Alert archive / California / Red Flag Warnings in 2026
Red Flag Warning 1, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this red flag warning at Jun 9, 2026, 9:38 AM PDT for 4 counties in California. It took effect at Jun 10, 2026, 11:00 PM PDT. It was in force for 10 hr. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Jun 9, 2026, 9:38 AM PDT (16:38 UTC)
- In effect from
- Jun 10, 2026, 11:00 PM PDT
- Expired
- Jun 11, 2026, 9:00 AM PDT
- In force
- 10 hr
- Issued by
- NWS San Francisco Bay Area, CA
Counties Alameda County, CA, Contra Costa County, CA, Napa County, CA, Sonoma County, CA
The radar
The Sacramento radar (KDAX), 65 km from the middle of the area, began a volume at 16:38 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Oakland, CA (KOAK), launched 12:00Z, 4.6 hours before the alert went out and 47 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 489 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 90 m²/s²
- 0-3 km storm-relative helicity
- 107 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
921 WWUS86 KMTR 091638 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 938 AM PDT Tue Jun 9 2026 ...RED FLAG WARNING IN EFFECT FROM 11 PM WEDNESDAY TO 9 AM PDT THURSDAY DUE TO WIND AND LOW RELATIVE HUMIDITY FOR NORTH BAY INTERIOR MOUNTAINS AND EAST BAY HILLS... ....Hot, dry, and windy conditions combined with mixed vegetation, such as grass, will lead to critical fire weather conditions Wednesday night into Thursday morning... CAZ504-515-100200- /O.NEW.KMTR.FW.W.0001.260611T0600Z-260611T1600Z/ North Bay Interior Mountains-East Bay Hills- 938 AM PDT Tue Jun 9 2026 ...RED FLAG WARNING IN EFFECT FROM 11 PM WEDNESDAY TO 9 AM PDT THURSDAY... The National Weather Service in San Francisco CA has issued a Red Flag Warning. * AFFECTED AREA...East Bay Hills and North Bay Interior Mountains. * TIMING...From 11 PM Wednesday to 9 AM PDT Thursday. * WINDS 20 FOOT...Northwest winds 10 to 20 mph with gusts up to 45 mph. Ridge top wind gusts may exceed 60 mph. * RELATIVE HUMIDITY...Relative Humidity between 12 to 18 percent. * IMPACTS...Extreme fire behavior and rapid rates of spread likely on new and existing wildfires. There will be an increased risk for power outages. PRECAUTIONARY/PREPAREDNESS ACTIONS... Please advise responding agencies or fire crews in the field of this fire weather alert. Never leave burning debris or camp fires unattended; extinguish them completely. Avoid using equipment or machinery that could create a spark. Secure tow chains to avoid dragging and subsequent sparks. Never toss cigarette butts out of your vehicle's window. Remember, one less spark, one less flame. Familiarize yourself with your emergency plan! Where will you go? How will you get there? Do you have your go kit ready to go? Who will you call to let others know you are safe? Visit ready.gov/plan for more information. && $$ KR
5 follow-up statements
517 WWUS86 KMTR 100143 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 643 PM PDT Tue Jun 9 2026 ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 PM WEDNESDAY TO 9 AM PDT THURSDAY DUE TO WIND AND LOW RELATIVE HUMIDITY FOR NORTH BAY INTERIOR MOUNTAINS AND EAST BAY HILLS... ....Hot, dry, and windy conditions combined with mixed vegetation, such as grass, will lead to critical fire weather conditions Wednesday night into Thursday morning... CAZ504-515-101300- /O.CON.KMTR.FW.W.0001.260611T0600Z-260611T1600Z/ North Bay Interior Mountains-East Bay Hills- 643 PM PDT Tue Jun 9 2026 ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 PM WEDNESDAY TO 9 AM PDT THURSDAY... * AFFECTED AREA...East Bay Hills and North Bay Interior Mountains. * TIMING...From 11 PM Wednesday to 9 AM PDT Thursday. * WINDS 20 FOOT...Northwest winds 10 to 20 mph with gusts up to 45 mph. Ridge top wind gusts may exceed 60 mph. * RELATIVE HUMIDITY...Relative Humidity