993
FXUS65 KTWC 181044
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
344 AM MST Thu Jul 18 2024

.SYNOPSIS...Temperatures will remain 4 to 7 degrees 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...Residual thunderstorm activity across
southern Cochise and Santa Cruz counties continue to linger at the
time of this writing forming off outflows from evening convection in
Sonora. CAMs have somewhat struggled on resolving this and similar
activity over the past few nights, but anticipate it gradually
diminishing as it pushes west into south central Pima county this
morning.

PWATS are currently running around normal for this time of year at
around an inch near the NM state line to around 1.3 inches in the
Tucson Metro to around 1.5 inches across western Pima county. The
overall upper air pattern over the past couple of days has been
characterized by a mid/upper level high drifting west over AZ/NM.
The flow pattern resulting from the high is currently
easterly/southeasterly, but as the high continues to meander
northwest over the next few days we will see the flow pattern
gradually becoming more easterly/northeasterly heading into the
weekend. The northeasterly flow regime favors storms forming off the
higher terrain/Mogollon Rim and then propagating into the lower
deserts of Southeast Arizona through the late afternoon hours. Right
now, Saturday and Sunday appear to be the best chances for
convection of that nature.

For today, HREF/CAMs are depicting scattered showers and
thunderstorms primarily forming over Santa Cruz and southeastern
Pima counties this afternoon as well as in the White Mountains and
elevated terrain. The main concerns with these storms continues to
be gusty outflow winds and locally heavy rainfall leading to the
possibility for isolated occurrences of flash flooding. Temperatures
will be a degree or two warmer across southeast Arizona today and
tomorrow resulting in isolated areas of major HeatRisk. Decided to
hold off on heat related products at this time as there is not
enough widespread Major HeatRisk to warrant a headline.

&&

.AVIATION...Valid through 19/12Z.
SCT-BKN clouds at 8k-12k ft AGL gradually diminishing from east to
west after 18/12Z and forming again after 18/19Z associated with SCT
TSRA/SHRA development. MVFR conditions in TSRA, with mountain
obscurations, vsby reductions, and wind gusts to 40+ kts. Outside of
TSRA, SFC winds at most locations will remain under 12 kts favoring
SWLY thru NWLY directions during the afternoon/early evening hours
and variable in direction at other times. 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 during
the afternoon will primarily be southwest through northwest into the
weekend.

&&

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

&&

$$

DVS

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