Areal Flood Advisory 22, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
942 AM MST Mon Jul 5 2021

.SYNOPSIS...Another good chance of showers and thunderstorms today
before some drying starts to curtail thunderstorm coverage the
rest of the week. As this happens, temperatures will climb several
degrees. Conditions look favorable for an increase in
thunderstorm chances by next weekend or early next week.

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.DISCUSSION...A few showers and thunderstorms were already
developing over the Sky Islands in SE AZ this morning. The morning
upper-air sounding at Tucson was still depicting a moist air mass
over the area. That said, looking at more of the same as the past
few days in terms of potential impacts from locally heavy rainfall
and strong thunderstorm winds. No changes expected to the forecast
for this morning. Please refer to the previous discussion section in
this product for more details.

&&

.AVIATION...Valid through 06/18Z.
SCT-BKN clouds 7k-10k ft MSL through the period with layers above at
times. Expect some isolated -SHRA/-TSRA this morning. This afternoon
expect another round of isolated to scattered SHRA/TSRA mainly from
Tucson eastward. Best chances will be south and east of Tucson. Wind
gusts to 40 kts possible near storms. Sfc winds will be SE this
morning becoming NW this afternoon and evening with speeds 5-10 kts.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Expect slightly reduced storm coverage this week
with isolated to scattered showers and thunderstorms mainly from
central Pima County eastward. Best chances each day will be along
the international border and and AZ/NM border. Min RH values will
generally be in the 20-35 percent range for lower elevations through
the weekend with very good overnight recoveries. Tuesday looks to be
the driest day with RH values in the upper teens from Tucson
northwestward. General winds will be light through the week and
following normal daily trends when not influenced by storms. The
only exception is the Gila River Valley which will see elevated
winds today and Tuesday.

&&

.PREV DISCUSSION.../issued at 305 AM MST Mon Jul 5 2021/
Some early morning shower activity around Tucson metro and
especially near the border. A few lighting strikes down there with
one or two storms generating up to 1 inch of rainfall per hour.
Things will slack off by sunrise, but we'll still probably have a
few showers around.

Our excessively deep moisture with precipitable water values around
1.9 inches and surface dewpoints in the upper 60s to lower 70s is
going to start to recede over the next 24 hours. For today, we
should be able to support a nice solid monsoon day with scattered
showers and thunderstorms, along with typical wet microburst
concerns. Localized flooding and damaging winds associated with
strongest storms.

For the rest of the week, the high center is still on schedule to
shift into a less favorable position to our north and northwest.
As our mid level flow backs around to the northeast in response,
we'll have less moisture upstream. We should start the drying trend
by this afternoon, with model ensemble means dropping precipitable
water values into the 1.10 to 1.30 inch range by Wednesday. Less
moisture is going to mean fewer thunderstorms, but we shouldn't see
a total shutdown. Temperatures will jump several degrees but should
remain within a degree or two of climate normals.

We'll keep an eye on easterly waves, surge activity, and a
repositioning of the high into a more favorable location. Some of
that could come together as early as next weekend, with an upswing
in activity possible by early next week.

&&

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

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