Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 171555
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
855 AM MST Fri Nov 17 2017

.SYNOPSIS...
The dry streak and above normal temperatures will persist through
next week. A storm system passing by to the north of the area
will bring somewhat cooler conditions to the area this weekend,
though this will be short-lived. A building area of high pressure
is expected to bring near record warmth by the middle of next
week.

&&

.DISCUSSION...
An extended fetch of subtropical moisture continues to stream into
the SW Conus with a positively tilted trough and associated cold
front descending towards the four corners region from the Pacific
NW. Embedded within the subtropical fetch are subtle low amplitude
shortwaves coincident with sufficient moisture and an upslope
component around the H7 layer. While the boundary layer remains dry,
some of the resulting virga showers have been reaching the sfc
through northern La Paz and Maricopa counties necessitating a modest
increase in POPs through this area. Otherwise, the thicker cloud
cover had held overnight temperatures in check, and should act to
partially mute insolation the remainder of the day.

&&

.PREVIOUS DISCUSSION...
/514 AM MST Fri Nov 17 2017/
Cooler conditions are expected this weekend as the aforementioned
trough moves steadily through the Four Corners region tonight and
into the Plains Saturday, though temperatures will remain above
normal. The trough will also bring a shot of dry air along with a
break from the high clouds.

Latest model guidance is in good agreement next week, depicting
gradual height rises associated with a building ridge across the
eastern Pacific and the intermountain West. Latest operational GFS
continues to trend warmer while NAEFS 500 mb height percentiles
approach record values, which will translate into near record high
temperatures Wednesday and Thanksgiving. PoPs remain near 0
percent, so the long dry stretch will continue.

&&

.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL; and
Southeast California/Southwest Arizona including KIPL and KBLH:

A weak weather system passing by well to the north will bring
increased winds today with some gusts into the teens this
afternoon at most terminals, especially for KIPL and KBLH. SCT to
BKN mid and high clouds will persist through the evening with
clearing eventually moving through the region early Saturday.
Fairly typical diurnal trends are expected through this afternoon,
but increased synoptic winds may lead to more a north or
northeasterly wind direction late tonight into Saturday.

Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Sunday through Thursday:
Increasing high pressure aloft will bring warming conditions
during the first part of next week with temperatures reaching into
the middle 80s across the deserts late in the period. Minimum RH
values will generally fall into the teens each afternoon through
the period. Light winds will dominate for the duration of the
forecast.

&&

.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.

&&

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

&&

$$

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DISCUSSION...MO/Hirsch
AVIATION...Kuhlman
FIRE WEATHER...Kuhlman


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