838
FXUS65 KTWC 292118
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
218 PM MST TUE JUL 29 2025
SYNOPSIS
A LOW GRADE MONSOON DAY IS EXPECTED TODAY ACROSS SOUTHEASTERN
ARIZONA. THUNDERSTORMS THAT DO FORM MAY PRODUCE GUSTY WINDS THAT
KICK UP BLOWING DUST, MAINLY EAST OF TUCSON. GREATER CHANCES FOR
THUNDERSTORMS RETURN WEDNESDAY AND THURSDAY.
KEY MESSAGES
-A LOW GRADE MONSOON DAY IS EXPECTED TODAY ACROSS SOUTHEASTERN
ARIZONA. THUNDERSTORMS THAT DO FORM MAY PRODUCE GUSTY WINDS THAT
KICK UP BLOWING DUST, MAINLY EAST OF TUCSON.
-GREATER CHANCES FOR THUNDERSTORMS RETURN WEDNESDAY AND THURSDAY.
-HIGH TEMPERATURES ARE EXPECTED TO REMAIN ABOVE AVERAGE THROUGH
THE WEEK.
DISCUSSION
THERE ARE CURRENTLY A FEW CLOUDS BUILD-UPS IN THE
WHITE MOUNTAINS AND CHIRICAHUA MOUNTAINS THIS EARLY AFTERNOON.
SOME OF THE LATEST RECENT CAMS LIKE THE HRRR AND UA WRF HRRR ARE
MUCH MORE BULLISH WITH A LINE OF THUNDERSTORMS COMING FROM THE
WHITE MOUNTAINS AND WORKING THEIR WAY SOUTHWARD THROUGH
GRAHAM/GREENLEE THEN TO COCHISE COUNTY. OTHER CAMS LIKE THE NAM
NEST AND HRW ARW HAVE LESS STORM COVERAGE OVERALL. THE MAIN
CONCERN WITH ANY STORMS THAT DO FORM IS GUSTY OUTFLOW WINDS AT
30-40 MPH AND BLOWING DUST ALONG COMMON DUST PRONE AREAS FROM
WILLCOX TO SAN SIMON INTO SOME AREAS OF COCHISE COUNTY AS WELL.
THIS IS THANKS TO OUR DRYER LOW LEVELS OF THE ATMOSPHERE CREATING
DCAPE VALUES OF 1200-1800 J/KG ALLOWING FOR MORE DOWNWARD
ACCELERATION AND STRONGER OUTFLOW WINDS.
LOOKING PAST TODAY, AS ALWAYS THE ACTIVITY TOMORROW WILL DEPEND ON
HOW MUCH THE ATMOSPHERE CAN RECOVER. THE HREF IS SHOWING A SIMILAR
PATTERN SIMILAR TO TODAY WITH MORE OF A STRONGER SIGNAL FOR
STRONGER OUTFLOW WINDS TOMORROW. DEPENDING ON HOW MUCH MOISTURE
FORM NEW MEXICO CAN MOVE IN, THE MAIN CONCERNS FOR THUNDERSTORMS
COULD BE BOTH STRONG OUTFLOW WINDS AND FLASH FLOODING FROM LOCALLY
HEAVY RAINFALL.
THIS PATTERN CONTINUES INTO THURSDAY AS WELL BEFORE THE HIGH
PRESSURE SLOWLY BEGINS TO MOVE WESTWARD DRYING OUT MUCH OF THE
AREA BEGINNING FRIDAY INTO THE WEEKEND, SLOWLY LOWERING THE
CHANCES FOR SHOWERS AND THUNDERSTORMS EACH DAY. MODELS ARE STILL
STRUGGLING WITH HOW LONG THE HIGH PRESSURE WILL STAY TO THE WEST
OF THE AREA OR IF IT WILL MOVE EAST. THE DRIER 'WEST' SCENARIO
WOULD KEEP US DRY AND INCREASE TEMPERATURES, WHILE THE 'EAST'
SCENARIO WOULD SLOWLY BRING BACK MOISTURE TO THE AREA. ONLY TIME
WILL TELL HOW THIS PLAYS OUT WHEN THE MODELS GET INTO MORE
AGREEMENT.
AVIATION
VALID THROUGH 31/00Z.
FEW-SCT CUMULUS THRU THE FORECAST PERIOD FOR AREAS TUCSON
EASTWARD WITH BASES AROUND 9K-13K FEET. ISOLATED SHOWERS AND
THUNDERSTORMS AFTER 29/21Z THRU 30/09Z FOR AREAS EAST OF TUCSON WITH
GUSTY WINDS POSSIBLE WITH ANY STORM. OUTSIDE OF THUNDERSTORMS,
WINDS TO AROUND 10 KTS WITH OCCASIONAL AFTERNOON GUSTS TO 15-20
KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
MONSOON MOISTURE REMAINS IN PLACE FROM TUCSON-
NOGALES EASTWARD TODAY. THIS MOISTURE WILL GRADUALLY SPREAD
WESTWARD THROUGH THURSDAY WITH MINIMUM RELATIVE HUMIDITY VALUES
REMAINING ABOVE 25 PERCENT. ISOLATED TO SCATTERED THUNDERSTORMS
POSSIBLE EACH DAY THROUGH THE WORK WEEK, WITH GREATER CHANCES
WEDNESDAY AND THURSDAY. ERRATIC WINDS POSSIBLE WITH ANY
THUNDERSTORM, OTHERWISE WINDS GENERALLY BELLOW 12 MPH WITH JUST
THE OCCASIONAL AFTERNOON GUSTINESS. A DRYING TREND ARRIVES THIS
WEEKEND, LOWERING THUNDERSTORM CHANCES AND DROPPING MINIMUM
RELATIVE HUMIDITY VALUES.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
TETRAULT
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