002
FXUS65 KTWC 072158
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
258 PM MST WED JAN 7 2026
SYNOPSIS
A WINTER WEATHER SYSTEM WILL MOVE ACROSS ACROSS
SOUTHEAST ARIZONA TODAY...RESULTING IN NUMEROUS VALLEY RAIN AND
MOUNTAIN SNOW SHOWERS. THIS SYSTEM WILL BE FOLLOWED BY ANOTHER
COOLER WEATHER SYSTEM THURSDAY RESULTING IN SCATTERED VALLEY RAIN
AND MOUNTAIN SNOW. THUNDERSTORMS ARE POSSIBLE. THIS SECOND SYSTEM
WILL ALSO USHER IN UNSEASONABLY COOL TEMPERATURES TO THE AREA,
WITH FREEZING MORNING LOW TEMPERATURES POSSIBLE ACROSS THE TUCSON
METRO AREA FRIDAY AND SATURDAY MORNINGS.
KEY MESSAGES
A SERIES OF WINTER WEATHER SYSTEMS WILL IMPACT SOUTHEAST ARIZONA LATE
THIS MORNING THROUGH THURSDAY NIGHT.
1. WINTER WEATHER ADVISORIES:
A WINTER WEATHER ADVISORY IS IN EFFECT FOR THE MOUNTAINOUS AREAS
INCLUDING THE WHITE MOUNTAINS, GALIURO, PINALENO, CATALINA, AND
RINCON MOUNTAINS TODAY THROUGH 11 PM MST THURSDAY EVENING.
2. MOUNTAIN SNOW ACCUMULATIONS:
THE BULK OF THE PRECIPITATION IS EXPECTED TO OCCUR THIS AFTERNOON
INTO THIS EVENING WITH THE SNOW LEVELS AROUND 7000 TO 7500 FEET.
GIVEN THE HIGH MOISTURE CONTENT OF THIS FIRST SYSTEM, SNOWFALL
ACCUMULATIONS WILL BE LIMITED TO 2 TO 6 INCHES DESPITE THE HEAVIER
PRECIPITATION.
THE SECOND PART OF THE STORM SYSTEM WILL RESULT IN ADDITIONAL
WIDESPREAD SNOW DEVELOPING THURSDAY THROUGH THURSDAY EVENING. SNOW
LEVELS WILL DROP TO AROUND 5000 FEET BY THURSDAY EVENING. THIS
SYSTEM IS COLDER AND WILL BE MORE EFFICIENT IN PRODUCING SNOWFALL.
EXPECT AN ADDITIONAL 4 TO 8 INCHES OF SNOWFALL ABOVE 6000 FEET.
TOTAL STORM TOTAL SNOW ACCUMULATIONS TODAY THROUGH THURSDAY WILL
BE 8 TO 12 INCHES ABOVE 8000 FEET WITH LOCALLY HIGHER AMOUNTS AT
THE MOUNTAIN PEAKS. ELEVATIONS BETWEEN 6000 AND 8000 FEET WILL SEE
2 TO 8 INCHES OF SNOW.
2. VALLEY RAINFALL:
WIDESPREAD RAIN SHOWERS FOR THE VALLEYS OF SOUTHEAST ARIZONA TODAY
THROUGH THURSDAY NIGHT. THE HEAVIEST (MODERATE-INTENSITY) RAINFALL
WILL OCCUR THIS AFTERNOON INTO THIS EVENING. RAINFALL RUNOFF MAY
RESULT IN SIGNIFICANT PONDING OF WATER IN NORMALLY DRY WASHES,
ROADWAY DIPS AND OTHER LOW-LYING AREAS. STORM-TOTAL RAINFALL AMOUNTS
BETWEEN 0.25-0.75 INCHES WITH LOCALLY HIGHER AMOUNTS ARE
ANTICIPATED. A FEW EMBEDDED THUNDERSTORMS ARE POSSIBLE ON
THURSDAY, POTENTIALLY BRINGING BRIEF HEAVIER RAINFALL AMOUNTS.
