434
FXUS65 KTWC 111541
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
840 AM MST THU SEP 11 2025
SYNOPSIS
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL
CONTINUE THROUGH FRIDAY, MAINLY FROM TUCSON SOUTH AND EASTWARD.
GUSTY WINDS, BRIEF HEAVY RAIN, BLOWING DUST AND LIGHTNING WILL BE
THE MAIN HAZARDS. OUTSIDE OF THE THUNDERSTORMS, EXPECT BREEZY WINDS
THROUGH FRIDAY. HIGH TEMPERATURES WILL LOWER SEVERAL DEGREES THROUGH
SATURDAY, WHEN HIGHS WILL TOP OUT A COUPLE OF DEGREES BELOW NORMAL.
THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS SOUTHEAST OF TUCSON
ON SATURDAY, WITH DRY CONDITIONS AREAWIDE ON SUNDAY. TEMPERATURES
WARM BACK UP A COUPLE OF DEGREES NEXT WEEK, ALONG WITH A RETURN OF
SLIGHT CHANCES OF AFTERNOON AND EVENING THUNDERSTORMS.
UPDATE
ARIZONA REMAINS SANDWICHED BETWEEN A TROUGH TO THE WEST
AND HIGH PRESSURE ALOFT CENTERED OVER THE TEXAS PANHANDLE. SOUTH TO
SOUTHWEST FLOW CONTINUES TO ADVECT MOISTURE NORTHWARD ACROSS THE THE
FORECAST AREA. THE LATEST BLENDED TPW IMAGERY INDICATES PW VALUES IN
THE 0.75 TO 1 INCH RANGE ACROSS THE SOUTHERN HALF OF ARIZONA.
VISIBLE SATELLITE IMAGERY SHOWS SCATTERED MID LEVEL CLOUDS ACROSS
THE EASTERN TWO-THIRDS OF THE FORECAST AREA, WITH SURFACE DEWPOINTS
GENERALLY IN THE 50S TO LOWER 60S. THE LATEST HIGH-RES GUIDANCE
MODELS POINT TO THUNDERSTORM INITIATION BETWEEN 1100-1200, WITH
SCATTERED COVERAGE EAST OF A NOGALES TO TUCSON TO ORACLE LINE THIS
AFTERNOON AND EVENING. WITH THE TROUGH AXIS SHIFTING EASTWARD
TONIGHT INTO EARLY FRIDAY, CONVECTION MAY CONTINUE WELL INTO THE
EVENING (AND EVEN OVERNIGHT) HOURS TONIGHT GIVEN THE UPPER LEVEL
DYNAMICS/SUPPORT. THE MAIN THREATS WILL BE GUSTY OUTFLOW WINDS,
AREAS OF BLOWING DUST AND LIGHTING. WHILE HEAVY RAINFALL WILL ALSO
BE POSSIBLE WITH THE STRONGEST THUNDERSTORMS, MEAN FLOW OF AROUND 20
KTS SHOULD KEEP THIS THREAT ON THE MINIMAL SIDE.
PREV DISCUSSION
/ISSUED AT 222 AM MST THU SEP 11 2025/
CLEAR SKIES THIS MORNING ACROSS SOUTHEAST ARIZONA AS THE REGION
REMAINS UNDER SOUTHWESTERLY FLOW ALOFT BETWEEN WEST COAST TROUGHING
AND HIGH PRESSURE ALOFT ACROSS TEXAS. THIS PLACES OUR AREA UNDER A
FAVORABLE MOIST FLOW BETWEEN THESE SYSTEMS WITH PWAT VALUES HIGH
ENOUGH (AROUND 1 TO 1.2 INCHES) TO RESULT IN SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON INTO EVENING. THE PATTERN IS OVERALL
VERY CLOSE TO WHAT WE EXPERIENCED YESTERDAY AS THE FEATURES ALOFT
DRIVING OUR WEATHER REMAIN IN SIMILAR POSITIONS. WITH THAT SAID,
EXPECT SCATTERED SHOWERS AND THUNDERSTORMS (25-40 PERCENT CHANCES)
FROM THE TUCSON AREA AND POINTS EASTWARD THIS AFTERNOON AND EVENING.
