Areal Flood Advisory 2, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
115 PM MST Wed Jun 30 2021

.SYNOPSIS...Scattered thunderstorms are expected into this evening,
primarily over higher terrain and from Tucson south and west.
Thereafter expect widely scattered to scattered showers and
thunderstorms through the weekend with high temperatures generally a
few degrees cooler than average.

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.DISCUSSION...Convective development ongoing early this afternoon as
expected, initially across the higher terrain with gradual
development in valley locations. Considerable cloudiness east of a
line from Bisbee-Safford may limit convection for these areas with
more general scattered shower activity. PWAT values currently range
from 1.25" to 1.5" from Tucson westward and 1.1" to 1.3" east of
Tucson. These values are certainly high enough to generate locally
heavy rainfall where enough solar insolation occurs, especially
given fairly slow storm motion towards the south and southwest less
than 10 mph. The main concern will continue to be across burn scar
regions including the Bighorn on the Catalinas as flash flooding can
occur there with as little as 0.5" per hour. Showers and perhaps a
few thunderstorms have the potential to linger well into the evening
hours aided by the inverted trough over far eastern sections of the
area.

PWAT values are progged to be on the increase on Thursday, at or
above 1.5" for areas from Tucson westward. However, there is
considerable uncertainty on how Thursday shakes out and much of that
will depend on what evolves today and tonight. There is the
potential for considerable cloudiness limiting convective
development. However, in areas that get enough sun, showers and
thunderstorms may produce areas of heavy rainfall given the deeper
moisture profile.

Looking at Friday and through the weekend, an overall favorable
early monsoon pattern will continue for early July as inverted
troughiness extending northward from Sonora may give convection a
bit of a boost. The general steering pattern will be from the east
as the high pressure aloft remains centered to our north. Still
plenty of moisture into early next week as well for daily rounds of
mainly afternoon and evening showers and thunderstorms as the high
remains to our north.

High temperatures will remain a few degrees below normal through
Monday then increase to near normal values by the middle of next
week.

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.AVIATION...Valid through 02/00Z.
Expect SCT-BKN clouds 10k-14k ft MSL for most of the period.
Scattered SHRA/TSRA will be possible over most of the area through
about 01/04Z with perhaps a bit of a lull overnight, then increasing
aft 01/18Z. Wind gusts 40-50 kts will be possible near TSRA.
Otherwise, SFC winds mostly ELY/SELY 8-12 kts with gusts to 20 kts
in the afternoon. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Monsoonal moisture continues to increase across
southeast Arizona, allowing for daily showers and thunderstorms
through the weekend. Minimum humidities generally reach the 20s and
30s in the lower elevations and 40s in the mountains with very good
overnight recoveries. Easterly breezes continue for much of the
area, gradually shifting to a typical diurnal pattern Friday into
the weekend with speeds less than 15 mph.

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

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