353
FXUS65 KPSR 310952
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
252 AM MST Fri Jan 31 2025

.SYNOPSIS...
High pressure will continue to build over the southwestern United
States through the beginning of next week. This will lead to
temperatures warming to near normal today and going above normal
this weekend and continuing into next week. Afternoon high
temperatures will warm to 10 to 15 degrees above normal by the
beginning of next week, with the lower deserts topping out in the
low-to-mid 80s. Dry conditions will also continue through the next
week.

&&

.DISCUSSION...
Early this morning the nighttime microphysics satellite channel
shows some fog development starting to move into the Imperial
Valley. Additional fog develop is possible through this morning and
visibilities could fall below 0.5 a mile leading to hazardous travel
conditions. If you encounter fog this morning remember to turn on
your low-beam lights and drive slowly and cautiously. The fog will
start to lift and conditions will start to improve around sunrise.
All fog should be gone by 9-10am.

Upper-air analysis this morning reveals a closed low pressure system
in the Central Plains along with ridging building over western
CONUS. With the low pressure system well east of the region and high
pressure moving in afternoon high temperatures will be 5-7 degrees
warmer than yesterday across south-central Arizona. The lower
deserts will see highs in the mid-to-upper 60s and low 70s and the
higher terrain areas will be in the low-to-mid 60s. Also with the
high pressure building over the region today, skies will remain
mostly clear with few high cirrus clouds moving into the region this
evening. Winds will also be light today with speeds generally around
5 mph.

Models remain in good agreement with the overall pattern through the
beginning of next week, with ridging continuing to build over the
Southwestern US with troughing moving into the Pacific NW. This will
result in warming temperatures through the beginning of next week
for our area. Temperatures climb to above normal tomorrow then go
well above normal by the beginning of next week. For tomorrow, lower
desert high temperatures are forecasted to be in the low-to-mid 70s
and higher terrain areas are forecasted to see high temperatures in
the upper 60s. On Sunday temperatures warm even more with the lower
deserts topping out in the upper 70s to low 80s and the higher
terrain seeing temperatures in the low 70s. By Monday and Tuesday
temperatures will be 10-15 degrees above normal with much of the
lower deserts forecasted to see temperatures in the low-to-mid 80s.
Afternoon high temperatures will even be near record levels in
Phoenix on Monday and Tuesday. The NBM currently give Phoenix a 20%
chance of tying the record (86 degrees) on Monday and a 40% chance
of tying the record (85 degrees) on Tuesday.

For the later half of next week the global ensemble models start to
disagree on the overall pattern. The disagreement between the models
is in regards to the evolution of the aforementioned trough that
will be moving into the Pacific NW over the weekend. The trough is
expected to stay well north of our region, however, it looks to
dampen the riding that will be overhead. This would lead to a
slight decrease in temperatures. However, the current forecast
calls for temperatures remaining above normal (afternoon high
temperatures in the 70s across the lower deserts and mid-to-upper
60s in the higher terrain). Dry conditions, for our area, are
expected to continue through next week.

&&

.AVIATION...Updated at 0525Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Light winds, mostly AOB 7 kts, will follow their typical diurnal
trends. Extended periods of variability to nearly calm winds will
be common, especially late Friday morning into the afternoon.
Expect FEW-SCT cloud decks AOA 20 kft AGL will start to move over
the airspace late Friday afternoon into the evening.

Southeast California/Southwest Arizona including KIPL and KBLH:
The primary aviation concern through the period will be the
potential for reduced visibilities at KIPL from patches of dense
fog that may develop within the Imperial Valley early Friday
morning. Latest HREF probabilities for surface visibilities
temporarily dropping below 1 SM continue to range widely from
10-60% across portions of the Imperial Valley between 11-17Z. Due
to the expected patchy nature of the dense fog, a TEMPO group with
MVFR visibility between 12-16Z has been maintained, however, if
southeast winds pick up during the early morning hours, fog with
IFR/LIFR visibilities may briefly move over the terminal. This
will bear watching, and is completely dependent on dense fog
developing overnight (low to moderate confidence at present).
Otherwise, expect extended periods of variability and light winds
generally AOB 5 kts at both terminals, with mostly clear skies and
FEW cirrus moving in Friday afternoon.

&&

.FIRE WEATHER...
High pressure will continue to build over the region through the
beginning of next week, resulting in warming temperatures.
Temperatures will be near normal today before going above normal
tomorrow and well above normal for the beginning of next week.
MinRHs will be in the 20s today and fall into the teens tomorrow
and continue into the beginning of next week. Light winds will
tend to follow their typical diurnal patterns.

&&

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

$$

DISCUSSION...Berislavich
AVIATION...Whittock
FIRE WEATHER...Berislavich