Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Las Vegas Nevada
244 am PDT Sat Aug 23 2014
Synopsis...mostly dry weather is expected through the beginning of
the week...with thunderstorm chances limited to Lincoln County today
and Mohave County Monday night and Tuesday. Temperatures will be
near normal for late August.
Short term...through Monday night...early morning satellite loop
showed main low center over the northern Great Basin moving slowly
east. The tail of a vorticity lobe plus a surface cold front over
northern Nevada were combining to produce thunderstorms near the
White Pine/Lincoln County line. The overall progression of the
storms was slowly to the east. Surface observation showed breezy to locally
windy conditions with seasonable temperatures. As the main low
slowly moves away...thunderstorm chances will come to an end by this
evening. The longwave trough will reload Sunday as more energy dives
down from British Columbia into the Pacific northwest...with our
area remaining dry with afternoon southerly breezes. By Monday night
this new low will be moving from the northern Great Basin into the
northern rockies...and tapping into subtropical moisture coming up
from Mexico. Recent model trends have taken this moisture plume a
little farther west...so introduced small probability of precipitation into northern Mohave
County Monday night. Temperatures will be within a few degrees of
normal through the period.
Long term...Tuesday through Saturday.
Models have been fairly consistent over the past 24 hours showing a
middle/upper level trough digging into the Great Basin Monday afternoon
into Tuesday. The GFS continues to be the weakest with this
system...but overall the models are in fairly good agreement. A big
question mark is the potential of a tropical system moving north
with some moisture possibly getting pulled into the base of the
trough. The models are showing an increase in precipitable water values moving into
the far southern areas of the County Warning Area along with some increased
instability. Have gone ahead and increased probability of precipitation for Mohave County
Tuesday afternoon and again Wednesday as the moisture may stick
around a little as high pressure starts to build into the area.
There is some indication that moisture may stick around into the
weekend over the far southern areas of the County Warning Area and although no
particular day looks like a widespread thunderstorm day we should
still see at least a slight chance each afternoon. Temperatures are
forecast to be slightly below normal Tuesday and Wednesday...but
climb to slightly above normal by the weekend.
Aviation...for McCarran...aside from brief periods of easterly
winds each afternoon...no operationally significant weather is
expected through the weekend.
For the rest of southern Nevada...northwest Arizona...and southeast
California...aside from a few thunderstorms over Lincoln County
today...no operationally significant weather is expected through the
Spotter information statement...spotter activation is not expected
at this time.
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