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Area forecast discussion 
National Weather Service Reno Nevada
307 PM PDT sun Jul 5 2015


Low pressure near the California coast will bring the threat for
isolated to scattered showers and thunderstorms through the
upcoming week, especially in the afternoons and evenings. Moisture
remains elevated so locally heavy rainfall will be possible with
thunderstorms. Temperatures will remain near average early this
week before falling below average.


Short term...

Adjusted thunderstorm timing out in the basin and range Monday and
bumped up pop/thunderstorm chances over northeast California for
Tuesday night, otherwise no major changes to the short term

Thunderstorms have popped up over southeastern Mono County and
Mineral County west of Highway 95 this afternoon. Over western
Lassen County, a couple storms have popped up as the rain-cooled
(from last night and this morning) atmosphere there has modified
quickly with afternoon sun. For northern Washoe County, cumulus
are beginning to develop and a few showers or storms are expected
into this evening. Elsewhere, modest cumulus are developing with
an isolated shower or storm hard to rule out with moderate (but
lower than recently) moisture remaining in the area today.

As far as the nature of thunderstorms today, instability is
moderate (500-1000 j/kg), motions are quite anemic (less than 10 mph)
and precipitable waters remain over 0.75" so heavy rain is the primary threat to
life and property into this evening. While flash flooding is
certainly possible in/near steep terrain and on recent wildfire
burn scars, storm coverage should remain isolated to widely
scattered so the flash flooding threat remains very low for the
overall area.

With no upper forcing of note, convection this evening should end
by around sunset. On Monday, thunderstorm coverage is prognosticated to
increase as low pressure off the California coast begins to move
towards the coast. This is expected to bring increasing divergence
and cooling aloft (increasing instability), with afternoon heating
bringing scattered thunderstorms first to the Sierra followed by a
push off into western Nevada late in the afternoon and during the
evening. Instability and moisture looks similar to today so storms
generally will be of similar character.

Tuesday, the GFS/NAM indicate the approach of an upper disturbance
around the low off the California coast. This will bring an
additional round of scattered afternoon thunderstorms. Flow aloft
is expected to increase with the disturbance and model soundings
show some mainly directional wind shear in the cloud-bearing
layer. This could bring increased organization/lifespans to
thunderstorms for Tuesday afternoon and evening. Models still
depict rather high pwats, especially north of about Highway 50, so
heavy rain and localized flash flooding remain a threat.

Tuesday night, the 12z GFS/NAM show the possibility for nocturnal
convection persisting for northeast California and northern and
far western Nevada as the aforementioned upper disturbance
continues to rotate around its parent low. The sref also keeps a
low chance for nocturnal thunderstorms over northeast California
Tuesday night. With all this in mind, I have increased overnight
pop for much of the region with the highest pop in northeast
California. Snyder

Long term...Wednesday through Sunday...

Models track the low off the California coast into northern
California/western Nevada for middle week before lifting into the
Pacific northwest either Saturday or Sunday. This will should lead
to a cloudy, cool and wet pattern for the region. At this time the
best chance of precipitation could be focused north of Highway 50
Wednesday to Friday, as a deformation zone develops on the northeast
side of the low. Afternoon should drop into the 80s across western
Nevada with 70s for the Sierra before warming up a bit for next
weekend. Brong



Showers and thunderstorms should decrease by 06z with best chance
for thunderstorms is over Lyon, eastern Mono and western Mineral
counties, with just a 10-15% chance of storms impacting krno and
kmmh. Little to no activity will occur around ktrk/ktvl until
tomorrow. The stronger storms could produce outflow winds to 50 mph,
small hail and heavy rain.

As low pressure nears the California coast Tuesday, showers and
thunderstorms will build up along the Sierra crest and far western
Nevada. Main threats are heavy rain, winds to 50 miles per hour and hail.

The low will persist for the latter half of the week with an ongoing
threat for showers and thunderstorms. Brong


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