High Wind Warning 2, NWS Phoenix, AZ

819 
WWUS75 KPSR 300358
NPWPSR

URGENT - WEATHER MESSAGE
National Weather Service Phoenix AZ
858 PM MST Sun Jan 29 2023

CAZ562-300500-
/O.CAN.KPSR.HW.W.0002.000000T0000Z-230130T0700Z/
Imperial County Southwest-
758 PM PST Sun Jan 29 2023

...HIGH WIND WARNING IS CANCELLED...

Winds have decreased in Southwest Imperial County. Gusts up to 30
mph are expected over the next few hours.

$$

JH

Area Forecast Discussion
National Weather Service Phoenix AZ
216 PM MST Sun Jan 29 2023

.SYNOPSIS...
A low pressure system moving through the Southwest early this week
will result in scattered showers and isolated breezy conditions.
The passage of this system will also allow temperatures to retreat
from near normal levels into a below normal category through the
middle of the week. Dry weather will return during the latter half
of the week with temperatures climbing back to seasonal normals.

&&

.DISCUSSION...
Clear skies abound across the Desert Southwest today. Further
upstream, a positively-tilted trough is evident on water vapor
imagery across northern California. Ahead of this trough,
southwesterly flow is helping to boost temperatures across the
region. High temperatures are expected to reach the upper 60s this
afternoon across the lower deserts, which will likely be the
warmest readings in over two weeks, though this will still be a
few degrees below normal. The warmer conditions will result in
somewhat stronger winds mixing down to the surface later this
afternoon and evening, resulting in areas of breezy conditions.
The most anomalous ECMWF EFI wind values are situated across
portions of southeastern California and southwestern Maricopa
County, where gusts of 30 mph are anticipated. However, even
across the Phoenix area, wind gusts up to 20 mph are possible
later this afternoon, before subsiding in the evening.

A return to cooler and wetter conditions is expected early this
week as the trough moves slowly towards San Diego Monday and to
Yuma by Tuesday. Latest NBM indicates high temperatures will again
struggle to reach the 60 degree mark in Phoenix both days.
Meanwhile, some precipitation is expected though the multi-model
mean has trended drier. Model clusters are more or less stratified
by each ensemble system, with the ECMWF indicating a deeper low
and consequently more rainfall, while the GEFS and CMC are
noticeably drier. Timing of the precipitation is more certain than
the intensity and the best chance appears to be Monday night and
Tuesday, when vorticity and jet-forced ascent is maximized ahead
of the low pressure system. Despite the favorable lift, weak IVT
will generally limit rainfall amounts. Most likely rainfall totals
range from around a tenth of an inch in the Phoenix area, up to
roughly a third of an inch across the Imperial Valley in
southeastern California. However, a few ECMWF members still
suggest a slight (10 percent) chance of considerably more
precipitation above three quarters of an inch.

Latest model consensus indicates the aforementioned low will
drift slowly into northern Sonora Wednesday. A drier northerly
flow will develop behind this system, resulting in a continuation
of the below normal temperatures but an end to the rain chances.
Thereafter, a steady warming trend is likely as a broad ridge
migrates eastward through the intermountain West late in the week.
A return to the 70 degree mark is likely by Friday in Phoenix,
and there is a 30 percent chance temperatures could even reach the
mid 70s by next Sunday.

&&

.AVIATION...Updated at 1755Z.

South-Central Arizona including KPHX, KIWA, KSDL, KDVT:
Light southerly winds will continue through midday before
eventually veering to a westerly/southwesterly component this
afternoon. Breezy conditions will increase heading into the
afternoon with some gusts up to around 20 kts possible. Winds
taper off this evening before switching back around to an easterly
component then transition to a southeasterly component overnight.
Low clouds will begin to increase tonight with BKN CIGs expected
to develop around 3-4 kft overnight into early tomorrow morning.
In addition, VCSH is anticipated near the end of the TAF period at
around 18Z-00Z.

Southeast California/Southwest Arizona including KIPL and KBLH:
Breezy southwesterly winds are expected this afternoon with gusts
up to around 25 kts before weakening this evening. Otherwise,
mostly clear skies are expected with a few clouds developing
around 4-5 kft during the latter part of the period.

&&

.FIRE WEATHER...
Ahead of a weather disturbance moving through the region early this
week, locally gusty winds will develop this afternoon for a brief
period across much of the area. The best opportunity for wetting
rainfall will occur Monday and Tuesday through western districts as
temperatures return into a below normal range through the middle of
the week. Afternoon minimum humidity levels will increase into a 30-
50% range with the passage of this weather system with overnight
recovery will be excellent in a 60-100% range. Conditions will
rapidly dry during the latter half of the week as minimum humidity
levels fall closer to 25-40% and temperature warm back closer to the
seasonal normal providing a good opportunity for prescribed burning.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 11 PM PST this evening for CAZ562.

&&

DISCUSSION...Hirsch
AVIATION...Smith/Leffel
FIRE WEATHER...18