143
FXUS65 KTWC 302041
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
141 PM MST FRI MAY 30 2025
SYNOPSIS
TEMPERATURES WILL REMAIN SLIGHTLY ABOVE NORMAL
THROUGH SATURDAY. A WEATHER SYSTEM THIS WEEKEND WILL BRING A
SUBSTANTIAL MOISTURE INCREASE INTO THE REGION, INITIALLY WITH A
SLIGHT CHANCE OF MAINLY DRY THUNDERSTORMS ALONG THE AZ/NM BORDER
TODAY, THEN SLIGHT CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS
SATURDAY. WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS WILL OCCUR
SUNDAY INTO EARLY MONDAY WITH DRY CONDITIONS RETURNING
THEREAFTER. BELOW NORMAL TEMPERATURES RETURN SUNDAY INTO EARLY
NEXT WEEK.
DISCUSSION
TODAY, HIGH CLOUDS ARE PUSHING INTO THE AREA AS
MID LEVEL MOISTURE CONTINUES TO BE USHERED IN AS THE CLOSED LOW
OFF THE WEST COAST OF BAJA REGRESSES EVER SO SLIGHTLY WESTWARD. IN
THE TROPICS TROPICAL STORM ALVIN CONTINUES IT'S NORTHWARD TRACK,
AS IT IS NOW LOCATED ABOUT 300 MILES SOUTH OF CABO, MEXICO. NHC
FORECASTS KEEP ALVIN ON A NORTHERLY TRACK INTO THE WEEKEND,
WEAKENING TO A REMNANT LOW ON SATURDAY. AS IT TRAVELS NORTH THE
PLACEMENT OF THE AFOREMENTIONED LOW WILL HELP ADVECT AN ANOMALOUS
AMOUNT OF MOISTURE INTO THE REGION THIS WEEKEND. THE BULK OF WHICH
REACHES SOUTHEAST ARIZONA SUNDAY INTO EARLY MONDAY.
THIS AFTERNOON THROUGH SATURDAY, MID-LEVEL MOISTURE WILL BEGIN TO
PUSH INTO EASTERN SOUTHERN ARIZONA. MOST OF THE ACTIVITY WILL
REMAIN TO OUR EAST TODAY IN NEW MEXICO, HOWEVER AN ISOLATED DRY
THUNDERSTORM OR TWO WILL BE POSSIBLE OVER THE HIGHER TERRAIN OF
COCHISE, GRAHAM, AND GREENLEE COUNTIES. TOMORROW THERE IS A BETTER
CHANCE FOR DRY THUNDERSTORMS MAINLY TO THE SOUTH AND EAST OF
TUCSON AS THE MID-LEVEL MOISTURE INCREASES FURTHER. PRECIPITABLE
WATER WILL BE AROUND 0.8" TO 1.0" BY SATURDAY, WHICH IS NEAR 200
PERCENT OF NORMAL FOR THIS TIME OF YEAR. LIKE TODAY, THE LOWER
LEVELS WILL STILL BE DRY SO VERY LITTLE IF ANY MEASURABLE RAIN IS
EXPECTED. ANY THUNDERSTORMS THAT DO FORM WILL LIKELY BE TIED TO
THE TERRAIN SINCE THE UPPER LEVEL LOW WILL BE TOO FAR AWAY TO LEND
MUCH IN THE WAY OF SYNOPTIC LIFT. THE MAIN THREATS WITH ANY STORM
WILL BE GUSTY OUTFLOWS AND LIGHTNING WHICH COULD LEAD TO NEW FIRE
STARTS. TEMPERATURES WILL BE AROUND NORMAL TO A FEW DEGREES ABOVE
NORMAL. SOME AREAS IN THE GILA RIVER VALLEY AND NORTHERN GREENLEE
COUNTY WILL REACH MODERATE HEATRISK TODAY AND TOMORROW THEN
RETURN TO MINOR HEATRISK, LIKE THE REST OF SOUTHERN ARIZONA, FOR
THE REMAINDER OF THE WEEK.
