406
FXUS65 KTWC 141006
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
306 AM MST Fri Jun 14 2024

.SYNOPSIS...Virga showers stick around through this morning north
and west of Tucson, then expect dry conditions into the middle of
next week. Temperatures remain above normal through the weekend,
with an Excessive Heat Warning in effect for portions of
southeastern Arizona Saturday and Sunday. Then temperatures
decrease to around normal or a couple degrees above normal into
the middle of next week.

&&

.DISCUSSION...Radar shows ongoing very weak virga showers over the
eastern portion of the CWA. These virga showers progressed from
west to east over the region Thursday as an upper level low moved
through southern California helping to advect mid-level moisture
into Arizona. This upper level low will continue moving east
pushing the moisture and cloud cover/virga further east as it
does. Virga will persist through mid-morning with the mid to the
high level clouds clearing out by early afternoon. One lightning
strike has already been observed, and can`t rule out one or two
more through the early morning hours.

The passage of the upper level low will also lead to breezy winds
east of Tucson this afternoon. Gusts could reach up to 40 mph at
some places as intense surface heating mixes stronger winds aloft
down to the surface. Because of this and very low RH values (3-9
percent) a Red Flag Warning is still in effect. Temperatures today
will be a few degrees above normal.

Over the weekend high pressure builds in over the region centered
over Baja California. This will bring temperatures back to similar
levels seen this past Tuesday and Wednesday. Because of this have
opted to upgrade the Excessive Heat Watch to a Warning Saturday
and Sunday.

Beginning late Sunday the high begins to get pushed south as a
fairly strong upper level low moves into the Pacific Northwest.
This will decrease 500mb heights over Arizona leading to
temperatures around normal to a couple degrees above normal for
the first half of the work week. This will also lead to breezy
winds, especially Monday. However there is still some uncertainty
in ensembles with how far south the core of the low will travel,
which could affect high temperatures and the strength of the
winds.

By Thursday ensembles show a very broad area of high pressure
dominating the eastern 2/3 of the U.S. with the desert Southwest
on the western periphery. This could lead to another round of
Excessive heat Thursday and Friday. However, this pattern would
put Arizona in favorable easterly flow for mid to even lower level
moisture advection. Right now the NBM has PoPs of 15-30 percent
along the AZ/NM border next week Thursday and Friday.

&&

.AVIATION...Valid through 15/12Z.
BKN clouds around 13k-20k feet AGL this morning mainly east of
KTUS and KOLS, clearing out by late morning. Virga/light
sprinkles will persist in Graham/Greenlee Counties through mid-
morning. SFC winds less than 10 kts through this morning. After
14/17Z winds become SWLY/WLY with speeds of 10-18 kts and gusts
20-30 kts. The strongest winds will be at KDUG and KSAD terminals.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Weak virga showers will persist through the
morning with a lightning strike or two possible. Expect min RH
values of 3-9 percent in the lower elevations and 7-15 percent in
the mountains through this weekend, along with poor overnight
recoveries between 20-35 percent in most locations. 20-foot winds
will follow typical diurnal patterns, with afternoon/early evening
gustiness due to strong surface heating. Winds will increase today
especially in areas near the Arizona / New Mexico border, where a
Red Flag Warning remains in effect. Another chance of increased
winds may arrive on Monday.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 11 AM Saturday to 8 PM MST Sunday
for AZZ504>506-509.

Red Flag Warning from 11 AM this morning to 8 PM MST this
evening for AZZ152.

Excessive Heat Warning from 11 AM to 8 PM MST Saturday for
AZZ501-502.

&&

$$

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