795
FXUS65 KTWC 221635
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
935 AM MST Sat Jun 22 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.

.UPDATE... The 12Z sounding at KTWC came in signaling lots of
moisture in the area with a PWAT of 1.65 inches. Southerly flow
suggests moisture will continue to move into the area with PWATS
pushing closer to 2 inches into the early afternoon/ evening
hours. This morning there is a thick layer of clouds over much of
southeastern Arizona with pockets of clear to mostly clear skies
in parts of southeastern Pima county, eastern Santa Cruz county,
and western Cochise county. With so much cloud cover this will
make widespread surface heating difficult suggesting that the
areas with more prolonged surface heating will have a higher
likelihood to see isolated thunderstorms.

Atmospheric instability is not as intense as yesterday with
surface CAPE forecast to be around 1000-2000 J/kg and DCAPE around
500-1000 J/kg. Timing of storms will likely begin around noon to
1 PM MST in Santa Cruz and Cochise counties possibly becoming
more widespread as the day continues. There is uncertainty on how
widespread and how intense the storms will be today. This is due
to whether enough widespread surface heating will occur and
enhance instability leading to thunderstorm development. If
storms are to develop, given the high atmospheric moisture and the
slow mean wind aloft, storms will move slowly and be heavy rain
producers with strong gusts possible. Thunderstorms will taper off
around 9 to 10 PM MST this evening.

&&

.DISCUSSION...Deep monsoon season conditions with unseasonably
high moisture levels for late June will continue. Surface
dewpoints in the 60s with precipitable water values between 1.3
and 1.7 inches. Additional moisture is pushing up the gulf and
western Mexico, with Hermosillo dewpoints jumping 25 degrees into
the 60s over the past 24 hours. KYUX vad wind profile showing a
solid 15-20kt southerly flow up to 4k ft deep. We`re seeing a lot
of light shower activity embedded in debris cloud pushing up from
the south this morning. We`ll not be able to match yesterday`s
insolation and moisture may actually end up being too high for
stronger storms with organized outflows. Perhaps too much of a
good thing. Regardless, we once again have Marginal risks from
both SPC (for thunderstorm winds) and WPC (for excessive rainfall)
for today, and that looks reasonable for now.

As central and western areas (generally west of Tucson) continue
to see increasing moisture, we`ll actually see some modest drying
filtering into eastern areas. We may be down a bit in much of
Cochise and Graham counties today after being worked over last
night and this morning.

Still, ensemble means continue to spread the ridge further west
with the high center reconsolidating overhead the first half of
the new week. Warmer mid levels and weaker moisture support
should start to tamp storm coverage down a bit, but additional
surface heating will counter that somewhat. The bottom line is we
keep a chance of thunderstorms going well into next week, however
we should start to rely more on recirculated boundary layer
moisture with the overall trend down. It`s looking more and more
as if we will keep enough moisture around to avoid more excessive
heat headlines. There`s even a hint that we may see some moisture
reinforcement from newly awakened Sinaloa and Sonora later next
week.

&&

.AVIATION...Valid through 23/12Z.
SCT-BKN clouds 7K-12k ft AGL. SCT -SHRA with ISOLD -TSRA this
morning, increasing chances between 22/18Z-23/03Z. TSRA and BKN
CIGS around 6k ft AGL possible thru 23/03Z. East to southeast
winds 10-15 kts. Stronger and erratic outflows possible with
storms. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...A strong increase in moisture will bring better
RH values along with a chance of thunderstorms into 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.
&&

$$

Update...Malarkey
Previous... Meyer

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