606
FXUS65 KTWC 300910
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
210 AM 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
WATER VAPOR SHOWS A CLOSED LOW SPINNING OFF THE
NORTHERN COAST OF BAJA WITH RIDGING TO THE NORTH, WHICH WILL KEEP
THE LOW IN ITS CURRENT POSITION THROUGH MOST OF THE WEEKEND. AT
THE SURFACE A WEAK MOISTURE SURGE FROM THE GULF OF CALIFORNIA HAS
MADE IT TO TUCSON AS EVIDENCED BY GUSTY SOUTHWEST WINDS THIS
EVENING AND A 10-15 DEGREE INCREASE IN DEWPOINTS OVER THE LAST 3
HOURS. IN THE TROPICS TROPICAL STORM ALVIN IS LOCATED ABOUT 450
MILES SOUTH OF CABO. NHC FORECASTS KEEP ALVIN ON A NORTHERLY TRACK
INTO THE WEEKEND. 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.
TODAY AND SATURDAY SOME MID-LEVEL MOISTURE BEGINS TO INTRUDE INTO
THE EASTERN PORTION OF THE CWA. HI-RES GUIDANCE KEEPS MOST
ACTIVITY TODAY EAST OF OUR AREA IN NEW MEXICO. HOWEVER AN ISOLATED
DRY THUNDERSTORM OR TWO WILL BE POSSIBLE OVER THE HIGHER TERRAIN
OF COCHISE, GRAHAM, AND GREENLEE COUNTIES. SATURDAY WILL SEE
BETTER CHANCES FOR DRY THUNDERSTORMS AS THE MID-LEVEL MOISTURE
INCREASES FURTHER. PWATS WILL BE AROUND 0.8" BY SATURDAY, WHICH IS
NEAR 200 PERCENT OF NORMAL FOR THIS TIME OF YEAR. HOWEVER THE
LOWER LEVELS WILL STILL BE DRY SO EXPECT VERY LITTLE IF ANY
MEASURABLE RAIN. 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.
SUNDAY PWATS INCREASE TO AROUND 300 PERCENT OF NORMAL WHICH IS
AROUND 1.1"-1.4". AREAS IN WESTERN PIMA COUNTY COULD SEE VALUES AS
HIGH AS 1.5". SURFACE DEW POINTS WILL ALSO LIKELY INCREASE INTO
THE 50S SUNDAY EVENING INTO MONDAY MORNING. AT THE SAME TIME THE
CLOSED LOW BEGINS TO MOVE EASTWARD AND OPENS UP AS IT MOVES INTO
ARIZONA. THIS WILL LEAD TO WIDESPREAD SHOWER ACTIVITY WITH
EMBEDDED THUNDERSTORMS SUNDAY INTO MONDAY MORNING. RIGHT NOW IT
LOOKS LIKE THE BULK OF THE RAIN FALLS SUNDAY AFTERNOON INTO THE
EVENING. HOWEVER THIS WILL DEPEND ON THE SPEED OF THE TROUGH.
MODELS DO HINT AT LINGERING OVERNIGHT ACTIVITY AS THE LOW LIFTS
INTO THE FOUR CORNERS REGION. RAINFALL TOTALS RANGE FROM 0.2"-0.6"
IN THE VALLEYS WITH UP TO AN INCH IN THE MOUNTAINS. LOCALLY
HIGHER AMOUNTS WILL BE POSSIBLE ESPECIALLY WHERE THERE ARE
TRAINING STORMS. GIVEN THE DRY CONDITIONS FROM THE PAST FEW
MONTHS, RUNOFF WILL LIKELY BE AN ISSUE AND COULD LEAD TO SOME
LOCALIZED FLOODING. THIS COULD ESPECIALLY BE A PROBLEM ON
AREA BURN SCARS SUCH AS THE CODY FIRE. WPC HAS SOUTHEAST ARIZONA
UNDER A MARGINAL THREAT FOR FLASH FLOODING. THANKS TO THE
MOISTURE HIGH TEMPERATURES WILL BE ABOUT 8-10 DEGREE BELOW NORMAL
SUNDAY AND MONDAY.
DURING THE DAY MONDAY PWATS STEADILY DECREASE IN THE WAKE OF THE
LOW WITH SCATTERED SHOWER ACTIVITY DECREASING FROM WEST TO EAST
DURING THE MORNING INTO THE AFTERNOON. ENSEMBLES BRING ANOTHER
CLOSED LOW THROUGH SOUTHEAST ARIZONA TUESDAY, HOWEVER THE MOISTURE
WILL BE GONE WITH JUST A SLIGHT CHANCE FOR PRECIP IN THE WHITE
MOUNTAINS. THE MAIN IMPACT IT WILL HAVE IS TO BRING GUSTY
SOUTHWEST WINDS. AFTER TUESDAY HIGH TEMPERATURES CLIMB BACK TO
AROUND NORMAL.
AVIATION
VALID THROUGH 31/12Z.
SCT-BKN CLOUDS MAINLY AOA 15K FT THROUGH THE VALID PERIOD. THIS
AFTERNOON FEW-SCT CLOUDS AT 10K FT AGL WILL BE POSSIBLE EAST OF
KTUS. GENERALLY LIGHT AND TERRAIN DRIVEN WINDS LESS THAN 12 KTS
THROUGH THE FORECAST PERIOD WITH WLY/SWLY AFTERNOON GUSTS AROUND
18 KTS. 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.
HARDIN
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