632
FXUS66 KSTO 181830
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1130 AM PDT MON MAY 18 2026
KEY MESSAGES
- RED FLAG WARNING EXPIRES THIS EVENING.
- LESS WIND REST OF THE WEEK BUT ABOVE NORMAL TEMPERATURES
RETURNING WITH WIDESPREAD MODERATE HEAT RISK THURSDAY.
DISCUSSION
..TONIGHT AND TUESDAY
THE UPPER TROUGH/INSIDE SLIDER THAT BROUGHT US WIDESPREAD GUSTY
WINDS IS QUICKLY MOVING OFF TO THE EAST AND CAUSING SEVERE WEATHER
IN THE CENTRAL U.S. THIS WILL SHIFT UPPER WINDS FROM THE NORTH TO
A MORE ZONAL WESTERLY DIRECTIONS. IN OTHER WORDS, LESS WIND FOR
THE REST OF THE WEEK. RELATIVE HUMIDITIES WILL REMAIN LOW THIS
WEEK BUT NOT AS DRY AS TODAY.
ONCE THE PATTERN SETTLES IN ON TUESDAY/WEDNESDAY IT LOOKS TO STAY
PRETTY CONSISTENT. WARMEST DAY LOOKS TO BE ON THURSDAY WITH VERY
LITTLE SPREAD IN MAXIMUM TEMPERATURE IN THE NBM PERCENTILES.
CURRENTLY LOOKS LIKE WIDESPREAD MODERATE HEAT RISK WITH
TEMPERATURES IN THE 90S TO APPROACHING 100 IN THE NORTH.
CONFIDENCE PRETTY HIGH THAT TEMPERATURE FORECAST SHOULDN'T CHANGE
TOO MUCH. HEATRISK PROBABILITIES VERY LOW TO REACH ABOVE MODERATE
RISK BUT WILL KEEP AN EYE ON THIS. THINGS LOOK TO COOL DOWN ENOUGH
FRIDAY INTO THE WEEKEND BUT STILL VERY WARM. NO RAIN IN SITE RIGHT
NOW IN THE 7 DAY FORECAST.
AVIATION
VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS. NORTHERLY
WINDS 15-20 KTS WITH GUSTS 20-30 KTS FOR THE VALLEY AND DELTA
UNTIL AROUND 00Z-03Z TUESDAY. NORTHEAST TO EAST WIND GUSTS UP TO
20-35 KTS THROUGH MID-DAY TODAY.
STO WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING FOR BUTTE COUNTY
BELOW 1000 FT-C. SAN JOAQUIN COUNTY INCLUDING STOCKTON-C. SOLANO
COUNTY INCLUDING FAIRFIELD-C. STANISLAUS COUNTY INCLUDING
MODESTO-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-NE
SAN JOAQUIN VALLEY BELOW 1000 FT-SW SOLANO COUNTY INCLUDING
VALLEJO-SAC METRO/W. EL DORADO/AMADOR COUNTY-SACRAMENTO COUNTY
DELTA-SAN JOAQUIN COUNTY DELTA-SHASTA METRO-SUTTER/YUBA COUNTIES
BELOW 1000 FT-TRACY TRIANGLE BELOW 1000 FT-W. STANISLAUS COUNTY
ABOVE 1000 FT & I-5-W. YOLO COUNTY INCLUDING CAPAY/I-505.
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