829
FXUS66 KHNX 100428
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
928 PM PDT SAT AUG 9 2025
UPDATE
AVIATION SECTION UPDATED.
KEY MESSAGES
1. HEAT-WAVE STARTED THIS WEEKEND AS TRIPLE DIGIT HEAT EXPECTED
THROUGH AT LEAST TUESDAY.
2. THERE IS A 60 TO 90 PERCENT CHANCE OF HIGH TEMPERATURES OF
AT LEAST 100 DEGREES THIS WEEKEND WITH A 20 TO 40 PERCENT
CHANCE OF REACHING 105 DEGREES.
3. MINOR FIRE RISK WITH WIDESPREAD MINIMUM RELATIVE HUMIDITY
BETWEEN 15 AND 25 PERCENT FOR THE NON-DESERT AREAS. MINIMUM
RELATIVE HUMIDITY EXPECTED TO BE LESS THAN 10 PERCENT IN THE
MOJAVE DESERT WITH BREEZY WINDS IN THE AFTERNOON TO EVENING.
DISCUSSION
HIGH PRESSURE RIDGE NOW DOMINATING THE AREA AS A HEAT-WAVE
STARTS ACROSS CENTRAL CALIFORNIA. CONFIDENCE IN TRIPLE DIGIT
TEMPERATURES IS HIGH AS ENSEMBLE CONSENSUS ALL LEAN IN THE
DIRECTION OF A THREE DAY HEAT-WAVE. WHILE PROBABILITY OF
EXCEEDANCE (POE) OF REACHING 105 DEGREES REMAINS BELOW 50%,
EXCEPT FOR A FEW AREAS, POE OF 100 DEGREES HAS WIDESPREAD MAX
PERCENTAGES ABOVE 90% THROUGH MONDAY. THESE HIGH POE PERCENTAGES
INCREASED CONFIDENCE IN THE HEAT ADVISORY CURRENTLY IN EFFECT
FOR THE SAN JOAQUIN VALLEY AND ADJACENT FOOTHILLS. LITTLE CHANGE
IS EXPECTED THROUGH TUESDAY AHEAD OF A DISTURBANCE THAT WILL
BEGIN A COOLING TREND BY MIDWEEK.
ENSEMBLE TEMPERATURE ANALYSIS HAS BEEN VERY CONSISTENT WITH THE
ONSET OF THE CURRENT HEAT-WAVE. HEAT ADVISORY HAS BEEN ISSUED
FOR A THREE (TO POSSIBLY FOUR) DAY STRETCH AS MAX TEMPERATURES
RANGE FROM 100 TO 105 DEGREES. THE RIDGE PATTERN GENERATING THE
HEAT-WAVE IS ALSO RESPONSIBLE FOR KEEPING WINDS ACROSS THE
REGION LIGHT. EXCEPT FOR LOCAL WIND FAVORED AREAS THAT BECOME
BREEZY DURING THE AFTERNOON PERIOD, WILL EXPECT WINDS TO REMAIN
LIGHT AND DIURNALLY DRIVEN.
UNTIL THE RIDGE PATTERN BREAKS DOWN DUE TO A PASSING PACIFIC
NORTHWEST DISTURBANCE, THE REGION WILL BE DOMINATED BY A
SOUTHWESTERLY WIND FLOW. THAT FLOW WILL PUSH MONSOONAL MOISTURE
EAST AND AVOID CENTRAL CALIFORNIA. WITHOUT A SOUTHEASTERLY WIND,
THE LACK OF MOISTURE WILL KEEP THE REGION DRY. LONG RANGE
ENSEMBLE ANALYSIS SHOWS VERY GOOD AGREEMENT IN KEEP SOUTHERN
CALIFORNIA DRY THROUGH DAY SEVEN (NEXT SATURDAY).
AVIATION
06Z UPDATE:
VFR CONDITIONS ARE EXPECTED IN THE SAN JOAQUIN VALLEY FOR THE NEXT
24 HOURS.
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 UNTIL 11 PM PDT MONDAY FOR CAZ300>317-319-321.
PUBLIC.....MOLINA/BSO
AVIATION...JPK/BSO
WEATHER.GOV/HANFORD
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