Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 250454

Area Forecast Discussion
National Weather Service Phoenix AZ
954 PM MST Sat Mar 24 2018

Updated DISCUSSION and AVIATION sections.


A cooling trend will continue Sunday with high temperatures
remaining in the 70s through Tuesday. It will also be a bit breezy
at times - especially Tuesday. Warmer weather returns during the
latter portion of next week.


A disturbance, within a large region of upper troughing centered
near the west coast of North America, is exiting Arizona this
evening leaving behind clear skies. The most notable impact for
our forecast area was the strong winds over far southeast
California ...mainly Imperial County. Peak gusts there were in the
40-45 mph range. Interestingly, stations to the west of there did
not register winds that strong - except for a notoriously windy
mountain pass location along I-8 near the San Diego County line.
Some plumes of dust were apparent at times in the GOES-16 Channel
2 imagery emanating from far western Imperial County. Hard to know
what the visibilities were since they were generally north of the
2 stations in Imperial County that measure visibility. However,
winds have trended downward as seen in the 04Z observations.
Expect this trend will continue.

Expect cooler temperatures for Sunday with continued gradual
downward trend heading into Tuesday, when the next system is
forecast to arrive. Model suites seem to have a relatively good
handle on the system, which will take a track over the Great Basin
and exhibit a neutral to positive tilt once it arrives in our
area. Those factors, along with antecedent surface dew points in
the teens, will not be favorable at all for precipitation. Most
notable impact will be a reinforcing push of winds and bottoming
out of our temperatures. Given the projected speeds Tuesday on the
backside of the low, continued with the potential of blowing dust
primarily along and west of the Colorado River.

Thursday and into next weekend, large ridge builds over the
West Coast which will warm our temperatures several degrees above
normal. Possible that Phoenix grabs its first 90F day of the
season on Saturday.


South-Central Arizona including KPHX, KIWA, and KSDL:
Moderate to strong southwesterly flow aloft will continue through
Sunday. Winds in the lowest 2-3kft ASL will favor south and
southeasterly directions through Sunday morning before mixing
(from surface heating) leads to southwesterly directions. At the
surface, winds will follow familiar diurnal patterns.

Southeast California/Southwest Arizona including KIPL and KBLH:
Moderate to strong southwesterly flow aloft will continue through
Sunday. At the surface, west and southwest winds will continue to
weaken overnight but remain somewhat strong just above the surface
but not enough to mention low level wind shear at this time.
Surface winds strengthen again Sunday afternoon but not as strong
as they were today (Saturday).

Aviation Discussion not updated for amended TAFs.


Monday through Friday...
A large area of low pressure will affect the Desert Southwest
early next week, but overall dry conditions will prevail. The low
will usher in cooler air with temperatures falling to below normal
levels through Tuesday. Breezy to windy conditions will also be an
issue during this time leading to increased fire danger conditions
mainly across southeast California and southwest Arizona as
afternoon humidities drop below 15% both days. High pressure will
then build back into the region during the latter part of next
week bringing much warmer conditions starting Thursday. Winds will
diminish on Wednesday and become fairly light starting Thursday.
Minimum RH values of 10-20% are likely through the end of the


Spotters should follow standard reporting procedures.




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