Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
838 FXUS65 KTWC 292118 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 218 PM MST Tue Jul 29 2025 .SYNOPSIS...A low grade monsoon day is expected today across southeastern Arizona. Thunderstorms that do form may produce gusty winds that kick up blowing dust, mainly east of Tucson. Greater chances for thunderstorms return Wednesday and Thursday. && .KEY MESSAGES... -A low grade monsoon day is expected today across southeastern Arizona. Thunderstorms that do form may produce gusty winds that kick up blowing dust, mainly east of Tucson. -Greater chances for thunderstorms return Wednesday and Thursday. -High temperatures are expected to remain above average through the week. && .DISCUSSION...There are currently a few clouds build-ups in the White Mountains and Chiricahua Mountains this early afternoon. Some of the latest recent CAMs like the HRRR and UA WRF HRRR are much more bullish with a line of thunderstorms coming from the White Mountains and working their way southward through Graham/Greenlee then to Cochise county. Other CAMs like the NAM Nest and HRW ARW have less storm coverage overall. The main concern with any storms that do form is gusty outflow winds at 30-40 mph and blowing dust along common dust prone areas from Willcox to San Simon into some areas of Cochise County as well. This is thanks to our dryer low levels of the atmosphere creating DCAPE values of 1200-1800 J/kg allowing for more downward acceleration and stronger outflow winds. Looking past today, as always the activity tomorrow will depend on how much the atmosphere can recover. The HREF is showing a similar pattern similar to today with more of a stronger signal for stronger outflow winds tomorrow. Depending on how much moisture form New Mexico can move in, the main concerns for thunderstorms could be both strong outflow winds and flash flooding from locally heavy rainfall. This pattern continues into Thursday as well before the high pressure slowly begins to move westward drying out much of the area beginning Friday into the weekend, slowly lowering the chances for showers and thunderstorms each day. Models are still struggling with how long the high pressure will stay to the west of the area or if it will move east. The drier `west` scenario would keep us dry and increase temperatures, while the `east` scenario would slowly bring back moisture to the area. Only time will tell how this plays out when the models get into more agreement. && .AVIATION...Valid through 31/00Z. FEW-SCT cumulus thru the forecast period for areas Tucson eastward with bases around 9k-13k feet. Isolated showers and thunderstorms after 29/21Z thru 30/09Z for areas east of Tucson with gusty winds possible with any storm. Outside of thunderstorms, winds to around 10 kts with occasional afternoon gusts to 15-20 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Monsoon moisture remains in place from Tucson- Nogales eastward today. This moisture will gradually spread westward through Thursday with minimum relative humidity values remaining above 25 percent. Isolated to scattered thunderstorms possible each day through the work week, with greater chances Wednesday and Thursday. Erratic winds possible with any thunderstorm, otherwise winds generally bellow 12 mph with just the occasional afternoon gustiness. A drying trend arrives this weekend, lowering thunderstorm chances and dropping minimum relative humidity values. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Tetrault Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson