647
FXUS65 KPSR 180019
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
519 PM MST Sun May 17 2026

.UPDATE...Updated 00Z Aviation Discussion.

&&

.KEY MESSAGES...

- Widespread breezy to locally windy conditions are expected this
  afternoon through this evening, and will continue tonight
  through early Monday morning across Southeast California
  following a cold front.

- Elevated to locally critical fire weather conditions are
  anticipated for a few hours this afternoon and evening for the
  Eastern Arizona higher terrain, where a Red Flag Warning will be
  in effect.

- Afternoon high temperatures will be near normal today and then
  drop to 4 to 6 degrees below normal for Monday and Tuesday
  before slowly warming back up again.

&&

.SHORT TERM /TODAY THROUGH MONDAY/...
Broad troughing continues to encompass the Western CONUS with breezy
to windy conditions again today and into early Monday morning.
Another shortwave will be dropping south through NV this afternoon
and evening before progressing eastward across UT and CO Monday
morning. The pressure gradient will tighten in response leading to
another wave of breezy to windy conditions lasting well into late
this evening. Gusts across the entire CWA will generally be between
25-35 mph tonight with even stronger gusts (40+ mph) in southeast
CA, and the higher terrain areas.

In Imperial County downsloping winds this afternoon/evening can even
push gusts upwards of 50 mph. Additionally, a dry cold front is
expected to drop south through southeast CA and southwest AZ tonight
with rather strong N-NW post-frontal winds, especially across
eastern Riverside County where gusts up to 40-50 mph are possible.
Due to these factors a Wind Advisory remains in effect for the
Imperial Valley area and then an additional Wind Advisory will begin
for Riverside County and along the Colorado River Valley near
midnight tonight, lasting into the morning hours. The area of most
concern during this time will be along I-10, especially between
Desert Center and the Indio Valley, where HREF probabilities of peak
wind gusts >50 mph are maximized (60%), and can result in blowing
dust and reduced visibilities.

These gusty winds this afternoon and evening will not only affect
the western region but in the eastern higher terrain areas leading
to elevated and marginally critical fire weather conditions. A Red
Flag Warning remains in effect for southern Gila County and the
Tonto National Forest where afternoon and evening winds are forecast
to be strongest in combination with minimum RHs of 10-15% and dry
fuels.

Otherwise, as the shortwave troughs pass just to the north of our
region temperatures will also be affected, with high temperatures
today in the low to mid 90s, or right around normal for this time of
year. Temperatures drop further for Monday with lower deserts likely
failing to reach 90F. There will also be a narrow band of PBL
moisture and forcing along and just ahead of the cold front Monday
morning. Enough to at least lead to some lower clouds in south-
central AZ near sunrise, otherwise skies will be mostly clear.
Additionally, there are a couple HREF members producing a few
sprinkle showers out of these clouds, but overall PoP is under
10%.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As the potent weekend shortwave trough departs the Mountain West,
to drive severe weather in the Plains, a measure of broad
cyclonic flow over the Western U.S. will remain and likely
persist through the remainder of the upcoming work week. Heights
aloft will rebound though, closer to seasonal averages, and so
temperatures are expected to warm through the middle of the week,
with seasonally dry conditions continuing. Meanwhile, a strong
midlevel ridge will remain nearly stationary off the Pacific
Northwest Coast through much of next week, with most global
guidance showing a subtropical jet forming under the ridge and
developing a few weak disturbances. A few of which may be sent
downstream and near/over the Southwest U.S.. Regardless of the
details and how weak troughing over the West- Central CONUS
eventually resolves, essentially all solutions currently show the
region remaining completely dry, with periods of mid-high level
clouds and slowly warming temperatures through the work week.

&&

.AVIATION...Updated at 0019Z.

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

The main aviation concerns will be a period of gusty SW winds
this evening. SW winds with gusts of 20-30 kt are expected through
05-06Z this evening. Winds will then lighten to around 10 kt, but
maintain their SW direction into the overnight hours. Winds will
then go S-SE around 09-11Z, with speeds aob 10kt. A early shift to
SW winds is expected by 14-15Z, with winds picking up speed into
the teens during the afternoon. Some occasional gusts into the
upper teens are possible. FEW high clouds this evening will move
out overnight, with FEW-SCT CU as low as 4-5 kft AGL expected to
develop around sunrise, but are only expected to last for a few
hours.

Southeast California/Southwest Arizona including KIPL and KBLH:

Periods of gusty winds and reduced visibilities due to blowing
dust will be the main aviation weather concerns throughout the
TAF period. At KIPL, winds will maintain a westerly component
while at KBLH winds will fluctuate from the south to southwest
into the overnight hours. At KIPL, wind gusts up to 20-25 kts
becoming common through the evening. A period of stronger winds
(30-35kt) is likely between 00-04Z. Brief visibility restrictions
will be possible with the strongest gusts due to blowing/lofted
dust. Wind speeds will then lessen during the overnight hours. At
KBLH, wind gusts reaching 20-30 kt will be common through the
evening. A cold front will enter the area from the north and
switch winds abruptly at KBLH overnight and at KIPL early tomorrow
morning. Skies will remain mostly clear through most of this
morning with FEW high clouds this evening.

&&

.FIRE WEATHER...
Elevated and marginally critical fire weather conditions are
expected through this afternoon and evening for a few hours as
winds increase across the region. A Red Flag Warning remains in
effect for southern Gila County and the Tonto National Forest for
this afternoon through this evening. The winds will steadily
increase through the afternoon, with peak wire weather conditions
(strongest winds and lowest RH) likely between 1500-2000MST. Wind
gusts in the warned area will peak around 25-35 mph and RH values
will minimize around 10-15%. While RH increases above critical
levels after 2000MST the elevated breezes are likely to continue
through midnight, which may make controlling any new/existing
fires challenging. Wind gusts up to 25-35 mph will be common
across all districts this afternoon, but will be strongest across
southeast CA with westerly sundowner winds in Imperial County up
to 40-50 mph and northerly gusts up to 35-50 mph across much of
eastern Riverside County later tonight through early Monday
following a cold front passage around midnight. There will be very
dry air following the front that will create elevated fire
conditions across Riverside County, even during the overnight
hours. Minimum RH values will be closer to 15-20% across the
western districts. Lingering northerly breeziness down the Lower
Colorado River is expected Monday, but this gradient wind should
weaken heading into the afternoon and winds elsewhere Monday
afternoon will be weaker than today with gusts up to 15-25 mph.
Beyond Monday, weather conditions will be seasonally hot and dry
(Min RHs around 5-15%), with winds mostly reaching up to 15-25 mph
in the afternoons.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Red Flag Warning until 11 PM MST this evening for AZZ133.

CA...Wind Advisory from 11 PM this evening to 11 AM PDT Monday for
     CAZ560-561-564-568>570.

     Wind Advisory until 1 AM PDT Monday for CAZ562.

     Wind Advisory until 11 PM PDT this evening for CAZ563-566-567.

&&

$$

SHORT TERM...Benedict/Ryan
LONG TERM...Benedict/Whittock
AVIATION...Berislavich/Salerno
FIRE WEATHER...Benedict/Ryan