530
FXUS65 KTWC 100931
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
231 AM MST WED SEP 10 2025
SYNOPSIS
ISOLATED DAILY SHOWER AND THUNDERSTORM CHANCES REMAIN
THROUGH FRIDAY, GENERALLY FROM TUCSON EASTWARD. EXPECT SOME BREEZES
THROUGH FRIDAY. SLIGHTLY ABOVE NORMAL TEMPERATURES TODAY THEN
SEASONABLE TEMPERATURES THEREAFTER.
DISCUSSION
CLEAR SKIES ACROSS SOUTHEAST ARIZONA AS THE AREA IS
BETWEEN A RIDGE OF HIGH PRESSURE FROM WEST TEXAS/CHIHUAHUA AND AN
UPPER LOW OVER NORTHERN CALIFORNIA AND ASSOCIATED LONGWAVE TROUGH
EXTENDING SOUTH FROM THERE. THE SOUTH TO SOUTHWESTERLY FLOW ALOFT
WILL INCREASE MID LEVEL MOISTURE AS SOUTHEAST ARIZONA IS PERFECTLY
SITUATED ON THE PERIPHERY OF THESE WEATHER SYSTEMS TO TRANSPORT
INCREASED MOISTURE NORTHWARD FROM SONORA. WITH THAT SAID, PWATS WILL
BE AROUND 1 INCH, WHICH COMBINED WITH SOME LIFT DUE FROM THE
APPROACHING TROUGH WILL BE ENOUGH TO SUPPORT MORE CONVECTION THAN
THE PAST COUPLE OF DAYS. HREF/CAMS ARE IN GOOD AGREEMENT FOCUSING ON
ISOLATED THUNDERSTORMS (15-30 PERCENT CHANCES) FOR
COCHISE/GRAHAM/GREENLEE COUNTIES TODAY WITH TUCSON ON THE WESTERN
EDGE AND THIS SEEMS REASONABLE. MAIN CONCERN TODAY IS GUSTY OUTFLOW
WINDS WITH DCAPE VALUES UP AROUND 2000 J/KG. WE CAN'T RULE OUT A
SEVERE THUNDERSTORM OR TWO WITH ANY STORMS THAT HAVE MORE SUSTAINED
UPDRAFTS AND THE HREF DOES INDICATE A 10 PERCENT CHANCE OF 40-KM
NEIGHBORHOOD PROBABILITIES OF GREATER THAN 50 KTS ACROSS GRAHAM
COUNTY. OUTSIDE OF ANY THUNDERSTORMS, GIVEN THE INCREASED PRESSURE
GRADIENT FROM THE APPROACHING TROUGH, WINDS WILL BE ON THE BREEZY
SIDE WITH GUSTS UP TO AROUND 25-35 MPH. HIGH TEMPERATURES TODAY WILL
BE ABOUT 5 DEGREES ABOVE NORMAL.
NOT MUCH CHANGE FOR THURSDAY AND EVEN FRIDAY AS THE TROUGH SLOWLY
NUDGES EASTWARD INTO THE GREAT BASIN. THIS WILL CONTINUE TO RESULT
IN BREEZY AFTERNOON WINDS WITH ISOLATED SHOWERS AND THUNDERSTORMS,
GENERALLY FROM THE TUCSON AREA EASTWARD. TEMPERATURES DURING THIS
TIME WILL NUDGE DOWN TO SEASONABLE LEVELS.
THIS WEEKEND THE TROUGH WILL EJECT EAST ALLOWING FOR SOME DRYING
WHICH SHOULD SHUNT THUNDERSTORM CHANCES BACK INTO SONORA/CHIHUAHUA.
HOWEVER, ANY DRYING WILL BE SHORT LIVED AS THE MOISTURE NEVER GETS
TOO FAR AWAY AND A RETURN TO MORE SOUTHERLY FLOW WILL ALLOW A RETURN
OF SOME MOISTURE AND THUNDERSTORM CHANCES EARLY TO MID NEXT WEEK.
THE MONSOON ISN'T QUITE DONE WITH US YET BUT THIS IS CLEARLY A
TRANSITION PATTERN.
AVIATION
VALID THROUGH 11/12Z. SCATTERED 10K-13K FEET CEILINGS
WITH ISOLATED -SHRA/-TSRA THIS AFTERNOON AND EARLY EVENING, MAINLY
EAST OF KTUS-KOLS. WITH ANY THUNDERSTORM EXPECT VARIABLE AND GUSTY
WINDS UP TO 40 KNOTS. SURFACE WINDS LIGHT AND TERRAIN DRIVEN THRU
10/15Z, THEN BECOMING SOUTHWESTERLY AND INCREASING TO 12-18 KNOTS
WITH GUSTS TO 30 KNOTS BETWEEN 10/18Z AND 11/03Z. SURFACE WINDS THEN
DIMINISH AND BECOME LIGHT AND TERRAIN DRIVEN THROUGH THE END OF THE
VALID PERIOD. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
MINIMUM RELATIVE HUMIDITIES MAINLY 15-30 PERCENT
THROUGH THE WEEK, THOUGH A BIT HIGHER THURSDAY AND FRIDAY. ISOLATED
SHOWERS AND THUNDERSTORMS MAINLY EAST OF TUCSON THROUGH FRIDAY.
GUSTY AND ERRATIC WINDS ARE EXPECTED WITH THUNDERSTORMS.
OTHERWISE, OUTSIDE OF THUNDERSTORMS, EXPECT BREEZY SOUTHWESTERLY
WINDS EACH AFTERNOON THROUGH FRIDAY WITH SUSTAINED WINDS OF 12-18
MPH AND GUSTS OF 25-35 MPH. HIGH TEMPERATURES SLIGHTLY ABOVE NORMAL
TODAY THEN SEASONABLE THEREAFTER.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
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