644
FXUS65 KTWC 092155
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
255 PM MST MON FEB 9 2026
SYNOPSIS
AN INCREASE IN MOISTURE FROM THE SOUTH MAY BRING ISOLATED SHOWERS
AND POTENTIALLY A THUNDERSTORM LATE TONIGHT THROUGH TUESDAY,
MAINLY EAST AND SOUTH OF TUCSON. ANOTHER WEATHER
SYSTEM IS THEN EXPECTED LATE THURSDAY THROUGH FRIDAY RESULTING IN A
CHANCE FOR VALLEY RAIN AND HIGH ELEVATION SNOWFALL. OTHERWISE,
AFTERNOON HIGH TEMPERATURES WILL REMAIN 6-10 DEGREES ABOVE NORMAL
THROUGH THE MIDDLE OF NEXT WEEK.
DISCUSSION
THIS AFTERNOON, AN UPPER LOW CONTINUES TO SIT WEST OF THE SOUTHERN
BAJA PENINSULA. WHILE THIS LOW IS DRIVING CONVECTION OVER AREAS
OF CENTRAL SONORA, THE DIVERGENT FLOW ALOFT ASSOCIATED WITH THE
LOW REMAINS WELL TO THE SOUTH OF THE SOUTHERN ARIZONA BORDER ALONG
WITH THE HEALTHIER MOISTURE FIELD. POCKETS OF SHALLOW CUMULUS HAS
DEVELOPED OVER HIGH ELEVATION LOCATIONS IN SANTA CRUZ AND COCHISE
COUNTIES THIS AFTERNOON AS FAR SOUTHERN ARIZONA SITS ON THE
PERIPHERY OF THE MOISTURE GRADIENT.
THE UPPER LOW IS EXPECTED TO OPEN AND LIFT EAST-NORTHEAST THROUGH
TUESDAY, NUDGING THE MOISTURE GRADIENT NORTH INTO FAR SOUTHERN
ARIZONA. THE MOISTURE FIELD, CHARACTERIZED BY MID-40S SURFACE DEW
POINTS AND PRECIPITABLE WATER APPROACHING 0.6-0.8 INCHES, WILL
ALLOW FOR AN ISOLATED CHANCE OF SHOWERS OR A THUNDERSTORM ON
TUESDAY. WHILE ACTIVITY CAN'T BE RULED OUT EARLY IN THE MORNING
OR POTENTIALLY LATE TONIGHT AS THE MOISTURE GRADIENT ADVANCES
THROUGH THE INTERNATIONAL BORDER, THE LACK OF APPRECIABLE UPPER
LEVEL SUPPORT (WITH THE UPPER LOW STILL CENTERED WELL TO THE
SOUTH) KEEP ANY CHANCES ON THE LOW END. THIS REASONING ALSO GOES
FOR TUESDAY AFTERNOON/EVENING WITH CHANCES MAINLY IN THE 10-20
PERCENT RANGE MAINLY IN AREAS EAST OF CENTRAL PIMA COUNTY. SNOW
LEVELS ARE EXPECTED TO REMAIN ABOVE THE MOUNTAINS WITH THIS
SYSTEM.
THE NEXT UPPER LEVEL WAVE IS EXPECTED TO CROSS THE REGION THURSDAY
NIGHT THROUGH FRIDAY, WITH MAIN CHANCES FOR PRECIPITATION FOCUSED
ON FRIDAY. THERE HAVE BEEN SOME RECENT TIMING DIFFERENCES IN WHEN
THIS WAVES ARRIVES (WITH ONSET OF PRECIPITATION RANGING FROM
THURSDAY EVENING TO FRIDAY MORNING), WITH THE CURRENT ENSEMBLE
SPREAD LEANING TOWARDS LIGHT PRECIPITATION BEGINNING LATE THURSDAY
EVENING. A MID-LEVEL JET WILL SWING THROUGH THE MAIN TROUGH
SOMETIME BETWEEN EARLY FRIDAY MORNING AND FRIDAY AFTERNOON,
PUTTING SOUTHEASTERN ARIZONA UNDER THE LEFT EXIT REGION OF THIS
JET WITH FAVORABLE ASCENT FOR PERIODS OF MODERATE RAINFALL RATES.
THE TRACK OF THE HEAVIER RAINFALL RATES LOOKS TO FAVOR AREAS IN
THE EASTERN THREE COUNTIES OF COCHISE, GRAHAM, AND GREENLEE, WITH
STILL SOME MODEL TO MODEL AND RUN TO RUN VARIABILITY IN THE WEST
TO EAST LOCATION OF THIS TRACK. THEREFORE SOME SHIFTING IN
PRECIPITATION FORECASTS CAN STILL BE EXPECTED IN THE COMING COUPLE
DAYS. THE OVERALL CEILING OF RAINFALL POTENTIAL HAS INCREASED IN
RECENT MODEL RUNS, WITH HIGHER END AMOUNTS RANGING FROM 0.2"-0.5"
IN THE VALLEYS AND UP TO 0.6" IN THE MOUNTAINS, THOUGH MANY AREAS
WILL BE ON THE LOWER END OF THIS RANGE. THE PROGRESSIVE NATURE OF
THIS WAVE WITH HIGH SNOW LEVELS KEEP FORECAST SNOWFALL
ACCUMULATIONS LIGHT WITH JUST A FEW INCHES CURRENTLY FORECAST ATOP
THE CATALINA, PINALENO, AND WHITE MOUNTAIN RANGES.
