875
FXUS65 KTWC 311009
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
309 AM MST THU JUL 31 2025
SYNOPSIS
SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND EVENING
ACROSS MUCH OF SOUTHEASTERN ARIZONA. PERIODS OF HEAVY RAIN, ISOLATED
STRONG WIND GUSTS, AND BLOWING DUST WILL BE HAZARDS WITH ANY
THUNDERSTORM TODAY. AN ISOLATED FLASH FLOOD THREAT ACCOMPANIES
TODAY'S THUNDERSTORM ACTIVITY. THUNDERSTORM CHANCES BEGIN TO
DECREASE FRIDAY AS DRY AIR MOVES IN THROUGH THE WEEKEND. EXTREME HEAT
IS EXPECTED FRIDAY THROUGH THE WEEKEND AS HIGH TEMPERATURES
BECOME 7 TO NEAR 10 DEGREES ABOVE NORMAL. TEMPERATURES REMAIN
ABOVE NORMAL THROUGH NEXT WEEK.
KEY POINTS
-SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND EVENING
ACROSS MUCH OF SOUTHEASTERN ARIZONA. CHANCES BEGIN TO DECREASE
FRIDAY AS DRY AIR MOVES IN THROUGH THE WEEKEND.
-PERIODS OF HEAVY RAIN, ISOLATED STRONG WIND GUSTS, AND BLOWING
DUST WILL BE HAZARDS WITH ANY THUNDERSTORM TODAY. AN ISOLATED
FLASH FLOOD THREAT ACCOMPANIES TODAY'S THUNDERSTORM ACTIVITY.
-EXTREME HEAT IS EXPECTED FRIDAY THROUGH THE WEEKEND AS HIGH
TEMPERATURES BECOME 7 TO NEAR 10 DEGREES ABOVE NORMAL.
TEMPERATURES REMAIN ABOVE NORMAL THROUGH NEXT WEEK.
DISCUSSION
A SUBTLE WESTWARD SHIFT OF THE UPPER LEVEL HIGH WILL BRING
ATMOSPHERIC MOISTURE WEST ALONG WITH IT, AS WELL AS DRIVE GULF OF
CALIFORNIA MOISTURE NORTHWARD THROUGH WESTERN PIMA COUNTY. WHILE
THE OVERALL HIGH-END VALUES OF PRECIPITABLE WATER ACROSS
SOUTHEASTERN ARIZONA WON'T DIFFER HEAVILY FROM PREVIOUS DAYS, THIS
WILL SPREAD THUNDERSTORM CHANCES FURTHER WEST THAN WHAT'S BEEN
SEEN PREVIOUSLY THIS WEEK. HIGHEST COVERAGE STILL REMAINS
LIKELIEST IN EASTERN LOCATIONS, BUT 20-40 PERCENT THUNDERSTORM
CHANCES ARE FORECAST WESTWARD PAST SELLS AND THROUGH CENTRAL
PINAL COUNTY. SLOW STORM MOTIONS WILL PROVIDE AN ISOLATED FLASH
FLOODING RISK, WHILE STRONG WIND GUSTS WITH BLOWING DUST CAN'T BE
RULED OUT. AT LEAST SOME ISOLATED CONVECTION SHOULD LINGER THROUGH
LATE THIS EVENING BEFORE EVENTUALLY FULLY DIMINISHING.
GOING FORWARD THE MAIN CONCERN IN THE COMING DAYS WILL BE HEAT.
THE UPPER LEVEL HIGH IS EXPECTED TO CENTER OVER SOUTHERN ARIZONA
AND SOUTHERN CALIFORNIA BY THIS WEEKEND, DRIVING MOISTURE
SOUTHWARD OUT OF SOUTHEASTERN ARIZONA AND TEMPERATURES UPWARD.
FORECAST HIGHS ARE 7 TO NEAR 10 DEGREES ABOVE NORMAL FRIDAY
THROUGH THE WEEKEND, HEIGHTENING HEATRISK. AN EXTREME HEAT WARNING
REMAINS IN EFFECT FOR FRIDAY THROUGH SUNDAY. THUNDERSTORM CHANCES
FRIDAY BEGIN TO DIMINISH (MAINLY 20-50 PERCENT AT THE HIGHEST)
AND DROP FURTHER THROUGH THE WEEKEND.
AN EASTWARD SHIFT OF THE UPPER LEVEL HIGH IS EXPECTED TO OCCUR
NEXT WEEK, WITH SOUTHEASTERN ARIZONA REMAINING UNDER STRONG
POSITIVE HEIGHT ANOMALIES. THIS WILL KEEP TEMPERATURES WELL ABOVE
NORMAL, WITH UNCERTAINTY IN HOW WELL MOISTURE RETURNS. FOR NOW IT
LOOKS MORE LIKELY MOISTURE WILL BE SLOW TO MOVE BACK IN THROUGH
AT LEAST THE FIRST HALF OF NEXT WEEK, KEEPING THE CPC 6-10 DAY
OUTLOOK LEANING DRIER THAN NORMAL FOR SOUTHEASTERN ARIZONA. THIS
OUTCOME WOULD ALSO OPEN THE DOOR FOR ADDITIONAL DAYS OF HIGH-END
HEAT.
AVIATION
VALID THROUGH 01/12Z.
ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP ACROSS
SOUTHEASTERN ARIZONA AFTER 31/18Z, THEN DIMINISHING AFTER 01/04Z.
BRIEF PERIODS OF HEAVY RAINFALL AND GUSTY ERRATIC WINDS POSSIBLE
WITH ANY THUNDERSTORM. WINDS GENERALLY BELOW 12 KTS AWAY FROM
THUNDERSTORM ACTIVITY, WITH OCCASIONAL AFTERNOON GUSTS TO 20 KTS.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
MINIMUM RELATIVE HUMIDITIES MAINLY ABOVE 20 PERCENT TODAY ACROSS
SOUTHEASTERN ARIZONA. SCATTERED THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON AND EVENING. OVERALL WINDS ARE EXPECTED TO REMAIN UNDER
15 MPH WITH OCCASIONAL AFTERNOON GUSTINESS, HOWEVER STRONG ERRATIC
WINDS ARE POSSIBLE WITH ANY THUNDERSTORM. A DRYING TREND IS
EXPECTED THROUGH THE WEEKEND WITH HIGH TEMPERATURES BUMPING UP.
TWC WATCHES/WARNINGS/ADVISORIES
EXTREME HEAT WARNING FROM 10 AM FRIDAY TO 8 PM MST SUNDAY FOR
AZZ501>507-509-515.
PUBLIC...EDWARDS
AVIATION...EDWARDS
FIRE WEATHER....EDWARDS
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