared to the next few days. This
is in response to deepening trough of low pressure over the western
states. Not unusual for us to see this "first taste of fall" around
early to mid September. -Chris

&&

.REV Watches/Warnings/Advisories...
NV...Fire Weather Watch from Tuesday afternoon through Tuesday
     evening NVZ450-458.

     Fire Weather Watch from Wednesday afternoon through Wednesday
     evening NVZ450-458.

     Fire Weather Watch from Thursday morning through Thursday
     evening NVZ450-458.

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

     Fire Weather Watch from Wednesday afternoon through Wednesday
     evening CAZ270-278.

     Fire Weather Watch from Thursday morning through Thursday
     evening CAZ270-278.

&&

$$

For more information from the National Weather Service visit...
http://weather.gov/reno



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