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Area forecast discussion 
National Weather Service Reno Nevada
217 PM PDT Monday Jul 28 2014

abundant moisture will continue pushing north into the region
with varying chances for thunderstorms through the week. An upper
level disturbance could bring a few stronger thunderstorms on
Tuesday. Temperatures will remain near or slightly above normal.


Short term...
the only significant changes to the short term portion of the
forecast were to increase chances for convection over the northern
portions of the County Warning Area both Tuesday and Wednesday. Also...afternoon
winds were raised to typical afternoon Zephyr speeds with gusts
up to 25 miles per hour along the Sierra front tomorrow. Otherwise the
forecast was left largely as inherited.

Convection developed across the far southern County Warning Area before noon today
and is slowly lifting north and redeveloping. Dew points as of
early afternoon remain in the 30s north of Highway 50...but have
crept into the 40s over southern areas. The dew points should
continue to increase through the next couple of days...but
forecast soundings do show some decrease in precipitable waters Tuesday before
increasing again Wednesday.

Moisture would be much deeper...and the flash flood potential
higher...if the high center was a bit farther west than it is
currently located. Right now it is over central New Mexico more
than The Four Corners region. There is also a trough off shore
that is keeping some drier air across parts of far northern
California. Storm motions from the forecast soundings are a little
faster over the western portions of the County Warning Area than we would like to
see for flash flooding. There is a wave moving north today that
could produce stronger storms Tuesday...especially over the
southern and western portions of the area. This could result in
some locally heavy rains...but we do not think the coverage would
sufficient to issue a Flash Flood Watch at this time. This wave
will progress into northeastern California and extreme
northwestern Nevada by Tuesday afternoon kicking off faster
thunderstorms. This raises some fire weather concerns for these
locations. However...atmospheric moisture will be elevated from
about 0.75 to around 1 inch allowing for more precipitation.
Still...with storm speeds over 20 miles per hour...dry strikes will be

Subtle waves in the flow will determine in large part where the
bulk of the thunderstorms will develop each day. The amount of
residual cloudiness will also control the coverage. If enough
clouds exist early each day then coverage may be limited as
instability is decreased. This could result in more shallow
convection with mainly showers or virga. 20/mb

Long term...Thursday through Monday...
extended forecast will keep mention of showers and thunderstorms
going through early next week across most areas. Daytime highs are
expected to be a few degrees above normal each day, but presence
of cloud cover and isolated to scattered precipitation should keep highs
mainly in the 90s for lower elevations and middle to upper 80s for
Sierra valleys. Mild nights will continue with lows mainly in the
60s for lower elevations and upper 40s to middle 50s near the Sierra.

Moisture and instability will likely remain in place through early
next week as large scale weather pattern is unlikely to change very
much. Persistent ridge over the southwest US is projected to expand
north to The Four Corners region by this weekend. Meanwhile, weak
upper low is expected to approach the northern California coast. Some
southwest flow aloft may limit convection from the Tahoe basin
northward to southwest Lassen County Thursday and Friday, but latest
GFS/European model (ecmwf) are trending toward a more southerly flow by the weekend
as upper low off the northern California coast drifts slowly south. This
would bring the possibility of thunder back to the Sierra and
northeast California Saturday and Sunday. Some showers are also possible
overnight this weekend from residual moisture or convective outflow

By Monday, the low is currently projected to drift back north and
decrease the thunderstorm threat near the Tahoe basin and northern
Sierra again. However, this process may be slow to evolve so while
the current outlook will keep convection out of Tahoe and parts of
northeast CA, these areas may eventually have a mention of thunder

The main uncertainty is where and when the greatest threat for
thunderstorm coverage will occur. Smaller scale shortwave features
are not resolved very well in timing or location on medium range
guidance. On days without significant forcing or upper dynamics,
thunderstorm coverage will be more sparse with only a few locations
receiving heavy rainfall from slow moving cells with precipitable
water values generally between 0.75 and 1 inch. On days where
shortwave energy is involved, the convection will become better
organized and the possibility of heavy rain or local flooding will

At this time, slightly better thunderstorm chances are indicated in
areas north of Susanville-Gerlach Thursday, then spreading to
Mineral-Mono counties and parts of west central Nevada east of
Reno-Carson City from Friday through Sunday. Mjd

showers and embedded thunderstorms will mainly stay south and east
of Highway 50 through tonight. At the main terminals, the best
chance for precipitation will be at kmmh where rain may occur for a few
hours this evening. For Tuesday, the better thunderstorm potential
is expected north of I-80 and south of Highway 50 but isolated
convection could occur across any portion of the region. Some
outflow gusts to 30-40 knots are possible near thunderstorms, otherwise
winds will remain light. Mjd

Rev watches/warnings/advisories...


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