520
FXUS66 KHNX 130605
AFDHNX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
1105 PM PDT WED AUG 12 2026
KEY MESSAGES
1. CHANGING WEATHER PATTERNS BRING COOLER WEATHER AND THE NEXT
REGIONAL CHANCES FOR RAIN THIS WEEK.
2. POTENTIAL FOR THUNDERSTORMS ACROSS THE AREA AGAIN TOMORROW,
RANGING FROM 5 TO 10% IN THE SAN JOAQUIN VALLEY UP TO 40% ALONG
THE SIERRA NEVADA CREST.
3. THREAT OF DAMAGING WIND FROM STRONG THUNDERSTORMS ALONG THE
SAN JOAQUIN VALLEY AND SIERRA NEVADA.
DISCUSSION
A TROUGH OFF THE COAST OF CALIFORNIA WILL BE RESPONSIBLE FOR A
NOTICEABLE COOLDOWN ACROSS THE REGION THROUGH THIS WEEK AS HIGHS
DIP BELOW NORMAL FOR THE FIRST TIME IN SEVERAL WEEKS. THIS WILL
COINCIDE WITH A MARKED INCREASE IN THUNDERSTORM CHANCES AND
ACTIVITY ACROSS THE SIERRA NEVADA MOUNTAINS AND MAY REACH INTO
THE SAN JOAQUIN VALLEY AS SEEN EARLIER THIS MORNING. THIS
ACTIVITY MAY ALSO BE INCREASED DUE TO A SMALL AREA OF STRONGER
VORTICITY THAT IS MODELED TO MOVE THROUGH CENTRAL CALIFORNIA
AHEAD OF THE TROUGH. CURRENT CHANCES FOR THIS ACTIVITY IS AROUND
30-40% ALONG THE SIERRA NEVADA CREST AND ABOUT 5-10% IN THE
VALLEY, MAINLY FROM 11AM THROUGH 8PM TOMORROW. THERE IS ALSO A
10% CHANCE FOR ISOLATED DRY THUNDERSTORMS IN THE SIERRAS FROM
MADERA COUNTY NORTHWARDS, WHICH MAY PRODUCE LITTLE WETTING RAIN
WITH FREQUENT LIGHTNING, INCREASING THE CHANCE FOR NEW FIRE
STARTS.
FROM FRIDAY ONWARDS, THUNDERSTORM CHANCES DROP OFF A CLIFF AND
WILL REMAIN LESS THAN 10% THROUGH THE REST OF THIS WEEK AS THE
TROUGH BROADENS AND LOSES ITS ENERGY THROUGH THAT TIME.
TEMPERATURES WILL ALSO REMAIN BELOW NORMAL THROUGH FRIDAY
BEFORE A SMALL WARM UP OF A FEW DEGREES TAKES PLACE OVER THE
WEEKEND DUE TO THE BROADENED TROUGH, WHILE STILL REMAINING A FEW
DEGREES BELOW NORMAL. LOOKING TO THE LONG TERM, TEMPERATURES MAY
BECOME ABOVE NORMAL ONCE AGAIN BY THE WEEKEND AFTER NEXT, AS THE
CLIMATE PREDICTION CENTER HAS OUR AREA UNDER LEANING ABOVE
NORMAL TEMPERATURES BY THE DAY 8 THROUGH 14 OUTLOOK, ALONG WITH
A LEANING ABOVE NORMAL FOR PRECIPITATION, SUGGESTING ANOTHER
MONSOONAL MOISTURE PUSH IS POSSIBLE DURING THAT TIME PERIOD.
AVIATION...
VFR CONDITIONS PREVAILING FOR SAN JOAQUIN VALLEY (SJV).
SCATTERED TO BROKEN CLOUD COVER ABOVE 10,000 FEET ALONG
FOOTHILLS OF EASTERN SJV, SIERRA NEVADA, AND KERN COUNTY DESERT
AND SLOPES. REGION WIDE THREAT OF THUNDERSTORMS, WITH GREATEST
PROBABILITY (30-40%) ALONG THE SIERRA NEVADA CREST UNTIL 03Z
THURSDAY. LOWER (10-15%) PROBABILITIES IN THE MOJAVE DESERT AND
SAN JOAQUIN VALLEY. MVFR TO HIGH-END IFR CONDITIONS POSSIBLE
WITHIN THUNDERSTORMS FROM DECREASED VISIBILITY AND CLOUD
CEILINGS.
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
NONE.
EW
WEATHER.GOV/HANFORD
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