Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus65 kvef 230945 

Area forecast discussion
National Weather Service Las Vegas Nevada
245 am PDT Wed Oct 23 2019

Synopsis...a low pressure system clipping the region will start
increasing northerly winds today and peak on Thursday, especially
down the Colorado River valley. Another dry system and cold front
may pass over the weekend, proving another round of gusty north

Discussion...through Tuesday.

The main focus through the entire forecast period is gusty winds
and fire weather concerns.

An upper-level trough digging down from Montana to The Four
Corners region today into Thursday will tighten up north-south
thermal and pressure gradients starting today. Expect winds to
respond in the Colorado River valley and begin their ramp up
today and peak Thursday morning. The strongest gusts look to be in
the usual areas: the Overton Arm down to Virgin Basin on Lake
Mead, and from Cottonwood Cove to Lake Havasu in the Colorado
River Valley.

High pressure will nose in for Friday, though some breezes will
linger in the Colorado River valley. The next trough enters the northwest
US Saturday and digs southward through the region Sunday. While
there is general agreement that this next one will have a further
westward track, with the European model (ecmwf) being significantly more westward
than the GFS.

With the rather active pattern, temperatures will Ebb and flow
around seasonal normals, with cooler-than-normal temperatures
behind cold fronts, and warmer-than-normal temperatures ahead of

Fire weather...critical fire weather is expected down the
Colorado River valley on Thursday. Winds will relax across the
region for Friday and Saturday, but conditions will remain rather
dry. Another system could bring more widespread gusty winds and
elevated fire danger to the region Sunday.

Aviation...for McCarran...VFR with light and variable winds
throughout the morning hours today before a shift to the northeast
between 020-060 occurs shortly after mid-day. Winds should pick up
at that point as well with an increase in gusts to 18-20 kts.
Lower confidence in the overnight period as there are some
indications that winds could stay gusty or become light and
variable. However, a more substantial increase in winds, again
out of the north- northeast, is expected Thursday. Opted to keep
the elevated winds in the taf for now but amendments may be needed
during this timeframe.

For the rest of southern Nevada, northwest Arizona and southeast
California...the focus for wind impacts today will again be along
the Colorado River and include the keed/kifp sites. Gust potential
up to 25-30 kts will be possible at times this afternoon. Las
Vegas Valley sites of kvgt/khnd as well as kbih will also see an
uptick in winds this afternoon but only should see gusts to 20-25
kts or so. Minimal impacts expected for kdag today.


Spotter information statement...spotters are encouraged to report
any significant weather or impacts according to Standard operating


National Weather Service Glossary of Abbreviations