073
FXUS65 KPSR 012020
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
120 PM MST Sat Jun 1 2024

.SYNOPSIS...
Seasonably hot and dry weather conditions will persist
through early next week with temperatures running 3 to 5 degrees
above normal. By the middle through latter half of next week, high
pressure is forecast to strengthen across much of the western United
States, resulting in hotter temperatures as highs get closer to 110
degrees across much of the lower deserts.

&&

.DISCUSSION...
A quasi-zonal flow pattern continues to persist across the Desert
Southwest with subtropical ridging across central Mexico and
troughing across the northern tier of the western United States.
This overall flow pattern will persist through at least Monday
with temperatures remaining steady state with highs topping out
between 100-105 degrees across the lower deserts. A very weak
shortwave extending from base of the trough over the Pacific
Northwest will skirt the region through Sunday, however, no
discernible sensible weather impacts are expected from it other
than just slightly enhancing the afternoon and early evening
breeziness.

The weather pattern starts to shift heading into the Tuesday-
Wednesday timeframe as an upper-level ridge of high pressure
begins to amplify across much of the western United States. At the
same time, a weak cutoff low will develop and sit just off the
central Baja Peninsula. With the developing ridge, the upper-level
height fields are likely to rise to between 589-593dm, resulting
in hotter temperatures during the middle to latter half of the
week. Temperatures on Wednesday are likely to range between
105-110 degrees across most of the lower desert communities and
likely be a touch warmer on Thursday with highs ranging between
106-111 degrees. These hotter temperatures will certainly will
elevate the HeatRisk to moderate areawide with areas of major
HeatRisk materializing on Thursday as temperatures approach 110
degrees.

Heading into Friday and next weekend, guidance has come into
better agreement in showing the cutoff low over the Baja Peninsula
moving northward through southern CA/western AZ, which will lower
the upper-level height fields and result in a slight cooling
trend with temperatures closer to 105 degrees. Ensembles also
hint that potentially another larger scale trough from the Pacific may
move into the west coast later next weekend, however, differences
are noted in the overall strength and positioning and thus what
impacts if any it will have in our region is unknown at this time.
With the cutoff low near the Baja Peninsula late next week, the
south to southeast flow on the east side will likely advect some
moisture into AZ with a slight chance of isolated afternoon
convection across the higher terrain areas of eastern AZ.

&&

.AVIATION...Updated at 1715Z.

South-Central Arizona including KPHX, KIWA, KSDL, KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:

No major aviation concerns are expected during the TAF period.
Metro Phoenix sites will see typical diurnal tendencies with
occasional afternoon gusts in the mid-teen to around 20 kts. Much
like yesterday, periods of variability will be observed during
directional shifts, especially at KPHX. Out in SE California,
diurnal trends can be expected with afternoon and evening
breeziness, with gusts at IPL being more frequent than BLH. Clear
skies will prevail through the forecast window.

&&

.FIRE WEATHER...
Little to no change in the weather pattern will keep seasonably
dry and hot conditions in place through early next week. Expect
lower desert highs between 100 and 105 degrees, or 3-5 degrees
above average each day. Hotter temperatures are expected by the
middle to latter half of the week as readings close in at 110
degrees. MinRH values will continue to run between 5-15% across
the majority of the area each day, while overnight recoveries will
continue to range from poor to fair at around 25-40%. Winds will
overall be fairly light following diurnal tendencies with periodic
afternoon gusts of 15-20 mph.

&&

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

$$

DISCUSSION...Lojero
AVIATION...RW
FIRE WEATHER...Kuhlman/Lojero