994
FXUS66 KSTO 022045
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
145 PM PDT MON JUN 2 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 REMAINS IN EFFECT UNTIL 8 PM THIS EVENING FOR
THE NORTHERN AND CENTRAL SACRAMENTO VALLEY AND INTO THE COASTAL
RANGE DUE TO LOW HUMIDITY AND GUSTY WINDS. ELEVATED FIRE WEATHER
CONCERNS RETURN WEDNESDAY WITH SOME GUSTY NORTHERLY WINDS AND LOW
HUMIDITY. WARM AND DRY WEATHER IS EXPECTED TO PERSIST THROUGH
THIS WEEK. BREEZY ONSHORE WINDS WILL BRING SOME NIGHTTIME COOLING
INTO THE DELTA AND ADJACENT AREAS. THERE ARE 5-15% CHANCES OF PM
ISOLATED MOUNTAIN SHOWER/THUNDERSTORM FOR THE REST OF TODAY AND
AGAIN WEDNESDAY, THURSDAY AND FRIDAY, PRIMARILY ALONG THE SIERRA
CREST SOUTH OF HIGHWAY 50, BUT NO SIGNIFICANT IMPACTS ARE EXPECTED
AT THIS TIME. TEMPERATURES TREND HIGHER THIS WEEKEND.
KEY MESSAGES
* TODAY :
-CRITICAL FIRE WEATHER CONTINUES INTO THIS EVENING ACROSS THE
NORTHERN AND CENTRAL SACRAMENTO VALLEY AND ADJACENT NORTHERN
COASTAL RANGE, WITH GUSTS TO 30 TO 40 MPH, MINIMUM HUMIDITY
9-20%.
--PROBABILITY OF WIND GUSTS > 30 MPH: 60-100%, HIGHEST WITHIN
NORTHERN SACRAMENTO VALLEY AND ADJACENT COASTAL RANGE.
-ABOVE NORMAL HIGHS TODAY WITH AREAS OF MODERATE HEATRISK
-SLIGHT CHANCES ISOLATED SHOWER OR THUNDERSTORM AROUND 5-10%
ACROSS PORTIONS OF THE SIERRA SOUTH OF HIGHWAY 50 THIS AFTERNOON
AND EARLY EVENING.
* TUESDAY - FRIDAY:
-BROAD NORTHWESTERLY FLOW PATTERN ALOFT EXPECTED TO PERSIST
THROUGH THE WEEK.
-PERIODICALLY BREEZY WINDS EXPECTED TO CONTINUE WITHIN THIS FLOW
PATTERN AS TEMPERATURES SETTLE SLIGHTLY ABOVE NORMAL WITH AREAS
OF MODERATE HEATRISK.
-ELEVATED FIRE WEATHER CONCERNS WEDNESDAY WITH GUSTY NORTHERLY
WINDS AND LOW HUMIDITY.
--PROBABILITY OF WIND GUSTS > 30 MPH: 50-80%, HIGHEST WESTERN
PORTION OF THE NORTHERN SACRAMENTO VALLEY AND ADJACENT COASTAL
RANGE.
--LOW RELATIVE HUMIDITY WITH LIMITED OVERNIGHT RECOVERY EXPECTED
AS BREEZY NORTH WINDS INCREASE TUESDAY EVENING.
-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, THURSDAY AND
FRIDAY PM ALONG THE SIERRA CREST SOUTH OF HIGHWAY 50.
* SATURDAY - SUNDAY:
-PROBABILITY OF VALLEY HIGH TEMPERATURES > 95F:
--NORTHERN/CENTRAL SACRAMENTO VALLEY: 80-95%
--DELTA, S. SACRAMENTO VALLEY, N. SAN JOAQUIN VALLEY: 25-45%
CHANGES FROM PREVIOUS FORECAST
-ELEVATED FIRE CONCERNS HAVE TRENDED HIGHER ON WEDNESDAY, THOUGH
WINDS ARE NOT EXPECTED TO BE AS STRONG AS TODAY.
AVIATION
VFR CONDITIONS PREVAIL OVER INTERIOR NORCAL NEXT 24 HOURS.
SURFACE WINDS AROUND 10-20 KTS, WITH GUSTS 20-30 KTS OVER THE
WESTERN PORTIONS OF THE NORTHERN AND CENTRAL SACRAMENTO VALLEY AND
HIGHER TERRAIN OF THE SIERRA. WINDS BEGIN TO TAPER OFF AFTER 19Z
OVER THE NORTHERN AND CENTRAL VALLEY WITH LINGERING GUSTS ACROSS
THE DELTA THROUGH 12Z TUE.
STO WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 8 PM PDT THIS EVENING 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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