348 FXUS65 KTWC 140921 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 221 AM MST Mon Apr 14 2025 .SYNOPSIS... Unseasonably warm temperatures continue through much of the coming work week, with afternoon breeziness. A weather system moving into the Desert Southwest late in the week into the weekend will provide cooler afternoon temperatures and even a slight chance of light precipitation. && .DISCUSSION... Water vapor imagery early this morning depicts an eastern Pacific trough with a downstream channel of sub-tropical moisture aloft over northern Sonora and Arizona. This moisture feed has produced widespread upper level clouds, with dry air remaining in the low to mid levels underneath. The previous evening KTWC RAOB depicts a deep mixed layer up past 600mb, an indicator that any features coming off this eastern Pacific trough in its current state will have a difficult time producing precipitation. Today will feature lighter winds than yesterday as southeastern Arizona is between mid-level jet features. Still, breezy 10 to near 20 mph winds out of the southwest will be common this afternoon. As the air mass aloft hasn`t changed substantially, neither will today`s high temperature forecast from yesterday with highs in the mid 80s to lower 90s across desert locations. A series of jet streaks ejecting from the eastern Pacific trough, culminating with the trough crossing the region this weekend, will bring breezy to windy conditions to southeastern Arizona through much of this week. The first crosses late Monday to early Tuesday, producing a very slight signal of light precipitation in central to western Arizona by a few EC/GEPS ensemble members. Given antecedent dry air and the weak amplitude of the crossing shortwave, any measurable precipitation looks very unlikely. Then Wednesday and Thursday a more substantial southwest-northeast oriented jet sets up over the region. With dry air still in place, this period should be the more likely time frame for near critical to potentially critical fire weather conditions, especially Thursday. The arrival of strong mid-level winds better lines up with diurnal mixing potential on Thursday, but if they arrive earlier Wednesday may also be a concern. Thursday also begins a period of progressively cooler temperatures that is expected through the weekend. The initially closed eastern Pacific low is forecast to open and push east, forced by a northern stream wave dropping south through the Great Basin late Thursday through Friday. The trough axis should be crossing the region on Saturday, which should bring chances for precipitation. Though guidance is fairly consistent in this feature, both inconsistency in its depth and a likely weak moisture profile keeps any precipitation potential on the light side. Breezy winds will accompany this transition each day through the weekend, which again may produce near critical fire weather conditions near the New Mexico border on Friday, depending on how quick moisture pushes in. Temperatures should fall to around normal by Friday and then below to potentially well below normal on Saturday before rising again in the following days as the trough exits east. && .AVIATION...Valid through 15/12Z. SCT-BKN clouds at 15k-20k feet, clearing after 15/06Z. Winds becoming south to southwesterly and increasing to 9-15 kts after 14/17Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Dry conditions and above normal temperatures are expected to continue through much of the coming work week. Breezy south to southwest winds of 10 to near 20 mph expected late morning through early evening today with minimum relative humidities of 8 to 12 percent in lower elevations and 12 to 18 percent in mountain areas. Similar conditions are expected Tuesday. Winds may see an uptick Wednesday and then especially Thursday. Though temperatures come down somewhat Thursday, critical fire weather conditions look more likely with near critical conditions Wednesday. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson