Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 261222 AAA

Area Forecast Discussion...UPDATED
National Weather Service Reno NV
522 AM PDT Mon Jun 26 2017

.UPDATE...Short Term/Fire Weather

We are adding a slight chance for thunder for northwest
NV/Surprise Valley this morning, as latest observed/model data
indicates a weak upper level shortwave moving northward across
far western NV. Recent satellite images have shown an increase in
mid level ACCAS cloud cover (indicator of elevated instability)
from Reno northward to Pyramid Lake. While these areas have
limited potential for thunder, farther north (roughly between
Gerlach and the Oregon border), there is better opportunity for
isolated elevated convection forming through mid-late morning as
the 06Z NAM projects the nose of a 70 kt upper jet to move across
far northwest NV. The NAM also generates light QPF in this area,
although we aren`t expecting much in the way of precip reaching
the ground due to relatively fast cloud/cell motions--ridge winds
at Slide Mtn/Peavine are currently from the southeast or south at
20-30 mph. The greater concern with this elevated convection
would be isolated dry lightning strikes. MJD


.PREVIOUS DISCUSSION... /Issued 234 AM PDT Mon Jun 26 2017/


Gusty winds and a very dry air mass will produce critical fire
weather conditions and choppy lakes this afternoon and evening.
Temperatures will cool down to near seasonal averages through
midweek, then slowly warm up again late in the week with mainly
dry weather prevailing.


The triple digit heat will take a break from the region for much
of the upcoming week, as trough passage across the Pacific
Northwest today squashes the ridge axis to near the U.S.-Mexico
border through at least midweek. Highs mainly in the 90s today for
western NV valleys will fall to the upper 80s-lower 90s Tuesday-
Wednesday with dry air mass leading to more typical cooler nights
for our high desert climate (lows mainly in the 40s and 50s).

The main weather impact today will be gusty winds up to 40 mph
this afternoon and evening, combined with low humidity. Further
details are highlighted in the Fire Weather segment below. While
nearly all of the region will be too dry and stable for
convection, a small area of residual moisture combined with some
forcing associated with the main trough passage could trigger a
few short lived thunderstorms from Cedarville northward to the
Oregon border this evening.

For Tuesday and Wednesday, the weather turns generally benign
with dry westerly flow over much of the region, leading to more
typical zephyr-type breezes (gusts mainly around 25 mph) each
afternoon and evening. MJD

LONG TERM...Thursday and beyond...

A shortwave ridge will be passing across the area Thursday which
promises dry and warmer temperatures with generally light winds.
Highs will return to mid-upper 90s across western NV with low 80s in
the Sierra. The upper ridge will shift east Fri-Sat as a weak
shortwave trough moves into the western US in advance of a stronger
trough approaching the Pacific Northwest. There could be enough
instability for a few storms as this shortwave passes, but there
continues to be low confidence as some models maintain a
consolidated trough passage and a drier westerly flow. For now we
have kept out the mention of any showers/storms. One thing that
does seem more certain is the lack of a cooldown, with
temperatures remaining nearly steady from Thursday through next
weekend. A stronger trough is possible along the Pacific
Northwest coast by the middle of next week which would bring dry
conditions and a return to the afternoon/evening breezes. Hohmann


A trough moves inland today with stable conditions but increasing
winds. Surface wind gusts 30-35 kts and ridge gusts 40-45 kts will
raise the potential for some turbulence. Winds aloft and surface
gradients will relax Tue-Wed with winds decreasing a bit each
day. Hohmann


A period of critical fire weather conditions is likely today as a
trough moves into the region. Much drier air will spread into the
northern Sierra and western NV with increasing southwest surface and
ridge winds by afternoon. Widespread wind gusts 30-40 mph and
humidity levels falling to around 10 percent will enhance the push
of any fire starts or hold overs from isolated lightning on Sunday.
Locally breezy conditions will prevail Tuesday although wind gusts
will be lower (generally 25-30 mph). Very dry air will continue to
push into the area from about I-80 southward through Wednesday. This
will keep minimum humidity levels below 15% with some mid and upper
slopes having poor recoveries. Hohmann


.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from 1 PM this afternoon to 11 PM PDT this
     evening NVZ450-453-458-459.

     Lake Wind Advisory from 1 PM this afternoon to 11 PM PDT this
     evening for Washoe Lake in NVZ003.

     Lake Wind Advisory from 1 PM this afternoon to 11 PM PDT this
     evening NVZ004.

CA...Red Flag Warning from 1 PM this afternoon to 11 PM PDT this
     evening CAZ278.



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