317
FXUS65 KTWC 162145
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
245 PM MST Fri May 16 2025

.SYNOPSIS...High temperatures through early next week will generally
be near normal. Breezy to windy conditions returning over the
upcoming weekend as a system passes through bringing elevated fire
weather conditions.

&&

.DISCUSSION...Over the weekend into early next week a series of
disturbances associated with a dry and particularly strong Pacific
system will be passing through the desert southwest resulting in
gusty southwest winds Saturday through Monday.

The first of these disturbances is a shortwave that will move over
the Baja/Gulf of California and into southeast Arizona tomorrow.
Southwest winds will be breezy tomorrow with the shortwave passage.
Sustained winds of 15-20 mph and gusts up to 30 mph are expected.

The second disturbance is an upper low moving in from the Pacific NW
Sunday. As the low moves inland it will dip south and deepen
creating slightly stronger southwest winds on Sunday afternoon.
Sustained southwest winds of 15-25 mph with gusts of 35-40 mph
expected.

The third and final disturbance will pass over the Great Basin into
northern Arizona on Monday as the aforementioned low really deepens
over the Rockies and ejects into the central plains. Northwest winds
from this final disturbance have come up from previous guidance, but
mainly highlights Graham and Greenlee counties. Latest NBM
probabilistic guidance depicts a slight chance (10-20%) for 24-hour
max wind gusts in excess of 55 mph across the Gila and Aravaipa
valleys of Graham, Greenlee, and eastern Pinal counties on Monday.
There is slightly higher chances (20-30%) for maximum gusts in
excess of 55 mph over the higher peaks of Mt. Graham, Guthrie Peak,
and the Galiuro Mountains. There is still some uncertainty in just
how strong the wind field will be associated with this system.

The uptick in winds for tomorrow, Sunday, and Monday will lead to
possible patchy blowing dust and elevated to near-critical fire
weather concerns. A fire weather watch remains in effect from Sunday
morning through Sunday evening for Graham, Greenlee, and eastern
portion of Santa Cruz counties, including the Sky Islands of
southeast Arizona.

Following the passage of the final disturbance we start to see a
ridge building overhead for the upcoming Memorial Day weekend
resulting in a sudden increase in daily high temperatures. The
latest Climate Prediction Center guidance depicts a moderate risk
(40-60%) for excessive heat across portions of the Desert Southwest
including our lower desert areas in Pima, Pinal, and Santa Cruz
counties. Elsewhere for our eastern desert valleys there is a slight
risk (20-40%) for excessive heat.

&&

.AVIATION...Valid through 18/00Z.
FEW to BKN clouds AOA 20-25k ft AGL from KSAD to KOLS line from thru
17/16Z. After 17/18Z, FEW-SCT AOA 20k ft AGL moving from west to
east across the area through the end of the forecast period. SFC
winds SWLY at 9-14 kts gusts to 16-22 kts thru 17/03Z becoming
terrain driven and under 10 kts thereafter. Tomorrow, SFC winds pick
up becoming SWLY again after 17/16Z with speeds of 15-21 kts and a
few gusts up to 30 kts. Strongest winds expected near KALK. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...High temperatures will be near normal this afternoon
and again tomorrow afternoon. Typical breezes this afternoon for
much of southeast Arizona, with breezy conditions persisting across
Cochise, Graham and Greenlee counties where 20-foot wind speeds will
be around 15 mph and gusts up to 25-30 mph during the mid/late
afternoon hours. Increasing west/southwest winds are expected over
the upcoming weekend as another storm system moves to our north.
Near critical to critical fire weather conditions are expected this
weekend and into Monday.

Sunday winds of 15 to 25 mph with gusts of 35 to 40 mph are
expected. Fire Weather Watch in effect from 10 AM to 7 PM on Sunday.
Monday is now looking to be the windiest of the period across the
Gila Valley of Graham, Greenlee, and far eastern Pinal counties with
winds 15 to 25 mph and gusts around 40 mph. Minimum relative
humidities will hover near 15 percent for a few hours. However, an
increase in relative humidity is expected on Monday.

Temperatures will be 2 to 4 degrees below normal Sunday, lowering
to 9 to 12 degrees below normal next Monday, warming to well
above normal levels by the middle of next week.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Sunday morning through Sunday evening
for AZZ151>154.

&&

$$

DVS

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