between 12 to 18 percent. * IMPACTS...Extreme fire behavior and rapid rates of spread likely on new and existing wildfires. There will be an increased risk for power outages. PRECAUTIONARY/PREPAREDNESS ACTIONS... Please advise responding agencies or fire crews in the field of this fire weather alert. Never leave burning debris or camp fires unattended; extinguish them completely. Avoid using equipment or machinery that could create a spark. Secure tow chains to avoid dragging and subsequent sparks. Never toss cigarette butts out of your vehicle's window. Remember, one less spark, one less flame. Familiarize yourself with your emergency plan! Where will you go? How will you get there? Do you have your go kit ready to go? Who will you call to let others know you are safe? Visit ready.gov/plan for more information. && $$ DialH
056 WWUS86 KMTR 101254 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 554 AM PDT Wed Jun 10 2026 ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 PM THIS EVENING TO 9 AM PDT THURSDAY DUE TO WIND AND LOW RELATIVE HUMIDITY FOR NORTH BAY INTERIOR MOUNTAINS AND EAST BAY HILLS... ....Hot, dry, and windy conditions combined with mixed vegetation, such as grass, will lead to critical fire weather conditions Wednesday night into Thursday morning... CAZ504-515-102100- /O.CON.KMTR.FW.W.0001.260611T0600Z-260611T1600Z/ North Bay Interior Mountains-East Bay Hills- 554 AM PDT Wed Jun 10 2026 ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 PM THIS EVENING TO 9 AM PDT THURSDAY... * AFFECTED AREA...East Bay Hills and North Bay Interior Mountains. * TIMING...From 11 PM this evening to 9 AM PDT Thursday. * WINDS 20 FOOT...Northwest winds 10 to 20 mph with gusts up to 45 mph. Ridge top wind gusts may exceed 60 mph. * RELATIVE HUMIDITY...Relative Humidity between 12 to 18 percent. * IMPACTS...Extreme fire behavior and rapid rates of spread likely on new and existing wildfires. There will be an increased risk for power outages. PRECAUTIONARY/PREPAREDNESS ACTIONS... Please advise responding agencies or fire crews in the field of this fire weather alert. Never leave burning debris or camp fires unattended; extinguish them completely. Avoid using equipment or machinery that could create a spark. Secure tow chains to avoid dragging and subsequent sparks. Never toss cigarette butts out of your vehicle's window. Remember, one less spark, one less flame. Familiarize yourself with your emergency plan! Where will you go? How will you get there? Do you have your go kit ready to go? Who will you call to let others know you are safe? Visit ready.gov/plan for more information. && $$ Canepa
297 WWUS86 KMTR 102044 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 144 PM PDT Wed Jun 10 2026 ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 PM THIS EVENING TO 9 AM PDT THURSDAY DUE TO WIND AND LOW RELATIVE HUMIDITY RECOVERY FOR NORTH BAY INTERIOR MOUNTAINS AND EAST BAY HILLS... ....Dry and windy conditions combined with some dry vegetation will lead to a critical fire weather threat late tonight into Thursday morning... CAZ504-515-110600- /O.CON.KMTR.FW.W.0001.260611T0600Z-260611T1600Z/ North Bay Interior Mountains-East Bay Hills- 144 PM PDT Wed Jun 10 2026 ...RED FLAG WARNING REMAINS IN EFFECT FROM 11 PM THIS TONIGHT TO 9 AM PDT THURSDAY... * AFFECTED AREA...East Bay Hills and North Bay Interior Mountains. * TIMING...From 11 PM this evening to 9 AM PDT Thursday. * WINDS 20 FOOT...Northerly winds 10 to 20 mph with gusts up to 45 mph. * RELATIVE HUMIDITY RECOVERY...Thursday morning relative humidity of less than 40 percent. * IMPACTS...Extreme fire behavior and rapid rates of spread likely on new and existing wildfires. There will be an increased risk for power outages. PRECAUTIONARY/PREPAREDNESS ACTIONS... Please advise responding agencies or fire crews in the field of this fire weather alert. Never leave burning debris or camp fires unattended; extinguish them completely. Avoid using equipment or machinery that could create a spark. Secure tow chains to avoid dragging and subsequent sparks. Never toss cigarette butts out of your vehicle's window. Remember, one less spark, one less flame. Familiarize yourself with your emergency plan! Where will you go? How will you get there? Do you have your go kit ready to go? Who will you call to let others know you are safe? Visit ready.gov/plan for more information. && $$ Bain
