074
FXUS65 KTWC 041002
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
302 AM MST MON MAY 4 2026
SYNOPSIS
A PACIFIC STORM SYSTEM WILL APPROACH AND CROSS THE
REGION THROUGH WEDNESDAY. BREEZY WINDS ARE EXPECTED TODAY AND
TUESDAY WITH THIS SYSTEM, AS WELL AS A CHANCE OF SHOWERS AND
THUNDERSTORMS FROM THIS EVENING THROUGH TUESDAY. HIGH
TEMPERATURES ARE EXPECTED TO FALL BELOW NORMAL TUESDAY AND
WEDNESDAY, THEN RISE BACK ABOVE NORMAL THE LATTER HALF OF THE
WEEK. WELL ABOVE NORMAL TEMPERATURES ARE LIKELY BY THIS WEEKEND.
DISCUSSION
A CLOSED LOW SITTING OVER THE CALIFORNIA COAST THIS MORNING WILL
GRADUALLY OPEN AND CROSS THE REGION EASTWARD OVER THE COMING
SEVERAL DAYS. SUB-TROPICAL MOISTURE STREAMING THROUGH THE BASE
OF THIS LOW HAS PROVIDED CIRRUS COVERAGE OVER SOUTHEASTERN
ARIZONA WITH INCREASING PRECIPITABLE WATER VALUES. SHOWER
CHANCES BEGIN TO INCREASE THIS EVENING (A FEW CAN'T BE RULED OUT
LATE THIS AFTERNOON) AS THE UPPER LOW APPROACHES. SHOWER
COVERAGE SHOULD TRANSITION FROM WEST TO EAST THROUGH TUESDAY
MORNING AS THE ASSOCIATED LOW LEVEL FRONT MOVES INTO THE REGION,
WITH ADDITIONAL CHANCES TUESDAY AFTERNOON WITH ISOLATED TO
SCATTERED CONVECTION. OVERALL COVERAGE HOWEVER REMAINS SOMEWHAT
UNCERTAIN AS SYNOPTIC SUPPORT FROM THE INCOMING UPPER LEVEL JET
WILL BE MISPLACED TO THE NORTH FROM THE LOW LEVEL FRONT. 00Z
HIGH RESOLUTION MODELS HIGHLIGHT THIS PROBLEM WITH DISAGREEMENT
BETWEEN THE 00Z HRRR DELAYING SHOWERS A GOOD 3-6 HOURS BEHIND
OTHER MODELS IN THE HREF SUITE. OVERALL, GREATEST CHANCES FOR
SHOWERS IS FROM LATE THIS EVENING THROUGH EARLY TUESDAY
MORNING, THEN SPOTTY CONVECTION WILL BE POSSIBLE TUESDAY
AFTERNOON MAINLY EAST AND NORTH OF TUCSON. THE AFOREMENTIONED
MISMATCH OF LOW AND UPPER LEVEL FEATURES WILL ALSO KEEP RAINFALL
TOTALS LIGHT, GENERALLY 0.01-0.2 INCHES IN THE VALLEYS AND UP
TO 0.5 INCHES IN THE MOUNTAINS, WITH GREATER TOTALS POSSIBLE IN
THE CATALINAS, RINCONS, PINALENOS, AND WHITE MOUNTAINS.
BREEZY WINDS OUT OF THE SOUTHWEST TODAY AND TUESDAY WITH COOLER
TEMPERATURES TUESDAY AND WEDNESDAY WILL ACCOMPANY THIS SYSTEM,
BOTH MAXIMIZING ON TUESDAY. 15-20 MPH WINDS AND GUSTS TO 35 MPH
WILL BE COMMON TUESDAY AFTERNOON (MAINLY EAST OF CENTRAL PIMA)
WITH STRONGER WINDS ACROSS PORTIONS OF SANTA CRUZ AND COCHISE
COUNTY WHERE GUSTS TO 40 MPH WILL BE POSSIBLE. FORECAST HIGH
TEMPERATURES TODAY WILL BE ABOUT 2-4 DEGREES BELOW NORMAL, THEN
4-10 DEGREES BELOW NORMAL TUESDAY AND WEDNESDAY. SOME GUIDANCE
CONTINUES TO SHOW LINGERING CIRCULATION ALOFT ON THURSDAY, WHICH
MAY KEEP SOME MOISTURE IN THE AREA WITH THE LOW-END CHANCE OF A
SHOWER. HOWEVER THE OVERALL TREND WILL STILL FAVOR WARMING AND
DRYING CONDITIONS WITH WELL ABOVE NORMAL TEMPERATURES LIKELY BY
THIS WEEKEND.
AVIATION
VALID THROUGH 05/12Z.
BKN-OVC CIRRUS AOA 20K FEET WITH FEW-SCT 15K FOOT CEILINGS, THEN
FEW-SCT 10K-15K CEILINGS AFTER 04/12Z. FURTHER LOWERING OF
CEILINGS LIKELY AS A FRONT MOVES INTO THE REGION FROM THE WEST
AFTER 05/03Z, ALONG WITH ISOLATED TO SCATTERED RAIN SHOWERS. THESE
SHOWERS SHOULD MOVE THROUGH KTUS-KOLS-KSAD IN A WINDOW FROM
05/03Z-05/12Z, AND KDUG AROUND 05/10Z-05/15Z, THOUGH THERE
REMAINS SOME UNCERTAINTY IN THE TIMING OF THEIR DEVELOPMENT AS
WELL AS THEIR COVERAGE. WINDS OUT OF THE SOUTHWEST WILL INCREASE
AFTER 04/16Z AND BECOME 12-18 KTS WITH GUSTS TO 25 KTS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
A PACIFIC STORM SYSTEM WILL CONTINUE TO APPROACH THE REGION
TODAY, INCREASING SOUTHWESTERLY WINDS THIS AFTERNOON TO 15-20
MPH WITH GUSTS TO 35 MPH. AS THE SYSTEM CROSSES ON TUESDAY WINDS
WILL INCREASE TO 18-25 MPH WITH GUSTS UP TO 40 MPH, ESPECIALLY
FROM SANTA CRUZ EASTWARD THROUGH SOUTHERN COCHISE COUNTY.
MOISTURE WILL INCREASE WITH INCOMING CHANCES FOR SHOWERS AND A
FEW THUNDERSTORMS FROM THIS EVENING THROUGH TUESDAY. MINIMUM
RELATIVE HUMIDITY IN THE VALLEYS TODAY WILL BE 15-20 PERCENT AND
20-30 PERCENT IN THE MOUNTAINS, INCREASING TO ABOVE 20 PERCENT
IN THE VALLEYS AND ABOVE 30 PERCENT IN THE MOUNTAINS ON TUESDAY.
TEMPERATURES 4-10 DEGREES BELOW NORMAL ARRIVE WITH THIS SYSTEM
TUESDAY AND WEDNESDAY. RELATIVE HUMIDITY QUICKLY DRIES OUT THE
SECOND HALF OF THE WEEK FROM WEDNESDAY ONWARDS. WELL ABOVE
NORMAL TEMPERATURES ARE EXPECTED BY THE WEEKEND.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...EDWARDS
AVIATION...EDWARDS
FIRE WEATHER...EDWARDS
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