WHILE BRIEF LOCALLY HEAVY RAIN IS POSSIBLE, INDIVIDUAL STORM MOTIONS
AROUND 20 MPH WILL REDUCE THE FLASH FLOODING THREAT. THE MAIN
CONCERNS WILL ONCE AGAIN BE GUSTY WINDS (AND BLOWING DUST) GIVEN THE
RELATIVELY DRY SUB-CLOUD LAYER. OUTSIDE OF THUNDERSTORM INFLUENCES,
EXPECT SOME BREEZES WITH GUSTS AROUND 25-30 MPH EXPECTED.
NOT MUCH CHANGE ON FRIDAY, THOUGH THE TROUGH GRADUALLY NUDGING
EASTWARD WILL PUSH THE HIGHEST THUNDERSTORM CHANCES (GENERALLY 30-
50 PERCENT) ACROSS COCHISE/GRAHAM/GREENLEE COUNTIES WITH THE TUCSON
AREA ON THE WESTERN EDGE OF THE ACTIVITY (~20 PERCENT).
A MORE NOTABLE CHANGE THIS WEEKEND AS DRIER AIR CONTINUES TO BUILD
IN FROM THE WEST AS THE TROUGH FINALLY EJECTS EASTWARD. STILL ENOUGH
LINGERING MOISTURE FOR SLIGHT CHANCES OF THUNDERSTORMS (AROUND 10-20
PERCENT) IN COCHISE AND SANTA CRUZ COUNTIES. TEMPERATURES SATURDAY
WILL COOL DOWN TO ABOUT 3 TO 5 DEGREES BELOW NORMAL LEVELS. DRY
CONDITIONS ARE EXPECTED SUNDAY FOR THE ENTIRE FORECAST AREA.
THE WEEKEND DRYING WILL BE SHORT LIVED AS THE MOISTURE ONLY BRIEFLY
GETS PUSHED TO OUR SOUTH AND EAST. AS THE FLOW BECOMES MORE
SOUTHERLY NEXT WEEK THAT WILL ALLOW NORTHWARD MOISTURE TRANSPORT
WITH THUNDERSTORM CHANCES ONCE AGAIN RETURNING TO THE FORECAST. NEAR
NORMAL TEMPERATURES ARE EXPECTED EARLY TO MID NEXT WEEK.
AVIATION
VALID THROUGH 12/18Z.
SCT-BKN CLOUDS AT 11K-14K FT AGL MAINLY EAST OF A KOLS TO KTUS LINE
THRU 11/18Z. SCT-BKN CLOUDS AT 8K-11K FT AGL AREAWIDE BETWEEN 11/18Z
AND 12/06Z, WITH DECREASING CLOUDS AFT 12/06Z. SCATTERED -SHRA/-TSRA
MAINLY EAST OF KTUS-KOLS LINE BETWEEN 11/19Z AND 12/04Z. GUSTY AND
ERRATIC WINDS TO 45 KTS POSSIBLE WITH ANY THUNDERSTORM. OTHERWISE,
SLY/SWLY SFC WIND AT 10-16 KTS WITH GUSTS TO 20-25 KTS THRU 12/04Z.
AFT 12/04Z, SFC WIND LESS THAN 10 KTS AND VARIABLE IN DIRECTION.
FIRE WEATHER
MINIMUM RH VALUES WILL BE IN THE 20-35 PERCENT RANGE
THROUGH SATURDAY, LOWERING INTO THE 15-30 PERCENT RANGE SUNDAY AND
MONDAY. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED FROM THE
TUCSON AREA EASTWARD TODAY AND FRIDAY, WITH A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS SOUTH AND EAST OF TUCSON ON SATURDAY. DRY
AREA-WIDE SUNDAY, THEN A SLIGHT CHANCE OF THUNDERSTORMS RETURN AGAIN
NEXT WEEK. GUSTY AND ERRATIC WINDS ARE EXPECTED WITH THUNDERSTORMS.
OTHERWISE, OUTSIDE OF THUNDERSTORM OUTFLOWS, EXPECT BREEZY SOUTH TO
SOUTHWEST AFTERNOON AND EARLY EVENING 20-FOOT WINDS THROUGH FRIDAY,
WITH SUSTAINED WINDS OF 10-18 MPH AND GUSTS UP TO 30 MPH. HIGH
TEMPERATURES WILL BE NEAR NORMAL THE NEXT 7 DAYS, WITH SLIGHTLY
BELOW NORMAL HIGH TEMPERATURES ON SATURDAY.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
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