995
FXUS65 KPSR 182005
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
105 PM MST THU DEC 18 2025
KEY MESSAGES
- DRY AND TRANQUIL WEATHER CONDITIONS WITH WELL-ABOVE NORMAL
TEMPERATURES WILL PREVAIL ACROSS THE REGION INTO EARLY NEXT
WEEK.
- A CHANGE IN THE WEATHER PATTERN IS EXPECTED MID TO LATE NEXT
WEEK WITH COOLER TEMPERATURES AND POTENTIALLY INCREASED
PRECIPITATION CHANCES.
SHORT TERM /TODAY THROUGH FRIDAY/
UNSEASONABLY WARM WEATHER AND DRY, TRANQUIL CONDITIONS CONTINUE AS
STRONG UPPER LEVEL RIDGING PERSISTS ACROSS THE DESERT SOUTHWEST.
EARLY AFTERNOON RAP ANALYSIS SHOWED THE CENTER OF THE RIDGE OF
HIGH PRESSURE POSITIONED WEST OF THE BAJA PENINSULA WITH 500 MB
HEIGHTS ACROSS THE FORECAST AREA AROUND 582-585 DM. AS THE UPPER
LEVEL RIDGE GRADUALLY SHIFTS EASTWARD, HEIGHTS WILL RISE SLIGHTLY
FOR FRIDAY, PROMOTING A WARMER AFTERNOON TO END THE WORKWEEK.
AFTERNOON HIGHS FRIDAY ACROSS SOUTH-CENTRAL AND SOUTHWEST ARIZONA
ARE FORECAST TO TOP OUT 2-3 DEGREES WARMER THAN TODAY AS
TEMPERATURES CLIMB INTO THE UPPER 70S TO AROUND 80 DEGREES, WITH
SIMILAR READINGS EXPECTED ACROSS SOUTHEAST CALIFORNIA. AFTERNOON
TEMPERATURES READING AROUND 10-15 DEGREES ABOVE NORMAL WILL
CONTINUE INTO THE WEEKEND.
LONG TERM /SATURDAY THROUGH LATE NEXT WEEK/
UPPER-LEVEL RIDGING WILL CONTINUE TO PERSIST ACROSS THE DESERT
SOUTHWEST THROUGHOUT THE WEEKEND AND EARLY NEXT WEEK, CONTINUING
THE DRY AND TRANQUIL WEATHER PATTERN. TEMPERATURES WILL CONTINUE
TO REMAIN UNSEASONABLY WARM THROUGHOUT THIS PERIOD WITH AFTERNOON
HIGHS ACROSS THE LOWER DESERTS RANGING BETWEEN THE UPPER 70S TO
LOW 80S, WHICH WILL BE A GOOD 10-15 DEGREES ABOVE NORMAL FOR THIS
TIME OF THE YEAR. IN FACT, THERE IS A HIGH PROBABILITY (>70%) OF
PHOENIX BREAKING RECORD HIGHS, ESPECIALLY BY SUNDAY AND MONDAY,
ACCORDING TO THE LATEST NBM.
MODEL GUIDANCE CONTINUES TO SHOW A PATTERN CHANGE HEADING TOWARDS
THE MIDDLE AND LATTER PORTION OF NEXT WEEK AS THE UPPER-LEVEL
RIDGE MOVES EASTWARD INTO THE SOUTHERN PLAINS, ALLOWING A DEEP
PACIFIC TROUGH TO BUILD OFF THE WEST COAST. EXAMINING THE ENSEMBLE
CLUSTER ANALYSIS, THERE CONTINUES TO BE LARGE SPREAD IN THE
OVERALL STRENGTH AND POSITIONING OF THE TROUGH. NEVERTHELESS, THE
ENSEMBLES SHOW ABUNDANT MOISTURE SPREADING INTO THE REGION OUT
AHEAD OF THE TROUGHING FEATURE LATE TUESDAY INTO WEDNESDAY WITH
IVT VALUES FORECAST TO EXCEED 250 KG/M/S. THIS INCREASING MOISTURE
WILL PROMOTE PRECIPITATION CHANCES BEGINNING NEXT WEDNESDAY, WITH
THE HIGHEST CHANCES ACROSS THE WESTERN DESERTS. PRECIPITATION
CHANCES MAY CONTINUE THROUGH THE END OF NEXT WEEK, HOWEVER, THIS
WILL ALL BE DEPENDENT ON THE OVERALL STRENGTH AND POSITIONING OF
THE TROUGH. GIVEN THAT THIS WILL BE A WARM WEATHER SYSTEM, ALL OF
THE PRECIPITATION, EVEN ACROSS THE HIGHER TERRAIN, SHOULD FALL AS
RAIN. WITH THE INCREASING CLOUDS AND PRECIPITATION CHANCES, ALONG
WITH DECREASING HEIGHTS ALOFT, TEMPERATURES MID TO LATE NEXT WEEK
ARE EXPECTED TO COOL DOWN BUT WILL LIKELY STILL REMAIN ABOVE
NORMAL.
AVIATION
UPDATED AT 1712Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT; AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER CONCERNS UNDER SOME PASSING HIGH CIRRUS CLOUD
DECKS CAN BE EXPECTED THROUGHOUT THE TAF PERIOD. THE OVERALL WIND
PATTERN WILL CONTINUE TO EXHIBIT LIGHT AND DIURNAL TENDENCIES
WITH EXTENDED PERIODS OF VARIABLE TO EVEN CALM CONDITIONS,
ESPECIALLY AT KSDL, KIPL, AND KBLH.
FIRE WEATHER
PERSISTENT 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 AND FOLLOW FAMILIAR DIURNAL
PATTERNS. AFTERNOON MINRHS WILL RANGE BETWEEN 20-30% WITH GOOD
OVERNIGHT RECOVERIES OF 40-70%.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...SMITH
LONG TERM...LOJERO
AVIATION...RYAN/LOJERO
FIRE WEATHER...LOJERO/KUHLMAN
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