3. VERY COLD TO FREEZING TEMPERATURES ARE EXPECTED BOTH FRIDAY AND
SATURDAY MORNING FOR THE VALLEYS FROM TUCSON EAST. POTENTIAL FOR
ICY ROADS THURSDAY NIGHT TO FRIDAY MORNING.
DISCUSSION
AVAILABLE CAMERAS, RAIN GAUGES, AND RADAR SHOW RAIN
SHOWERS AND MOUNTAIN SNOW COMING DOWN ACROSS SOUTHEAST ARIZONA. SO
FAR, RAIN TOTALS IN THE VALLEYS HAVE BEEN 0.25-0.30 INCHES WITH
POCKETS OF 0.50 INCHES. SNOWFALL...WITH THE RESOLUTION AND LACK
OF PROPER MEASURING REFERENCE, IT APPEARS TO BE AROUND AN INCH OR
TWO IN SUMMERHAVEN. IT LOOKS MORE WET AND HEAVY. THIS SHOWS THE
FREEZING LEVEL IS BATTLING ITSELF OUT TO DROP DOWN MORE IN
ELEVATION. IT WILL LIKELY HAPPEN THIS AFTERNOON.
REST OF TODAY...RAIN SHOWERS AND SNOW SHOWERS WILL CONTINUE TO
PUSH THROUGH. THE MODELS SHOW THE MAIN ACTIVITY TAPERING DOWN
AFTER 10PM WITH THE LINGERING SNOW SHOWERS ON THE MOUNTAINS. THE
ENSEMBLE MODELS, INCLUDING THE HI-RES, HAVE A LARGE RANGE OF
LIQUID AMOUNTS FOR THE 24 HOUR PERIOD AND THE TOTAL STORM TOTAL.
THIS MAKES SENSE BECAUSE OF HOW PROGRESSIVE THIS SYSTEM HAS BEEN
IN THE LAST 24 HOURS. MODELS ARE STILL CATCHING UP. THEREFORE, THE
VALLEYS WILL LIKELY RECEIVE AROUND 0.25 INCHES TO 0.75 INCHES
WITH LOCALLY HEAVIER AMOUNTS. AREAS SOUTH OF TUCSON CAN SEE THE
HIGHER AMOUNTS BECAUSE OF THE BETTER MOISTURE WITHIN THE SYSTEM.
SNOW TOTALS WILL INCREASE UP TO 2 TO 8 INCHES THROUGH TONIGHT. THE
PEAKS CAN SEE HIGHER AMOUNTS.
TOMORROW, ANOTHER ROUND OF RAIN SHOWERS AND MOUNTAIN SNOW. THERE
ARE TWO DIFFERENCES WITH THIS ROUND. FIRST, THERE IS COLDER AIR TO
WORK WITH. THIS WILL INCREASE THE SNOW EFFICIENCY WITHIN THE
MOUNTAINS AND DROPPING THE SNOW LEVELS DOWN TO 5000 FEET BY THE
LATE AFTERNOON. THIS CAN BRING A DUSTING OF SNOW IN THE EASTERN
VALLEYS AND FOOTHILLS AND WHATEVER WET SURFACE HAS THE POTENTIAL
TO FREEZE IN THE OVERNIGHT PERIOD. HAZARDOUS TRAVEL CONDITIONS ARE
POSSIBLE IN THE EASTERN COUNTIES LATE THURSDAY NIGHT TO FRIDAY
MORNING. SECONDLY, THERE IS GROWING CONFIDENCE FOR THUNDERSTORMS
DUE TO THE DYNAMICS WITHIN THE FRONTAL SYSTEM. THIS CAN BRING
STRONG GUSTY WINDS, BRIEF LOCALLY HEAVY RAINFALL (AND BOOSTING
MOUNTAIN SNOW AS WELL), AND SMALL HAIL. THE FRONT WILL SWEEP
QUICKLY FROM THE THE NORTH TO THE SOUTHEAST AND OUT OF THE AREA BY
10PM THURSDAY NIGHT.
