Severe Thunderstorm Warning 124, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
134 PM MST Mon Jul 15 2024

.SYNOPSIS...Temperatures slightly above normal through the rest
of this week, with typical mid July moisture levels across the
region. This will result in the daily chances for showers and
thunderstorms. The main threats will continue to be strong gusty
outflow winds and heavy rainfall leading to localized flash
flooding.

&&

.DISCUSSION...Area radars indicate scattered shower/thunderstorm
development mainly east/southeast of Tucson and in the White
Mountains attm. Movement of the storms was west at 5-10 mph. The
GOES-16 ECONUS Total Precipitable Water (PW) imagery continues to
show values ranging from near 0.75 inches in the White Mountains, to
around 1 inch in Cochise/Graham counties to over 1.50 inches in
central/western Pima County. The U of A WRF and SPC HREF models both
indicate the areas south/southeast of Tucson to be the most active
today, shifting into central Pima County during the evening hours
tonight. As for the Tucson metro area, both of these models have
minimal convection occuring across Tucson today. However, both
models do bring convection into far eastern/southeastern Pima County
between 4-6 pm today, so if any organization of these storms takes
place, or propagation along outflow boundaries occur, then
convection will be a possibility in Tucson.

Otherwise, a typical mid July monsoon pattern will continue through
the rest of the work week. The mid/upper level high will meander
between the Four Corners and west Texas, which keeps southeast
Arizona in a favorable east/southeast moisture transport regime. The
biggest uncertainty will be the day to day variability in shower and
thunderstorm coverage, any big days versus down days, and the amount
of debris clouds delaying convection initiation. Overall, each day
this week will have the potential for mainly afternoon and evening
showers and thunderstorms. By this weekend, an amplified ridge
builds across the western United States and the mid/upper level high
becomes centered to our north over the Great Basin. This is still a
favorable position for monsoon activity across southeast Arizona,
although as the mid level flow shifts to more of a northeasterly
direction, thunderstorms may have a greater potential of moving off
the rim into the lower deserts. High temperatures will be near
normal today and then 2-4 degrees above normal through the weekend.

The main concerns this week will continue to be the strong, gusty
outflow winds and areas of heavy rainfall leading to localized flash
flooding.

&&

.AVIATION...Valid through 17/00Z.
SCT-BKN clouds at 8k-12k ft AGL thru 16/04Z and again aft 16/18Z,
with diminishing cloud cover between 16/04Z and 16/18Z. SCT
TSRA/SHRA thru 16/04Z, mainly south/southeast of KTUS and in the
White Mountains. SCT TSRA/SHRA developing areawide again aft 16/19Z.
MVFR conditions in TSRA, with mountain obscurations, vsby reductions
and wind gusts to 40+ knots. Outside of TSRA, SFC wind at most
locations 12 knots or less favoring a SWLY thru NWLY direction
during the afternoon/early evening hours and variable in direction
at other times. The exception will be in the upper Gila River valley
near KSAD where WLY/NWLY SFC wind will be 15-19 kts with gusts to 28
kts thru 16/04Z and again aft 16/18Z. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Deeper moisture remains across southeast Arizona,
with typical mid July moisture levels expected through at least the
upcoming weekend. This will result in the daily cycle of mainly
afternoon and evening showers and thunderstorms. The main threats
will be strong, gusty and erratic outflow winds and heavy rainfall
leading to localized flash flooding. Minimum relative humidity
values will be 20-30 percent in most lower elevation locations and
25-40 percent in mountain areas. Away from thunderstorms, 20-foot
winds will generally be 15 mph or less, with afternoon/early evening
gusts to 20-25 mph and light winds overnight. Wind direction will
primarily be southwest through northwest through most of the week.
The exception will be in the upper Gila River valley around Safford,
where afternoon/early evening winds will be west-northwest at 15-20
mph and gusts to 25-30 mph through Tuesday.

&&

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

&&

Zell

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