602
FXUS65 KVEF 111937
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1237 PM PDT Tue Jun 11 2024

.SYNOPSIS...Hot and dry conditions continue over the next few
days. A slight decrease in temperatures is expected later this week
as low pressure passes to the south of the ridge, but temperatures
will remain above average. A more noticable cooldown and increased
winds are possible next week with a change in the weather pattern.
Uncertainty remains at this time regarding the intensity of the
cooldown and winds.

&&

.SHORT TERM...Tonight through Saturday

The primary weather concern in the short term is heat. A 500 mb
ridge with maximum heights around 595 dm is in place over the
southwest United States as a low pressure system spins off the
Southern California coast. The result is above average temperatures
at the surface and Moderate (Level 2) to Major (Level 3) HeatRisk
through Wednesday within the forecast area. Therefore, the Excessive
Heat Warning for sections of Inyo, Mohave, southern Nye, and Clark
County including Las Vegas will remain in effect from now into
Wednesday evening. This level of heat will affect anyone without
effective cooling and hydration and extra caution is advised.

The previously mentioned low pressure system will cut under the
ridge and move east through southern California and Arizona on
Thursday and Friday. Falling heights aloft should help bring
temperatures down a few degrees on Thursday, but highs will still be
5 to 10 degrees above normal for this time of year. Afterwards, the
warming trend continues on Friday and Saturday as the shortwave
exits to the east and pressure builds again. Southerly to
southwesterly winds aloft should bring breezy surface winds,
especially along high terrain. Lastly, moisture associated with the
low will increase PWAT values in northwest Arizona on Thursday to
over 100 percent of normal for this time of year, or .4 to .6
inches. However, most of the moisture with the system appears
elevated as seen on current satellite imagery. Forecast soundings
also show an inverted V pattern with most of the moisture aloft and
dyer air near the surface. A few isolated rain showers may form on
Thursday, but most precipitation may evaporate before reaching
the ground given RH values in the teens to single digits.
Lightning is not a concern in northwest Arizona given a lack of
atmospheric instability over the area with the greatest moisture.
However, a few thunderstorms may develop in Inyo County over the
Sierra crest. Although there is less moisture, there is better
instability and lift over the mountains.

.LONG TERM...Early Next Week.

The weather pattern is expected to transition late this weekend and
early next week as we lose the influence of the ridge. Low
confidence in how everything sets up synoptically though as there
are significant differences in long range model camps on how an
incoming trough will interact with the weakening ridge. Many models
have some flavor of the trough digging south into the region from
the Pacific Northwest, however there are differences in how deep the
trough digs and how quickly it will continue its eastward
progression. Increasing confidence there will be some type of
cooling trend but unsure what temperatures will look like. NBM
ensemble high temperature spread for that time period is very large
with anything from near normal to well below normal, especially
early next week.

Depending on the exact setup of the trough, winds could increase as
well. Currently, there are some ensemble members of 40 MPH or higher
gusts on area meteograms for Sunday into early next week, so the
chance for impactful winds is non-zero. More notable, with dry
conditions and the potential for increasing winds, fire danger would
increase. SPC fire weather outlooks highlight a 40% potential for
increased fire danger on Saturday and Sunday in portions of southern
Nevada into western Arizona. Will need to monitor wind and fuel
trends in case fire danger rapidly increases.

&&

.AVIATION...For Harry Reid...Expecting a predominantly light and
diurnal wind pattern through the TAF period, with east/southeast
winds at times this afternoon and south/southwest at night. Speeds
generally in the 5-8 knot range, with only a slight chance of wind
gusts exceeding 10+ knots this afternoon. Clear skies.

For the rest of southern Nevada, northwest Arizona and southeast
California...Light and diurnal winds anticipated at all of the area
TAF sites through tonight. Sustained winds should peak around 8-12
knots this afternoon and evening, with occasional gusts up to 16
knots possible. Mostly clear skies as just a few mid-level and high
clouds linger over the lower Colorado River Valley and KBIH.

&&

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

&&

$$

SHORT TERM...Meltzer
LONG TERM...Nickerson
AVIATION...Gorelow

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