Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 261551

Area Forecast Discussion
National Weather Service Phoenix AZ
851 AM MST WED OCT 26 2016

Strong high pressure building over the region will lead to warming
temperatures through the end of this week with record highs possible
at some locations on Thursday. A slight cool down will occur for the
weekend and early next week, but temperatures will still remain well
above normal and the dry weather will continue for the majority of
the region.


Latest streamline analysis shows an anticyclone in the eastern
Pacific with a ridge axis extending northward into the Desert
Southwest. Mainly clear skies are expected today with temperatures
generally 2 to 6 degrees warmer than those observed yesterday. Minor
adjustments were made to the short-term temperatures this morning.
Otherwise, the forecast remains on track.


Clear skies are abundant across the Desert Southwest this morning as
an upper level ridge continues to build into the region. Models have
trended stronger with this ridge over the past several runs with
500mb heights now forecast to reach 590dm tonight. Warming aloft will
continue into Thursday while also translating to warmer surface
temperatures. Highs today will easily reach into the lower 90s over
the lower deserts with a few spots possibly hitting 95. The warmest
day still looks to be Thursday with 850mb temperatures of 24-25C over
south-central Arizona, or near 99% of climo for this time of year.
Thursday`s highs across the lower deserts should top out in a 92-98
degree range, potentially reaching record highs at Yuma and Phoenix.

By Thursday night, an Pacific low pressure trough reaches the
California coast helping to displace the upper level ridge eastward
over New Mexico and Texas. The track of this Pacific low still keeps
the majority of the dynamics and moisture out of our area, but we
can`t rule out a few showers across southeast California on Friday
with best chances over JTNP. This trough will drop our heights aloft
(500mb heights of 582-585dm), leading to a 2-5 degree drop in highs
for Friday. Dry southwesterly flow with little change in temperatures
is shown into Saturday.

A deep northern Pacific trough dips southward down the West Coast
Saturday night into Sunday before moving into Oregon and northern
California later Sunday. As with the previous trough, this one should
mostly miss us to the northwest, but a slight chance of showers will
exist on Sunday mainly over JTNP. Little change in the jet stream
pattern is seen for early next week keeping any potential weather
systems to our north. The dry southwesterly flow should keep us under
mostly clear skies with temperatures near to a few degrees above
normal for next Monday-Wednesday.


.AVIATION...South-Central Arizona including KPHX, KIWA, and KSDL:

No aviation concerns through the TAF period. Winds will stay light
aob 10 kts and follow normal diurnal headings. Skies will remain
mostly clear with a few clouds aoa 10kft passing over terminals.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation concerns through the TAF period. Winds will stay light
and skies will remain clear. At KBLH, winds will be out of the
northwest, with a few hours of easterlies between the 20Z to 02Z
time-frame. At KIPL, winds will favor a west to northwesterly

Aviation discussion not updated for amended TAFs.


Friday through Tuesday...

Two Pacific weather systems will brush the Desert Southwest Friday
through Sunday. The tracks of these systems will keep the majority
of the moisture out of our area; however, a few showers across
southeast California cannot be ruled out on Friday and Sunday, mainly
over JTNP. These weather systems will also aid in dropping temperatures
in the lower deserts, with high temperatures gradually falling from
the the low to mid 90s on Friday into the 80s on Tuesday.

Minimum humidities will remain near the 20 to 30 percent range each
day with good overnight recoveries. Winds will remain light and
follow normal diurnal headings through the entire period, except for
some periods of afternoon breeziness up to 20 mph in southeast
California Sunday through Tuesday.


Spotter activation will not be needed this week.




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