Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Las Vegas Nevada
935 am PDT Friday Aug 28 2015
Synopsis...thunderstorm coverage is expected to be less today and
even less on Saturday as drier air moves into the region.
Temperatures will remain several degrees above normal through Sunday
before falling back to slightly below normal by the beginning of
Update...current forecast looks good and no updates are needed at
this time. Little change noted in the morning model data with the
best moisture/instability across the eastern half of the area. Any
storms that develop should be mainly anchored to the higher terrain
and will be capable of localized heavy rain and gusty winds. Across
much of the forecast area...temperatures are currently running 3-5
degrees warmer than at this time yesterday except in the far western
areas where temperatures are similar or slightly cooler. Abundant sunshine
should allow for efficient surface heating today.
Previous discussion...210 am PDT...
Short term...through Sunday night... although thunderstorm coverage
is expected to be a little less today there is enough moisture and
instability to allow afternoon thunderstorms to develop. Precipitable water values
are only down slightly from yesterday and the afternoon forecasted
sounding only shows a weak cap aloft. Think that thunderstorms will
again develop this afternoon over mainly the higher terrain of
Mohave...Clark and eastern San Bernardino counties. Did expand probability of precipitation
further into San Bernardino County and left probability of precipitation alone everywhere
else. Heavy rain will again be possible with any storm. By
Saturday...it looks like the drier air will work over much of the
area leaving only slight chances of thunderstorms over extreme
eastern Mohave County. Most of the area will also see breezy
southwest winds Saturday and again Sunday as a trough moves onto the
West Coast. This will bring fairly warm temperatures through Sunday
before a cooling trend begins Monday.
Long term...Monday through Friday.
Mean trough axis forecast to be along the West Coast next week
leading to a dry southwest flow. High level moisture from the
subtropics gets tapped into with both the GFS/European model (ecmwf) showing a swath
of high clouds Monday night and Tuesday before that shifts east
Wednesday. Look for afternoon/evening breezes each day. Right now,
pattern does not look strong enough for wind headlines but that will
be monitored as we move closer to next week. Guidance has
temperatures dropping a degree or two each day between Monday and
Thursday with values at or slightly below normal.
Aviation...for McCarran...the area should see fairly light winds
today with a easterly component developing after 17z. Wind speeds up
to 7kts will be possible through the afternoon. Southwest winds 6-
7kts will develop after 03z this evening. Few-scattered clouds 10-12k feet
from late morning to early evening.
For the rest of southern Nevada...northwest Arizona...and southeast
California...isolated thunderstorms again today over the higher
terrain of Mohave...Clark...and eastern San Bernardino counties with
winds remaining under 10kts over most locations. Few-scattered clouds
around 10k feet this afternoon.
Spotter information statement...spotters are encouraged to report
any significant weather conditions according to Standard operating
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