Area Forecast Discussion
Issued by NWS Reno, NV
FXUS65 KREV 251452 AAA
Area Forecast Discussion...UPDATED
National Weather Service Reno NV
752 AM PDT MON JUL 25 2016
Quick update to add haze to the forecast near and south of Highway
50 as smoke from the Sobranes Fire in Monterey County moves in.
This fire will continue to burn actively the next couple days, but
have only added the haze through this evening. As the flow aloft
from the southwest becomes lighter and eventually goes flat, we
should see less smoke impacts east of the Sierra Crest as the week
goes on regardless of how it burns.
Hot and dry conditions with mainly light late day breezes are
expected for the next several days as strong high pressure builds
into the Great Basin. The warmest temperatures are likely Wednesday
through Friday, with slight cooling next weekend. Some increase in
moisture will lead to a few thunderstorms later this week through
.PREVIOUS DISCUSSION... /Issued 214 AM PDT MON JUL 25 2016/
The much-advertised strong ridge of high pressure will expand
across the Great Basin and send temperatures upward during the
next few days, with highs pushing into the triple digits for many
lower elevation sites. By Wednesday, some of the warmer valleys in
West Central NV may reach 105 degrees. Low humidity will continue
each day with afternoon minimums in the single digits for most
locations and around 10% near the Sierra, and marginal to poor
humidity recoveries each night.
Generally light late day breezes are expected through midweek,
with gusts mainly below 25 mph. Little to no cloud cover is
expected through Tuesday, except for areas south of US-50 where a
modest amount of mid level moisture and weak convergent flow may
lead to a little more flat cumulus development each afternoon.
With further heating Wednesday, cumulus buildups should increase
especially for Mono-Mineral Counties, but the potential for
thunderstorms remains slim due to limited forcing and continued
warm temperatures aloft. MJD
LONG TERM...Thursday through Sunday...
Another model cycle...another change. Previously the ECMWF had
started to trend toward the GFS with developing a weak trough
along the CA coast. This would have allowed moisture to increase
through the early part of the extended period...with a better
chance for convection by Friday and Saturday.
The latest ECMWF has largely abandoned that solution and reverted to
its prior solution of maintaining a ridge over much of the region
through at least Saturday. The GEFS ensemble members now show more
spread with some preferring the GFS solution...but not developing
the trough until late Friday night. A few GEFS ensemble members more
closely resemble the ECMWF.
So here`s the bottom line. The forecast was changed very little to
avoid flip-flopping. We had only slight chance pops anyway and this
is still reasonable. The GFS is being consistent...but we are not
inclined to go completely to its solution. The ECMWF solution...even
with its lack of moisture advection could still lead to isolated
convection due to the shear build up of low to mid level heating and
pooling of mid level moisture.
Oh...the heat; surface temperatures in the valleys below 5000 feet
should reach the 100-106 range by Thursday and possibly Friday. The
Sierra valleys reach the upper 80s to lower 90s. Some cooling is
possible...to only a few degrees above normal by Sunday as a trough
edges closer to the region and cooling develops aloft. This trough
would also keep most convection south of Highway 50 by Sunday. 20
Continued dry with afternoon zephyr breezes today through
Wednesday. Surface gusts east of the Sierra could reach near 20
knots each day.
Forecast models are at odds beyond Wednesday...but most hint at some
increase in afternoon cumulus buildups...especially south of
Highway 50. There is a slight chance of thunderstorms developing
as early as Thursday...but better chances for the Friday/Saturday
time frame. This would lead to turbulence and gusty surface winds
with possible restrictions to visibility due to blowing dust. 20
For more information from the National Weather Service visit...