Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
368 FXUS65 KTWC 150942 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 242 AM MST Wed Jul 15 2026 .KEY MESSAGES... - Scattered thunderstorms are expected this afternoon and evening with a threat of heavy rainfall and strong outflow winds. - Increasing moisture and a disturbance from the east will bring more widespread shower and thunderstorm chances on Thursday with a risk for flash flooding. Another day of increased chances may occur again on Friday, though coverage may depend on lingering cloud cover from Thursday`s activity. - High temperatures will be a few degrees below normal today and cool further through the end of the week. && .SYNOPSIS... Scattered thunderstorms are expected to develop over much of southeastern Arizona this afternoon, with lower chances in southeastern Cochise county. Heavy rainfall and strong wind gusts will be possible with any thunderstorm. More widespread chances for showers and thunderstorms are forecast on Thursday and potentially Friday with a risk of flash flooding. High temperatures will be a few degrees below normal today and cool further through the end of the week. && .DISCUSSION... Ample atmospheric moisture remains across the region today with satellite derived precipitable water values ranging from 1.1 inches along the New Mexico border to 1.8 inches in western Pima county early this morning. Flow aloft has turned northeasterly, which will produce a northeast to southwest storm motion this afternoon and evening. Most 00Z high resolution models advertise widely scattered thunderstorms developing in the early afternoon today, with lowest chances in southeastern Cochise. Drying in the mid- levels along with modest shear will bring a localized gusty wind and blowing dust threat. The 00Z HREF highlights a 50-70 percent chance of a 35 mph wind gust within 25 miles of any point from storms from off the White Mountains southwest through Pinal, Pima, and Santa Cruz counties. A low end but non- zero chance of a severe wind gust will also be possible with any thunderstorm. Heavy rainfall will be likely with storms and may carry a flash flooding threat, though their motion today should preclude a widespread problem. Attention turns to Thursday and Friday where an increase in precipitable water and the arrival of an easterly wave ramp up shower/thunderstorm chances across the region. Precipitable water values will rise to 1.4 inches east to near 2 inches in western Pima with surface dew points over 60 degrees becoming common. These increasing thunderstorm chances (60-80 percent on Thursday) should produce a flash flooding risk as heavy rain rates will be likely amid the above normal moisture field. A headline may be necessary once high- resolution modeling better captures Thursday, depending on how the anticipated coverage of a flash flooding risk pans out. On Friday the easterly wave will continue to be an influence, however convective debris from the previous day may impact Friday`s thunderstorm chances. This weekend into next week the upper ridge gradually becomes more centered over the Four Corners region, bringing favorable easterly flow in southeastern Arizona for continued monsoon activity. && .AVIATION...Valid through 16/12Z. FEW-SCT ceilings 12k-15k through the morning. Scattered thunderstorms expected to develop after 15/19Z and diminishing after 16/03Z, though isolated activity may linger longer into the night. Heavy rainfall, mountain obscurations, and erratic strong wind gusts 35-40 kts possible with any thunderstorm. Outside of thunderstorms, surface winds generally light and under 10 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Daily chances for thunderstorms will continue each afternoon and evening through the coming week with day to day variability. More widespread chances for showers and thunderstorms are likely Thursday and potentially Friday. Minimum relative humidity 25-30 percent in the lower desert locations and above 40 percent in the mountains this week. Winds this week will remain mainly light and under 15 mph, though strong and erratic winds will be possible with any thunderstorm. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Edwards AVIATION...Edwards FIRE WEATHER...Edwards Visit us on Facebook, X, YouTube, and at weather.gov/Tucson