356
FXUS65 KTWC 212028
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
128 PM MST Fri Jun 21 2024

.SYNOPSIS...A strong increase in moisture will bring daily chances of
thunderstorms to the area into next week. Some storms will
generate strong outflow winds with locally heavy rain possible.
This will also knock several degrees off of the heat. We may see
temperatures climb back up a bit as high pressure settles
overhead next week.

&&

.DISCUSSION...Partly to mostly cloudy skies early this afternoon
across southeast Arizona with considerable mid and high level
cloudiness. We`re now seeing cumulus clouds developing due to the
heating, moisture and instability across the region as PWAT values
range from 1 to 1.5 inches across the area. Gusty east to southeast
winds continue this afternoon but wind speeds have certainly
diminished compared to yesterday and earlier this morning. HREF/CAMs
are showing convective development this afternoon primarily in a
north-south zone across central portions of the forecast area. The
center of this line would be from around Nogales-Tucson-Kearny.
MLCAPE values are locally in the 1000-1500 J/KG range this afternoon
per the latest RAP mesoanalysis with DCAPE values near 2000 J/KG.
This will result in strong/gusty outflow winds from the thunderstorm
activity that does develop. In addition, some locally heavy rainfall
of around 0.5"-1" is expected with the stronger storms. The
convection will make it a bit farther west today compared to
yesterday as greater moisture levels allow additional westward
development on outflow boundaries. In addition, some areas of
blowing dust may occur primarily in Pinal County due to gusty
outflow winds. A few of the CAMs are persisting shower activity into
the overnight but stronger thunderstorms will mainly occur through
the afternoon into early evening.

Additional moisture will move into the area tonight and Saturday
from Sonora and the Gulf of California. This will raise the PWAT
values this weekend into the 1.25" (eastern areas) to around 2"
(western deserts). These are very anomalous for late June, running
about 3 to 4 standard deviations above normal. With abundant
moisture and the mid/upper level high to our east, our region will
continue to see a favorable steering flow from the southeast. That
combination of deep moisture, favorable steering and instability
will result in scattered mainly afternoon and evening showers and
thunderstorms this weekend for the entire forecast area. The
stronger storms will have both wind and localized flooding threats,
as rain amounts in excess of 1 inch are possible with the stronger
storms. Temperatures will drop back down to seasonable levels this
weekend.

For Monday and continuing through next week, the mid/upper level
high will gradually strengthen and shift a bit closer to southeast
Arizona. Therefore, while the moisture isn`t going anywhere and will
be recycled each day, the mid/upper level high location and
potential subsidence will tend to shift the focus of convective
activity a bit closer to the higher terrain overall with the better
chances starting to focus a slightly more towards areas from Tucson
south and eastward. Temperatures will nudge back up next week,
running a few degrees above normal.

&&

.AVIATION...Valid through 23/00Z.
SCT-BKN clouds 10-14k ft AGL. SCT -TSRA will with TSRA and BKN CIGS
around 6k ft AGL possible thru 22/03Z. Sct -SHRA then possible
overnight but confidence is low. East to southeast winds 10-20 kts,
diminishing after 22/03Z. Stronger and erratic outflows possible
with storms. Additional SCT -TSRA activity expected aft 22/18Z thru
the end of the period. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Gusty east to southeast winds continue to diminish
this afternoon. A strong increase in moisture will bring better RH
values along with a chance of thunderstorms into at least early next
week. Some storms will generate strong and erratic outflow winds.
Moisture is expected to be deep enough for some storms to generate
locally heavy rain.

Temperatures may heat back up by mid week as high pressure builds
nearly overhead, however we should keep some storm chances around.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

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