792
FXUS65 KPSR 051152
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
452 AM MST Sun May 5 2024

.UPDATE...Updated 12z Aviation Discussion.

&&

.SYNOPSIS...
A dry weather system passing across the northern portion of the
region today will help to bring fairly widespread windy
conditions by this afternoon as well as dropping temperatures to
slightly below normal. The weather pattern for the rest of the
week will keep dry conditions in place while temperatures will
warm back into a normal range through at least mid week.

&&

.DISCUSSION...
A mostly dry Pacific low pressure system is currently moving
eastward across northern California into Nevada with the base of
the trough reaching into our region. IR satellite shows
considerable high cloudiness currently moving through our region
and this will continue into the afternoon hours before skies begin
to clear out. A dry cold front is also starting to push through
the area with objective analysis showing the front now mostly
through southeast California. The front will eventually make its
way through most of Arizona later this morning, but it will also
be washing out as it does leaving the coolest air to the west of
the Phoenix area. Forecast highs today show readings only in the
upper 70s across southeast California to the mid to upper 80s
across Phoenix and other lower desert areas in south-central
Arizona.

The main forecast concerns for today will be the gusty winds which
will likely result in areas of elevated fire weather conditions.
Winds early this morning continue to occasionally gust to between
30-40 mph across southeast California and this will expand into
much of Arizona by late morning or early afternoon. The rest of
this afternoon into early this evening should see winds gusting to
between 25-35 mph across the south-central Arizona lower deserts,
including the Phoenix area, to as high as 35-45 mph across
southeast California into the higher terrain north and east of
Phoenix.

Starting Monday, the center of the Pacific trough will quickly
lift to the northeast through Colorado into the Northern Plains
leaving drier west northwesterly flow across the Desert Southwest.
Winds will be considerably lighter over our area on Monday, while
temperatures remain a few degrees below normal. The trough is then
expected to deepen again as it becomes nearly stationary centered
over the Northern Plains while the western fringes of the trough
stays over the Great Basin into northern portions of our region
through at least mid week. This synoptic set-up should bring more
breezy conditions over our area into the middle part of the week,
while temperatures slowly warm back into a normal range with highs
back to around 90 degrees or the lower 90s by Tuesday or
Wednesday. Eventually the influence of this trough will begin to
wane later this week as a ridge tries to build over portions of
the Western U.S. Ensemble guidance is still unsure when this ridge
will be able to fully displace the remnant trough from our
region, but either way it seems our temperatures will mostly
likely warm further by next weekend with the NBM indicating highs
into the mid to possibly upper 90s by Friday or Saturday.

&&

.AVIATION...Updated at 1150Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Strong SW to W winds will be the primary aviation weather concern
through the TAF period. This morning, winds have finally turned
SE to S with speeds mostly aob 8 kt sustained. These directions
will only be favored through 14-16Z before turning again out of
the SW as speeds gradually increase over the morning hours. Gusts
will develop later this morning and peak out of the west this
afternoon at between 25-30 kts across all terminals. A dry cold
front will sweep the area this evening, potentially bringing a
brief jump in speeds as well as a slightly more northerly
component to the predominant west winds. Winds will calm over the
evening until speeds are aob 6 kt at all terminals. Confidence in
a full east switch overnight is low, but periods of variability
can be anticipated. FEW-SCT and at times BKN clouds will traverse
the region this afternoon with bases mostly aoa 20 kft and briefly
down to 8-10 kft.

Southeast California/Southwest Arizona including KIPL and KBLH:

Winds will be the primary aviation weather concern through the TAF
period. Slightly stronger winds than Saturday are expected at the
terminals, with westerly to southwesterly gusts mostly to 30-35
kts. Gusts may occasionally reach up to 40 kts. The strong winds
will be capable of generating blowing dust which will likely lead
to slantwise visibility reductions at a minimum, but could also
briefly reduce surface visibility as well. A cold front will
eventually pass through KBLH around 01Z and shift winds to the NW.
Winds subside at both terminals after sunset. Expect to see
fluctuating coverage of high clouds throughout the period.

&&

.FIRE WEATHER...
A weather system moving just to the north of the region today
will bring breezy to windy conditions areawide. Wind gusts of
25-35 mph are likely in many areas this afternoon with upwards of
40-45 mph possible across portions of southeast California and
over the high terrain north and east of Phoenix. The strong winds
and dry conditions with humidities as low as 20% today could lead
to elevated fire weather conditions. Lighter winds are expected
by Monday with MinRHs lowering to around 10%, with fair to good
overnight recoveries. Weak high pressure will then remain over
the region through much of the coming week as temperatures
return to slightly above normal by late week. Seasonably dry
conditions are expected this week with MinRHs dropping to around
10% each day starting Monday. Winds this week will be fairly
light most days, except for Tuesday and Wednesday when winds will
be more elevated with afternoon gusts between 20-30 mph in some
areas.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 9 AM PDT this morning for CAZ560.

     Wind Advisory until 8 PM PDT this evening for CAZ563>567.

     Wind Advisory until 11 PM PDT this evening for CAZ562.

&&

$$

DISCUSSION...Kuhlman
AVIATION...Whittock/Benedict
FIRE WEATHER...Kuhlman