Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Las Vegas Nevada
808 PM PST Sat Jan 31 2015
Synopsis...a dry northwest flow will develop over the region
tonight and persist through much of the coming week with
temperatures running well above normal.
Update...clouds have completely shredded out this evening. Going
forecast supports this trend so no update planned at this time.
245 PM PST Sat Jan 31 2015
Short term...through Monday night.
Dry northerly flow could be seen on satellite loops and surface
observations spreading over southern Nevada in the wake of the low
pressure system digging down into northern Mexico. Clouds will
continue to diminish from north to south through early evening
leaving a mostly clear sky across the region overnight. Any
potential for fog should be confined to southeast Mohave County as
north breezes dry out the boundary layer for most zones. Upstream
surface dewpoints were in the middle 20s across south central Nevada
and this drier air mass will spread down over most of the forecast
area tonight through Sunday morning. High res models indicate north
breezes will persist along the Colorado River valley Sunday morning
then diminish in the afternoon. Light winds can then be expected
across the region through Monday under a northwest flow aloft with a
ridge holding along the West Coast. Some middle and high level clouds
will move across the region at times...courtesy of moisture plume
off the Pacific northwest...but there will be plenty of sunshine
Sunday into Monday. Temperatures will increase slightly from Sunday
to Monday with readings running several degrees above normal.
Long term...Tuesday through Friday.
Models continue to stay in agreement with each other through this
period. A ridge located along the California coast Tuesday morning
will slide eastward...amplifying Wednesday into Thursday. Guidance
continues to show this ridge breaking down as an atmospheric river
pushes into central and northern California. Showers will be
possible in the sierras on Friday night into Saturday as the
atmospheric river slides southward. Increased probability of precipitation to allow for a
chance of showers in the sierras during this timeframe. The
potential for gusty downslope winds is also noteworthy Friday
through Saturday morning as a wave is prognosticated to break across the
region. At this time the sierras look to be the most favorable area
but perhaps breezy conditions will also affect the Inyo and Spring
Mountains Friday evening into Saturday morning.
Kept temperatures similar to what they were in the previous
package...but bumped high temperatures down a degree or two Friday into the
weekend with the possibility of an increase in cloud cover. Guidance
continues to suggest that temperatures will be well above seasonal
normals through the end of the period...perhaps as much as 10-12
degrees above normal. Records continue to look out of reach...but
will be Worth watching.
Aviation...for McCarran...a dry northerly flow aloft spreading
over southern Nevada will lead to a clearing sky this evening. Wind
speeds should drop below 9 knots after sunset as the direction
becomes predominantly northwest. Variable winds with speeds less
than 6 knots can be expected Sunday.
For the rest of southern Nevada...northwest Arizona...and southeast
California...clouds will clear from northwest to southeast this
evening. Areas of fog may develop south and east of Kingman Arizona
overnight through early Sunday morning. North winds gusts 20-30
knots can be expected along the Colorado River valley from
Laughlin-Bullhead City to Needles through late Sunday morning. Light
Spotter information statement...spotter activation is not expected
at this time.
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