037
FXUS65 KTWC 280930
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 AM MST FRI AUG 28 2026
SYNOPSIS
EXPECT DAILY AFTERNOON AND EVENING THUNDERSTORMS
THROUGH AT LEAST MONDAY. AFTER MONDAY STORM CHANCES BEGIN TO
DECREASE. HIGH TEMPERATURES WILL REMAIN WELL ABOVE NORMAL
THROUGH SATURDAY WITH AN EXTREME HEAT WARNING IN EFFECT FOR MUCH
OF SOUTHEAST ARIZONA. TEMPERATURES ARE FORECAST TO FALL TO NEAR
NORMAL SUNDAY THROUGH EARLY NEXT WEEK.
DISCUSSION
CURRENT RADAR SHOWS WEAK SHOWERS AROUND KITT PEAK
WITH CLOUD COVER ELSEWHERE ACROSS THE CWA. LIGHT SHOWER
ACTIVITY WILL BE POSSIBLE FOR THE REMAINDER OF THE NIGHT, LIKELY
DISSIPATING BY EARLY MORNING. ALOFT THE MONSOON RIDGE IS
CENTERED OVER THE AZ/NM BORDER AND WILL SLOWLY DRIFT EASTWARD
INTO NEW MEXICO LATER TODAY. PWAT VALUES RANGE FROM 1.5" NEAR
AJO TO 1.0" ALONG THE AZ/NM BORDER. THIS AFTERNOON AND EVENING
EXPECT ANOTHER ROUND OF SCATTERED CONVECTION FROM CENTRAL PIMA
COUNTY EASTWARD. STORMS LIKELY WON'T BE QUITE AS STRONG AS
THURSDAY LOOKING AT HREF PROBABILITIES. BUT STILL CAN'T RULE OUT
AND ISOLATED SEVERE WIND THREAT. SURFACE DEWPOINTS WILL BE IN
THE 50S AND MODEL SOUNDINGS SHOW INVERTED V PROFILES WITH DCAPE
AROUND 1500 J/KG. INITIAL CONVECTION WILL LIKELY BE OVER THE
SKY ISLANDS, THEN MOVE INTO THE LOWER DESERTS PROGRESSING
WESTWARD ALONG OUTFLOWS. HIGH TEMPERATURES WILL BE 6-8 DEGREES
ABOVE NORMAL WITH THE EXTREME HEAT WARNING STILL IN EFFECT
THROUGH SATURDAY.
THIS WEEKEND THE RIDGE BECOMES CENTERED OVER THE SOUTHERN PLAINS
AND A WEAK TROUGH MOVES INTO SOUTHERN CALIFORNIA KEEPING
ARIZONA UNDER SOUTHERLY MID-LEVEL FLOW. MODELS SHOW A SLIGHT
INCREASE IN MOISTURE WITH PWAT VALUES INCREASING BY ABOUT 0.20".
SURFACE DEWPOINTS ALSO INCREASE TO THE LOW TO MID 60S. THIS
WILL LEAD TO AN INCREASE IN MONSOON ACTIVITY OVER THE WEEKEND
AND INTO MONDAY. EXPECT DAILY SCATTERED THUNDERSTORMS DURING THE
AFTERNOON AND EVENING WITH THE MAIN THREATS BEING STRONG TO
SEVERE OUTFLOWS AND LOCALLY HEAVY RAINFALL LEADING TO FLASH
FLOODING. IT'S ALSO POSSIBLE FOR SOME OVERNIGHT ACTIVITY
SATURDAY AND SUNDAY NIGHTS THANKS TO SYNOPTIC SCALE FORCING AS
THE WEAK TROUGH MOVES THROUGH THE REGION. DEPENDING ON HOW
ACTIVE THE NIGHTS ARE, THIS COULD LEAD TO ONE OR MORE DOWN DAYS.
AFTER MONDAY TROUGHING STAYS IN PLACE TO THE WEST AND OVER THE
PACIFIC NORTHWEST KEEPING ARIZONA UNDER SOUTHERLY TO
SOUTHWESTERLY FLOW. MOISTURE VALUES STAY SLIGHTLY ABOVE NORMAL,
BUT STORM CHANCES DECREASE AS A MORE TRANSITIONAL MONSOON
PATTERN SETS UP. STILL EXPECT DAILY AFTERNOON AND EVENING
THUNDERSTORM CHANCES BUT COVERAGE WILL LIKELY BE REDUCED WITH
THE BEST CHANCES ALONG THE INTERNATIONAL BORDER. TEMPERATURES
ALSO DECREASE TO AROUND NORMAL SUNDAY INTO THE MIDDLE OF NEXT
WEEK.
AVIATION
VALID THROUGH 29/12Z.
SCT-BKN CLOUDS 8K-12K THROUGH THE PERIOD WITH ANOTHER BKN CLOUD
LAYER AOA 20K FT AGL THIS AFTERNOON AND EVENING. ISOLATED TO
SCATTERED SHRA/TSRA WILL BE POSSIBLE STARTING AROUND 28/20Z AND
CONTINUE INTO THE EVENING. THUNDERSTORMS HAVE THE POTENTIAL TO
PRODUCE STRONG WIND GUSTS, BUT OTHERWISE SURFACE WINDS WILL BE
SOUTHWEST 5-10 KTS THIS AFTERNOON AND EVENING. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
ISOLATED TO SCATTERED THUNDERSTORMS THIS
AFTERNOON, WITH AN ACTIVE PERIOD EXPECTED THROUGH MONDAY (30 TO
70 PERCENT DAILY THUNDERSTORM CHANCES). TEMPERATURES WILL
REMAIN WELL ABOVE NORMAL TODAY WITH A COOLING TREND THIS WEEKEND
INTO EARLY NEXT WEEK. MINIMUM RELATIVE HUMIDITY VALUES MAINLY
10 TO 20 PERCENT IN THE VALLEYS AND 20 TO 30 PERCENT IN THE
MOUNTAINS TODAY. MINIMUM RH VALUES INCREASE TO 20 TO 40 PERCENT
STARTING SATURDAY IN VALLEYS AND 30 TO 50 PERCENT IN THE
MOUNTAINS. WINDS WILL GENERALLY REMAIN LESS THAN 15 MPH AND
TERRAIN DRIVEN THROUGH THE WEEK.
TWC WATCHES/WARNINGS/ADVISORIES
EXTREME HEAT WARNING UNTIL 8 PM MST SATURDAY FOR AZZ501>509.
HARDIN
VISIT US ON FACEBOOK, X, YOUTUBE, AND AT WEATHER.GOV/TUCSON
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page