Area forecast discussion
National Weather Service Las Vegas Nevada
340 am PDT sun may 19 2013
Synopsis...an upper level disturbance will produce scattered
showers and a few thunderstorms over east central Nevada today while
dry and mild conditions continue across the rest of the region. A
weak cold front will then bring local gusty north winds tonight
and Monday with slightly cooler temperatures. A storm moving into
the Pacific northwest by Tuesday will bring persistent breezy
conditions to the region from middle week into the Holiday weekend
with temperatures near seasonal normals.
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Short term...today through Tuesday night...the forecast area will
remain under a northwest flow aloft on the back side of a broad
trough rolling across the Rocky Mountain states into the plains.
This will allow disturbances to slide down through the Great Basin
today and tonight. A disturbance could be seen on satellite loops
extending over northern Nevada this morning with additional energy
upstream across western Oregon and Washington. The latest
operational models are in good agreement at tracking this energy
across eastern Nevada and southwest Utah this afternoon and tonight
before it dives into Arizona and New Mexico early Monday. Sufficient
middle level moisture...instability and dynamic support will be over
northern and eastern Lincoln County to produce isolated to scattered
showers and a few thunderstorms. Convection will end this evening as
a dry front pushes down through the southern Great Basin and Mojave
Desert tonight with north winds developing behind it. The latest
high resolution models indicate speeds will generally be in the
15-25 miles per hour range. Winds will be stronger down the Colorado River
valley and persistent gusts around 35 miles per hour will be possible from
Laughlin to Needles Monday morning through early afternoon. This
will create fire weather concerns for this area and a Fire Weather
Watch remains in effect. Wind speeds should decrease fairly quickly
Monday afternoon as the surface pressure gradient relaxes along the
eastern Nevada border and a shortwave ridge between low pressure
systems moves overhead Monday night and early Tuesday. Attention
will then turn to a deep low pressure system as it drops into the
Pacific northwest and brushes northwest Nevada Tuesday night. High
temperatures will only vary 3-5 degrees during the period.
Long term...models in good agreement in showing a deep area of low
pressure remaining nearly stationary over Oregon Wednesday through
Friday. The main impacts from this system for our area will be a
fairly long period of gusty southwest winds. We really are not
expecting to see much of a temperature drop with this
system...except possibly the far northwest portions of the County Warning Area. The
remainder of the area will continue to see temperatures a few
degrees above normal. Precipitation also looks to remain north of
the area and the gusty winds and dry conditions will lead to an
increased concern for fire weather hazards. By Friday night this low
is forecast to lift northeast with a baggy weak trough remaining
over the West Coast through the weekend. This should bring lighter
winds to the area...but keep temperatures a few degrees above
normal.
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Aviation...for McCarran...southwest winds around 10 kts to continue
through middle morning before turning more northwest after 19z with
speeds up to 10 kts. Winds are forecast to turn north to northeast
after 00z Monday with speeds up to 15kts at times. Few-scattered clouds
around 10k feet this afternoon and evening and there will be a
slight chance of a shower or thunderstorm in the Mormon Mesa
corridor.
For the rest of southern Nevada...northwest Arizona...and southeast
California...winds over much of the area will be west to northwest
through much of today as a weak system passes through the area. Most
areas will see wind speeds 10-15 kts with a few locations seeing
winds up to 20 kts. Lincoln County will see the greatest coverage of
clouds with mainly scattered-broken 10-12k feet and a slight chance of a
thunderstorm. The remainder of the area will see skc-few120.
&&
Fire weather...a dry cold front will push down through southern
Nevada and northwest Arizona Sunday night/early Monday. This will
bring moderate north winds to much of the region with the strongest
winds along the Colorado River valley. Wind gusts to near 40 miles per hour are
possible along the stretch from Laughlin-Bullhead City to Needles
late Monday morning through early afternoon. This will create the
potential for critical fire weather condition as relative humidity
values fall below 15 percent. A Fire Weather Watch is in effect for
this period for the Colorado River zones.
&&
Vef watches/warnings/advisories...
Nevada...Fire Weather Watch from Monday morning through Monday afternoon
for nvz466.
Arizona...Fire Weather Watch from Monday morning through Monday afternoon
for azz101.
California...Fire Weather Watch from Monday morning through Monday afternoon
for caz229.
&&
$$
Adair/gorelow
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