998
FXUS66 KSTO 020025 AAA
AFDSTO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SACRAMENTO CA
525 PM PDT SUN JUN 1 2025
FOR ADDITIONAL DETAILS ON WEATHER AND EXPECTED IMPACTS OVER THE
NEXT 7 DAYS, PLEASE VISIT WEATHER.GOV/STO/BRIEFING.
DISCUSSION
SYNOPSIS
A RED FLAG WARNING IS IN EFFECT FOR THE NORTHERN AND CENTRAL
SACRAMENTO VALLEY AND INTO THE COASTAL RANGE ON MONDAY FROM LOW
HUMIDITY AND GUSTY WINDS. OTHERWISE, WARM AND DRY WEATHER IS
EXPECTED TO PERSIST TODAY INTO NEXT WEEK ALONGSIDE PERIODICALLY
BREEZY WINDS. LASTLY, 5-15% PM MOUNTAIN SHOWER/THUNDERSTORM
CHANCES ARE ANTICIPATED TODAY AND WEDNESDAY-THURSDAY, PRIMARILY
ALONG THE SIERRA SOUTH OF HIGHWAY 50 BUT NO MAJOR IMPACTS EXPECTED
AT THIS TIME.
KEY MESSAGES
* TODAY - MONDAY:
-NEAR NORMAL HIGHS TODAY WITH GRADUAL WARMING AND AREAS OF
MODERATE HEATRISK RETURNING BY MONDAY.
-ELEVATED FIRE WEATHER CONCERNS THIS EVENING.
-CRITICAL FIRE WEATHER CONDITIONS DEVELOP EARLY MONDAY MORNING
AND CONTINUE INTO THE EVENING ACROSS THE NORTHERN AND CENTRAL
SACRAMENTO VALLEY AND ADJACENT NORTHERN COASTAL RANGE.
--LOW RELATIVE HUMIDITY WITH LIMITED OVERNIGHT RECOVERY EXPECTED
AS BREEZY NORTH WINDS INCREASE SUNDAY EVENING.
--PROBABILITY OF WIND GUSTS > 30 MPH: 50-95%, HIGHEST WITHIN
NORTHERN SACRAMENTO VALLEY AND ADJACENT COASTAL RANGE.
-SLIGHT SHOWER OR THUNDERSTORM CHANCES AROUND 5-15% ACROSS
SHASTA COUNTY MOUNTAINS THIS EVENING, RETURNING TO PORTIONS OF
THE SIERRA SOUTH OF HIGHWAY 50 ON MONDAY.
* TUESDAY - FRIDAY:
-BROAD NORTHWESTERLY FLOW ALOFT EXPECTED TO PERSIST THROUGH THE
WEEK WITH SOME INCREASING HEIGHTS ALOFT.
-PERIODICALLY BREEZY WINDS EXPECTED TO CONTINUE WITHIN THIS FLOW
PATTERN AS TEMPERATURES SETTLE SLIGHTLY ABOVE NORMAL WITH AREAS
OF MODERATE HEATRISK.
-PROBABILITY OF VALLEY HIGH TEMPERATURES > 95F:
--NORTHERN/CENTRAL SACRAMENTO VALLEY: 60-90%
--DELTA, S. SACRAMENTO VALLEY, N. SAN JOAQUIN VALLEY: 20-40%
-SLIGHT THUNDERSTORM CHANCES AROUND 5-15% WEDNESDAY PM AND
THURSDAY PM ALONG THE SIERRA SOUTH OF HIGHWAY 50.
CHANGES FROM PREVIOUS FORECAST
-RED FLAG WARNING HAS BEEN ISSUED OVER THE NORTHERN AND CENTRAL
SACRAMENTO VALLEY AND ADJACENT NORTHERN COASTAL RANGE FROM 2 AM
TO 8 PM MONDAY.
AVIATION
VFR CONDITIONS PREVAIL OVER INTERIOR NORCAL NEXT 24 HOURS. SURFACE
WINDS AROUND 10-15 KTS, WITH GUSTS UP TO 20 KTS FROM 20Z TO 06Z
MON. IN THE VALLEY AND UP TO 25 KTS ACROSS THE DELTA. BREEZY
WINDS LINGER OVER THE NORTHERN SAC. VALLEY WITH NORTH WINDS 10 TO
20 KTS AND GUSTS UP TO 20-30 KTS FROM 09Z MON. THROUGH 18Z MON.
STO WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING FROM 2 AM TO 8 PM PDT MONDAY FOR CENTRAL
SACRAMENTO VALLEY IN GLENN, COLUSA, YUBA, NORTHERN SUTTER, AND
BUTTE COUNTY BELOW 1000 FT-EASTERN MENDOCINO NF-EASTERN PORTION
OF SHASTA/TRINITY NF-NORTHERN SACRAMENTO VALLEY TO SOUTHERN
TEHAMA COUNTY LINE BELOW 1000 FT-SOUTHEAST EDGE SHASTA-TRINITY
NF AND WESTERN PORTIONS OF TEHAMA-GLENN UNIT.
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