Mount Lemmon, Arizona Weather Forecast Discussion

313
FXUS65 KTWC 282033
AFDTWC
Area Forecast Discussion
National Weather Service Tucson AZ
133 PM MST Sun Sep 28 2025
.SYNOPSIS...Drier air has moved in across most of the area this
afternoon with just a few showers and thunderstorms limited mainly
to Graham and Greenlee Counties. Drier conditions prevail areawide
starting Monday. High temperatures near normal to start the work
week, warming to above normal levels later in the week.
&&
.DISCUSSION...Upper low is currently located across north central AZ
and is continuing to move towards the east-northeast this afternoon.
Considerably drier air across southeast AZ this afternoon and this
is seen by lower surface dewpoints dropping into the 40s for many
locales and a 0.74 inch PWAT per the 18Z KTWC sounding. Just a bit
more moisture and dynamics in Graham/Greenlee Counties this
afternoon to support very isolated showers and thunderstorms, with
areas outside of that region staying dry today.
A more typical weather regime for the end of September and early
October for our region this week with transient shortwave ridging
Monday, followed by southwest flow as a weak shortwave passes well
to our north on Tuesday. Thereafter, increased heights with broader
ridging the second half of the work week. This will lead to a return
to dry conditions area-wide with near normal temperatures Monday,
warming to about 5 degrees above normal later in the week.
&&
.AVIATION...Valid through 30/00Z.
SKC-SCT 8k-10k ft AGL thru . ISOLD -SHRA/-TSRA northeast of a KTUS-
KDUG line thru 29/02Z. SFC winds SWLY/WLY 8-14 kts thru 29/03z, then
becoming SELY less than 8 kts. SWLY/WLY winds resume at 6-12 kts aft
29/19Z. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Isolated showers and thunderstorms this afternoon
across Graham and Greenlee Counties with generally dry conditions
elsewhere. Winds generally south to southwest through this week with
speeds up to 15 mph and gusts up to 20-25 mph. Minimum RHs between
25-35 percent this afternoon will lower through the week as a drier
airmass becomes more established across Southeast Arizona, lowering
to 15-25 percent the second half of the work week. Temperatures will
be near normal Monday, warming to above normal levels the second
half of the work week.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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NWS TWC Office Area Forecast Discussion