562
FXUS65 KREV 240912
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
212 AM PDT Tue Sep 24 2024

.SYNOPSIS...

* A dry and mild pattern with weak RH recoveries on mid-slopes and
  ridgetops across western NV is expected this week.

* Increased southwest winds are in the forecast on Wednesday and
  Saturday ahead of a couple of dry frontal passages during this
  week.

* Cool nights with afternoon highs generally ranging 4-8 degrees
  above seasonal averages are expected going into the start of
  the weekend.

&&

.DISCUSSION...

The latest upper air RAP analysis for this morning shows an upper
air ridge over the western CONUS with an upper air low residing off
the coast of southern CA. Current satellite imagery and surface
observations report dry conditions and light winds across the region
underneath mostly clear skies this morning. Going through the
remainder of today, forecast guidance shows the upper air ridge
progressing eastward which will allow the aforementioned low to open
up into a trough as it merges back into the jet stream by the
evening hours. As a result of this upper air setup, dry conditions
look to persist across the region with generally light winds in
the forecast underneath mostly sunny skies. Daytime high
temperatures for today look to range between the lower and upper
80s in the valley areas while Sierra Mountain communities in
higher elevations have highs ranging between the lower 60s and the
upper 70s. Tonight`s low temperatures look to range between the
upper 40s and the upper 50s in the valley areas while the Sierra
Mountain communities expect to be in the upper 30s to middle 40s
range.

For tomorrow, models are showing the CWA`s upper air flow taking
a southwesterly direction in the Wednesday afternoon and evening
hours due to the position of the upper air trough. This will lead
to a dry frontal passage across the CWA at the surface during the
evening hours with some increased winds out of the southwest ahead
of the front in the afternoon. The quickest winds look to be seen
in wind prone areas as well as in northern areas along the OR
border. The latest NBM probabilities show around a 70-80% of wind
gusts of 30 mph or higher on Wednesday afternoon within Eastern
Modoc, Northeastern Lassen, and Northern Washoe Counties. As
minimum relative humidity values in these areas continue to be
forecast in the middle to upper teens, elevated to localized
critical fire weather conditions look to be possible during the
afternoon hours in these areas. Will continue to monitor this in
case the critical fire weather conditions look to be become more
widespread in upcoming forecast packages.

On Thursday, slightly cooler temperatures are expected within the
region behind the cold front with lighter winds. These winds look to
persist into Friday as well with daytime temperatures rebounding
a bit by warming back up. On Saturday, forecast guidance shows
another potential upper air trough moving towards the CWA which
will cause yet another dry frontal passage at the surface during
the day. While winds are expected to increase during the
afternoon, the latest NBM guidance shows only around a 10% chance
for afternoon wind gusts to reach 25 mph or greater in areas
closer to the OR border which is lower than previous runs. Will
continue to monitor this in case the probabilities creep back up
and cause fire weather concerns to increase again.

Going into the beginning of next week, dry conditions expect to
continue across the CWA behind the front with lighter winds on
both Sunday and Monday. Ensemble guidance does look to show some
signal for enhanced winds once again in the area on next Tuesday
with the arrival of another potential trough. While forecast
confidence at this time is low this far out, will watch to see if
this signal is in future forecast runs going forward. -078

&&

.AVIATION...

VFR conditions are expected at all REV TAF sites throughout today
underneath mostly clear skies. On Wednesday, southwesterly winds are
forecast to pick up a bit with afternoon gusts up to around 20-25
kts that may yield areas of turbulence along and east of the Sierra
as a dry frontal passage tracks through the region. Very low chances
for precipitation are also currently in the forecast for the region
through the remainder of this week. -078

&&

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

$$