744
FXUS66 KHNX 010540
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
1040 PM PDT SUN AUG 31 2025
UPDATE
UPDATED AVIATION SECTION.
KEY MESSAGES
1. WARM THAN NORMAL TEMPERATURES AS CHANCES FOR TRIPLE-DIGITS
SIT AT AROUND 80-100 PERCENT ON MONDAY. SLIGHT COOLING TREND AS
MOISTURE ENTERS THE REGION. BETTER COOLING BY LATE IN THE WEEK.
2. A SLIGHT CHANCE (10-20 PERCENT) FOR THUNDERSTORMS OVER THE
SIERRA NEVADA ON TUESDAY. GREATER THUNDERSTORM CHANCES AROUND
MID-WEEK.
3. MARGINAL (AT LEAST 5 PERCENT) RISK OF FLOODING IN THE VERY
HIGH ELEVATIONS OF THE SIERRA NEVADA DUE TO THE INCREASING
POTENTIAL FOR THUNDERSTORMS TUESDAY THROUGH THURSDAY.
DISCUSSION
HIGH PRESSURE RIDGE IS THE DOMINATE FEATURE ACROSS THE WEST AS
CENTRAL CALIFORNIA HEATS-UP EARLY THIS WEEK. BASED ON CURRENT
TRENDS, THE SAN JOAQUIN VALLEY IS EXPECTED TO SEE CONSIDERABLE
HIGHS TEMPERATURES AT OR ABOVE 100 DEGREES. WITH THE RIDGE
PATTERN STILL BUILDING, MONDAY’S TEMPERATURES WILL RUN HIGHER AS
HEAT-RISK REACHES INTO THE MAJOR CATEGORY. ISSUED A HEAT
ADVISORY FOR THE MONDAY TIME-FRAME WHEN THE HEATING PEAKS.
DISTURBANCES OFF THE PACIFIC COAST WILL INTERACT WITH THE RIDGE
PATTERN AS AN INCREASE IN THE SOUTHERLY FLOW DRAWS UP MONSOONAL
MOISTURE TOWARD THE DISTRICT. A CHANGE IN THE WEATHER PATTERN
WILL OCCUR EARLY THIS WEEK AS ABUNDANT MOISTURE ENTERS THE AREA
PROVIDING A POTENTIAL FOR SIGNIFICANT PRECIPITATION.
ENSEMBLE MOISTURE ANALYSIS IS SHOWING A SURGE OF THE MONSOONAL
MOISTURE EXPECTED TO REACH CENTRAL CALIFORNIA BY TUESDAY. ONCE
THE RIDGE IS SHIFTED BY THE OFF-SHORE DISTURBANCES INTERACTING
WITH THE RIDGE, A STRONGER SOUTHERLY FLOW WILL ALLOW FOR A
NORTHWARD SURGE OF MOISTURE THAT WILL SEE ADDITIONAL SOURCES OF
MOISTURE INTRODUCED FROM THE TROPICS. ENSEMBLE UPPER-AIR
ANALYSIS IS STILL SHOWING A WEAK DISTURBANCE AIMING FOR THE
MONTEREY/BAY-AREA WITH ENOUGH ENERGY TO FIRE-UP CONVECTION
ACROSS THE INTERIOR CENTRAL CALIFORNIA AREA. THEREFORE, BY
TUESDAY, PROBABILITY OF MEASURABLE PRECIPITATION (POP) ALONG
WITH INSTABILITY ANALYSIS SHOWS INCREASING PERCENTAGES AS
SIGNIFICANT MOISTURE HAS THE POTENTIAL OF ENTERING THE REGION.
WITH POP VALUES REACHING 40 TO 60 PERCENT, A GOOD CHANCE EXIST
OF GENERATING SIGNIFICANT ACCUMULATIONS. THUNDERSTORMS MAY EVEN
HAVE THE CAPACITY OF INTRODUCING HEAVY RAIN AS GUIDANCE SHOWS
PERCENTAGES REACHING AT LEAST 5 PERCENT OF MEETING EXCESSIVE
PRECIPITATION CRITERIA FROM TUESDAY THROUGH THURSDAY ACROSS THE
SIERRA NEVADA AND THE MOUNTAINS AND DESERT OF KERN COUNTY.
THE RIDGE PATTERN IS SHIFTED EAST STARTING ON FRIDAY AS THE
PROBABILITIES OF COOLING AND DRYING INCREASE ACROSS CENTRAL
CALIFORNIA. FRIDAY WILL BE A PERIOD OF TRANSITION AS DRYING AND
COOLING WILL START WITH LINGERING MOISTURE AND HEAT STILL IN
PLACE. NEXT WEEKEND IS SHOWING HIGHER PROBABILITIES OF
SIGNIFICANT COOLING AND DRYING AS A DISTURBANCE DIGS THROUGH
NORTHERN CALIFORNIA. BY THAT POINT, CONVECTION WILL BE LIMITED
TO THE BACK-COUNTRY OF YOSEMITE.
AVIATION
06Z UPDATE:
VFR CONDITIONS WILL PREVAIL ACROSS THE CENTRAL CALIFORNIA
INTERIOR FOR THE NEXT 24 HOURS. LESS THAN 10% CHANCE OF SIERRA
CREST THUNDERSTORMS DURING THE PERIOD.
AIR QUALITY ISSUES
NONE.
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
HEAT ADVISORY FROM NOON MONDAY TO MIDNIGHT PDT MONDAY NIGHT
FOR CAZ300>304-306>314-316-317-319-321.
PUBLIC...MOLINA
AVIATION....MCCOY
WEATHER.GOV/HANFORD
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