Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 251043

Area Forecast Discussion
National Weather Service Reno NV
343 AM PDT Tue Jul 25 2017


Thunderstorms are expected again today for northeast California
and western Nevada. Stronger storms could bring damaging winds,
as well as heavy rain with localized flash flooding. Drier air
intrudes Wednesday resulting in reduced coverage of thunderstorms,
with dry weather expected Thursday through Saturday. Near average
high temperatures rise to above average late in the week.



Main change to the short term forecast was to add a flash flood
watch today for the Basin and Range of west-central and northwest
Nevada, as well as the Surprise Valley of eastern Modoc County.
Heavy rain is still possible with thunderstorms over far western
NV this afternoon; however, the main coverage of storms is
expected to be focused in the Pine Nut and Virginia Ranges and
points east so the Reno-Carson City-Minden area was left out of
the watch.

This morning, very isolated convection or residual cloud cover
remains in central NV along a moisture gradient, as well as in
northeast CA (Plumas/Lassen Counties) in the divergent flow
region of an upper low centered near Fort Bragg, CA. Minimal
activity is expected this morning, with another round of scattered
thunderstorms expected to develop with daytime heating today.

Thunderstorms are expected to once again fire over extreme eastern
California and far western Nevada, with initiation in simulations
around midday or so. Simulations from the HRRR/GFS/NAM all indicate
a quick shifting of convection into west-central and northwest
NV, as well as extreme northeast CA, by late afternoon. With PWATs
still between 0.8" and 1" and sounding shear profiles fairly similar
to Monday, thunderstorms have the potential to be similar in
character to Monday. This means the stronger storms could last
longer than the usual pulse variety, with heavy rainfall and strong
outflow winds over 45 mph. The heavy rainfall will bring the
threat for some flash flooding, with the main area of concern from
the Virginia and Pine Nut Ranges eastward into the Basin and Range.
Showers and thunderstorms could once again linger well into the
night, mainly east of an Alturas to Lovelock to Hawthorne line.

Wednesday, coverage of afternoon thunderstorms is expected to wane
some as the upper low moves inland and pushes the best convergence
for storms farther north and east, mainly north of Pyramid Lake
and well south and east of Reno. Thursday, dry weather is expected
for the region as drier and more stable southwest flow moves
overhead. -Snyder

.LONG TERM...Friday through Monday...

The Four Corners ridge remains in place through the weekend. Latest
GFS runs have started to show a pair of weak shortwaves moving into
northern CA/NV Friday night through Sunday, bringing chances for
thunderstorms back faster than we were previously thinking. We`ve
added in a slight chance of thunderstorms for Friday Night and
Saturday, although with the ECMWF showing thunderstorm chances
further east, our confidence is fairly low at this time.

The ridge will continue to amplify through the weekend and into
early next week. Temperatures will continue to increase with 100
degrees temperatures possible again for western Nevada. Southerly
flow aloft will also bring additional monsoonal moisture to the
region for the weekend and early next week, with increasing chances
for thunderstorms especially for areas south of Highway 50. Hoon


Scattered thunderstorms will again develop this afternoon and
evening, mainly along and east of Highway 395. More storms will then
continue into the overnight hours as low pressure edges closer to
our area.

The main threats will be abundant lightning, small hail, gusty
outflow winds and heavy rainfall. Blowing dust will be possible for
terminals in the Basin and Range. Strongest storms will be capable
of producing flash flooding today. There is a 20% chance of
thunderstorms today at KRNO/KCXP/KMMH, with better chances east of
Highway 395 towards KLOL and KNFL around 40-50%. Hoon/Boyd



Another day of scattered thunderstorms is on tap for today, although
the main coverage will remain east of Highway 395. Abundant lightning
over the last 48 hours has sparked many new fires around the region,
including several large fires that are uncontained. Firefighters
should be prepared for gusty outflow winds again today that will
create shifting and erratic wind gusts and potential for extreme
fire behavior.

Storms have been wetter over the last 24 hours with higher chances
of wetting rains expected today as well. That being said, we cannot
rule out a chance of a few new lightning fires for today. Gusty
outflow winds up to 45 mph are be possible today, but heavy rain,
flash flooding, and abundant lightning are the main threats.

Drier southwest flow returns on Wednesday, although some isolated
storms will still be possible in west-central Nevada and north of
Susanville-Gerlach. Drier air moves into the region Thursday and
Friday, although chances for thunderstorms return again Friday
night and through the weekend. Hoon


.REV Watches/Warnings/Advisories...
NV...Flash Flood Watch from 11 AM PDT this morning through this
     evening NVZ001-004-005.

CA...Flash Flood Watch from 11 AM PDT this morning through this
     evening CAZ070.



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