Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 252010

Area Forecast Discussion
National Weather Service Reno NV
110 PM PDT Mon Sep 25 2017


Periods of high clouds and light valley winds are expected
through the week. Gusty east winds are possible near the ridge
lines tonight and Tuesday night. A ridge of high pressure along
the west coast is gradually getting stronger leading to a slow
warming trend. A weak upper level wave will brush by the region by
late in the weekend and could bring a few showers to the Oregon



Light winds in valleys
Warming by end of the week
Few showers next week

Little has changed with the forecast thinking this cycle. A ridge
to the west and a trough to the east will keep a north to
northeast flow over the area through Thursday. This will result in
below average temperatures and fairly light winds in the valleys.
A north to south jet aloft and an increased gradient in the mid
levels courtesy of the interaction between the ridge and a closed
low over the Desert Southwest will keep east-northeast flow
stronger at the ridges through Tuesday night.

Flow weakens at all levels Wednesday then becomes more westerly
Thursday as the ridge is flattened and another long wave trough
moves toward the west coast. This will allow temperatures to rise
to around normal by Thursday/Friday.

The forecast models begin to diverge by the weekend with the GFS a
little more aggressive with an upper trough digging east into
southeast Oregon and north central Nevada...but does not produce
much in the way of precipitation. The ECMWF trough is not as
deep...but brings some light QPF to areas near the Oregon border.

By Monday the GFS continues to deepen the trough and dig it a
little farther back to the west with precipitation near the
Oregon border and some cooling. Meanwhile...the ECMWF develops a
deeper low along the Oregon coast. That would be warmer for our
area and with better precipitation chances in northeast
California. Since the models are in significant disagreement
regarding pattern evolution...we will opt to keep pops just below
slight chance for now and show and increase in cloud cover and
minimal cooling for early next week.



VFR conditions with occasional high clouds are expected through
late this week. The exception will be patchy morning fog in the
Martis and Sierra Valleys that may produce periods of IFR/MVFR
visibility. Light winds are expected at the TAF sites and in the
rest of the valleys as well. Stronger east winds are possible over
the ridges...especially the Sierra...through Tuesday night. Areas
of turbulence are possible above the ridgelines and to the
west...or downstream...of each ridge line.


.REV Watches/Warnings/Advisories...


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