AS WE PROGRESS INTO SUNDAY, MORE TROPICAL MOISTURE WILL SURGED
INTO OUR AREA AND THE CLOSED LOW WILL OPEN AND MOVE EASTWARD INTO
ARIZONA. PRECIPITABLE WATER WILL BE AROUND 1.1"-1.4" WITH AREAS
IN CENTRAL TO WESTERN PIMA COUNTY THAT COULD SEE VALUES AS HIGH AS
1.5". THIS WILL LEAD TO WIDESPREAD CHANCES FOR SHOWERS AND
EMBEDDED THUNDERSTORMS ACROSS SOUTHERN ARIZONA. CURRENTLY, MODELS
SHOW SHOWERS AND STORMS MOVE INTO THE AREA BEGINNING IN FAR
WESTERN PIMA COUNTY EARLY SUNDAY MORNING PROGRESSING EASTWARD AS
THE DAY GOES ON REACHING TUCSON MID-DAY. THE SHOWERS WILL CONTINUE
TO MOVE EASTWARD EXITING SOUTHERN ARIZONA MONDAY. PRECIPITATION
AMOUNTS WILL BE AROUND 0.25" TO 0.5". LOCALLY, SOME AREA MAY SEE
CLOSER TO 1.0" DUE TO HEAVIER SHOWERS OR MULTIPLE ROUNDS OF RAIN
SHOWERS. GIVEN THE DRY CONDITIONS OVER THE PAST FEW MONTHS, RUNOFF
WILL LIKELY BE AN ISSUE AND COULD LEAD TO SOME LOCALIZED
FLOODING. THIS COULD ESPECIALLY BE A PROBLEM ON BURN SCARS AREAS
SUCH AS THE CODY FIRE. WPC HAS SOUTHEAST ARIZONA UNDER A MARGINAL
THREAT FOR FLASH FLOODING.
AS THE LOW PROGRESSES NORTHEASTWARD OUT OF ARIZONA LATE MONDAY,
ANY MOISTURE LEFT BEHIND WILL DRY OUT AND TEMPERATURES WILL
GRADUALLY RISE BACK TO NORMAL. ENSEMBLES BRING ANOTHER QUICK-
MOVING, CLOSED LOW THROUGH SOUTHEAST ARIZONA TUESDAY, HOWEVER
THERE WILL BE LIMITED MOISTURE WITH JUST A SLIGHT CHANCE FOR
PRECIP IN THE WHITE MOUNTAINS. THE MAIN IMPACT FROM THIS SECONDARY
LOW WILL BE GUSTY SOUTHWEST WINDS TUESDAY AFTERNOON.
AVIATION
VALID THROUGH 01/00Z.
GENERALLY LIGHT AND TERRAIN DRIVEN WINDS THROUGH THE FORECAST PERIOD
WITH A FEW AFTERNOON GUSTS. INCREASING CLOUDS AT 15K-25K FEET AFTER
30/21Z. A FEW CLOUD BUILD-UPS IN EASTERN LOCATIONS MAY PRODUCE VERY
LIGHT RAIN OR GUSTY OUTFLOW WINDS THIS AFTERNOON, AND AGAIN ACROSS
PORTIONS OF SOUTHEASTERN ARIZONA SATURDAY AFTERNOON. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
AN EVOLVING WEATHER PATTERN TODAY THROUGH THE
WEEKEND WILL DRAW MOISTURE INTO THE REGION. THUNDERSTORM ACTIVITY
TODAY WILL MOSTLY STAY IN NEW MEXICO, BUT SOME BUILDUPS WILL BE
POSSIBLE ALONG THE AZ/NM BORDER. OVERALL MOISTURE NEAR THE SURFACE
REMAINS LOW TODAY WITH MINIMUM RELATIVE HUMIDITY VALUES IN THE
SINGLE DIGITS TO 12 PERCENT. ADDITIONAL MOISTURE PUSHES INTO
SOUTHEASTERN ARIZONA SATURDAY BRINGING MINIMUM HUMIDITY VALUES TO
12 TO 22 PERCENT. THIS WILL LEAD TO A BETTER OPPORTUNITY FOR CLOUD
BUILD- UPS AND DRY LIGHTNING, ESPECIALLY ALONG THE HIGHER TERRAIN
OF COCHISE, GRAHAM, AND GREENLEE COUNTIES. SUNDAY INTO MONDAY
SHOULD FEATURE ADEQUATE MOISTURE FOR A HIGH LIKELIHOOD OF
WIDESPREAD WETTING RAIN OPPORTUNITIES WITH EMBEDDED THUNDERSTORMS.
OVERALL WINDS REMAIN LIGHT BUT GUSTY AND ERRATIC WINDS WOULD
OCCUR WITH ANY THUNDERSTORM ACTIVITY. DRY WEATHER RETURNS BY
TUESDAY.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC AND FIRE WEATHER...MALARKEY
AVIATION...EDWARDS
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