Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 182100
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
200 PM MST Mon Mar 18 2024

.SYNOPSIS...An upper level low over Arizona will bring unsettled
weather, especially into this evening to locales northeast of Tucson
where scattered showers and even a few thunderstorms are expected.
Precipitation chances shift Tuesday and Wednesday into the higher
terrain of Graham and Greenlee County with dry conditions elsewhere.
Dry and warmer area-wide Thursday through Saturday, then another
storm system by Sunday into early next week with cooler
temperatures, gusty winds and precipitation chances.

&&

.DISCUSSION...The upper low has retrograded west this afternoon into
southeast California. Our forecast area is now on the eastern flank
of this system and we`re seeing scattered showers and isolated
thunderstorms from Tucson northeastward. In addition, strong east to
southeast winds continue for eastern sections of our forecast area
and we`ve had a gust to 45 MPH at Safford airport in the past couple
of hours. Latest HREF/HRRR is in good agreement with the placement
of convection this afternoon and matches what we`re seeing on radar.
Main area of concern with a few stronger storms is eastern Pinal and
western Graham County. The strongest storms will have gusty winds to
around 40 mph and small hail. As we get into the evening hours,
showers will tend to diminish with the main focus shifting into
Graham and Greenlee Counties. The strong gradient winds for eastern
areas will also lessen as the afternoon progresses and into the
evening. Snow levels today are 8000 to 8500 feet with several inches
of additional snow possible on the mountain peaks around 9000 feet.

The upper low is finally going to shift eastward Tuesday across
central Arizona. However, drier air on the southern flank of the
system should keep most of our forecast area dry with the exception
of the White Mountains and adjacent higher terrain of
Graham/Greenlee Counties. The low will shift into New Mexico
Wednesday as it opens up with slight chances of showers continuing
for the White Mountains with dry conditions elsewhere. Temperatures
will remain near seasonal normals for most locales through Wednesday.

Drier and warmer conditions Thursday through Saturday with transient
shortwave ridging Thursday and Friday. West to southwest flow aloft
increases slightly Saturday ahead of the next system with an uptick
in breezes. The more notable changes come in by Sunday/Monday as
another trough moves into the western US. Still some differences in
the ensembles on timing and trajectory but confidence is increasing
in a cooling trend with gusty winds and precipitation chances Sunday
into early next week.

&&

AVIATION...Valid through 20/00Z.
SCT-BKN clouds 7k-10k ft MSL mainly from KTUS eastward. SCT
-SHRA and ISOLD -TSRA mainly to the northeast of KTUS across eastern
Pinal, Graham and Greenlee counties thru 19/03Z. SFC winds ELY/SELY
for KSAD and KDUG 15-25 kts with gusts 30 to 35 kts this afternoon,
diminishing to around 10 kts aft 19/02Z. Further west for KTUS/KOLS,
westerly/southwesterly SFC winds 6 to 12 kts this afternoon,
becoming variable at 10 kts or less tonight. SFC winds become
SWLY/WLY 8-16 kts aft 19/12Z for all locales. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...Scattered showers and isolated thunderstorms into
this evening from Tucson northeastward, then Tuesday and Wednesday
mainly in the White Mountains. Temperatures near normal through
Wednesday, then warming to above normal by Thursday. Gusty east to
southeast winds with gusts above 30 mph for eastern areas today,
otherwise typical diurnal wind patterns are expected through the
week with minimum RHs remaining above 20% through Wednesday then
dipping into the teens in the valleys thereafter. Dry Thursday
through Saturday then another weather system around Sunday and early
next week with gusty winds, cooler temperatures and rain chances.

&&

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

&&

$$

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