361
FXUS65 KTWC 230831
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
131 AM MST FRI JAN 23 2026
SYNOPSIS
A PACIFIC LOW PRESSURE SYSTEM WILL CROSS THE REGION
THROUGH THIS WEEKEND. ON AND OFF PERIODS OF RAIN WILL OCCUR TODAY
THROUGH SATURDAY ACROSS MUCH OF SOUTHEASTERN ARIZONA. ACCUMULATING
SNOW IS LIKELY THROUGH EARLY SUNDAY IN MOUNTAIN ELEVATIONS ABOVE
7000 FEET, WITH A WINTER WEATHER ADVISORY IN EFFECT. WELL BELOW
NORMAL TEMPERATURES ARE EXPECTED SATURDAY AND SUNDAY BEFORE A
WARMING TREND ARRIVES EARLY NEXT WEEK.
KEY MESSAGES
1. WINTER WEATHER ADVISORY IN EFFECT FROM 5 PM THIS AFTERNOON TIL 5
AM SUNDAY FOR THE CATALINA AND PINALENO MOUNTAINS AS WELL AS THE
WHITE MOUNTAINS OF GRAHAM AND GREENLEE COUNTIES. SNOW ACCUMULATIONS
OF 6 TO 12 INCHES ABOVE 7000 FEET.
2. LOWER ELEVATION RAINFALL TOTALS BETWEEN 0.5-1.25, GREATER IN
HIGHER TERRAIN, WITH HIGHER AMOUNTS EAST OF TUCSON. EXPECT PONDING
ON ROADWAYS AND WATER IN NORMALLY DRY WASHES.
3. TEMPERATURES BECOME 8-12 DEGREES BELOW NORMAL THIS WEEKEND. A
WARMING TREND IS EXPECTED FOLLOWING THIS SYSTEM EARLY NEXT WEEK.
DISCUSSION
LATEST WV SATELLITE IMAGERY SHOWS AN UPPER LOW NEAR
32N/121W OR A COUPLE HUNDRED MILES WEST TO SOUTHWEST OF SAN DIEGO.
OUT AHEAD OF THIS UPPER LOW, A SUBTROPICAL TAP OF MOISTURE IS
CURRENTLY PUSHING INTO SOUTHEAST ARIZONA AND THAT IS REFLECTED BY
THE WIDESPREAD LIGHT TO MODERATE RAIN ESPECIALLY ACROSS SANTA CRUZ
AND COCHISE COUNTY WITH MORE SCATTERED SHOWER ACTIVITY ELSEWHERE
EARLY THIS MORNING. GIVEN THE WARM NATURE OF THIS SYSTEM AT THIS
POINT, SNOW LEVELS ARE GENERALLY AT OR ABOVE MOUNTAIN TOPS. THE
UPPER LOW IN THE EASTERN PACIFIC WILL CONTINUE TO MOVE TOWARDS THE
SOUTHEAST TODAY, THEN INLAND AROUND THE BAJA SPUR TONIGHT AND THEN
ACROSS SONORA SATURDAY. MEANWHILE, A NORTHERN STREAM SHORTWAVE (THAT
IS ALSO HELPING EJECT THE SOUTHERN STREAM SYSTEM EASTWARD) WILL HELP
PRODUCE ADDITIONAL FORCING AND LIFT SATURDAY INTO SATURDAY NIGHT
ACROSS SOUTHEAST ARIZONA. WHAT THIS ALL BOILS DOWN TO IS AN EXTENDED
PERIOD ON AND OFF VALLEY RAIN AND MOUNTAIN SNOW FROM TODAY THROUGH
EARLY SUNDAY MORNING. WITH A BIT MORE INSTABILITY ON SATURDAY, WE
CAN'T RULE OUT A RUMBLE OF THUNDER ESPECIALLY SATURDAY AFTERNOON.
WE'RE NOT SEEING A WHOLE LOT OF CHANGE THIS FORECAST CYCLE WITH QPF
AMOUNTS WHICH WILL GENERALLY RANGE FROM ABOUT 0.50" TO 1.25" FROM
TUCSON EASTWARD WITH SOME HIGHER AMOUNTS IN THE MOUNTAINS AND LESSER
AMOUNTS TO THE WEST OF TUCSON. SNOW LEVELS THROUGH THE DAY TODAY
WILL REMAIN AT OR ABOVE MOUNTAIN TOPS, THEN HOVER AROUND 8000-8500
FEET TONIGHT INTO SATURDAY MORNING, THEN LOWERING TO AROUND 7000
FEET BY SATURDAY EVENING. THIS WILL TRANSLATE TO AROUND 6 TO 12
INCHES OF SNOW ABOVE 7000 FEET, THOUGH SOME SPOTS RIGHT AT THE
MOUNTAIN PEAKS COULD SEE A BIT MORE. A WINTER WEATHER ADVISORY IS IN
EFFECT FOR THE SKY ISLANDS FROM TUCSON NORTHEASTWARD FROM 5 PM THIS
AFTERNOON UNTIL 5 AM SUNDAY.
BELOW NORMAL TEMPERATURES RETURN STARTING TODAY AND CONTINUE THROUGH
MONDAY WITH THE COOLEST TEMPERATURES OVER THE WEEKEND WHEN HIGHS
WILL BE ABOUT 7 TO 10 DEGREES BELOW NORMAL.
ONCE THE SYSTEM DEPARTS ON SUNDAY, DRIER WEATHER WILL RETURN THROUGH
THE THE END OF THE FORECAST PERIOD AS RIDGING BUILDS IN BY THE
MIDDLE OF NEXT WEEK. THIS WILL RESULT IN A WARMING TREND WITH HIGHS
NEAR NORMAL BY TUESDAY AND WEDNESDAY.
AVIATION
VALID THROUGH 24/00Z. MAINLY BKN-OVC CONDITIONS AT 4-8K
FT AGL WITH PERIODS OF -SHRA/SHRA CONTINUING THROUGH THE END OF THE
VALID PERIOD FOR ALL TERMINALS. MVFR CONDITIONS ARE POSSIBLE DURING
PERIODS OF SHRA ACTIVITY. SFC WINDS LIGHT AND TERRAIN DRIVEN THROUGH
23/18Z, THEN S/SW 6-12 KTS AT KOLS-KDUG WITH LIGHTER WINDS FURTHER
NORTH THRU 24/03Z WITH LIGHT AND TERRAIN DRIVEN WINDS RETURNING
THEREAFTER. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
AN AREA OF LOW PRESSURE WILL IMPACT OUR REGION
TODAY THROUGH SATURDAY NIGHT INTO SUNDAY MORNING. EXPECT ON AND OFF
VALLEY RAIN AND MOUNTAIN SNOW, ALONG WITH COOLER TEMPERATURES AND
HIGHER RELATIVE HUMIDITY. 20-FOOT WINDS WILL BE LESS THAN 15 MPH AND
TERRAIN DRIVEN. A RETURN TO DRY CONDITIONS SUNDAY INTO NEXT WEEK
WITH TEMPERATURES RETURNING TO NEAR NORMAL BY TUESDAY.
TWC WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY FROM 5 PM FRIDAY TO 5 AM MST SUNDAY FOR
AZZ510-511-514.
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