Scientific Forecaster Discussion
fxus65 kvef 221711
Area forecast discussion
National Weather Service Las Vegas Nevada
1011 am PDT Tue Oct 22 2019
Synopsis...dry and seasonal weather is expected to continue
through the work week with periods of breezy north winds,
particularly on Thursday. Temperatures will climb through Wednesday
before cooling to near normal for the latter half of the week and
into the weekend.
Update...overall the forecast is on track, with mild
temperatures and clear skies expected today. There is a stiff north
breeze down the lower Colorado River valley that will continue
through most of the day. That said, wind from Laughlin/Bullhead City
southward to Lake Havasu have been increased to account for stronger
than advertised winds there. Elsewhere, winds will be light.
Discussion...today through next Tuesday.
Above-average temperatures and gusty afternoons will continue
through Tuesday as a result of the position of a longwave trough
to our east and ridging off the coast of California to our west.
What the result looks like for US is a dry northwesterly flow that
will help raise temperatures to 5-8 degrees above average on
Wednesday and perpetuate afternoon northerly winds, particularly
down the Colorado River valley where northerly winds tend to
topographically funnel and enhance.
The main story this week, though, centers around Thursday. The
area of high pressure off the coast of California will begin its
progression inland Thursday morning, resulting in the northerly
bending of the overhead flow. Concurrently, a disturbance will
slide down the trough to our east, resulting in a dry cold frontal
passage. These events happening simultaneously will cause a
significant tightening of gradients over southern Nevada and
northwestern Arizona, and thus, a northerly wind event. European model (ecmwf)
ensemble members indicate northerly gusts 25-30 mph in the Las
Vegas Valley and gusts in the mid-40s down the Colorado River
valley during the day on Thursday. Winds are expected to die down
through the overnight hours with lingering gusts down the Colorado
River valley possible. High temperatures Thursday will drop 6-10
degrees back to seasonal normals.
As the aforementioned area of high pressure moves overhead, winds
will calm and temperatures will slowly increase going into the
weekend. This recovery is expected to be brief as the next weather
Still low confidence at this time regarding the early-next-week
weather system as models have yet to resolve timing or placement of
the next evolving trough. Regardless, models are in agreement that
this system is mostly dry, so anticipated impacts include a drop in
temperatures and gusty winds.
Aviation...for McCarran...another minimal impact day today with
generally light winds below 8 kts throughout the taf period. Typical
diurnal patterns are expected with a light east-northeasterly
influence in the afternoon and return to southwest for the evening.
No cloud cover expected.
For the rest of southern Nevada, southwest Arizona and southeast
California...minimal impacts are expected today for Las Vegas Valley
terminals as well as kbih and kdag. However, north winds today
across the Colorado River valley are expected to become breezy
resulting in keed/kifp seeing elevated winds after 16z. Kifp should
see gust potential up to about 25 kts this afternoon. Otherwise, no
other impacts expected.
Spotter information statement...spotters are encouraged to report
any significant weather or impacts according to Standard operating