Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 181025

Area Forecast Discussion
National Weather Service Reno NV
325 AM PDT Thu Jul 18 2019


Typical mid-summer heat is expected through the upcoming week,
with Sunday and Monday most likely to be the warmest days. A
brief thunderstorm or two may develop over western Lassen County
today and Friday, otherwise dry conditions will prevail through
Saturday. Conditions may become more favorable for afternoon
thunderstorms starting Sunday and continuing through next week.



No notable changes were made for the short term, which will
feature primarily dry conditions with daytime highs near or
slightly above average, as we approach the warmest part of the
year based on local climatology.

For today and Friday, afternoon cumulus buildups are most likely
in the typical convergence zones of northern/western Lassen County
and Mineral-Mono counties, then shifting to mainly Mineral-Mono
counties by Saturday. There`s a small potential for a couple of
brief late afternoon cells forming just east of Lassen Peak today
and Friday, although mid level temperatures appear to be warm
enough to cap most convective development.

Winds today look to be similar to yesterday with gusts 25-30 mph
as a shortwave brushes across the Pacific Northwest. Lighter late
day breezes are expected Friday-Saturday as a ridge of high
pressure builds across more of the Great Basin, resulting in
weaker flow across the Sierra and western NV. MJD

.LONG TERM...Sunday through Wednesday...

The only changes we made to the extended forecast this morning
were very minimal; mainly making some very minor adjustments to
low temperatures.

Most of the model solutions are in line with the previous few
cycles. The simulations start to try building a ridge into the
southwestern U.S. That would lead to increased high temperatures
over our region each day during the extended period; highs could
reach the mid 90s to near 100 each day in the lower valleys and
the 80s in the Sierra valleys...which is a bit above normal.

The building ridge would also mean increased mid-level moisture
moving north into our area along the western periphery of the
ridge. This increased moisture...along with increased low-mid
level instability...would support increasing chances for
thunderstorms each day starting as early as Sunday. Sunday...being
the first day for thunderstorms...we would expect mainly dry
thunderstorms while the chances for showers increase starting

Now some of the solutions have thrown a monkey wrench into the
works this morning. The operational GFS...and a few of its
ensemble members...are trying to squash the ridge back to the
southeast and drive a longwave trough back into the west coast
late Tuesday or early Wednesday. This would effectively end most
of the thunderstorm chances west of a line from Winnemucca to
Bridgeport for Tuesday and Wednesday. While we must consider this
solution...most models are not trending this way. And it must be
acknowledged this has been the pattern much of the summer thus

This change in a few models lowers confidence in thunderstorm
chances next week...but we have opted to leave the forecast
virtually unchanged for now. We will see what subsequent model
cycles hold in store. XX



VFR conditions continue for the next few days, with wind gusts
20-25 kt for the main terminals mainly from 21-04Z today, then
becoming lighter for Friday-Sunday. Shallow fog remains possible
in the Martis Valley near KTRK this morning and again Friday
morning, although aviation-related impacts look minimal. MJD


.REV Watches/Warnings/Advisories...


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