893
FXUS65 KTWC 050925
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
225 AM MST MON MAY 5 2025
SYNOPSIS
A STRONG PACIFIC WEATHER SYSTEM WILL BRING COOLER
TEMPERATURES OVER THE COMING DAYS WITH PERIODIC CHANCES FOR
SCATTERED SHOWERS...POSSIBLY WITH AN EMBEDDED THUNDERSTORM. LIGHTER
WINDS WITH AFTERNOON BREEZES TODAY AND TUESDAY. TEMPERATURES WILL
THEN REBOUND THE SECOND HALF OF NEXT WEEK, WITH THE POSSIBILITY
FOR THE CENTURY MARK RETURNING NEXT WEEKEND.
DISCUSSION
A SERIES OF DISTURBANCES ROTATING AROUND A STRONG
PACIFIC STORM SYSTEM POSITIONED OVER SOUTHWEST ARIZONA THIS
MORNING WILL RESULT IN A COUPLE OF WAVES OF RAIN SHOWERS WITH EVEN
SOME HIGH ELEVATION SNOW OVER THE NEXT FEW DAYS. STRONG WINDS
EVIDENT ON THE LATEST WATER VAPOR IMAGERY ALONG THE SW PERIPHERY
OF THE UPPER-LOW WILL SERVE TO ELONGATE THE UPPER LOW AS IT MOVES
ACROSS ARIZONA TODAY, SHIFTING IT FROM A POSITIVE-TILT TO A MORE
NEUTRAL-TILT ALONG EASTERN ARIZONA THIS AFTERNOON. AS THIS
HAPPENS, THE MID AND UPPER TROUGH AXIS WILL SWING ACROSS SOUTHEAST
ARIZONA LATE THIS MORNING INTO EARLY THIS AFTERNOON. THIS FORCING
COMBINED WITH THE INCREASE IN MOISTURE ASSOCIATED WITH THE SYSTEM
ITSELF WILL RESULT IN A BAND OF SHOWERS DEVELOPING ACROSS CENTRAL
PIMA/SOUTHERN MARICOPA/SOUTHEAST PINAL DURING THE MID-MORNING AND
TRACKING ESE ACROSS EASTERN PIMA THIS AFTERNOON...THEN SLIGHTLY
WEAKENING THEM AS THEY MOVE INTO COCHISE COUNTY EARLY THIS
EVENING.
ALTHOUGH THE MEAN TROUGH MAINTAINS ITSELF ACROSS THE GREAT BASIN
AND SOUTHERN ROCKIES FOR THE NEXT FEW DAYS, THE UPPER-LOW CENTER
ALONG THE AZ/NM BORDER THIS AFTERNOON MOVES INTO NORTHERN NEW
MEXICO OVERNIGHT TONIGHT. THE COMBINATION OF AN AREA OF STRETCHING
DEFORMATION IN THE WAKE IN THE MID-UPPER LEVELS AND A LOW-MID
LEVEL BOUNDARY MOVING EAST ACROSS THE AREA WILL RESULT IN A
SECONDARY WAVE OF PRECIPITATION MOVING FROM CENTRAL ARIZONA AROUND
06Z TUESDAY (TONIGHT) EAST ACROSS SE PINAL AND INTO GRAHAM AND
GREENLEE COUNTIES BY 18Z TUESDAY. ANOTHER UPPER-LOW MOVING SOUTH
THRU THE GREAT BASIN AROUND THE MEAN TROUGH WILL THEN TRACK ACROSS
CENTRAL AND SE AZ WEDNESDAY. THE HEAVIEST PRECIPITATION WITH THIS
SYSTEM WILL BE ACROSS THE NORTHERN HALF OF ARIZONA. IN OUR NECK
OF THE WOODS, WE ARE LOOKING AT A 10-30 PERCENT CHANCE OF TOTAL
RAINFALL IN EXCESS OF A HALF INCH ACROSS THE NORTHERN ZONES (SE
PINAL/GRAHAM AND GREENLEE COUNTIES) WITH A 10-30 PERCENT CHANCE OF
0.75 INCHES OR MORE IN NORTHERN GRAHAM AND NORTHERN GREENLEE.
MOISTURE CONTENT WILL KEEP THE SNOWFALL ACROSS THE HIGHEST
ELEVATIONS AT BAY, BUT STORM TOTAL SNOWFALL AMOUNTS BETWEEN 3-5
INCHES WILL BE POSSIBLE IN HANNAGAN MEADOW.
AS WE MOVE INTO THE SECOND HALF OF THE WEEK, WE WILL SEE A RIDGE
OF HIGH PRESSURE BUILD INTO THE DESERT SOUTHWEST. EXPECT AFTERNOON
TEMPERATURES ACROSS THE OLD PUEBLO WARM BACK UP, NEARING THE CENTURY
MARK BY NEXT WEEKEND. THE LATEST NBM PROBABILITIES (05/05Z) FOR
MEETING OR EXCEEDING 100 DEGREES AT THE TUCSON INTERNATIONAL
AIRPORT (KTUS) ARE 27% FRIDAY/50% SATURDAY/58% SUNDAY. THERE IS
UNCERTAINTY WITH ENSEMBLE MEMBERS IN THE EXTENDED WITH THE
POTENTIAL FOR A WEAK UPPER-LOW TO UNDERCUT THE RIDGE NEXT
WEEKEND. SUSTAINED SOUTHEAST WINDS DUE TO THE RIDGING WILL IMPORT
MID-LEVEL MOISTURE INTO THE EASTERN ZONES, BUT THE PRESENCE OF A
WEAK LOW MAY RESULT IN ELEVATED CONVECTION NEXT WEEKEND. WE WILL
SEE...I AM SKEPTICAL AND THINK A MORE ESTABLISHED RIDGE WITH A
STRONGER WARM-UP IS MORE LIKELY.
AVIATION
VALID THROUGH 06/12Z. SCT-BKN CUMULUS AT 7K-10K FEET
THROUGH 05/16Z. LOWER CLOUD DECKS SCT-BKN 4K-7K FT AGL SCT -SHRA
WILL DEVELOP N AND W OF KTUS AROUND 05/16Z AND EXPAND IN COVERAGE
FROM WEST TO EAST THROUGH THE DAY WITH MOUNTAIN OBSCURATIONS
POSSIBLE. SLY SFC WINDS LESS THAN 12 KTS THRU 05/18Z, THEN SW
WINDS 12-17 KTS WITH GUSTS TO 25 KTS. THE STRONGEST WINDS WILL BE
ACROSS FAR SE AZ, NEAR KDUG. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
FIRE WEATHER
LIGHTER WINDS ARE EXPECTED MONDAY ACROSS SOUTHEAST
ARIZONA, WITH BREEZY TO LOCALLY WINDY SOUTHWEST WINDS 15-20 MPH
WITH GUSTS 25-30 MPH EXPECTED ACROSS COCHISE COUNTY. COOLER
TEMPERATURES AND HIGHER MINIMUM HUMIDITIES CAN BE EXPECTED THE
FIRST HALF OF THE WORK WEEK AS A PACIFIC STORM SYSTEM IMPACTS THE
REGION. SCATTERED SHOWERS WITH WETTING RAINS WILL BE POSSIBLE.
AS A PACIFIC THE ONGOING SYSTEM MOVES THROUGH. A WARMING AND
DRYING TREND IS EXPECTED FOR THE SECOND HALF OF THE WEEK.
TWC WATCHES/WARNINGS/ADVISORIES
NONE.
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