525  
FXUS65 KTWC 301625  
AFDTWC  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TUCSON AZ  
925 AM MST WED JUL 30 2025  
   
UPDATE  
 
FORECAST IS ON TRACK AND NO UPDATES ARE PLANNED. HREF MODEL DATA  
IS COMING IN AND CONTINUES TO HIGHLIGHT A SLIGHTLY MORE ACTIVE  
CONVECTIVE DAY THAN THE LAST SEVERAL. WE SHOULD START TO SEE  
THUNDERSTORMS FORM IN PORTIONS OF GRAHAM, GREENLEE, AND COCHISE  
COUNTIES AROUND MIDDAY TO EARLY AFTERNOON. STORMS SHOULD GENERALLY  
HAVE A NE TO SW TRAJECTORY TODAY. WHILE IMPACTS RELATED TO BOTH  
BRIEF LOCALLY HEAVY RAINFALL AND GUSTY WINDS WILL BE POSSIBLE WITH  
THUNDERSTORMS, ENSEMBLE GUIDANCE SUGGESTS THE RISK WITH DAMAGING  
WIND AND BLOWING DUST TO BE A LITTLE HIGHER THAN POTENTIAL  
FLOODING TODAY.  
 
 
   
SYNOPSIS  
 
THUNDERSTORM CHANCES CONTINUE THROUGH THE WORK WEEK, WITH HIGHEST  
CHANCES EAST AND SOUTH OF TUCSON. CHANCES BEGIN TO DECREASE  
FRIDAY AS DRY AIR PUSHES IN THROUGH THE WEEKEND. HIGH TEMPERATURES  
ARE EXPECTED TO REMAIN ABOVE AVERAGE THROUGH THE WEEK.  
 
 
   
KEY MESSAGES  
 
-THUNDERSTORM CHANCES CONTINUE THROUGH THE WORK WEEK. CHANCES  
BEGIN TO DECREASE FRIDAY AS DRY AIR PUSHES IN THROUGH THE  
WEEKEND.  
 
-ISOLATED HEAVY RAIN, STRONG WIND GUST, AND BLOWING DUST THREATS  
POSSIBLE WITH THUNDERSTORMS TODAY AND THURSDAY.  
 
-HIGH TEMPERATURES ARE EXPECTED TO REMAIN ABOVE AVERAGE THROUGH  
THE WEEK.  
 
 
   
DISCUSSION  
 
THUNDERSTORM CHANCES RETURN THIS AFTERNOON AND EVENING ACROSS  
SOUTHEASTERN ARIZONA. OVERALL MOISTURE CONTENT REMAINS ON THE  
MODEST SIDE, RANGING FROM AROUND 1 INCH ON THE 00Z TWC UPPER AIR  
OBSERVATION TO OVER 1.25 INCHES IN SOUTHEASTERN COCHISE COUNTY AS  
OBSERVED BY GOES. AN APPROACHING JET STREAK FROM THE WEST WILL  
INCREASE UPPER LEVEL DIVERGENCE TODAY, BRINGING THUNDERSTORM  
CHANCES UP A BIT COMPARED TO YESTERDAY. HOWEVER WITH ATMOSPHERIC MOISTURE  
CONTENT NOT EXACTLY STANDING OUT, 00Z HIGH RESOLUTION MODELS ARE  
IN DISAGREEMENT ON COVERAGE. THE MORE AGGRESSIVE SOLUTIONS BRING  
CONVECTION AS FAR WEST AS CENTRAL PIMA COUNTY WHILE MODELS LIKE  
THE NSSL-WRF ARE FAR MORE SPARSE. GIVEN INCREASING UPPER LEVEL  
SUPPORT IT LOOKS REASONABLE THAT THERE SHOULD BE A NUMBER OF  
THUNDERSTORMS TODAY, THOUGH ANY IMPACTS ARE MORE LIKELY KEPT  
TOWARDS THE AREAS WITH RICHER MOISTURE IN COCHISE, GRAHAM, AND  
SOUTHERN GREENLEE COUNTIES. ISOLATED HEAVY RAIN, STRONG WIND, AND  
BLOWING DUST THREATS ARE POSSIBLE WHERE STRONGER THUNDERSTORMS DO  
DEVELOP. THURSDAY SHOULD SEE A SIMILAR SETUP (THOUGH WITH  
INHERENT UNCERTAINTIES DEPENDING ON TODAY'S ACTIVITY). EARLIER  
SIGNS OF A SOUTHERLY MOISTURE BOOST HAVE COME DOWN AND THE  
PRECIPITABLE WATER LAYOUT SHOULDN'T STRAY FAR FROM YESTERDAY AND  
TODAY.  
 
FRIDAY WILL SEE THE TRANSITION OF AN UPPER LEVEL HIGH BECOMING  
CENTERED OVER SOUTHERN ARIZONA, WHICH SHOULD FULLY SET IN THIS  
WEEKEND. THIS WILL BRING JUST MODEST THUNDERSTORM CHANCES FRIDAY  
AFTERNOON AND EVEN LOWER-END CHANCES THIS WEEKEND, MAINLY CONFINED  
TO HIGH ELEVATION LOCATIONS AND THE SOUTHERN BORDER. HIGH  
TEMPERATURES WILL LIKELY COME UP A FEW DEGREES WITH THIS  
TRANSITION, WITH NBM PROBABILITIES FOR 110 IN TUCSON INCREASING TO  
35 PERCENT ON SUNDAY. NEXT WEEK SOUTHEASTERN ARIZONA SHOULD SEE  
SOME MOISTURE RETURN AS THE UPPER HIGH SHIFTS TO THE EAST. HOWEVER  
THERE REMAINS MODEL UNCERTAINTY REGARDING THE QUALITY OF THIS  
MOISTURE RETURN, LEADING TO A CPC OUTLOOK THAT LEANS BELOW NORMAL  
FOR PRECIPITATION IN THE 6-10 FORECAST.  
 
 
   
AVIATION  
VALID THROUGH 31/12Z.  
 
MAINLY SKC TO START THE FORECAST PERIOD THEN FEW-SCT CUMULUS WITH  
BASES AROUND 9K-13K FEET AFTER 30/19Z. ISOLATED TO SCATTERED  
THUNDERSTORMS POSSIBLE FROM 30/20Z THROUGH 31/07Z, WITH GREATER  
COVERAGE LIKELY NEAR AND EAST OF KSAD-KOLS. GUSTY ERRATIC WINDS  
POSSIBLE WITH ANY THUNDERSTORMS. OTHERWISE WINDS MAINLY UNDER 12  
KTS, WITH OCCASIONAL AFTERNOON GUSTS TO 20 KTS. AVIATION  
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.  
 
 
   
FIRE WEATHER  
 
MINIMUM RELATIVE HUMIDITIES MAINLY ABOVE 25 PERCENT EAST OF  
TUCSON-NOGALES, AND 10-20 PERCENT TO THE WEST. WINDS MAINLY LIGHT  
AND UNDER 12 MPH, WITH OCCASIONAL AFTERNOON GUSTS. THUNDERSTORM  
CHANCES CONTINUE THROUGH THURSDAY, THEN A DRYING TREND IS EXPECTED  
THROUGH THIS WEEKEND. FORECAST HIGH TEMPERATURES REMAIN ABOVE  
NORMAL THROUGH THE WEEKEND.  
 
 
 
 
   
TWC WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
PUBLIC...DANG/EDWARDS  
AVIATION...DANG/EDWARDS  
FIRE WEATHER....DANG/EDWARDS  
 
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab AZ Page
Main Text Page