227
FXUS65 KTWC 122042
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
142 PM MST WED NOV 12 2025
SYNOPSIS
HIGH TEMPERATURES WILL REMAIN 5 TO 10 DEGREES ABOVE
NORMAL THROUGH FRIDAY. A LOW PRESSURE SYSTEM IS THEN EXPECTED TO
IMPACT THE REGION THIS WEEKEND, BRINGING CHANCES FOR RAIN AND HIGH
ELEVATION MOUNTAIN SNOW, MUCH COOLER TEMPERATURES, AND BREEZY
CONDITIONS. UNSETTLED CONDITIONS ARE EXPECTED TO CONTINUE EARLY NEXT
WEEK ALONG WITH BELOW NORMAL TEMPERATURES.
DISCUSSION
AS A TROUGH IN THE EASTERN PACIFIC CONTINUES TO SLOWLY PUSH
SOUTHWARD, UPPER-LEVEL MOISTURE IS BEGINNING TO BE PUSHED INTO
THE SOUTHWEST US BRINGING HIGH LEVEL CLOUDS TO OUR AREA. WHILE THE
TROUGH SLOWLY APPROACHES OVER THE NEXT FEW DAYS, WEAK RIDGING
WILL BE THE MAIN UPPER-LEVEL PATTERN KEEPING TEMPERATURES AT THE
SURFACE 5 TO 10 DEGREES ABOVE NORMAL.
MENTIONED IN THE PREVIOUS DISCUSSION, THE AFOREMENTIONED TROUGH,
LIKELY BECOMING A CLOSED LOW OFF THE CALIFORNIA COAST BY FRIDAY,
POSES A HEFTY FORECAST CHALLENGE. MODEL RUNS CONTINUE TO SLOW THE
EVOLUTION OF THE TROUGH AND SUBSEQUENT CUT OFF LOW AND THE
ASSOCIATED IMPACTS TO THE SOUTHWEST US. THE TIMING FOR
PRECIPITATION IN THIS FORECAST PACKAGE BEGINS SATURDAY MORNING FOR
AREAS IN FAR WESTERN PIMA COUNTY AND CENTRAL ARIZONA PUSHING INTO
THE TUCSON AREA SATURDAY EVENING. 12Z DETERMINISTIC MODELS,
HOWEVER, SUGGEST THAT THE PRECIPITATION WILL NOT ARRIVE IN WESTERN
PIMA COUNTY UNTIL SATURDAY EVENING/ SUNDAY MORNING. IN ADDITION
TO THE UNCERTAINTY WITH THE TIMING OF PRECIPITATION, THERE IS
VARYING POSSIBILITIES FOR THE DEPTH OF THE TROUGH AND
CORRESPONDING COLD AIR THAT WOULD BE INTRODUCED TO THE AREA. THE
BIGGEST IMPACT THIS HAS IS ON THE CHANCE AND AMOUNT OF
PRECIPITATION AND HIGH ELEVATION SNOW. AS OF NOW, SNOW LEVEL IS
FORECAST TO GET DOWN TO 8,500 FT IN THE WHITE MOUNTAINS WITH
AROUND 1 TO 2 INCHES OF SNOW SATURDAY THROUGH SUNDAY NIGHT.
OVERALL THE MESSAGE REMAINS THAT THERE WILL LIKELY BE SOME SORT
OF COOL-DOWN WITH CHANCES FOR PRECIPITATION BY THIS WEEKEND...BUT
THERE REMAIN DETAILS TO BE WORKED OUT BEFORE THEN.
NEXT WEEK LOOKS FAVORABLE FOR MEAN TROUGHING TO CONTINUE ACROSS
THE REGION WITH CPC OUTLOOKS LEANING WETTER AND COOLER.
AVIATION
VALID THROUGH 14/00Z.
FEW TO SCT HIGH CLOUDS AOA 25K FT AGL WILL CONTINUE THROUGH 13/09Z
BECOMING SCT TO BKN AOA 25K FT AGL PERSISTING THROUGH THE
FORECAST PERIOD. SFC WINDS WILL FROM THE NORTHWEST GENERALLY LESS
THAN 12 KTS SHIFTING TO THE SOUTHEAST AFT 13/04Z. SFC WINDS
BECOMING NORTHWESTERLY AGAIN AFT 13/22Z THROUGH THE FORECAST
PERIOD. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
LIGHT TERRAIN DRIVEN WINDS MAINLY UNDER 12 MPH THROUGH WEDNESDAY
WITH MINIMUM RELATIVE HUMIDITIES OF 12 TO 22 PERCENT. A LOW
PRESSURE SYSTEM WILL LIKELY CROSS THE REGION BY THIS WEEKEND,
THOUGH RECENT TRENDS HAVE SHOWN A DELAY IN ITS ARRIVAL. CURRENT
FORECAST KEEPS FRIDAY WARMER AND DRIER THAN PREVIOUSLY ADVERTISED
WITH COOLER AND WETTER CONDITIONS ARRIVING SATURDAY, THOUGH MAY BE
DELAYED UNTIL SUNDAY IF THE SYSTEM CONTINUES TO SLOW. WINDS WILL
LIKELY INCREASE AND TURN SOUTHWEST WITH THE ARRIVAL OF THE LOW.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
MALARKEY
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