Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 241552
Area Forecast Discussion
National Weather Service Tucson AZ
852 AM MST WED AUG 24 2016
.SYNOPSIS...A drying trend will continue to keep most
thunderstorms north and east of Tucson through Thursday. Storm
coverage will increase across the area Friday and Saturday. High
temperatures will generally be within a few degrees of normal into
this weekend. Hotter temperatures are expected next week.
.DISCUSSION...Another unfavorable KTWC sounding for thunderstorms
this morning, with precipitable water values around 1 inch and
very limited convective potential. Even lower values are noted
south and southeast of Tucson on CIRA layered precipitable water
totals. Surface dew points are down about 5 degrees compared to 24
hours ago with another mix out into the 40s this afternoon.
That being said, conditions are favorable for strong outflow from
Mogollon Rim convection today (including mountains of far
northern Graham and Greenlee counties) to push through Graham and
eastern Pinal counties, with convection firing north and northeast
of Tucson. The problem is going to be moisture, since the further
south the outflow propagates, the drier the environment. Best
guess is that even with a decent outflow easily making it this
far south, Tucson will be hard pressed to see measurable precip as
development along the outflow becomes more limited. We will need
to watch for blowing dust with the outflow as well.
Please see the previous discussion below for additional details
beyond today and tonight.
.AVIATION...VALID THRU 25/18Z.
VFR conditions through the forecast period. Isold -TSRA/-SHRA
developing after 24/20z mainly over mountains north and east of
KTUS with most impact for KSAD. Clearing skies expected aft
25/04z. Surface wind generally less than 12 kts outside of
thunderstorm outflows during the afternoon. Aviation discussion
not updated for TAF amendments.
.FIRE WEATHER...Isolated thunderstorms will occur mainly near
mountains east and north of Tucson through Thursday. Increasing
storm coverage is then expected Friday through Sunday as
monsoonal moisture increases from the south. 20-foot winds into
the upcoming weekend will be terrain driven and less than 15 mph
in most locations. Expect the potential for strong and gusty winds
near thunderstorms and stronger afternoon and early evening winds
today in the upper Gila River valley, with northwest winds of
.PREV DISCUSSION...Thursday will see very isolated thunderstorm
activity, mainly along the international border and across the
White Mountains. Highs around normal.
For Friday, the WRFNAM is much more active than the WRFGFS as
moisture starts to return to the area. Made little change to the
official forecast as it does show an uptick in storm coverage. Could
end up being more active than what we are currently advertising.
Scattered showers and thunderstorms across most of the area on
Saturday. Highs for both Friday and Saturday will be a few degrees
Sunday, drier air starts to push in from the west limiting storms to
the eastern areas. Highs around normal.
Monday and Tuesday, upper ridge builds over the area resulting in
warmer high temperatures with triple digit highs returning to Tucson
and other lower elevation areas. Slight chance of afternoon and
early evening thunderstorms relegated to the higher terrain east of
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