065
FXUS65 KPSR 210424
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
924 PM MST Sun Jan 20 2019

.UPDATE...
Updated Aviation Discussion.

&&

.SYNOPSIS...
A dry cold front will arrive Monday, bringing cooler temperatures
and breezy conditions to the region. Wind will subside after
Monday, but the cool down will linger Tuesday and Wednesday.
Expect a solid warm up toward the end of the week and heading into
weekend.

&&

.DISCUSSION...
Quiet and warm weather across our forecast area this afternoon. A
long wave ridge is overhead but shifting to the east (ridge axis
nudging into NM now) as an upper level low approaches the West
Coast. Not good phasing with the incoming low, with the center
circulation well behind the moisture plume. Not much change in
forecast thinking as system is well grasped by models at this
point.

The upper level low will quickly move to about the Four Corners in
24 hours or so. Very little frontogenetical forcing noted with the
incoming system and without much moisture, any isentropic lift
won`t matter much. All in all should be a dry system for lower
elevations, just very minor pops north/east of Globe. More notable
features will be an increase in winds - first across SE CA tonight
then area-wide Monday. With the strong cross mountain winds, rotor
activity is likely which may develop variable but impactful winds
for Imperial and eastern Riverside counties. Right now, strongest
winds will be in the Joshua Tree NP area and far SW Imperial
County. Wind Advisories are in effect for those area. Also added
patchy blowing dust to western parts of our CWA.

Cool temperatures will also come with this system. High
temperatures Monday will be a good 5-10F cooler than today.
Tuesday and Wednesday mornings will be crisp, with sheltered and
higher elevation areas possibly seeing temperatures at or below
freezing.

A steady warming trend will start Wednesday and continue into the
weekend with a rather robust ridge entrenching itself across the
West. While news headlines will no doubt be filled with cold and
snow across the Eastern US, we will be on the flip side of that
weather pattern with above normal and dry weather.

&&

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

Light winds and BKN to OVC high clouds will persist through tonight.
A dry weather system will move through the region early Monday,
which will cause gusty westerly winds to develop late-morning
continuing through the afternoon hours. Gusts will be around 17-22
kts. Increasingly stronger winds with height will exist, especially
above 5 kft AGL, through the day Monday with the passage of a jet
streak over the region. FEW to SCT cumulus may accompany a passing
cold front during the late-morning. Skies then clear Monday
afternoon with dry northwesterly flow. Winds subside Monday night.

Southeast California/Southwest Arizona including KIPL and KBLH:

A dry weather system will bring windy conditions to SE CA during.
Late tonight, surface winds begin to increase, especially closer to
mountains. With strong winds above the surface overnight, LLWS
and/or rotor winds may become an issue especially along and east of
the coastal mountain range. Breezy winds will become more widespread
and uniform late Monday morning, easing the LLWS/rotor concern.
Gusts during the Monday afternoon will likely reach 20-25 kts. Winds
ease slightly Monday night, but breezy northerly winds may continue
with a tightened pressure gradient over/near the Lower Colorado
River Valley, especially at KBLH.

Aviation Discussion not updated for amended TAFs.

&&

.FIRE WEATHER...
Tuesday through Saturday:
An exiting weather system on Tuesday will bring gusty northerly
winds over the area, especially across the Lower Colorado River
Valley where gusts will approach 35 mph. Dry conditions under high
pressure aloft will then dominate through the rest of the period.
Below normal temperatures for Tuesday and Wednesday will rise
through the end of the week reaching above normal by Friday.
Humidity readings will remain fairly stable dipping down to
between 15 to 25 percent each day. After the breezy to windy
conditions on Tuesday, winds will generally be light beginning
Wednesday.

&&

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

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 1 PM PST Monday for CAZ560-562.

&&

$$

DISCUSSION...Iniguez
AVIATION...Iniguez/Benedict
FIRE WEATHER...Kuhlman

NWS PSR Office Area Forecast Discussion