858
FXUS65 KREV 100904
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
204 AM PDT Fri May 10 2024

.SYNOPSIS...

A warming trend continues across the Sierra and western Nevada with
above average temperatures expected by this weekend. The potential
for showers and thunderstorms also returns to the Sierra this
afternoon with slight chances through the weekend and into early
next week.

&&

.DISCUSSION...

The latest RAP analysis shows an upper air low over NV/UT and just
east of the CWA causing a northeasterly flow over the CWA this
morning. Current satellite imagery and surface observations report
variable winds across the region with some broken high clouds
moving through Churchill, Mineral and Mono Counties while the
remainder of the CWA sees mostly clear skies. Model guidance shows
the northeasterly flow over the CWA continuing through the rest
of today as the upper air low moves southward to over the AZ/NV/UT
border and an upper air ridge progresses over the Pacific
Northwest. Down below, models project a surface low moving into
the San Francisco area during the afternoon which will allow for
east-northeasterly winds in the northern half of the CWA and
north-northeasterly winds in the southern half that may gust up
to around 25 mph. While dry conditions are expected for most of
the region, portions of the region in Mono and Mineral counties
see a 10-15% chance of isolated showers and thunderstorms during
the late afternoon and evening with light snow possible for the
highest elevations. Not much moisture is anticipated with these
precipitation chances. As for today`s temperature forecast,
daytime high temperatures look to range between the middle to
upper 50s in the Sierra crest and the middle 70s in western NV.
Overnight low temperatures expect to be in the 30s and 40s with
higher elevations being slightly colder.

Looking to the weekend, model guidance projects the forward
portion of the aforementioned ridge to move over the CWA by
Saturday afternoon as the upper air low progresses eastward over
the Four Corners region. The axis of this upper air ridge is
forecast to move over the CWA on Sunday afternoon as a weak trough
proceeds into the Pacific Northwest with a weak upper air low
feature west of southern CA making an appearance over the
Pacific Ocean. At the surface, chances for precipitation look to
have tapered off a bit in the latest model runs though there may
be a 10% chance or less for isolated showers and thunderstorms in
the Sierra on Saturday followed by a slight increase to 10-15% on
Sunday afternoon. The warming trend is expected to persist with
some portions of the region seeing daytime highs around the 80
degree mark on Saturday and then up to the middle 80s on Mother`s
Day. It may be a pleasant weekend for some outdoor activities, but
please stay weather aware in case this changes.

For the new work week, forecast guidance depicts the Pacific
Northwestern trough progressing eastward and clipping the
northern portion of the CWA as it passes on Monday morning. At the
same time, the low to the southwest continues a trek eastward
across southern CA on Monday with both it and the trough making
their way east and past the CWA on Tuesday morning. Models than
show north-northwesterly flow over the CWA with these features
having passed by with an larger upper air ridge trailing them on
Tuesday. On Wednesday, ensemble guidance continues to show the
ridge dominating the pattern over the western CONUS. Some solution
differences are seen on Thursday and Friday with the latest run of
the GFS Ensemble showing a western ridge and eastern trough
pattern over the CONUS. The ECMWF and Canadian Ensembles however
both show a potential Canadian low suppressing the western ridge
later in the week instead causing a zonal flow over the CWA. With
this upper air pattern evolution aloft, a slight chance (10-20%)
for precipitation may be seen during Monday afternoon and evening
for southern portions of the region with the remainder staying dry
as the above normal temperatures continue. There looks to be a
weak cold front passing through the region early Tuesday morning,
but daytime temperatures look to rebound quickly by Tuesday
afternoon as highs in the 70s and 80s do look to continue. The
warming trend is currently forecast to resume on Wednesday along
with region-wide dry conditions and continue through Friday though
will continue to monitor ensembles for better agreement going
forward. -078

&&

.AVIATION...

VFR conditions will continue at all TAF sites to end the week. For
expected winds, breezy easterly afternoon winds will develop later
this morning and into the afternoon before shifting to lighter flow
on Saturday. The more typical west winds are slated to return on
Sunday afternoon. Breezes will remain in the 20-25 kt range each
afternoon through the weekend, with the lightest winds on Saturday.
As for precipitation chances, most TAF sites look to stay mostly dry
going into the weekend with the exception of KMMH that may see a
slight chance (10-15%) for isolated showers late this afternoon and
Sunday afternoon with lesser chances on Saturday. -078

&&

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

$$