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.
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AVIATION...DANG/EDWARDS
FIRE WEATHER....DANG/EDWARDS
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