Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 270353 AAA
AFDREV

Area Forecast Discussion...UPDATED
National Weather Service Reno NV
853 PM PDT Thu Apr 26 2018

.UPDATE...
Showers and thunderstorms that developed late in the afternoon
peaked between 5pm and 7pm when afternoon heating (instability and
terrain convergence) and upper level forcing were best aligned.
Wind gusts were generally in the 40-50 mph range with hail size
around pea to marble size for the stronger cells. While the
instability is waning a bit, upper level forcing will remain
present overnight and early Friday morning for a few showers and
maybe a lightning strike or two...mainly north of I-80 across far
northeast CA and northwest NV. Clearing was noted along the
Sierra crest from Tahoe southward into Mono County. We have made
some minor adjustments to the forecast this evening to reflect
these trends. For Friday, a drier and breezier day is still on tap.
Hohmann

&&

.PREVIOUS DISCUSSION... /Issued 239 PM PDT Thu Apr 26 2018/

UPDATE...
Quick update to add isolated showers/storms to Central Nevada in
Eastern Churchill and Pershing Counties. Buildups are present
there, and the GFS is continuing to show something there. X

PREVIOUS DISCUSSION... /Issued 129 PM PDT Thu Apr 26 2018/

SYNOPSIS...
A few showers and thunderstorms are expected tonight as a weak
wave moves through. Drier, breezy and cooler Friday before low
pressure moves inland for the weekend. Below average temperatures
are expected along with some showers and thunderstorms north of
Highway 50. The low only slowly pulls away into Tuesday with
the threat for showers and thunderstorms remaining with cool
temperatures.

SHORT TERM...
Not much change to the going forecast into the weekend with the
focus remaining on the upper low that only slowly moves onshore.
Scattered showers and isolated thunderstorms are still expected
into the evening hours near and just east of the Highway 395
corridor. Nothing has developed yet, but the high based cumulus
are showing a little more development at this hour. The showers
and storms may continue overnight north of Susanville and Lovelock
as the upper level front moves through.

Behind this front, there is subsidence and a dry slot that will
move over the Northern Sierra and Western Nevada. Drier, breezy
conditions are on track for Friday with limited chances for
showers or thunderstorms. If any do form, the would be very
isolated and likely confined to Central Nevada or the Lassen
Convergence Zone.

The core of the upper low is then expected to move through for the
weekend with showers gradually increasing Saturday morning. Much
better agreement this afternoon with the core of the low remaining
north of I-80. As such, the best chance of showers and storms will
be north of I-80 as well with limited chances down to Highway 50.
The core of the low will have cold temps with it, near or below -6
C. This will result in snow and/or pellet showers above 5500-6000
feet. Widespread accumulations are not expected, but a quick inch
of snow/pellets could accumulate in the heaviest showers/storms.
If driving, this could result in rapidly changing road conditions
over a very short distance, so keep that in mind if you encounter
any showers. X

LONG TERM...Next Week...
Moderate confidence continues for showers/storms early next week
followed by a warming trend. By Wednesday though, how quick we
warm up is low confidence as well as whether we completely dry
out.

The GFS is consistent with its previous runs dropping another
weak low through on Monday and slowly exiting to the south Tuesday
with ridging expected by Thursday. The EC has this low as well,
but then has a reinforcing wave for Wednesday and a much slower
movement of the low east, if at all. Monday/Tuesday, the
differences are not enough to change the overall idea of the
forecast for at least isolated showers and thunderstorms with
continued below average temperatures.

By Wednesday, the GFS shows a warm and dry forecast, similar to
what we are currently carrying. However, the EC and many of its
ensemble members are cooler and keep at least a threat of showers
and thunderstorms over Mono County through Friday. The slower
warming trend doesn`t have temps reaching near average until
Thursday or Friday. For now, will keep the forecast dry, but slow
the warming trend with near normal temps Wednesday to a little
above Thursday. X

AVIATION...
Focus remains on any shower/thunderstorm development this evening
with the best threat 00-04Z for KCXP/KRNO/KSVE, but still only
20%. The Sierra terminals have a smaller threat (10%) as the
crest is currently switching to SW winds which limits development
there. Peak gusts to 40 kts near storms and general VFR
conditions are expected.

Friday will see breezy SW winds and VFR conditions. Expect peak
gusts of 25-35 kts at area terminals with some mtn wave
turbulence. No LLWS is expected due to good mixing. Showers and
thunderstorms return for the weekend with the best threat north of
I-80. Some PL are possible in the heavier showers/storms with
lower snow levels near 6000 feet, but no runway accumulation is
expected. X

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

$$

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



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