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Forecast Discussion for Phoenix, AZ

000
FXUS65 KPSR 221034
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
334 AM MST Mon Jan 22 2018

.UPDATE...
Updated Aviation and Fire Weather sections.

&&

.SYNOPSIS...
After a cold start to the morning, temperatures will rebound into
the mid 60s for the lower deserts on Monday with a gradual
warming trend through Thursday. Another cold front moves through
during the latter part of the workweek leading to windy conditions
Thursday and much cooler temperatures on Friday. A warming trend
is forecast over the weekend as a ridge gradually builds over our
area.

&&

.DISCUSSION...

Chilly temperatures are being reported across our CWA this
morning as a cold airmass hangs on over our region. Residents will
be waking up to temperatures in the 30s across the Phoenix metro
while a few low desert locations have already dipped down below
freezing! High clouds associated with a jet streak have just
started moving in over our CWA this morning and will continue to
stick around through most of the day. Otherwise, winds will
continue to remain light for your Monday as synoptic gradients
remain weak creating yet another pleasant January day.

A transient ridge will begin nosing its way into our area come
Tuesday and pushing in drier air aloft. As a result, temperatures
will warm a good 5-8 degrees over Monday under crystal clear
skies. This pattern will hold through at least Wednesday. The
ridge is replaced by an incoming Pacific trough on Thursday with
models indicating its base will pass to our north. As such, we are
not expecting any precipitation over our area but some breezes,
mainly out in SE California, will likely materialize on Thursday.
Cooler air behind this trough will infiltrate our area on Friday
pushing high temperatures back down into the 60s for the lower
deserts.

This cool down looks only temporary as there is general agreement
among global models to quickly rebuild heights come Saturday.
This will commence yet another warming trend with highs pushing
into the mid 70s come Sunday. In fact, the NAEFS mean continues
to build heights through the early part of next week with 850/500
mb heights reaching the 90th percentile come Monday. Long range
guidance suggests this would bring surface temperatures into the
upper 70s for the lower deserts with the warmest locations
possibly eclipsing the 80 degree mark. In any event, dry weather
will prevail through the foreseeable future while unseasonably
warm temperatures return this weekend and into early next week.

&&

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

North and northeast oriented winds in the lower troposphere can be
expected today and getting stronger Tuesday. Surface winds over
south-central AZ (including metro Phoenix) will remain light
today and tonight. Further west, surface winds will favor
northerly directions and there will be some minor afternoon
breeziness. High clouds will increase through the morning before
before beginning to clear from west to east this afternoon.

Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Wednesday through Sunday: Well above normal temperatures can be
expected Wednesday and Thursday before a dry cold front moves
across the region later Thursday and Friday. The frontal passage
will lead to breezy to windy conditions along with cooler
temperatures and higher humidities. Over the weekend, a warming
trend begins and humidities decline significantly. North and
northeasterly breeziness can be expected as well.

&&

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

&&

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

$$

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DISCUSSION...Wilson
AVIATION...AJ
FIRE WEATHER...AJ

NWS Phoenix, AZ (PSR) Office Area Forecast Discussion

Discussion Script by Ken True at Saratoga Weather - WFO Script by SE Lincoln Weather