494
FXUS65 KPSR 281731
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1031 AM MST SUN DEC 28 2025
UPDATE
UPDATED 18Z AVIATION DISCUSSION.
KEY MESSAGES
- HIGH PRESSURE WILL SPREAD OVER THE REGION EARLY THIS WEEK
RESULTING IN MUCH DRIER CONDITIONS AND TEMPERATURES SLIGHTLY
ABOVE NORMAL.
- BREEZY TO LOCALLY WINDY CONDITIONS WILL BE SEEN OVER MUCH OF THE
AREA EARLY THIS WEEK WITH THE STRONGEST GUSTS AROUND 30 MPH.
- UNSETTLED WEATHER CONDITIONS ARE EXPECTED DURING THE LATTER HALF
OF THE WEEK WITH LIGHT RAIN CHANCES FOCUSED MAINLY FROM LATE
WEDNESDAY THROUGH EARLY FRIDAY.
SHORT TERM /TODAY THROUGH MONDAY/
A DECAYING TROUGH AXIS HAS SETTLED OVER THE REGION WITH
CONSIDERABLY DRIER AIR SURGING SOUTHWARD. THE TROUGH IS NOW
FORECAST TO STALL OUT TODAY INTO MONDAY BEFORE RIDGING FINALLY
TAKES OVER MONDAY NIGHT INTO TUESDAY AS ANY LINGERING ENERGY
DRIFTS OFFSHORE INTO A STATIONARY CUT-OFF LOW WEST OF BAJA. A
STRONG SURFACE HIGH TO OUR NORTH WILL ALSO HELP TO CREATE A STRONG
PRESSURE GRADIENT BY THIS AFTERNOON RESULTING IN LOCALLY WINDY
CONDITIONS DEVELOPING DOWN THE LOWER CO RIVER VALLEY. WINDS WILL
ALSO EVENTUALLY BECOME QUITE BREEZY OVER THE ARIZONA HIGH TERRAIN
STARTING THIS EVENING WITH SOME OF THIS BREEZINESS SEEPING INTO
THE PHOENIX AREA DURING THE OVERNIGHT HOURS. THE GRADIENT WILL
STAY FAIRLY STRONG INTO MONDAY WITH MORE WIDESPREAD BREEZY
CONDITIONS EXTENDING INTO A GOOD PORTION OF THE LOWER DESERTS.
TEMPERATURES TODAY WILL BE VERY SIMILAR TO YESTERDAY'S HIGHS WITH
READINGS MOSTLY IN THE UPPER 60S ACROSS THE LOWER DESERTS
FOLLOWED BY OVERNIGHT LOWS CLOSER TO SEASONAL NORMALS SUNDAY
NIGHT.
LONG TERM /TUESDAY THROUGH SATURDAY/
THE WEATHER PATTERN FOR LATER THIS WEEK REMAINS A BIT COMPLICATED
WITH A REX BLOCK TO OUR WEST EARLY IN THE WEEK LIKELY EVOLVING
WITH THE CUT-OFF LOW EVENTUALLY DRIFTING NORTHEASTWARD TOWARD OUR
REGION DURING THE MIDDLE PART OF THE WEEK. UPPER LEVEL RIDGING IS
LIKELY TO STILL DOMINATE ACROSS MUCH OF THE DESERT SOUTHWEST
THROUGH AT LEAST WEDNESDAY, BUT AS THE CUT-OFF LOW BEGINS TO
SHIFT CLOSER WE ARE LIKELY TO SEE MOISTURE PUSHING NORTHWARD INTO
OUR REGION STARTING TUESDAY. ENSEMBLE FORECAST PWATS ARE SEEN
RISING TO NEAR 200% OF NORMAL ACROSS SOUTHERN CALIFORNIA AND
SOUTHERN ARIZONA EARLY ON WEDNESDAY BEFORE INCREASING FURTHER AND
SPREADING THROUGH THE REST OF THE REGION WEDNESDAY NIGHT INTO
THURSDAY. HOWEVER, MUCH OF THIS MOISTURE WILL BE ALOFT AND IT WILL
TAKE AT LEAST UNTIL LATER ON THURSDAY FOR BOUNDARY LAYER
MOISTURE TO IMPROVE ENOUGH FOR ANY ACTUAL RAIN CHANCES. WE MAY SEE
SOME SCATTERED VERY LIGHT SHOWERS OR VIRGA ON WEDNESDAY, BUT
CHANCES FOR MEASURABLE RAINFALL SHOULD STAY BELOW 30%.
