664
FXUS66 KHNX 211733
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
933 AM PST SUN DEC 21 2025
KEY MESSAGES
1. A FLOOD WATCH IS IN EFFECT FOR THE SIERRA NEVADA BELOW 9,000
FEET AND FOOTHILLS, MAINLY YOSEMITE, AS WELL AS MARIPOSA AND
MADERA COUNTIES UNTIL MONDAY.
2. A SIGNIFICANT PATTERN CHANGE IS EXPECTED TO TAKE PLACE BY THIS
EVENING WITH PRECIPITATION LIKELY FOR THE SIERRA NEVADA AND ITS
FOOTHILLS FROM FRESNO COUNTY NORTHWARDS. MODERATE TO BRIEFLY
HEAVY PRECIPITATION IS POSSIBLE IN THESE AREAS FROM THIS EVENING
INTO SUNDAY.
3. A SECOND, STRONGER SYSTEM IS EXPECTED TO ARRIVE TUESDAY, WITH A
MODERATE RISK FOR HEAVY PRECIPITATION THROUGHOUT CENTRAL CALIFORNIA,
AND A MODERATE RISK FOR HEAVY SNOW IN THE SIERRA NEVADA
EXPECTED FROM CHRISTMAS EVE THROUGH FRIDAY OF NEXT WEEK.
DISCUSSION
SHOWERS CONTINUE TO MAINLY HANG TO OUR NORTH THIS MORNING AND
EARLY AFTERNOON. THE BEST CHANCES FOR MEASUREABLE PRECIPITATION
REMAIN NEAR YOSEMITE NP, CURRENTLY AT 70-80 PERCENT, WITH SNOW
LEVELS ABOVE 9,000 FEET UNTIL MONDAY. CHANCES FOR PRECIPITATION
ARE LOWER IN THE SAN JOAQUIN VALLEY, INCLUDING A 40-50 PERCENT
CHANCE TOWARDS MERCED COUNTY WHILE PROBABILITIES REMAIN BELOW 15
PERCENT MAINLY SOUTH OF FRESNO COUNTY THROUGH MONDAY.
PRECIPITATION CHANCES RETREAT NORTHWARD A BIT ON MONDAY
AFTERNOON INTO EARLY TUESDAY MORNING BEFORE THE NEXT SYSTEM
ARRIVES.
THE INITIAL SURGE OF MOISTURE AND SOUTHERLY FLOW ASSOCIATED
WITH THE SYSTEM ON TUESDAY ARRIVES TUESDAY MORNING AND GRADUALLY
PROGRESSES INLAND OVER OUR REGION BY THE AFTERNOON. ALONG THIS
FRONT, A PLUME OF MOISTURE FROM THE TROPICAL PACIFIC OCEAN WILL
TRAVERSE INTO OUR AREA. PRECIPITATION BEGINS IN EARNEST OVER OUR
ENTIRE FORECAST AREA BY LATER TUESDAY AFTERNOON. CHANCES
CONTINUE THROUGH AT LEAST FRIDAY. THE BULK OF THE PRECIPITATION
OCCURS CHRISTMAS EVE AND CHRISTMAS DAY AND TAPERS OFF A BIT
THURSDAY NIGHT INTO FRIDAY. SNOW LEVELS LOWER TO 7,000-8,000
FEET ON TUESDAY AND GRADUALLY LOWER TO 6,000 FEET BY THE EVENING
OF CHRISTMAS DAY. PROBABILITIES FOR AT LEAST ONE INCH OF
PRECIPITATION PER 24 HOURS EACH DAY FROM TUESDAY THROUGH FRIDAY
AFTERNOON IS BETWEEN 30 AND 50 PERCENT IN THE SOUTHERN HALF OF
THE VALLEY AND BETWEEN 65 AND 80 PERCENT FROM FRESNO NORTH TO
MERCED. HOWEVER, TUESDAY INTO WEDNESDAY BRINGS A 15 TO 30
PERCENT CHANCE OF 2 INCHES OR MORE OF RAIN IN THE VALLEY BEFORE
DECREASING TO LESS THAN 20 PERCENT. THE DESERT IS LOOKING AT A
55 TO 65 PERCENT CHANCE OF AN INCH OR MORE OF RAIN IN 24 HOURS