JUST AFTER THIS FORECAST PERIOD IN THE EARLY TO MIDDLE PORTIONS OF
NEXT WEEK MODELS ARE IN GOOD AGREEMENT WITH DEEPER TROUGHING TO
DEVELOP OVER THE EASTERN PACIFIC INTO THE WESTERN CONUS. SURFACE
WINDS SHOULD KICK UP FROM THE SOUTHWEST AS EARLY AS SUNDAY
(ASSUMING NO DELAY IN THE TROUGH ARRIVAL OCCURS) WITH
PRECIPITATION CHANCES RETURNING EARLY IN THE WORK WEEK. STILL
PLENTY OF DETAILS TO WORK OUT (CURRENT ENSEMBLE MEAN HEIGHT
ANOMALIES FAVOR A PATTERN THAT KEEPS THE GREATER PRECIPITATION
NORTH OF THE AREA WITH WIND BEING THE MAIN IMPACT) BUT IT WILL BE
A PATTERN WORTH WATCHING.
FINALLY TO POINT OUT THE IMPACT THE AFOREMENTIONED SYSTEMS WILL
HAVE ON SURFACE TEMPERATURES OVER SOUTHEASTERN ARIZONA, HIGH
TEMPERATURES REMAIN WELL ABOVE NORMAL THROUGH WEDNESDAY, THEN
LIKELY FALL TO NEAR TO BELOW NORMAL FRIDAY AND SATURDAY BEFORE
REBOUNDING ON SUNDAY. NEXT WEEK'S TEMPERATURES BECOME A BIT
MURKIER DUE TO THE UNCERTAINTY WITH THE INCOMING TROUGH, BUT
GENERALLY FAVOR NEAR NORMAL TO BELOW NORMAL TEMPERATURES.
AVIATION
VALID THROUGH 11/00Z.
FEW-SCT CLOUDS AROUND 6K-10K FEET SOUTH OF KTUS THROUGH KOLS-KDUG,
SPREADING NORTH THROUGH KTUS THIS EVENING. ISOLATED -SHRA POSSIBLE
NEAR KOLS-KDUG ON TUESDAY, THOUGH A STRAY SHOWER CAN'T BE RULED
OUT TONIGHT. WIND LIGHT AND TERRAIN DRIVEN THROUGH 10/15Z, THEN
SOUTH TO SOUTHEASTERLY 10-14 KTS WITH GUSTS TO 20 KTS THROUGH THE
REMAINDER OF THE FORECAST PERIOD. AVIATION DISCUSSION NOT UPDATED
FOR TAF AMENDMENTS.
FIRE WEATHER
A LOW PRESSURE SYSTEM NEAR THE SOUTHERN BAJA PENINSULA
THIS MORNING WILL MOVE ACROSS SONORA AND CHIHUAHUA MEXICO TUESDAY.
THE CLOSE PROXIMITY OF THIS SYSTEM WILL RESULT IN A NORTHERLY PUSH
OF LOW-LEVEL MOISTURE INTO THE AREA TONIGHT INTO TUESDAY, RESULTING
AN INCREASE IN RHS BETWEEN TODAY AND TUESDAY. THIS WILL ALSO
RESULT IN A SLIGHT CHANCE OF SHOWERS, POSSIBLY WITH AN EMBEDDED
THUNDERSTORM, FROM TUCSON SOUTH EAST TUESDAY. OTHERWISE,
AFTERNOON HIGH TEMPERATURES WILL REMAIN 6-10 DEGREES ABOVE NORMAL
THROUGH THE MIDDLE OF NEXT WEEK. MIN RH LEVELS WILL BE IN THE
15-25 PERCENT RANGE FOR THE VALLEYS AND 25-35 PERCENT FOR THE
MOUNTAINS TODAY, INCREASING TO 35-45 PERCENT VALLEYS AND 45 TO 65
PERCENT IN THE MOUNTAINS TUESDAY. ANOTHER LOW PRESSURE SYSTEM LATE
THURSDAY THROUGH FRIDAY WILL BRING INCREASING RHS, AND WETTING
RAINS ACROSS SOUTHEAST ARIZONA WITH LIGHT SNOWFALL IN THE HIGHEST
ELEVATIONS.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC...EDWARDS
AVIATION...EDWARDS
FIRE WEATHER....EDWARDS
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