THE NEXT TWO DAYS WILL HAVE COLD TO FREEZING MORNING TEMPERATURES
FROM TUCSON TO THE EAST. PROBABILITIES FOR FREEZING TEMPERATURES
IN TUCSON ON FRIDAY IS 50-60% AND SATURDAY EXPANDING TO 90%.
FREEZE HEADLINES WILL LIKELY TO COME IN THE NEAR FUTURES.
BEYOND, TEMPERATURES WILL START TO MODERATE BY THE END OF THE
WEEKEND INTO THE NEW WEEK. THERE WILL BE A TIGHT PRESSURE GRADIENT
FORMING ON SATURDAY THROUGH SUNDAY, POSSIBLY LASTING TO MONDAY.
THIS WILL BRING BREEZY TO GUSTY EASTERLY WINDS LATE IN THE
WEEKEND.
AVIATION
VALID THROUGH 09/00Z.
SCT-BKN 4-8K FT AGL BKN-OVC 8-10K FT AGL WITH SCATTERED TO
NUMEROUS -SHRA AND MOUNTAIN -SHSN THROUGH 08/06Z, THEN ISOLATED TO
SCATTERED THROUGH THE REST OF THE PERIOD. CIGS 2-5K FT AGL DURING
THE LATE AFTERNOON AND EARLY EVENING WITH MTN OBSCURATIONS
POSSIBLE. A FEW EMBEDDED -TSRA ARE POSSIBLE. SFC WINDS SLY/SWLY
10-12 KTS. GUSTS TO 25 KTS WILL BE POSSIBLE NEAR THE STRONGER
SHOWERS THIS AFTERNOON AND THIS EVENING. AFTER 08/18Z, SFC WINDS
SWLY AT 12-17KTS WITH GUSTS UP TO 30 KTS THROUGH THE END OF THE
FORECAST PERIOD. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.
FIRE WEATHER
A SERIES OF WINTER WEATHER SYSTEMS WILL IMPACT
SOUTHEAST ARIZONA LATE TODAY THROUGH THURSDAY NIGHT, RESULTING IN
NUMEROUS VALLEY RAIN AND MOUNTAIN SNOW SHOWERS. THE HEAVIEST
(MODERATE-INTENSITY) PRECIPITATION WILL OCCUR THIS AFTERNOON INTO
THIS EVENING. ANOTHER COOLER WEATHER SYSTEM WILL THEN MOVE ACROSS
THE AREA THURSDAY, RESULTING IN SCATTERED VALLEY RAIN AND MOUNTAIN
SNOW. EMBEDDED THUNDERSTORMS ARE POSSIBLE ON THURSDAY WHICH MAY
BRIEFLY BRING HEAVIER RAINFALL AMOUNTS.
THE SECOND SYSTEM WILL BE MORE EFFICIENT AT PRODUCING ACCUMULATING
MOUNTAIN SNOWFALL THAN THE FIRST SYSTEM. A WINTER WEATHER ADVISORY
IS IN EFFECT FOR THE WHITE MOUNTAINS, CATALINA AND PINALENO MOUNTAINS
LATE THIS MORNING THROUGH LATE THURSDAY NIGHT. THIS SECOND SYSTEM
WILL ALSO USHER IN UNSEASONABLY COOL MORNING LOW TEMPERATURES TO
THE AREA, WITH FREEZING TEMPERATURES ACROSS THE VALLEYS FROM
TUCSON EAST FRIDAY AND SATURDAY MORNINGS. OTHERWISE, AFTERNOON
TEMPERATURES ARE FORECAST TO FALL BELOW NORMAL WILL THIS SYSTEM
THURSDAY INTO THE WEEKEND. MINIMUM RHS TODAY AND THURSDAY BETWEEN
50-60 PCT IN THE VALLEYS AND 75-90 PCT IN THE MOUNATINS, LOWERING
TO 25-35 PCT IN THE VALLEYS AND 35-45 PCT IN THE MOUNATINS TODAY
FRIDAY INTO THE WEEKEND. GUSTY EAST TO SOUTHEAST WINDS WILL
DEVELOP LATE THIS WEEKEND.
TWC WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 11 PM MST THURSDAY FOR AZZ510-511-
514.
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