859
FXUS65 KTWC 210933
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
233 AM MST TUE JUL 21 2026
SYNOPSIS
THE COMBINATION OF AMPLE MOISTURE ACROSS SOUTHEAST ARIZONA AND
AN UPPER-LEVEL DISTURBANCE MOVING ACROSS PORTIONS OF THE AREA
FROM THE EAST WILL RESULT IN WIDESPREAD SHOWERS AND THUNDERSTORMS,
ESPECIALLY TO THE EAST AND SOUTH OF TUCSON. THESE STORMS WILL
BE CAPABLE OF PRODUCING HEAVY RAINFALL. A FLASH FLOOD WATCH
REMAINS IN EFFECT FOR GRAHAM, GREENLEE, COCHISE AND SANTA CRUZ
COUNTIES THIS THROUGH 10 PM MST THIS EVENING. OTHERWISE, DAYTIME
TEMPERATURES WILL REMAIN BELOW AVERAGE BY SEVERAL DEGREES INTO
MIDWEEK INCREASING TO ABOVE NORMAL LATE THIS WEEK INTO THIS WEEKEND.
DISCUSSION
THE COMBINATION OF AMPLE MOISTURE AND AN UPPER-
LEVEL DISTURBANCE PASSING ACROSS PORTIONS OF SOUTHEAST ARIZONA
FROM THE EAST TODAY WILL RESULT IN WIDESPREAD SHOWERS AND
THUNDERSTORMS...ESPECIALLY SOUTH AND EAST OF TUCSON. THESE
STORMS WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL, WITH
LOCALIZED RAINFALL AMOUNTS BETWEEN 1 AND 3 INCHES. GIVEN HOW
SATURATED SOILS ARE ACROSS THE AREA FROM STORMS OVER THE PAST
WEEK, THERE IS AN INCREASED POTENTIAL THAT RAINFALL RUNOFF TO
PRODUCE FLASH FLOODING. A FLASH FLOOD WATCH REMAINS IN EFFECT
FOR PORTIONS OF SOUTHEAST ARIZONA (INCLUDING GRAHAM, GREENLEE,
COCHISE AND SANTA CRUZ COUNTIES) THROUGH 10 PM MST THIS EVENING.
THE UPPER PATTERN THIS MORNING CONTINUES TO BE DEFINED BY THAT
SLOW MOVING UPPER-LOW (SEEN BY ITS DISTINCT SWIRL IN GOES WV
IMAGERY) IN WEST CENTRAL NEW MEXICO AND AN ANOMALOUSLY STRONG
RIDGE OF HIGH PRESSURE CENTERED OVER NORTHWEST KANSAS. THE UPPER
PATTERN REMAINS IN FLUX TODAY AS THE UPPER-LOW MOVES OVER GRAHAM
AND GREENLEE COUNTIES BY 21/18Z TODAY AS THE UPPER HIGH CENTER
MOVES SE INTO CENTRAL OKLAHOMA. GIVEN SLOWER TRAJECTORY OF THE
UPPER-LOW, MODEST LIFT/DEFORMATION ALOFT WILL REMAIN PRESENT
ACROSS THE EASTERN CWA TODAY WHEN DEEP MOISTURE REMAINS. THIS
WILL RESULT IN ANOTHER DAY OF WIDESPREAD SHOWERS AND THUNDERSTORMS
WITH THE POTENTIAL FOR HEAVY RAIN TO THE EAST AND SOUTH OF
TUCSON. THIS IS SUPPORTED ONCE AGAIN BY THE 21/00Z HREF WITH A
10 PERCENT PROBABILITY OF STORMS PRODUCING IN EXCESS OF 3 INCHES
OF RAINFALL IN THE FLASH FLOOD WATCH AREAS BETWEEN 21/18 AND
22/03Z. THESE AREAS GOT HIT PRETTY HARD WITH HEAVY RAIN
YESTERDAY, WHICH SHOULD INCREASE THE POTENTIAL THAT ANY
ADDITIONAL HEAVY RAIN TODAY WILL RESULT IN FLASH FLOODING.
DESPITE THE FACT THAT WE WILL STILL HAVE DAILY AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS THE SECOND HALF OF THE WORK
WEEK, THERE WILL BE A DISTINCT DOWNTURN IN ACTIVITY. THE UPPER-
HIGH CENTER WILL MOVE FROM OKLAHOMA TODAY TO SOUTHERN NEW MEXICO
24/00Z THURSDAY AFTERNOON THEN UP TO THE FOUR CORNER BY 26/00Z
SATURDAY AFTERNOON. THE APPROACHING UPPER-HIGH WILL INCREASE
AFTERNOON TEMPERATURES ONCE AGAIN TO AROUND 5 TO 8 DEGREES ABOVE
NORMAL. THE COMBINATION OF DRIER AIR AND MODEST MID-LEVEL FLOW
WILL INCREASE THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS NEXT
WEEKEND TO BE MORE OF THE SEVERE VARIETY. IN OTHER WORDS, THE
MONSOON ROLLS-ON.
AVIATION
VALID THROUGH 22/12Z. SCT-BKN 6-8K FT AGL BKN-OVC
8-12K FT AGL. AFTER 21/19Z THIS AFTERNOON THROUGH THE LATE
EVENING HOURS...WIDESPREAD SHOWERS AND THUNDERSTORMS WILL
DEVELOP ACROSS COCHISE, SANTA CRUZ, GRAHAM AND GREENLEE
COUNTIES. THESE STORMS WILL BE CAPABLE OF PRODUCING HEAVY
RAINFALL. KOLS AND KDUG ARE THE TERMINALS WITH THE BEST CHANCE
TO SEE THUNDERSTORMS WITH BRIEF MVFR POSSIBLE UNDER HEAVY +TSRA.
SFC WINDS GENERALLY LESS THAN 12KTS, EXCEPT FOR AROUND STORMS
WHERE VRB GUSTS TO 40KTS WILL BE POSSIBLE. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
DAILY CHANCES FOR THUNDERSTORMS WILL CONTINUE
EACH AFTERNOON AND EVENING THROUGH THE NEXT 7 DAYS WITH DAY TO
DAY VARIABILITY. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
EXPECTED EAST AND SOUTH OF TUCSON AGAIN TODAY. THESE STORMS WILL
BE CAPABLE OF PRODUCING HEAVY RAINFALL WITH THE POTENTIAL FOR
FLASH FLOODING. A FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 10
PM MST THIS EVENING FOR THE EASTERN PORTIONS OF SOUTHEAST
ARIZONA. MIN RHS 25-30% IN THE LOWER DESERT LOCATIONS AND ABOVE
40% IN THE MOUNTAINS THROUGH MID-WEEK. BY THURSDAY INTO THE
WEEKEND, RH COULD DIP INTO THE 17-22% RANGE FOR THE LOWER
DESERTS WEST OF TUCSON AND THE UPPER GILA RIVER VALLEY AS
TEMPERATURES WARM TO ABOVE AVERAGE. 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
FLOOD WATCH THROUGH THIS EVENING FOR AZZ503-507>513.
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