National Weather Service Raw Text Product

178 
FXUS65 KPSR 082132
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
232 PM MST Sun May 8 2022

.SYNOPSIS...
A low pressure system will move rapidly through the intermountain
West today, resulting in windy conditions tonight and a brief 
return to below normal temperatures tomorrow. Even cooler conditions
are likely Wednesday, particularly across southeastern California
as another low pressure system moves through the Desert 
Southwest. High pressure will build across the region late in the 
week, resulting in a warming trend along with possibly approaching
record high temperatures by Sunday.

&&

.DISCUSSION...
Latest water vapor imagery reveals a well-defined low pressure 
system moving steadily eastward through the Pacific Northwest 
embedded within a larger long-wave trough draped across the 
intermountain West. In response to the trough, temperatures this 
afternoon are running several degrees lower than at this time 
yesterday. Reaching the 100 degree mark is out of the cards for 
this afternoon in Phoenix, nevertheless slightly above normal 
temperatures are expected, particularly across south-central 
Arizona.

Main impact from the aforementioned low pressure system will be a
tighter pressure gradient and a subsequent increase in low-level 
winds across the Desert Southwest. Latest ECMWF ensemble has 
trended a bit stronger, suggesting gusts could reach as high as 35
mph in the Valley later this afternoon. Even stronger winds are 
anticipated across northern and eastern Arizona where gusts could 
reach 45-50 mph. Meanwhile, further west across the Imperial 
Valley blowing dust has already been detected on visible satellite
imagery and local web cams, and this threat will continue into 
this evening. In the wake of this system Monday, cooler conditions
are likely, with high temperatures struggling to reach the 90 
degree mark in the lower deserts.

Latest model guidance indicates the western CONUS trough will 
pivot sharply Tuesday as another short-wave trough digs southward 
down the California coast. The flow will amplify, resulting in a 
warming trend across Arizona. Another bout of windy conditions is 
likely Wednesday as the vort max moves into southern Nevada. 
Latest NBM indicates a tight thermal gradient will develop between
above normal temperatures across eastern Arizona and well-below 
normal temperatures across southeastern California. Some spots in 
the lower deserts near El Centro may even struggle to reach the 80
degree mark Wednesday afternoon.

General consensus from the GEFS/EPS suggests the persistent
western CONUS trough will be supplanted by an eastern Pacific 
ridge late in the week. This will result in a warming trend and a 
return to above normal temperatures Friday. An abrupt jump in 
temperatures is then likely Saturday/Sunday as the ridge builds 
eastward across the Desert Southwest. Latest NBM deterministic 
indicates a high temperature of 106 degrees in Phoenix next 
Sunday, which is approaching the record high of 107 degrees set in
1937. This equates to roughly an 18 percent chance of at least 
tying the record. NCEP cluster analysis reveals the possibility of
a weak trough that could temper the heat, though this only 
account for about 12 percent of the variability in the multi-model
ensemble. Now is a good time to start thinking about precautions 
to take to protect yourself from the heat.

&&

.AVIATION...Updated at 1730Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: 
Breezy west to southwest flow has set in across the area and will
persist through this evening. Wind gusts this afternoon will peak
near 22-28 kts. Speeds drop off and winds become less gusty
overnight. At KPHX winds will remain southwest all night, but may
switch to southeast or become light and variable at the other TAF
sites after 9Z or so. Skies will be mostly clear.

Southeast California/Southwest Arizona including KIPL and KBLH: 
Westerly wind will dominate today with speeds increasing into the
afternoon. At KIPL wind gusts may reach 35 kts after 21Z with some
visibility reductions due to patchy blowing dust. Winds will
remain elevated all night with wind gusts of 20-25 kts possible.
At KBLH wind gusts of 30-35 kts will develop this afternoon with
patchy blowing dust. Overnight winds quickly diminish and become
variable. Skies will be mostly clear. 

&&

.FIRE WEATHER...
Dry and generally breezy daytime conditions will prevail through
the period. Today will be cooler, but still slightly above normal,
while winds will again be breezy to windy during the afternoon and
evening. Fire weather conditions today will be elevated area-wide
with RHs as low as 10% this afternoon and wind gusts of 25-35 
mph, locally higher across Imperial County and in the higher 
elevations north and east of the Phoenix. The strong winds and low
RHs will result in critical fire weather thresholds being met
today across much of the higher elevations, including southern 
Gila County.

The cooling trend is generally expected to continue through the
middle of the week dropping to below normal for much of the area.
However, day to day breeziness with afternoon wind gusts commonly
in a 20-30 mph will remain possible through the rest of this 
week. Afternoon minimum RHs early this week will generally fall 
between 8-15%, but then lower further toward the end of the week 
as temperatures quickly rebound to above normal by Friday. 
Excessive heat is appearing more likely next weekend, which will 
exacerbate the seasonably dry conditions, however winds will 
generally be light as high pressure builds across the Desert 
Southwest.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Red Flag Warning until 8 PM MST this evening for AZZ133.

     Wind Advisory until 10 PM MST this evening for AZZ557-558-
     560>563.

CA...Wind Advisory until 9 PM PDT this evening for CAZ560-561-568.

     Blowing Dust Advisory until midnight PDT tonight for CAZ563>567.

     Wind Advisory until midnight PDT tonight for CAZ563>567.

     Wind Advisory until 5 AM PDT Monday for CAZ562.

&&

$$

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