FXUS65 KTWC 200809
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
109 AM MST Wed May 20 2026

.SYNOPSIS...
A dry weather system to our north will bring 
southwesterly breezes today with slightly less wind thereafter 
into the weekend. Temperatures will be slightly below to near 
normal for the rest of the week with Minor HeatRisk. Another
weather system will be moving into the region by the start of 
the new week, bringing slight chances for rain showers and 
thunderstorms. 

&&

.DISCUSSION...Water vapor imagery this morning continues to show
a broad trough axis across Utah towards Baja California. High
level moisture will continue to eject into the region in a form
of cloudy skies. This trough will continue another day of
southwesterly breezes across the region. As a result, elevated
fire weather conditions will exist for the areas east and south
of Tucson. 

A shot of energy from the Pacific Northwest will push the upper
level trough off tomorrow, but it will leave behind a weak low
circulation just east of Baja California. This low will
transition to our south throughout the week. Winds will start 
lessen more on Thursday through the start of the weekend. The 
weak low will bring upper atmospheric moisture into the region 
by the end of the week. Chances for rain showers will be less 
than 10% with this forecast package and mainly be cloud build 
ups and virga for Friday and Saturday afternoon. 

Chances for rain showers and thunderstorms will be increasing on
Sunday through Tuesday. A minor ridge will form to our east with
another low pressure coming from the Pacific which will bring
better moisture into the region. Ensemble model precipitable
water content will increase up to 0.61-0.78 inches; the 
25th-75th percentile at Tucson. Leading to 10-30% chances for 
rain showers and thunderstorms on Monday with the higher 
chances for areas east of Tucson. Forecasted rainfall amounts 
will be on the low end, less than 0.1 inches for this event 
which indicates a more of a dry thunderstorm environment for the
southeast Arizona. 

&&

.AVIATION...valid through 21/12Z. 
SCT-BKN clouds AOA 20K feet AGL and another FEW-SCT layer at or
around 15K feet AGL through the daytime period. SKC conditions 
will prevail after 21/03Z from the west and clearing east 
through the end of the forecast period. SFC winds this morning 
less than 12 kts and SLY/SELY, and again after 21/04Z. By 
20/18Z, SFC winds SWLY/WLY at 10-18 kts with gusts up high as 30
kts. Aviation discussion not updated for TAF amendments. 

&&

.FIRE WEATHER...
Dry and breezy conditions today resulting in elevated fire 
weather conditions for areas east and south of Tucson with
brief locally near critical conditions existing in the 
southeastern portion of Cochise County. For Thursday through 
Sunday, winds will be generally be less than 15 mph with min 
relative humidities sitting in the teens to the mid-20s. Mid to 
upper level moisture will approach as early as this weekend 
south and east of Tucson, but the more impactful moisture will 
likely hold off until early next week as another weather system 
approaches. There is a 10 to 30 percent chance of showers and 
thunderstorms Monday for much of southeast Arizona, and these 
chances will trend towards the New Mexico border Tuesday, 

&&

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

&&

$$


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