179
FXUS65 KTWC 151857
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
1157 AM MST WED OCT 15 2025
SYNOPSIS
DRY CONDITIONS AND BELOW NORMAL TEMPERATURES PREVAIL THIS WEEK.
EXPECT A WARMING TREND THIS WEEKEND TO NEAR NORMAL TEMPERATURES
SUNDAY INTO EARLY NEXT WEEK.
DISCUSSION
MOSTLY CLEAR SKIES WERE OBSERVED THIS MORNING ACROSS SOUTHEASTERN
ARIZONA, WITH POCKETS OF CUMULUS AS SURFACE DEW POINTS INTO THE
LOWER 50S INDICATE MODEST LOW LEVEL MOISTURE REMAINS. A DEEP UPPER
LEVEL TROUGH IS CENTERED OVER THE GREAT BASIN TODAY, WITH DRY
SOUTHWEST FLOW IN THE MID-LEVELS OVER SOUTHEASTERN ARIZONA. THE
UPPER TROUGH IS EXPECTED TO TRACK EAST THROUGH THE WORK WEEK,
PUTTING THE DESERT SOUTHWEST THROUGH A PERIOD OF LOW HEIGHT
ANOMALIES. UNSEASONABLY COOL TEMPERATURES WILL BE THE FEATURE THIS
WEEK WHILE THE TROUGHING PATTERN CONTINUES, WITH TEMPERATURES
ABOUT 6-12 DEGREES BELOW NORMAL OVER THE NEXT SEVERAL DAYS.
COLDEST LOWS ACROSS DESERT LOCATIONS WILL INCLUDE THE SULPHUR
SPRINGS VALLEY WITH LOWS INTO THE LOWER 40S (POTENTIALLY ISOLATED
UPPER 30S).
BY THIS WEEKEND THE MAIN UPPER TROUGH IS EXPECTED TO BE WELL EAST
OF THE REGION, WHILE A SHORTWAVE SHOULD BREAK OFF AND BECOME
CLOSED OVER THE EASTERN PACIFIC WEST OF THE BAJA PENINSULA. THE
LOSS OF THE MAIN TROUGH SHOULD ALLOW TEMPERATURES TO MODERATE
CLOSER TO NORMAL SUNDAY INTO EARLY NEXT WEEK, HOWEVER THIS IS
WHERE DETAILS BECOME A BIT MURKIER. THERE REMAINS DIFFERENCES IN
GUIDANCE IN HOW TO HANDLE THE EVENTUAL EASTWARD TRANSITION OF THE
PACIFIC CLOSED LOW, THE DEPTH OF A PACIFIC NORTHWEST TROUGH NEXT
WEEK THAT MAY IMPACT THIS TRANSITION, AND THE POTENTIAL FOR A
LEADING IMPULSE CROSSING THE REGION THIS WEEKEND. CERTAINLY A MESS
OF MOVING PARTS THERE WITH SUBSEQUENT UNCERTAINTY IN THE
TEMPERATURE TREND AND POSSIBLE MOISTURE RETURN. THE CURRENT
THINKING IS THAT MOST GUIDANCE DOESN'T BRING A BIG WARM UP, SO
TEMPERATURE PROBABILITIES TOP OUT AT AROUND NORMAL FOR THIS TIME
OF YEAR EARLY NEXT WEEK...WITH A HEALTHY CHANCE OF BELOW NORMAL
TEMPERATURES RETURNING...WHICH IS WHAT THE CURRENT FORECAST
ADVERTISES NEXT TUESDAY AND WEDNESDAY. THE FORECAST REMAINS DRY
BUT A NON-ZERO CHANCE OF MODEST MOISTURE RETURN CAN'T BE RULED
OUT.
AVIATION
VALID THROUGH 17/00Z.
MOSTLY SKC WITH A FEW CUMULUS AT 4K-7K FEET THROUGH 16/02Z.
SURFACE WINDS WEST TO SOUTHWEST 8-12 KTS THROUGH 16/03Z WITH
OCCASIONAL GUSTS TO 20 KTS. THEREAFTER, SURFACE WINDS LIGHT AND
TERRAIN DRIVEN. SURFACE WINDS REMAIN LIGHT AND UNDER 12 KTS ON
THURSDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
FIRE WEATHER
MINIMUM RH VALUES WILL BE 30-40 PERCENT IN THE VALLEY'S TODAY,
WITH HIGHER VALUES IN THE MOUNTAINS, THEN WILL LOWER INTO THE
20-30 PERCENT RANGE IN THE VALLEYS THURSDAY INTO THE WEEKEND.
20-FOOT WINDS MAINLY 15 MPH OR LESS THIS WEEK, WITH OCCASIONAL
GUSTS TO 20- 25 MPH. HIGH TEMPERATURES WILL BE BELOW NORMAL INTO
THIS WEEKEND, WARMING TO NEAR NORMAL LEVELS SUNDAY AND MONDAY.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC...EDWARDS
AVIATION...EDWARDS
FIRE WEATHER....EDWARDS
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