AS MOISTURE PEAKS ON THURSDAY, WE SHOULD SEE BETTER CHANCES FOR
SOME LIGHT SHOWERS, BUT OVERALL FORCING WILL BE VERY WEAK. UPPER
LEVEL FORCING IS LIKELY TO BE BASICALLY NOTHING, SO WE WILL HAVE
TO RELY ON WEAK LOW AND MID LEVEL FORCING WITH THE BEST FORCING
FOCUSED IN UPSLOPE AREAS ACROSS CENTRAL ARIZONA. NBM POPS HAVE AT
LEAST COME DOWN SOME WITH THE LATEST FORECAST RUNS WITH CHANCES
MAINLY IN A 20-30% RANGE FOR THE LOWER DESERTS OF SOUTHEAST
CALIFORNIA AND SOUTHWEST ARIZONA TO 30-50% ACROSS SOUTH-CENTRAL
INTO EASTERN ARIZONA. ASSUMING THE EVENT PLAYS OUT AS CURRENTLY
FORECAST, RAINFALL AMOUNTS FOR THURSDAY AND FRIDAY SHOULD BE
QUITE LIGHT WITH MOST AREAS SEEING LESS THAN 0.10" WITH SOME
LOCALIZED HIGHER AMOUNTS UPWARDS OF 0.25". WE ARE LIKELY TO SEE
MORE CLOUDS THAN RAIN AS SKIES SHOULD REMAIN QUITE CLOUDY FROM
WEDNESDAY THROUGH AT LEAST FRIDAY. A FOLLOW-ON TROUGH LOOKS TO BE
POSSIBLE GOING INTO NEXT WEEKEND, BUT AS OF NOW IT IS FAVORED TO
MOSTLY MISS OUR REGION TO THE NORTH. EXPECT HIGH TEMPERATURES TO
REMAIN FAIRLY STABLE FROM IN THE NORMAL RANGE TO MAYBE 4-7 DEGREES
ABOVE NORMAL, WHILE OVERNIGHT TEMPERATURES WILL BECOME QUITE MILD
LATER IN THE WEEK WITH LOWS MOSTLY IN THE 50S FOR A FEW DAYS DUE
TO THE CLOUDY SKIES.
AVIATION
UPDATED AT 1730Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION WEATHER CONCERNS EXPECTED THROUGH THE TAF
PERIOD. WINDS WILL BE LIGHT, E-NE THIS AFTERNOON, SHIFTING N-NW
AOB 8 KTS AROUND 21Z, THE GENERAL FLOW WILL BECOME LIGHT SHIFTING
W-NW AROUND 01Z, SPEEDS WILL GENERALLY BE AOB 4-5 KTS AND MAY
EXHIBIT SOME VARIABILITY TO CALM CONDITIONS AT TIMES. FEW-SCT HIGH
CIRRUS CLOUDS EXPECTED THROUGH THE PERIOD.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED THROUGH THE TAF PERIOD.
WIND DIRECTIONS WILL GENERALLY BE OUT OF THE N-NW WITH SPEEDS AT
KBLH AOB 10-15 KTS WITH PERIODS OF GUSTS UP TO 20 KTS THIS
AFTERNOON, KIPL WILL REMAIN LIGHTER THROUGH THE TAF WITH SPEEDS
AOB 6-8 KTS. EXPECT PERIODS OF GUSTS TO SUBSIDE AT KBLH BY THIS
EVENING. FEW-SCT HIGH CIRRUS CLOUDS ARE FORECAST TO MOVE IN THIS
AFTERNOON AND WILL PREVAIL THROUGH THE TAF PERIOD.
FIRE WEATHER
DRY WEATHER WITH TEMPERATURES NEAR TO SLIGHTLY ABOVE NORMAL WILL
BE SEEN THROUGH AT LEAST MONDAY. MINIMUM HUMIDITY LEVELS WILL
TUMBLE INTO A 25-35% RANGE TODAY WITH SOMEWHAT LOWER VALUES
MONDAY. WINDS WILL INCREASE TODAY, INITIALLY THROUGH THE LOWER
COLORADO RIVER VALLEY, THEN ACROSS RIDGE TOPS OF EASTERN
DISTRICTS TONIGHT AND MONDAY WHERE GUSTS OF 20-30 MPH WILL BE
COMMON. MOISTURE WILL BEGIN TO SEEP BACK INTO THE REGION MIDWEEK
RAISING HUMIDITIES AND BRINGING RAIN CHANCES BY AROUND THURSDAY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...KUHLMAN
LONG TERM...KUHLMAN
AVIATION...BERISLAVICH/95
FIRE WEATHER...KUHLMAN
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