500
FXUS65 KPSR 070546
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1046 PM MST Tue May 6 2025

.UPDATE...Updated 06z Aviation Discussion.

&&

.SYNOPSIS...
Unsettled weather continues with well below normal temperatures
and continued precipitation chances. Showers and thunderstorms are
expected this evening primarily across La Paz and eastern
Riverside Counties with much lower chances favoring the high
terrain Wednesday afternoon. Well below normal temperatures will
give way to a warming trend through the rest of the week with
strong high pressure boosting temperatures well above normal into
the triple digits by the end of the week.

&&

.DISCUSSION...
Unsettled weather continues across the region as troughing remains
in place over the southwest CONUS, promoting well below normal
temperatures and precipitation across the state. WV satellite
imagery and objective analysis this afternoon shows the primary low
center circulation now over New Mexico near the Texas Panhandle.
Meanwhile, a secondary vort max is clearly seen near Las Vegas and
has led to thunderstorm development around the Las Vegas area this
afternoon. This vort max will continue to progress towards the
south this evening and will lead to increasing rain chances across
parts of southeast California and southwest Arizona this evening.

Shower and thunderstorm development is expected to ramp up across
parts of La Paz and Riverside Counties this evening as the vort
max continues to propagate towards the south. Current moisture
remains anomalous for this time of year as PWAT anomalies remain
around 200% of normal with PWATs around 0.8-0.9". The adequate
moisture, forcing, and several hundred J/kg of CAPE will be
sufficient for thunderstorm development in the aforementioned
areas this evening and will be capable of producing locally heavy
rainfall and gusty winds. HREF paintball plots show high
confidence in this occurring with the potential for some localized
heavier rainfall amounts to around 0.75-1.00" possible with any
stronger thunderstorms. Thus, could see some advisory level
impacts with some of the activity this evening. PoPs for this
evening surrounding La Paz and eastern Riverside Counties peak
around 60-80%. HREF guidance show this activity diminishing
through the overnight hours with some leftover shower activity
trying to push into western Maricopa County Wednesday morning. By
Wednesday afternoon, the vort max will be pushing into southwest
Arizona near the Mexico international border. Rain chances
Wednesday afternoon will be primarily confined to higher terrain
areas north and east of Phoenix with chances across the lower
deserts less than 15%. A few isolated showers and thunderstorms
will be possible across southern Gila County during the afternoon
Wednesday before diminishing by the evening.

.PREVIOUS DISCUSSION...
As the upper level trough remains over our region, we will
continue to see below normal temperatures today and Wednesday, but
that won`t last long as by Thursday a high pressure ridge will
fully move into the region. H5 heights are forecast to quickly
rise to between 581-584dm on Thursday before peaking at 585-587dm
Friday into the weekend. Temperatures will respond very quickly to
the rising heights aloft and the drying conditions with highs
reaching into the low to mid 90s on Thursday and into the upper
90s to the lower 100s on Friday. NBM guidance seems to be finally
pinpointing on highs reaching between 101-105 degrees across the
Phoenix area and 103-107 across the western deserts for the coming
weekend. These readings are still several degrees away from
record territory, but it will still easily push our area into the
Moderate HeatRisk category for Friday-Sunday. Ensembles then
generally agree on a Pacific trough entering the Pacific Northwest
and eventually the Great Basin at some point early next week
providing a cooling trend over our area. Depending on the depth of
the trough, it may eventually drop our temperatures back to or a
bit below normal by next Tuesday or Wednesday.

&&

.AVIATION...Updated at 0545Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
The primary aviation concern through the TAF period will be
uncertainty in VCSH/SHRA conditions developing Wednesday morning.
The weather disturbance responsible for showers and thunderstorms
across the Colorado River Valley and surrounding areas will rotate
through South Central Arizona over the next 24 hours, though
confidence in VCSH/SHRA conditions is too low at any of the
terminals for inclusion at this time. Most activity is expected to
die out across Northwestern Maricopa County before moving
overhead. The most likely impact of this disturbance will be a
period of SCT-BKN clouds down to 6-7 kft AGL Wednesday morning.
Winds will begin to follow more typical diurnal trends, with
speeds generally remaining AOB 10 kts, however, depending on how
close SHRA activity gets to the terminals, stronger NW winds may
temporarily materialize early Wednesday morning.

Southeast California/Southwest Arizona including KIPL and KBLH:
The primary aviation concern through the TAF period will be
lingering -TSRA/SHRA conditions at KBLH for the next hour or two.
While shower activity remains in the vicinity, some erratic winds
will be possible, though directions will begin to favor NE. At
KIPL, west winds will go light and VRB overnight before
eventually establishing out of the NNE midday Wednesday. SKC skies
will return Wednesday late afternoon/evening.

&&

.FIRE WEATHER...
Unsettled weather continues across the region with precipitation
chances remaining in the forecast through Wednesday. Chances for
showers and thunderstorms will be highest across La Paz and
Riverside Counties this evening with gusty erratic outflow winds
possible. Temperatures will warm up through the rest of the week
as strong high pressure builds over the region with well above
normal temperatures for the end of the week. Min RHs will trend
down over the next several days with values ranging around 25-35%
Wednesday and 15-20% Thursday. Outside of any outflows, winds will
overall remain light, mostly at or below 10 mph, through the next
couple of days. The high pressure will eventually bring hot and
dry conditions for Friday through the upcoming weekend.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

$$

DISCUSSION...Smith
PREVIOUS DISCUSSION...Kuhlman
AVIATION...Whittock
FIRE WEATHER...Smith/Kuhlman