046
FXUS66 KSTO 101821
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1121 AM PDT WED JUN 10 2026
FOR ADDITIONAL DETAILS ON WEATHER AND EXPECTED IMPACTS OVER THE
NEXT 7 DAYS, PLEASE VISIT WEATHER.GOV/STO/BRIEFING.
KEY MESSAGES
-CRITICAL FIRE WEATHER CONDITIONS IN THE SACRAMENTO VALLEY
WEDNESDAY - THURSDAY DUE TO GUSTY NORTH WINDS AND LOW HUMIDITY.
-SIGNIFICANT WARM UP STARTING TODAY BRINGS ABOVE NORMAL TEMPS IN
THE LOWER ELEVATIONS WITH WIDESPREAD MODERATE HEATRISK / AREAS
OF MAJOR HEATRISK INTO THE WEEKEND & TRIPLE-DIGIT HIGHS
THURSDAY-SATURDAY.
DISCUSSION
ANOTHER CLEAR DAY EXPECTED AS CONDITIONS WARM AND DRY WITH RIDGING
AND HIGH PRESSURE BUILDING OVER THE AREA. WINDS BECOME STRONGER
AND MORE NORTHERLY TODAY INTO THURSDAY. AS NORTH WINDS INCREASE,
CONDITIONS WILL DRY OUT WITH DAYTIME RELATIVE HUMIDITY DROPPING
INTO THE SINGLE DIGITS TO TEENS ACROSS THE SACRAMENTO VALLEY WITH
LIMITED OVERNIGHT RECOVERY. ENSEMBLE GUIDANCE AND EFI CONTINUE TO
BE IN GOOD AGREEMENT WITH HIGHEST THREAT ACROSS THE TYPICAL
WESTERN SIDE OF THE SACRAMENTO VALLEY ALONG THE INTERSTATE 5
CORRIDOR.
OUR RED FLAG WARNING REMAINS IN PLACE FROM 11AM WEDNESDAY (TODAY)
TO 5PM THURSDAY, COVERING THE CENTRAL AND NORTHERN SACRAMENTO
VALLEY WITH ITS RESPECTIVE ADJACENT FOOTHILLS. NORTH WINDS 15 TO
25 MPH WITH GUSTS 30 TO 40 MPH FORECASTED, STRONGEST ALONG THE
WESTERN SIDE OF THE VALLEY. DAYTIME HUMIDITIES OF 9-15% PERCENT
AND OVERNIGHT HUMIDITIES MAXIMUMS 25-50%.
AS CRITICAL FIRE WEATHER CONDITIONS CONTINUE ON THURSDAY,
TEMPERATURES WILL ALSO SEE SIGNIFICANT INCREASES AS UPPER LEVEL
RIDGING BUILDS ALONG THE WEST COAST. TRIPLE DIGIT VALLEY HIGHS ARE
FORECASTED STARTING THURSDAY AND CONTINUING THROUGH AT LEAST THE
EARLY WEEKEND IN MANY LOCATIONS. WIDESPREAD MODERATE HEATRISK IS
EXPECTED STARTING THIS AFTERNOON, WITH AREAS OF MAJOR HEATRISK ON
FRIDAY AND SATURDAY ACROSS MAINLY THE FOOTHILLS. WE HAVE SEEN A
REDUCTION IN THE AREAL IMPACT OF OUR MAJOR HEATRISK CONDITIONS
BUT WILL STILL CARRY THE SAME THREAT AND IMPACT LEVEL OVERALL.
FOR THE AFOREMENTIONED HEAT, WE CONTINUE OUR HEAT ADVISORY FOR
THE NORTHERN AND CENTRAL SACRAMENTO VALLEY AND ADJACENT FOOTHILLS
FROM 11 AM THURSDAY, JUNE 11, TO 11 PM SATURDAY, JUNE 13. WHILE
OTHER AREAS IN THE VALLEY WILL BENEFIT FROM THE DELTA'S COOLING
INFLUENCE, ESPECIALLY IN THE EVENING, IT REMAINS IMPORTANT FOR
EVERYONE IN INTERIOR NORCAL TO PRACTICE HEAT SAFETY! STAY COOL AND
HYDRATED, AND CONSIDER CHECKING IN ON THOSE MORE SENSITIVE TO
HEAT.
BY WEEKEND'S END, WE CAN SEE SOME RELIEF FROM THE HEAT ACROSS THE
DELTA AND SACRAMENTO VALLEY AS THE DELTA BREEZE AND ONSHORE FLOW
WILL REDUCE HIGHS INTO THE MID TO UPPER 90S WITH THE NORTHERN
SACRAMENTO VALLEY AND ADJACENT FOOTHILLS RETAINING TRIPLE DIGITS
HIGHS.
AVIATION
VFR CONDITIONS WITH CLEAR SKIES OVER THE NEXT 24
HOURS. NORTH WINDS INCREASE THROUGH THE NORTHERN/CENTRAL
SACRAMENTO VALLEY TODAY WITH SUSTAINED WINDS 15 TO 20 KTS AND
GUSTS 25 TO 40 KTS. THE NORTHERN SAN JOAQUIN VALLEY WILL SEE
NORTHWEST WINDS 10 TO 15 KTS WITH GUSTS 20 TO 25 KTS. EAST GUSTS
OVER THE MOUNTAINS UP TO 40 KTS.
STO WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY FROM 11 AM THURSDAY TO 11 PM PDT SATURDAY FOR
BUTTE COUNTY BELOW 1000 FT-CENTRAL COLUSA COUNTY INCL. I-5-
CENTRAL GLENN CO & INTERSTATE 5-EASTERN COLUSA COUNTY-EASTERN
GLENN COUNTY-N. SAC VALLEY IN TEHAMA COUNTY-SHASTA METRO-SIERRA
(TEHAMA-PLUMAS) 1000-3000 FT-SUTTER/YUBA COUNTIES BELOW 1000 FT-
W TEHAMA CO FOOTHILLS 1000-3000 FT-W. GLENN/COLUSA FOOTHILLS
1000-3000 FT-W. SHASTA COUNTY 1000-3000 FT.
RED FLAG WARNING UNTIL 5 PM PDT THURSDAY FOR BUTTE COUNTY BELOW
1000 FT-C. YOLO/NE SOLANO INCLUDING WOODLAND-CENTRAL COLUSA
COUNTY INCL. I-5-CENTRAL GLENN CO & INTERSTATE 5-EASTERN COLUSA
COUNTY-EASTERN GLENN COUNTY-N. SAC VALLEY IN TEHAMA COUNTY-
SHASTA METRO-SUTTER/YUBA COUNTIES BELOW 1000 FT-W. GLENN/COLUSA
FOOTHILLS 1000-3000 FT-W. YOLO COUNTY INCLUDING CAPAY/I-505-YOLO
/ SOLANO COUNTY HILLS.
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