Area Forecast Discussion
Issued by NWS Reno, NV
FXUS65 KREV 242039
Area Forecast Discussion
National Weather Service Reno NV
139 PM PDT SAT SEP 24 2016
High pressure builds along the West Coast this weekend,
strengthening and shifting inland by the early part of next week.
This will bring dry conditions with near average temperatures this
weekend warming to above average on Monday. Winds will mainly be
light Sunday through Wednesday with breezy afternoon conditions
returning for the end of next week.
No changes were made to the ongoing forecast as a ridge of high
pressure builds along the west coast this weekend. Northerly flow
is transitioning to the northeast then east by tonight. Breezy
east winds with gusts of 25 to 35 mph are possible along Sierra
ridges overnight, otherwise winds will be light. The easterly flow
will limit mixing, slowing the warming trend this weekend. Once
the ridge axis shifts eastward, mixing will be improved with highs
around 10 degrees above normal Monday and Tuesday.
One item of note is a piece of energy which broke off of the area
of low pressure that passed over the Sierra and northwest Nevada
on Thursday. This feature is retrograding under the ridge with a
closed circulation setting up around Baja by the end of the
weekend. It has no implication on the weather in the near term
period, but could bring changes to the forecast midweek. See the
long term below for additional details. -Dawn
.LONG TERM...Wednesday through Saturday...
The low near Baja lifts northeast Wednesday in response to a
trough beginning to dig south near the Pacific Northwest coast.
The low weakens as it lifts and is absorbed into the flow, but
does have moisture entrained within it and will increase
instability. While the overall idea has been to keep this
feature lifting through far southern Nevada into Utah, the latest
trends have been slightly more westward than previous model runs.
Ensembles are all over the place, which isn`t surprising given how
this is evolving and would expect to see changes in solutions the
next several days. For now, will maintain the 10 percent chance
for precip mainly south of Highway 50 Wednesday afternoon/evening,
which does not include a mention of weather in the forecast.
The trough off the coast continues to dig south and begins to
shift inland along the coast toward the end of the week. This
will lead to increased afternoon and evening breezes Thursday
through Saturday. There have been timing and position differences
in how far south the trough will dig and exactly when it may move
onshore. At this point it appears the bulk of the moisture will
remain in the Pacific Northwest, but there is a chance showers may
develop along the southern end in extreme northern CA/NV next
weekend. Negative height anomalies suggest that a cooling trend
can be anticipated the first few days of October with numerical
guidance hinting at high temperatures 5 to 10 degrees below
VFR conditions with mostly clear skies will continue through the
weekend. Northerly winds will become easterly by tonight with
gusts 20 to 30 kts along Sierra ridges overnight. This may bring
some mountain wave activity to the west side of the Sierra. Winds
will be light surface and aloft Sunday into the first half of next
week. Southwest winds will be increasing midweek onward ahead of
an approaching trough. -Dawn
For more information from the National Weather Service visit...