151
FXUS65 KVEF 251951
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1251 PM PDT Wed Sep 25 2024

.SYNOPSIS...Temperatures will continue to increase through the end
of the week resulting in increased HeatRisk for portions of our
forecast area. Beginning Thursday morning, an Excessive Heat
Warning will be in effect for the Colorado River Valley through
Saturday.

&&

.SHORT TERM...The Rest of Today through Friday.

Breezy southwest winds developed across the region this afternoon as
a shortwave passed to the north. No impacts were reported so far
through the afternoon with these winds as gusts remained around 20-
25 MPH in most areas where gusts were able to develop. Winds will
diminish this evening and light winds are expected the rest of the
work week.

The ridge that was knocked backs lightly by the passing system in
the Northern Plains will build back westward into the region the
rest of the week. This will allow for increasing temperatures
through the period. Above normal temperatures are likely across the
region through the rest of the work week. Heat Risk increases with
the warming temperatures with Major HeatRisk (level 3 of 4) in the
Colorado River Valley on Thursday. On Friday, Major Heat Risk (3 of
4 ) expands into pockets of southern Mohave County, eastern San
Bernardino including Yucca Valley, and Death Valley. An Excessive
Heat Warning goes into effect for the Colorado River Valley
beginning Thursday morning, and if Major Heat Risk continues to
expand there may be a need to add parts of southern Mohave County
and San Bernardino County as temperatures continue to warm Friday
into the weekend. While this level of heat is generally not abnormal
for the Desert Southwest, it is unusual for this time of the year.
Given the fatigue of a long, hot summer on the body for a prolonged
time along with the brief cool down followed by this intense warm
up, the impact heat can be sneaky and swift if you are not prepared
or do not take precautions. Just because we have had temperatures
like this previously in the summer does not preclude the upcoming
heat from being dangerous.

.LONG TERM...Saturday through next Wednesday.

Saturday will be the hottest day of the forecast period as the
persistent upper-level area of high pressure centered over the Four
Corners region remains in place. The Excessive Heat Warning for the
Colorado River Valley (Lake Mead National Recreation Area and the
lower Colorado River Valley including Laughlin, Bullhead City, Fort
Mohave, Needles, and Lake Havasu City) will continue through
Saturday. We will continue to assess whether or not it needs to be
extended an additional day as we move through the week. Chances of
Las Vegas reaching 100 degrees are up to 90 percent on Saturday.
This is noteworthy, because 2024 currently ties the record number of
100-degree days with 1947 (with 100 days). If Las Vegas observes 100
again this week, then 2024 will break this record.

Through the week, a closed low will meander off the coast of
southern California. Over the weekend, this low will begin to move
inland. As it moves inland, it will weaken into an open wave and
sucked into the flow of the aforementioned upper-level high, pushing
it clockwise out of our area. Little, if any, moisture is associated
with this system, but the subtle drop in upper-level heights will
work to decrease temperatures by a few degrees. Note that the upper-
level high will remain in place, so temperatures will continue to
range 5-8 degrees above seasonal averages through midweek despite
the minor temperature drop.

&&

.AVIATION...For Harry Reid...No significant clouds, winds, or
weather expected through Friday.

For the rest of southern Nevada, northwest Arizona and southeast
California...Diurnal winds generally 10 knots or less are expected
at most regional TAF sites through Friday. The exception will be
KBIH, where south winds gusting up to 25 knots will develop this
afternoon and end around sunset. No significant clouds or weather
expected through Friday.

&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.

&&

$$

SHORT TERM...Nickerson
LONG TERM...Soulat
AVIATION...Morgan

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