085
FXUS65 KTWC 022146
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
246 PM MST Tue Jul 2 2024

.SYNOPSIS...Chances of showers and thunderstorms today through
Wednesday, then gradually diminishing during the rest of the
week. Some storms will generate strong winds and locally heavy
rainfall. With high pressure building in from the northwest,
daytime temperatures will be trending hotter Friday into at least
early next week.

&&

.DISCUSSION...Relatively deep moisture remains in place today with
precipitable water values ranging from 1.3 to 1.6 inches and
surface dewpoints in the upper 50s to lower 60s. Storms are well
supported in valley locations this afternoon as expected, with
brief pulse severe and heavy rain leading to localized flooding
issues. Coverage will diminish after sunset, however we`ll need to
keep an eye on potential strong outflow from organized convection
in northern Sonora. Wednesday should be another day for scattered
thunderstorms across much of the area.

By Thursday, strong high pressure will build into the desert
southwest from the west coast, resulting in an unfavorable
pattern for moisture along with hotter temperatures. Moisture
trends will definitely be down as a drier northwesterly flow
begins to push the deepest moisture southward, but the question is
how fast and how much? This will factor into both the
thunderstorm forecast and the heat forecast. We`re likely to hold
on to enough moisture to keep a daily chance of convection near
the international border, but areas as far north as Tucson will
get iffy at times late in the week into early next week. Sonora
should stay pretty active, which means we`ll likely see some
outflow moisture counter the drying trend in portions of SE AZ.
That makes potential excessive heat headlines a little more
problematic. It`s likely that we won`t need them across Santa Cruz
and Cochise counties as they maintain the most moisture and best
convection chances. The ebb and flow of our area on the edge of
deepest moisture makes it a tougher call. Even forecasting a few
degrees above the NBM makes some of the days Saturday into Monday
marginal as far north as Tucson and Safford. The pattern is going
to be much less favorable for storms, but the flow may not be
strong enough to scour us out.

&&

.AVIATION...Valid through 04/00Z.
SCT- BKN clouds at 7k-10k ft AGL. ISOLD- SCT TSRA/SHRA between
until 03/05Z. MVFR conditions near TSRA, with mountain
obscurations, VSBY restrictions and gusts to 40+ knots. Otherwise,
outside of TSRA outflows SFC wind generally 10 kts or less,
favoring a WLY/NWLY direction during the afternoon/early evening
and variable in direction at other times. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...There will be the daily chance for isolated to
scattered showers and thunderstorms mainly from Tucson east and
south through the end of the week, with a slight chance of showers
and thunderstorms along the International Border this weekend into
early next week. High pressure aloft will build to our northwest
late this week into early next week, which will result in drier and
hot conditions. The deeper moisture will get pushed south and east
of the region late this week into early next week, with Min RH
values lowering into the 10-18% range across the lower elevations
and 15-30% in the higher elevations. High temperature will warm
considerably late this week through the weekend, with highs 106-113
degrees from Tucson westward and in the Gila River Valley, and in
the upper 90s to 105 degrees across Santa Cruz and Cochise counties.
Excessive Heat will likely be an issue during this time frame.
Outside of any thunderstorm outflow winds, 20-foot winds will
generally be 15 mph or less each afternoon with the occasional gust
of 20-25 mph.

&&

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

$$


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