Joshua Tree, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

792
FXUS65 KVEF 011203
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
503 AM PDT Sun Jun 1 2025

.SYNOPSIS...Showers and thunderstorms are expected across much of
the forecast area starting today as low pressure pulls remnant
tropical moisture into the region. The greatest rainfall amounts
will likely be in northwestern Arizona tonight into tomorrow. Cooler
temperatures can also be expected areawide before they begin to
climb again midweek.

&&

.SHORT TERM...Today through Tuesday.

A low pressure system that is currently centered to the west of Baja
California will be the main driver of weather over the next few days
as it sends remnant moisture left over from Alvin towards the
forecast area. Isolated high based showers are already beginning to
form south of Interstate 40 this morning. However, air near the
surface is very dry and most droplets will evaporate before they
reach the ground. These virga showers should continue through at
least midday in the Mojave Desert. Instability-based convection
should begin over the southern Great Basin and eastern Sierra with
250 to 500 J/kg CAPE to work with, but any totals from these should
remain light. Given the high bases, strong outflow winds are a
possibility with any showers that form.

Greater moisture arrives with a push of 20 to 30 mph southerly winds
later today and tonight as the low drifts northeastward into
Arizona. This will send PWATs to the 1.2 to 1.6 inch range, or 250
to 300 percent of normal for early June. The greatest potential for
rainfall at this time will be along and south of Interstate 15.
Forecast soundings show the atmospheric column moistening in the low
levels, indicating that more rainfall should reach the surface and
flooding will become the primary threat rather than wind. The
heaviest precipitation should occur late tonight and into Monday
morning in northwestern Arizona. A Marginal Excessive Rainfall
Outlook is in place for southern Mohave County to reflect the flood
threat.

Rainfall chances continue through the day on Monday as the center of
the low moves into northern Arizona. Instability from the low should
sustain shower and thunderstorm activity in northwest Arizona and in
the southern Great Basin. As the low tracks east into the Four
Corners on Tuesday, another low will become positioned over northern
Baja, similar to the first low. By this time, over an inch of PWAT
remains over the forecast area, mainly in areas around the Colorado
River, and potential for isolated to scattered showers continues
over northwestern Arizona.

Today`s temperatures will be 5 to 10 degrees cooler than yesterday
as moisture and cloud cover increase and heights aloft decrease with
the approaching low. Temperatures will decrease another 5 to 10
degrees tomorrow, primarily north of Interstate 40 due to cloud
cover. By Monday, most areas should be in the Minor (Level 1)
HeatRisk category with a spot of Moderate (Level 2) in Death
Valley.

.LONG TERM...Wednesday through Sunday.

A northwest flow will set up over the region mid-to-late week. Along
this northwest flow, a series of shortwaves will glide down into the
southern Great Basin and Mojave Desert. With no mechanism to
shove remnant moisture out of the forecast area from the early-
week systems, these shortwaves will tap into the leftover
moisture, resulting in at least slight PoPs existing through
Thursday. Best chances will exist in the southeastern Great Basin
and eastern Mojave Desert on Wednesday and Thursday with breezy
south-southwest winds elsewhere (20-30 mph).

Despite these shortwaves, a growing ridge of high pressure over the
eastern Pacific as well as over northern Mexico will result in
increased 500 mb heights across the Desert Southwest. As such,
temperatures will continue to climb back to 4 to 6 degrees above
seasonal normals heading into the weekend, with temperatures
approaching 10 degrees above-normal heading into the next work week.
This will result in desert valleys reading high temperatures in the
100s once again, with widespread "Moderate" HeatRisk.

&&

.AVIATION...For Harry Reid...For the 12Z Forecast Package...South
southwest winds should persist this morning, with spotty gusts of 15
to 20 knots not out of the question. Gusts of around 25 knots will
become more common by late morning and persist through the
afternoon. Late this evening, chances for showers and thunderstorms
will move in from the south, and the main threat will be erratic
gusty winds. Chances for showers and thunderstorms will decrease,
but not go away entirely, early Monday morning.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 12Z Forecast Package...South to southwest winds
gusting 20 to 30 knots will be common across the region today,
especially from late morning through the evening. Chances for
showers and thunderstorms will begin over the Sierra crest around
midday and spread northeastward across the southern Great Basin
through tonight. Another area of thunderstorm chances will begin
along and south of Interstate 40 this afternoon and spread
northeastward to areas along and southeast of Interstate 15 through
tonight. The main threat with thunderstorms will be erratic gusty
winds, and a few of the storms over northwest Arizona could produce
locally heavy rain and low ceilings with terrain obscuration.
&&

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

&&

$$

SHORT TERM...Meltzer
LONG TERM...Soulat
AVIATION...Morgan

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