807
FXUS65 KTWC 090746
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
1246 AM MST WED SEP 9 2026
SYNOPSIS
SCATTERED THUNDERSTORMS THIS AFTERNOON AND THIS
EVENING, ESPECIALLY SOUTH AND EAST OF TUCSON. STORMS WILL BE
STRONGER THAN WE HAVE SEEN THE PAST SEVERAL DAYS, WITH HEAVY
RAINFALL LEADING TO LOCALIZED FLASH FLOODING AS THE PRIMARY
HAZARD FROM THESE STORMS, WITH A SECONDARY HAZARD OF STRONG
OUTFLOW WINDS TO 40-45 MPH EAST OF TUCSON. HIGH TEMPERATURES
WILL WILL FLUCTUATE BETWEEN NEAR NORMAL AND A FEW DEGREES BELOW
NORMAL.
DISCUSSION
THE UPPER PATTERN THIS MORNING IS DEFINED BY A
STRONG RIDGE OF HIGH PRESSURE EXTENDING FROM NEW MEXICO ALL THE
WAY OVER TO SOUTHERN APPALACHIA WITH TWO DISTINCT HIGH CENTERS
OVER CENTRAL NEW MEXICO AND CENTRAL TENNESSEE WITH AN INVERTED
TROUGH IN BETWEEN THESE TWO FEATURES OVER TEXAS. THE LATEST
GOES PRECIPITABLE WATER IMAGERY STILL INDICATED A MOIST AIRMASS
ACROSS SOUTHEAST ARIZONA WITH THE DEEPER MOISTURE RESIDING FROM
TUCSON WEST (PWATS BETWEEN 1.60 AND 2.00 INCHES) AND PWAT VALUES
1.40 TO 1.60 INCHES EAST OF TUCSON INTO SW NEW MEXICO AND NW
CHIHUAHUA MX. THIS AIRMASS IS RELATIVELY MOIST FOR THIS TIME OF
YEAR...GENERALLY BETWEEN 1.5 AND 2.0 STANDARD DEVIATIONS ABOVE
NORMAL.
THAT INVERTED TROUGH OVER TEXAS WILL TRACK WEST TODAY SHOVING
THE UPPER-HIGH CENTER OVER CENTRAL NEW MEXICO INTO CENTRAL
ARIZONA BY 10/00Z THIS AFTERNOON, THEN OVER TO WESTERN ARIZONA
BY 10/06Z THIS EVENING. THIS MOVEMENT WILL RESULT IN AN AREA OF
DECENT STRETCHING DEFORMATION/LIFT ALOFT ACROSS THE SE HALF OF
THE CWA TODAY. ALTHOUGH THE UPPER PATTERN WILL STILL BE A
FAVORED RIM-SHOT PATTERN TO MOVE STORMS FROM THE MOGOLLON RIM
TOWARD OUR NECK OF THE WOODS, THE ELONGATED NATURE OF THE UPPER
HIGH WILL RESULT IN A MORE NNE-TO-SSW THAN NE-TO-SW TRAJECTORY
OF STORMS ESSENTIALLY SHUNTING THE BEST AREA OF LIFT TO THE EAST
AND SOUTH OF TUCSON TODAY. MODELS HAVE SLIGHTLY BACKED OFF ON
THE 0-6KM AGL BULK SHEAR (20 KTS) TODAY...BUT THIS SHOULD STILL
BE ENOUGH TO HELP ORGANIZE AND CLUSTER SOME OF THE GENERALLY
PULSE-TYPE THUNDERSTORMS TODAY AS THEY TRACK SSW. THE ANOMALOUSLY
HIGH MOISTURE AVAILABLE ACROSS THE AREA WILL PROVIDE THE POTENTIAL
FOR HEAVY RAINFALL/ISOLATED FLASH FLOODING TODAY. THIS IS
SUPPORTED BY WPC'S AREA OF SLIGHT RISK FOR EXCEEDING FLASH
FLOOD GUIDANCE ON THEIR DAY 1 EXCESSIVE RAINFALL OUTLOOK (ERO)
EXTENDING ACROSS THE EASTERN 2/3 OF SOUTHEAST ARIZONA TODAY.
SO, THE PRIMARY HAZARD FOR STORMS TODAY WILL BE THE POTENTIAL
FOR HEAVY RAIN/ISOLATED FLASH FLOODING (ESPECIALLY TO THE
SOUTHEAST AND SOUTH OF TUCSON) WITH A SECONDARY THREAT FOR
STRONG THUNDERSTORM OUTFLOW WINDS/ISOLATED SEVERE OUTFLOW WINDS
(EAST OF TUCSON). THE TUCSON METRO AREA WILL BE ON THE PERIPHERY
OF BOTH OF THESE HAZARD AREAS TODAY DUE TO THE SSW TRAJECTORY
OF THE FLOW ALOFT.
OTHERWISE, WE WILL MAINTAIN ENOUGH MOISTURE ACROSS THE REGION
FOR MAINLY SCATTERED AFTERNOON AND EARLY EVENING THUNDERSTORMS
THIS WEEKEND INTO EARLY NEXT WEEK. THE MONSOON SEASON ROLLS-ON.
AVIATION
VALID THRU 10/12Z. SCT TO BKN CLOUDS 12-15K FT AGL
THROUGH 09/20Z, THEN SCT-BKN 8-10K FT AGL BKN-OVC 12-15K FT AGL
THIS AFTERNOON INTO THE EARLY EVENING. SCATTERED SHRA/TSRA TO
THE SOUTH AND EAST OF TUCSON WILL RESULT IN VSBY 3-5SM WITH CIGS
BKN-OVC 6-8K FT AGL FROM 09/21Z THRU 10/04Z. LOCALIZED THUNDERSTORM
OUTFLOW WINDS 35-40 KTS POSSIBLE EAST OF TUCSON. OTHERWISE, SFC
WINDS WILL GENERALLY BE LESS THAN 12 KTS AND TERRAIN DRIVEN THIS
MORNING, BECOMING WLY/NWLY 10-15 KTS DURING THE AFTERNOON. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
SCATTERED THUNDERSTORMS THIS AFTERNOON AND THIS
EVENING, ESPECIALLY SOUTH AND EAST OF TUCSON. STORMS WILL BE
STRONGER THAN WE HAVE SEEN THE PAST SEVERAL DAYS, WITH HEAVY
RAINFALL LEADING TO LOCALIZED FLASH FLOODING AS THE PRIMARY
HAZARD FROM THESE STORMS, WITH A SECONDARY HAZARD OF STRONG
OUTFLOW WINDS TO 40-45 MPH EAST OF TUCSON. HIGH TEMPERATURES
WILL WILL FLUCTUATE BETWEEN NEAR NORMAL AND A FEW DEGREES BELOW
NORMAL INTO EARLY NEXT WEEK. MIN RH VALUES MAINLY 20 TO 45
PERCENT IN THE VALLEYS AND 30 TO 60 PERCENT IN THE MOUNTAINS
OVER THE NEXT WEEK. RH RECOVERIES WILL CONTINUE TO BE EXCELLENT
OVERNIGHT. WINDS WILL GENERALLY REMAIN LESS THAN 15 MPH AND
TERRAIN DRIVEN THROUGH THE WEEK. EXPECT GUSTY AND ERRATIC WINDS
AROUND THUNDERSTORMS.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
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