Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 270912
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
212 AM PDT WED JUL 27 2016

.SYNOPSIS...

Hot and dry conditions with relatively light winds will continue
through the week. Some increase in moisture will lead to a few
afternoon and evening thunderstorms from Thursday through the
weekend, with temperatures easing down for the weekend as high
pressure weakens and clouds increase.

&&

.SHORT TERM...

Added isolated thunder to Lassen and northern Washoe Counties
Friday evening and threw in broad-brush haze for today with the
HRRR model bringing fire particulates from the Soberanes and Sand
Fires into the region with south to southwest flow aloft.

Very warm to hot afternoons continue this week under a strong
ridge of high pressure, with a few daily high temperature records
likely to be matched or even bested. Still, dry air and light
winds will make large diurnal temperature swings of 40-50 degrees
common around northeast California and western Nevada for at least
tonight. With some increase in cloud cover possible as high level
moisture begins to move up from southern California Thursday night
and Friday, lows may be moderated a bit after tonight.

Regarding thunderstorms, models continue to pick Thursday and
especially Friday for the formation of isolated cells. These
storms will be slow moving so some rain will fall. However, the
cores are likely to be small with very dry low levels. Dry lightning
and gusty outflow winds are possible with any storm, but fortunately
the storm coverage still looks isolated at this time. Storms were
added to Lassen and northern Washoe Counties for Friday evening based
on hints from the latest models. Models show increasing low level
convergence by Friday north of Susanville and Gerlach as westerly
flow kicks in late in the day. This may be enough for a few small
storms to pop up by Friday evening. -Snyder

.LONG TERM...Saturday through Tuesday...

Current medium range model guidance is on par with previous forecast
cycles so very few changes were made to the inherited forecast for
the weekend into early next week.

The main question will the coverage extent of convection Saturday
and how this will change over time as the upper level flow begins to
strengthen and become more west-southwest with time.

Saturday still looks to have the best coverage as flow aloft remains
fairly light. There are some hints of an increase in west-southwest
flow over the far northern forecast area by late Saturday. This does
not seem strong enough to scour any moisture out and may be just
enough to produce some mid level convergence. With relatively slow
storm motions any storms Saturday should be of the hybrid variety.

Upper flow begins to strengthen north of Interstate 80 by Sunday.
This should confine the storms to areas south of Highway 50. Storm
motions may be a bit faster so dry lightning strikes are likely to
be a bit more common. By Monday only the GFS is holding on to much
on the way of convective activity over far southern Mono County and
southern Mineral County. We have left these out for now. Winds
should increase a bit Monday as the pressure and thermal gradients
tighten. The same is true for Tuesday. These winds will not be
overly strong...maybe a little more than a typical zephyr...but
could be a fire weather concern if there are any small hold over
fires from lightning strikes the previous few days. 20

&&

.AVIATION...

Continued hot and dry with smoke and haze from fires in California.
Because of the distance from these fires...the smoke and haze should
not cause any significant restrictions to visibility for flight
operations.

A better chance for afternoon cumulus build ups exists today along
the Sierra and White Mountains south of Highway 50. By Thursday the
chance for isolated thunderstorms increases...then becomes better
for Friday and Saturday north along the Sierra and into northeast
California.

Gusty surface winds are a big threat with any storms along with
turbulence and lightning strikes. Many of the storms may produce
little in the way of precipitation except near the cores...so
visibility at the surface may only be restricted by blowing dust
associated with outflow winds. 20

&&

.REV Watches/Warnings/Advisories...
NV...Heat Advisory from 11 AM this morning to 11 PM PDT Friday
     NVZ001-004.

CA...None.
&&

$$

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


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