328
FXUS65 KPSR 191719
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1019 AM MST FRI DEC 19 2025
UPDATE
UPDATED 18Z AVIATION DISCUSSION.
KEY MESSAGES
- DRY AND TRANQUIL WEATHER CONDITIONS WITH WELL ABOVE NORMAL
TEMPERATURES WILL PREVAIL ACROSS THE REGION THROUGH EARLY NEXT
WEEK.
- A MORE UNSETTLED WEATHER PATTERN IS LIKELY TO DEVELOP LATER
NEXT WEEK WITH COOLER TEMPERATURES AND INCREASED PRECIPITATION
CHANCES
SHORT TERM /TODAY THROUGH SATURDAY/
THE LATEST OBJECTIVE ANALYSIS SHOWS A STRONG UPPER-LEVEL RIDGE
SITUATED OFF THE NORTHERN BAJA PENINSULA. UNDER THE INFLUENCE OF
THE RIDGE, THE DRY AND TRANQUIL WEATHER PATTERN THAT IS BEEN IN
PLACE NOW FOR THE LAST SEVERAL DAYS WILL CONTINUE. AFTERNOON HIGH
TEMPERATURES WILL CONTINUE TO RUN A GOOD 10-15 DEGREES ABOVE
NORMAL FOR MID-DECEMBER STANDARDS AS READINGS WILL TOP OUT IN THE
UPPER 70S TO AROUND 80 DEGREES THIS AFTERNOON AND ONCE AGAIN ON
SATURDAY ACROSS THE LOWER DESERTS.
LONG TERM /SUNDAY THROUGH LATE NEXT WEEK/
UPPER-LEVEL RIDGING WILL CONTINUE TO DOMINATE THE OVERALL WEATHER
PATTERN ACROSS THE DESERT SOUTHWEST THROUGH THE FIRST HALF OF
NEXT WEEK, CONTINUING THE DRY AND TRANQUIL CONDITIONS.
TEMPERATURES WILL CONTINUE TO REMAIN UNSEASONABLY WARM AS
AFTERNOON HIGHS TOP OUT IN THE UPPER 70S TO AROUND 80 DEGREES
ACROSS THE LOWER DESERTS. THERE CONTINUES TO BE A HIGH PROBABILITY
(>70% CHANCE) OF PHOENIX AT LEAST TYING TO EVEN BREAKING DAILY
RECORD HIGHS BOTH ON SUNDAY AND MONDAY ACCORDING TO THE LATEST
NBM.
A MORE UNSETTLED WEATHER PATTERN THEN IS LIKELY TO ENSUE HEADING
TOWARDS THE MIDDLE AND LATTER PORTION OF NEXT WEEK AS THE UPPER-
LEVEL RIDGE SHIFTS EASTWARD INTO THE SOUTHERN PLAINS, ALLOWING A
DEEP TROUGH TO BUILD JUST OFF THE WEST COAST. THE DETERMINISTIC
AND ENSEMBLE MODEL SUITE CONTINUE TO DIVERGE SIGNIFICANTLY ON THE
OVERALL STRENGTH AND POSITIONING OF THE TROUGH AS IT DEEPENS OFF
THE WEST COAST, LEADING TO A LOW CONFIDENCE FORECAST HEADING
TOWARDS THE LATTER PORTION OF NEXT WEEK. ABUNDANT MOISTURE IS
LIKELY TO SPREAD NORTHEASTWARD FROM THE SUBTROPICAL PACIFIC INTO
THE REGION FROM LATE TUESDAY INTO WEDNESDAY, WITH BOTH THE EPS AND
GEFS SHOWING PWATS RISING ABOVE 200% OF NORMAL. GUIDANCE IS
SHOWING A LEAD SHORTWAVE OUT AHEAD OF THE MAIN TROUGH MOVING
THROUGH THE GREAT BASIN, WHICH COMBINED WITH THE MOISTURE THAT
WILL BE IN PLACE, COULD GENERATE SHOWER ACTIVITY ACROSS PORTIONS
OF THE REGION DURING THE DAY ON WEDNESDAY. PRECIPITATION CHANCES
AFTER WEDNESDAY WILL THEN BE DEPENDENT ON THE OVERALL STRENGTH AND
POSITIONING OF THE MAIN TROUGH OFF THE WEST COAST AS IT
EVENTUALLY MIGRATES INLAND. WITH MORE ABUNDANT CLOUD COVER AND
POTENTIAL PRECIPITATION AS WELL AS THE DECREASING HEIGHTS ALOFT,
TEMPERATURES ARE LIKELY TO COOL DOWN LATER NEXT WEEK BY ABOUT 5-10
DEGREES FROM THE READINGS EARLIER IN THE WEEK BUT STILL REMAIN
ABOVE NORMAL.
AVIATION
UPDATED AT 1720Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT; AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER CONCERNS UNDER PERIODS OF HIGH CIRRUS DECKS
CAN BE EXPECTED THROUGHOUT THE TAF PERIOD. WINDS WILL REMAIN LIGHT
WITH SUBTLE DIURNAL DIRECTIONAL SHIFTS. EXTENDED PERIODS OF
VARIABLE AND CALM CONDITIONS WILL BE COMMON AS WELL.
FIRE WEATHER
HIGH PRESSURE ACROSS THE REGION WILL CONTINUE TO PROMOTE DRY AND
TRANQUIL WEATHER AS WELL AS UNSEASONABLY WARM TEMPERATURES, 10 TO
15 DEGREES ABOVE NORMAL, INTO EARLY NEXT WEEK. WINDS WILL
GENERALLY BE LIGHT UNDER 15 MPH. AFTERNOON MINRHS WILL RANGE
BETWEEN 20-30% WITH GOOD OVERNIGHT RECOVERIES OF 40-70%. A MORE
UNSETTLED PATTERN IN FORM OF COOLER TEMPERATURES AND INCREASED
PRECIPITATION CHANCES IS LIKELY LATER NEXT WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...LOJERO
LONG TERM...LOJERO
AVIATION...LOJERO/18
FIRE WEATHER...LOJERO
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