737
FXUS65 KPSR 051811
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1111 AM MST Sun May 5 2024

.UPDATE...Updated 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 1810Z.

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

Westerly to southwesterly winds are now in place this morning at the
TAF sites and will continue to become increasingly breezy through
the afternoon. By around 20Z, gusts are expected to climb upwards of
25-30 kts with a few gusts in excess of 30 kts. Gusty winds will
linger into the evening hours as a cold front pushes through the
region before winds weaken following the FROPA. Can`t rule out some
slantwise visibility concerns if today`s strong winds generate
lofted dust across the region. Light winds under 10 kts prevail
going into the overnight period, but directions are not expected to
make the typical diurnal easterly shift. Instead, westerly winds are
expected to hold into the overnight period with some light and
variable winds by early Monday morning. Otherwise, SCT-BKN clouds
generally aoa 10 kft will give way to mostly clear skies later this
evening.

Southeast California/Southwest Arizona including KIPL and KBLH:

Winds will remain the primary aviation weather concern for today.
Strong westerly winds gusting to around 35 kts will continue through
the afternoon at KIPL before gradually weakening going into this
evening. Winds at KBLH won`t be as strong, though a few gusts up to
around 35 kts will be possible through this afternoon. Winds at KBLH
will veer toward the northwest around 01Z as a cold front pushes
through the region before strong gusts subside following the
FROPA. Strong winds today may generate lofted blowing dust, which
may lead to slantwise visibility reductions and perhaps lowered
surface visibilities. SCT-BKN high clouds will give way to mostly
clear skies by this evening.

&&

.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 8 PM PDT this evening for CAZ563>567.

     Wind Advisory until 11 PM PDT this evening for CAZ562.

&&

$$

DISCUSSION...Kuhlman
AVIATION...Smith
FIRE WEATHER...Kuhlman