000
FXUS65 KPSR 122330
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
430 PM MST Mon Apr 12 2021

.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
Dry conditions will remain across the region this week, but the
influence of a weather disturbance north of the area will result in
a slow decline in temperatures through Thursday. Breezy to locally
windy conditions are forecast for Tuesday with locally daytime
breezy conditions through the rest of the week. Increasing high
pressure should then turn temperatures gradually warmer heading into
the weekend, likely topping 90 degrees again as early as Saturday.

&&

.DISCUSSION...
Nearly zonal flow is seen across the Desert Southwest this
afternoon, just south of a very broad cyclonic circulation
dominating most of the western and northern CONUS. A shortwave
trough within this flow is currently digging straight south into
Washington state. This shortwave will be the main driver of our
sensible weather through most of the week. As the trough shifts
southward into the Great Basin by the end of Tuesday, heights
aloft across the Desert Southwest will gradually lower resulting
in modestly cooler conditions. Highs are forecast to drop into the
mid to upper 80s starting Wednesday, with near normal readings for
the first time this month. The approaching trough will also cause
an increase in height packing across our region, thus leading to
stronger winds for Tuesday through Thursday. Winds Tuesday look
to be the strongest with widespread gusts into a 20-30 mph range
with locally higher gusts across southeast California. Winds
become particularly strong Tuesday evening/night for far southwest
Imperial county where gusts could reach 50-55 mph. Winds
Wednesday and Thursday do look to fall off somewhat with gusts
mostly ranging between 20-25 mph. Cloudier conditions these days
could limit mixing potential and max gust potential as well.

Model ensembles remain in good agreement showing the quasi-
stationary trough north of our region weakening and likely ejecting
some of its energy eastward on Friday. Another piece is likely to
hang out across the Great Basin before potentially tracking
southeastward through Arizona this weekend. Dry conditions are still
heavily favored during this period, while temperatures are more than
likely going to be trending warmer Friday into the weekend. There
have been some gulf surges the past couple of nights and expected
the next few, which boosts surface moisture. Some patchy advection
fog could work north toward Yuma and the Imperial Valley the next
couple of mornings. The lingering trough this weekend should keep
temperatures from rising much, but eventually an upper level
ridge is likely to overtake the region at some point early next
week. This transition to higher heights is likely to push daytime
highs back into the lower 90s by Sunday and potentially into the
mid to upper 90s later next week if the ridge does end up settling
over our region.

&&

.AVIATION...Updated at 2325Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Southwesterly to westerly winds will prevail through the rest of
this evening with speeds mostly between 8-12 kts. The overnight
easterly winds are anticipated to begin later than usual around
9Z. For tomorrow, another extended period of crosswinds are
possible as winds resume a mostly southerly heading between 16-19Z
at speeds of 6-10 kts. The westerly to southwesterly winds should
predominate by 20/21Z and last through the afternoon and evening
hours. The westerly winds will have stronger speeds of of 10-15
kts and gusts of 20-25 kts.

Southeast California/Southwest Arizona including KIPL and KBLH:
At KIPL, westerly winds are likely to prevail through the TAF
period, outside of a few hours with light and variable winds
Tuesday morning. For tonight, intermittent strong gusts of 20-25
kts are possible beginning around sunset and lasting until 6Z. At
KBLH, wind directions will oscillate between the south and
southwest through tomorrow. Stronger southwesterly/westerly winds
are anticipated at both TAF sites tomorrow afternoon and evening
with speeds nearing 15 kts and gusts approaching 25-30 kts.

&&

.FIRE WEATHER...
Thursday through Monday:
Near normal temperatures are expected Thursday and Friday, but
should gradually warm back up to the low 90s area wide by Sunday.
Afternoon breeziness will be common with the typical upslope
favored areas experiencing the strongest gusts. Stronger winds
will be likely Thursday and Sunday yielding a period of elevated
fire danger. Dry conditions will also prevail through the week
with afternoon minimum humidity values falling to 7-10% while
overnight recovery will be poor only bouncing back to a 20-40%
range.

&&

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

&&

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

$$

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

NWS PSR Office Area Forecast Discussion