097
FXUS65 KTWC 131010
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
310 AM MST THU NOV 13 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 SHOWERS,
COOLER TEMPERATURES, AND BREEZY CONDITIONS. UNSETTLED CONDITIONS
ARE EXPECTED TO CONTINUE NEXT WEEK ALONG WITH BELOW NORMAL
TEMPERATURES.
DISCUSSION
WATER VAPOR IMAGERY THIS MORNING DEPICTS A DEEP, CLOSING LOW OFF
THE WEST COAST, WITH A STREAM OF HIGH LEVEL MOISTURE THROUGH
SOUTHWEST FLOW FROM THE BASE OF THE TROUGH THROUGH THE DESERT
SOUTHWEST. WITH SOUTHEASTERN ARIZONA STILL SITTING UNDER A RIDGE
DOWNSTREAM FROM THIS EASTERN PACIFIC TROUGH, WARM DAYTIME
TEMPERATURES WITH PERIODS OF HIGH LEVEL CLOUDS WILL REMAIN THE
STORY INTO THE WEEKEND.
THE PACIFIC LOW AND ITS EVENTUAL WEST COAST CROSSING HAS BEEN A
PROBLEM FOR MODELS TO HANDLE THIS WEEK IN REGARDS TO TIMING,
DEPTH, AND PROGRESSION ACROSS THE REGION. CLOSED LOWS TEND TO MAKE
THEIR ENTRANCE FAR SLOWER THAN MODELS INDICATE AND THIS ONE HAS
BEEN NO EXCEPTION. THE MODEL RUN TO RUN TREND OVER THE PAST 24-48
HOURS HAS SEEN THE TROUGH'S ADVERTISED ARRIVAL DELAY FROM FRIDAY
TO NOW LATE SATURDAY TO SUNDAY. GFS/ECWMF/CMC ENSEMBLES DO DEPICT
NON- ZERO CHANCES OF EARLIER SATURDAY PRECIPITATION, MAINLY IN
WESTERN PIMA. HOWEVER GIVEN THE PATTERN A LATER ARRIVAL SEEMS MORE
REASONABLE. THE TEMPERATURE TREND WILL FOLLOW THE EVENTUAL TIMING
OF THIS TROUGH, WITH UNSEASONABLY WARM TEMPERATURES NOW LOOKING
LIKELY THROUGH SATURDAY, THEN COOLER SUNDAY.
AS FOR PRECIPITATION TOTALS, IT'S LOOKING INCREASINGLY LIKELY THAT
STRONGER UPPER LEVEL DYNAMICS WILL BE KEPT FURTHER NORTH THROUGH
CENTRAL TO NORTHERN ARIZONA, KEEPING SOUTHEASTERN ARIZONA OUT OF
THE THREAT FOR HEAVIER RAINFALL RAINFALL RATES. THE OVERALL SPREAD
OF RAIN AMOUNTS RANGE FROM A FEW HUNDREDTHS OF AN INCH TO AROUND
A HALF INCH ON THE HIGH END THROUGH THE END OF THE WEEKEND. WITH
THE NORTHERN TRACK OF THIS LOW, ACCUMULATING MOUNTAIN SNOW IS
LESS LIKELY WITH SNOW LEVELS ABOVE 9000 FEET.
NEXT WEEK STILL LOOKS TO BE ACTIVE AS ENSEMBLE MEAN HEIGHTS SHOW A
SERIES OF TROUGHS MOVING THROUGH THE SOUTHWEST REGION. THE 6-10
DAY CPC OUTLOOK SUBSEQUENTLY ADVERTISES LIKELY CHANCES FOR ABOVE
NORMAL PRECIPITATION AND BELOW NORMAL TEMPERATURES.
AVIATION
SCT-BKN CIRRUS AOA 20K FEET THROUGH MUCH OF THE FORECAST PERIOD.
SURFACE WINDS LIGHT, TERRAIN DRIVEN, AND UNDER 10 KTS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
WARM AND DRY THROUGH FRIDAY WITH LIGHT TERRAIN DRIVEN WINDS UNDER
12 MPH. A LOW PRESSURE SYSTEM WILL CROSS THE REGION THIS WEEKEND
AND BRING COOLER TEMPERATURES, INCREASED WINDS, AND CHANCES FOR
SHOWERS. SHOWER CHANCES MAY ARRIVE AS EARLY AS EARLY SATURDAY FOR
AREAS WEST OF TUCSON, BUT GREATER CHANCES SHOULD BE DELAYED UNTIL
LATE SATURDAY AND SUNDAY.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC...EDWARDS
AVIATION...EDWARDS
FIRE WEATHER....EDWARDS
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