Severe Thunderstorm Warning 251, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
157 PM MST Wed Sep 9 2026

.SYNOPSIS...Scattered thunderstorms this afternoon and this
evening, especially south and east of Tucson. Storms will be
stronger than we have seen the past several days, with heavy
rainfall leading to localized flash flooding as the primary
hazard from these storms, with a secondary hazard of strong
outflow winds to 40-50 mph east of Tucson. Thunderstorms chances
continue Thursday into the weekend. High temperatures will will
fluctuate between near normal and a few degrees below normal.

&&

.DISCUSSION...This morning's MCS has now turned into an MCV and
is moving towards Puerto Penasco with isolated storms over the
White Mountains, Chiricahuas, and Pinalenos. The atmosphere is
very moist with surface dewpoints in the low to mid 60s across
southeast Arizona. PWATs are 1.3" along the AZ/NM border, 1.5"
over Tucson, and 2" over far western Pima County. Aloft broad
high pressure covers most of the southern half of the country
with two centers over the AZ/NM border and the coast of South
Carolina. This will put southeast Arizona under east to
northeast steering flow, allowing for a possible rim shot day.
Storm movement will probably be more NE-SW coming off the rim
and more east to west elsewhere. CAMs show continued development
over the higher terrain east of Tucson as well as south through
the afternoon with storms then moving into the lower deserts
late afternoon into the evening. The last couple HRRR runs have
kept Tucson on the northern periphery of storm coverage, with
best chances for Tucson seeing storms this evening. The biggest
threat today will be heavy rainfall leading to flash flooding
with the best chances for this south and east of Tucson. The
09/12Z HREF is also hinting at a slight chance for isolated
strong to severe winds late this afternoon and evening over
Graham and eastern Pinal Counties as storms move off the rim.

High pressure stays centered to the west northwest over the next
couple of days keeping southeast Arizona under northeast flow.
Above normal moisture will still be in place leading to
continued storm chances south and east of Tucson Thursday and
Friday.

This weekend into early next week a closed low moves in the
Pacific Northwest and moves inland towards the northern Rockies.
This will shunt the ridge to the east over Texas or the
southeast U.S. Mid-level flow may briefly turn southwest but for
the most part will stay southerly to easterly, which will allow
moisture to stick around. Expect continued daily isolated to
scattered thunderstorms mainly from central Pima County eastward
with the main threat being heavy rainfall. As September
continues the sun angle will continue to lower with less intense
surface hearing. This will result in a slight reduction of
storm intensity without more upper level support, even with
above normal moisture.

&&

.AVIATION...Valid thru 11/00Z.
SCT-BKN 7-10k ft AGL BKN 14-18k ft AGL this afternoon into the
early evening as storms form. Scattered SHRA/TSRA mainly south
and east of Tucson thru 10/04Z. KTUS will be on the northern
periphery of storm activity and could see vicinity TSRA.
Localized thunderstorm outflow winds 30-40 kts possible.
Otherwise, SFC winds will generally be WLY/NWLY 5-10 kts during
the afternoon and evening, then light and terrain driven at
other times. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Scattered thunderstorms this afternoon and this
evening, especially south and east of Tucson. Storms will be
stronger than we have seen the past several days, with heavy
rainfall leading to localized flash flooding as the primary
hazard from these storms, with a secondary hazard of strong
outflow winds to 40-45 mph east of Tucson. Isolated to scattered
thunderstorms continue daily into early next week. High
temperatures will will fluctuate between near normal and a few
degrees below normal into early next week. Min RH values mainly
20 to 45 percent in the valleys and 30 to 60 percent in the
mountains over the next week. RH recoveries will continue to be
excellent overnight. Winds will generally remain less than 15
mph and terrain driven through the week. Expect gusty and
erratic winds around thunderstorms.

&&

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

&&

Hardin

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