Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 231010 CCA
AFDPSR

Area Forecast Discussion...CORRECTED
National Weather Service Phoenix AZ
310 AM MST Tue Jan 23 2018

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

&&

.SYNOPSIS...
After a cool start this morning, temperatures will quickly
recover this afternoon with highs warming each day through
Thursday. A weak cold front moves through during the latter part
of the workweek leading to a few breezes in SE California and
modest cooling on Friday. A warming trend is forecast over the
weekend and into early next week as a ridge gradually builds over
our area.

&&

.DISCUSSION...

Latest satellite imagery this morning shows clear skies across
nearly all of the desert southwest. The weak shortwave that
brought cirrus to our area yesterday has now moved off to our
south and east while a transient ridge is currently building over
CA this morning. Clear skies overnight have allowed for strong
radiational cooling with temperatures running similar to what
they were at this time 24 hours ago. The coldest locations around
Phoenix have already dipped into the mid 30s this morning with
several more degrees of additional cooling possible before
sunrise.

Despite the chilly start, temperatures will warm quickly today
with highs nearing 70 degrees this afternoon. This is due to the
aforementioned CA ridge that will be nosing its way into our CWA
this afternoon. Warming will continue into Wednesday as heights
build over our area while synoptic gradients -- and subsequently
surface winds -- remain weak. Models are in excellent agreement
with bringing a trough into the West Coast come Thursday with its
base skirting across northern AZ. Given this trajectory and the
already dry air entrenched across our area, we are certainly not
expecting any precipitation. However, a few breezes will likely
materialize out in SE California on Thursday with gusts staying in
the 20 to 30 mph range.

Now only modest cooling is expected behind this trough on Friday
as models have trended warmer with each run. Highs will likely top
out around 70 on Friday rather than the mid/upper 60s as
originally thought. Regardless, this cool down looks only
temporary as there is 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 Saturday
afternoon. 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:

 Winds in the lower troposphere will be a bit stronger than usual
and favor north and northeast directions today and easterly
directions Wednesday. Daytime surface winds will follow that same
directional pattern with local gustiness. Nighttime and morning
hours will see light surface winds - except perhaps near foothill
areas including some northern and eastern portions of metro
Phoenix. Skies will be clear through Wednesday.


Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Thursday through Monday: Above normal temperatures can be
expected Thursday before a dry cold front moves across the region
later Thursday and Friday. The brunt of the system tracks well to
the north and thus will not bring overly strong winds to the area.
However, there will be westerly breeziness in southeast
California Thursday afternoon and evening (less wind elsewhere).
Highs on Friday will be several degrees cooler across the
forecast area. Over the weekend and into early next week,
there will be a warming trend with lower deserts flirting with 80
degrees by Monday. In addition to the warming trend, there will
also be local north and northeast breeziness.

&&

.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



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