Area Forecast Discussion Issued by NWS Las Vegas, NV
000
FXUS65 KVEF 190935
AFDVEF
Area Forecast Discussion
National Weather Service Las Vegas NV
235 AM PDT Tue Mar 19 2024
.SYNOPSIS...Chances of afternoon showers and isolated thunderstorms
continue for northwestern Arizona and portions of far southern
Nevada and far southeastern California through the evening.
Conditions will dry out midweek as temperatures increase above
seasonal averages. An additional broad area of low pressure will
return gusty winds, cooler temperatures, and chances of
precipitation to the region this weekend.
&&
.SHORT TERM...Today through Friday.
A broad area of low pressure that has essentially parked over the
region since last week will shift eastward over central Arizona once
again today. Precipitable water (PWAT) values over southern Nevada,
southeastern California, and northwestern Arizona continue to range
from 0.50" to 0.60" this morning. Through the day today, this
moisture will slowly diminish as the low continues to shift eastward
out of our forecast area. However, before it fully exits, persistent
vorticity advection coupled with between 250 and 500 J/kg of CAPE
across Mohave County and the lower Colorado River Valley will return
chances of showers and isolated thunderstorms to the area this
afternoon. Best chances will exist in central and southern Mohave
County, though cannot rule out instances of shower activity in
southern Clark and eastern San Bernardino counties. Rain totals will
generally remain less than 0.25", though rain rates will be higher
beneath thunderstorms that form as well as over the higher terrain,
with up to 0.50" locally possible. Along the northern and western
edges of the moisture field, DCAPE values could exceed 500 J/kg,
resulting in gusty winds up to 40 mph with thunderstorm development -
similar to yesterday. Shower activity will subside after sunset.
On Wednesday, far eastern portions of Mohave County will have
minimal chances of shower activity as the aforementioned area of low
pressure opens up and pushes into New Mexico. Otherwise, a ridge of
high pressure will finally set up over the Desert Southwest, which
will allow temperatures to increase to above-average through the
remainder of the work week. 30% chance of Las Vegas experiencing the
first 80 degree day of the year on Friday.
Chances of 80F in Las Vegas on Thursday and Friday have come down
somewhat from the previous forecast package, likely due to a
premature squashing of the midweek ridge as well as the addition of
cloud debris from a broad area of low pressure pushing into the
Pacific Northwest. More on this in the LONG TERM section.
.LONG TERM...Saturday through Monday.
There is decent agreement in long range ensemble means that a broad
trough will push inland over the weekend, though there continues to
be disagreement in the strength and positioning of the trough as it
moves east. All solutions for this weekend would bring increasing
southwest winds to the region with increasing confidence for
widespread impactful wind gusts. Saturday currently shows the
highest and most widespread potential for impactful winds as
ensembles show moderate to high probabilities for the typical windy
south-southwest belt from the western Mojave Desert through southern
Nevada into northwest Arizona. Will need to watch for downslope
potential near the Sierra and Spring Mountains; however, downslope
winds will depend on the exact orientation of the trough as it moves
inland. Breezy winds will continue into Sunday, particularly in the
western Mojave Desert where EFIs are highlighting anomalous winds.
Models diverge in how and if the upper level trough will continue to
progress eastward early next week. Winds should diminish for the
start of the work week compared to the weekend, but the threat for
impactful winds continuing into Monday is not zero.
Lower confidence in impacts outside of winds for the extended
period. Precipitation is possible through the period, especially in
the Sierra and southern Great Basin; however, amounts and
precipitation potential will depend on the exact trajectory of the
system and how quickly it deepens once is moves inland. High
confidence that temperatures will cool down with well below normal
temperatures early next week.
&&
.AVIATION...For Harry Reid...Light winds this morning will become
northeast after 16z with speeds generally between 6-8 knots;
however, occasional gusts up to 12 knots can`t be ruled out in the
afternoon. Winds will become light and variable around sunset and
gradually shift more to the southwest around 6 knots by mid
evening and overnight. FEW-SCT clouds around 10k feet with
occasional clouds down to 8k feet at times. Some shower and
thunderstorm activity is possible this afternoon across northwest
Arizona, but not expected to impact airport operations.
For the rest of southern Nevada, northwest Arizona and southeast
California...Winds will generally remain under 10 knots across the
region with wind direction favoring a northwest to northeast
direction. Most TAF sites will see FEW-SCT clouds 8-10k feet. A few
showers and thunderstorms are expected to develop this afternoon
over NW Arizona and there is some potential outflow from these
storms may produce erratic, gusty conditions at KIFP and potentially
KEED as well.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
SHORT TERM...Varian
LONG TERM...Nickerson
AVIATION...Gorelow
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