Severe Thunderstorm Warning 286, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
117 PM MST Sat Aug 10 2024

.SYNOPSIS...
Isolated to scattered mainly afternoon and evening showers and
thunderstorms each day through the middle of next week. Storms
will have the potential for heavy rainfall and strong wind gusts.
High temperatures will be within a few degrees of normal through
the next week.

&&

.DISCUSSION...
Today's weather is being brought to us by an upper high centered
over SE New Mexico and Texas, and a weak upper low floating over
Baja California. Conditions are a bit more favorable for
convection relative to yesterday, with more instability and a
weaker cap in place. As of this writing, isolated convection has
started up generally from Pima / Pinal / Santa Cruz Counties and
westward. These are the areas with the best projected instability
today and should remain to be the areas of focus. With
precipitable water content around 1.50", and DCAPE values in the
1000-1500 J/kg range, both flash flooding and strong damaging
winds will be threats today.

We may see an uptick in convective activity on Sunday as
atmospheric moisture content increases again. While most of the
region will have some threat of thunderstorms on Sunday, the best
chances will be along the International Border.

For a few runs now, GFS and ECMWF ensembles have been hinting at
Monday potentially being the most active day across the region.
This may be dependent on the previous day's activity.

We start to see a bit of model disagreement starting Tuesday, and
this uncertainty propagates through the rest of next week. One
potential solution entails the upper high remaining over the
Southern Plains, and moist southerly flow keeping active
convection over the forecast area through next week. Another
potential solution has a ridge building over Arizona from the
eastern Pacific, with strong subsidence raising temperatures and
minimizing the potential for convection late in the week. Our
forecast is somewhere in the middle with this lower confidence.

&&

.AVIATION...Valid through 12/00Z.
SCT-BKN clouds at 6k-9K ft AGL and BKN-OVC clouds at 10k- 14k ft
AGL from 10/19Z through the end of the forecast period. Isolated
to scattered SHRA/TSRA persisting through 10/04Z before slowly
diminishing. The best chances of these storms will be from around
SAD-OLS and westward today. MVFR conditions near TSRA, with VSBY
restrictions, wind gusts to 45+ kts, heavy rain and mountain
obscurations. Outside of thunderstorm wind gusts, wind speeds will
be less than 12 kts, favoring an SELY/SLY direction. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...
Isolated to scattered mainly afternoon and evening showers and
thunderstorms are expected through the weekend, with an increase
in coverage early next week. Min RH values will be in the 20-30
percent range through the weekend, increasing early next week into
the 25-40 percent range in the valleys (and higher in the
mountains). Outside of thunderstorm outflow winds, 20-foot winds
will generally be 15 mph or less, with afternoon/early evening
gusts to 20-25 mph and light winds overnight.

&&

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

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Aviation...Dang
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