ENDING WEDNESDAY AFTERNOON BEFORE DECREASING TO 15 TO 25 PERCENT
ENDING THURSDAY AND FRIDAY. THE SIERRA NEVADA AND FOOTHILLS
STILL HAVE A 80-90 PERCENT CHANCE OF 2 INCHES OR MORE OF RAIN
EACH DAY. IN ADDITION TO THE THREAT OF HEAVY PRECIPITATION, WE
ARE MONITORING FOR INCREASED SOUTHERLY WINDS THAT COULD PRODUCE
STRONG ENOUGH GUSTS TO KNOCK OVER TREES. THE PROBABILITY FOR A
40 MPH GUST IN THE CENTRAL VALLEY IS AS MUCH AS 30-40 PERCENT
TOWARDS MERCED COUNTY WITH EVEN GREATER CHANCES IN THE COASTAL
RANGES (50-60 PERCENT). THE TIME FRAME IS FROM TUESDAY UNTIL
CHRISTMAS DAY FOR WINDS THIS STRONG.
BY FRIDAY, THE COLD FRONT PASSES, ALTHOUGH AN UPPER-LEVEL TROUGH
REMAINS INTO THE FOLLOWING WEEKEND THAT WILL PRODUCE LINGERING
SHOWERS. ABOVE AVERAGE PRECIPITATION REMAINS FAVORED IN OUR
AREA BEYOND NEXT WEEKEND, ALTHOUGH THE CHANCES HAVE LOWERED
COMPARED TO THE LAST COUPLE OF DAYS. THE 6-10 DAY OUTLOOK SHOWS
ABOUT A 40 TO 60 PERCENT CHANCE, WHILE THE 8-14 DAY OUTLOOK
LOWERS TO 33-40 PERCENT. ABOVE AVERAGE TEMPERATURES ARE AT
AROUND 33 TO 50 PERCENT FOR BOTH PERIODS.
AVIATION
IFR CEILINGS DUE TO PRECIPITATION OVER THE SIERRA NEVADA AND
ADJACENT FOOTHILLS FROM FRESNO COUNTY NORTHWARD. MVFR CONDITIONS
TEMPORARILY
MVFR CONDITIONS ARE EXPECTED FOR MAINLY NORTHERN PORTIONS OF
THE SAN JOAQUIN VALLEY DURING THE NEXT 24 HOURS WITH A SLIGHT
CHANCE OF SHOWERS AROUND MCE AND MER 16Z-20Z SUNDAY.
OTHERWISE, VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS.
AIR QUALITY ISSUES
ON SUNDAY DECEMBER 21 2025, FIREPLACE/WOOD STOVE BURNING STATUS IS:
NO BURNING UNLESS REGISTERED IN FRESNO, KERN, AND MADERA
COUNTIES. BURNING DISCOURAGED IN KINGS, MERCED, AND TULARE
COUNTIES, AND KERN (GREATER FRAZIER PARK AREA) AND SEQUOIA
NATIONAL PARK AND FOREST.
CERTAINTY
THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS HIGH.
THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM.
CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT
WWW.WEATHER.GOV/HNX/CERTAINTY.HTML FOR ADDITIONAL INFORMATION
AND/OR TO PROVIDE FEEDBACK.
HNX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM TUESDAY AFTERNOON THROUGH FRIDAY AFTERNOON
FOR CAZ300>317-319>322-327>339.
FLOOD WATCH THROUGH FRIDAY AFTERNOON FOR CAZ318-323>326.
WINTER STORM WARNING UNTIL 4 PM PST FRIDAY FOR CAZ323.
WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH FRIDAY
AFTERNOON FOR CAZ326>331.
JPK
WEATHER.GOV/HANFORD
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