752 WWUS86 KMTR 110533 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 1033 PM PDT Wed Jun 10 2026 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 AM PDT THURSDAY DUE TO WIND AND LOW RELATIVE HUMIDITY RECOVERY FOR NORTH BAY INTERIOR MOUNTAINS AND EAST BAY HILLS... ....Dry and windy conditions combined with some dry vegetation will lead to a critical fire weather threat through Thursday morning... CAZ504-515-111600- /O.CON.KMTR.FW.W.0001.260611T0600Z-260611T1600Z/ North Bay Interior Mountains-East Bay Hills- 1033 PM PDT Wed Jun 10 2026 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 AM PDT THURSDAY... * AFFECTED AREA...East Bay Hills and North Bay Interior Mountains. * TIMING...Until 9 AM PDT Thursday. * WINDS 20 FOOT...Northerly winds 10 to 20 mph with gusts up to 45 mph. * RELATIVE HUMIDITY RECOVERY...Thursday morning relative humidity of less than 40 percent. * IMPACTS...Extreme fire behavior and rapid rates of spread likely on new and existing wildfires. There will be an increased risk for power outages. PRECAUTIONARY/PREPAREDNESS ACTIONS... Please advise responding agencies or fire crews in the field of this fire weather alert. Never leave burning debris or camp fires unattended; extinguish them completely. Avoid using equipment or machinery that could create a spark. Secure tow chains to avoid dragging and subsequent sparks. Never toss cigarette butts out of your vehicle's window. Remember, one less spark, one less flame. Familiarize yourself with your emergency plan! Where will you go? How will you get there? Do you have your go kit ready to go? Who will you call to let others know you are safe? Visit ready.gov/plan for more information. && $$ DialH
941 WWUS86 KMTR 111558 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 858 AM PDT Thu Jun 11 2026 CAZ504-515-111700- /O.EXP.KMTR.FW.W.0001.000000T0000Z-260611T1600Z/ North Bay Interior Mountains-East Bay Hills- 858 AM PDT Thu Jun 11 2026 ...RED FLAG WARNING WILL EXPIRE AT 9 AM PDT THIS MORNING... The strong winds have decreased and will continue to ease throughout the day. Hence, the Red Flag Warning will be allowed to expire. $$ RGass
What forecasters said that day
The local office's own words before this red flag warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Francisco Bay Area, CA wrote its last area forecast discussion before this red flag warning went out at Jun 9, 5:14 AM PDT, 4 hours 24 minutes earlier. Its key messages:
- Updated at 1208 AM PDT Tue Jun 9 2026
- Chance for coastal drizzle continues through the morning hours
- Warmer and drier conditions expected Wednesday through Saturday
- Moderate risk of heat-related illnesses for interior locations on Wednesday and Thursday
- Elevated to near critical fire weather conditions in the interior Bay Area late Wednesday through Thursday
Area forecast discussion, Jun 9, 5:14 AM PDT, 4 hours 24 minutes before
Area Forecast Discussion
National Weather Service San Francisco CA
514 AM PDT Tue Jun 9 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1208 AM PDT Tue Jun 9 2026
- Chance for coastal drizzle continues through the morning hours
- Warmer and drier conditions expected Wednesday through Saturday
- Moderate risk of heat-related illnesses for interior locations
on Wednesday and Thursday
- Elevated to near critical fire weather conditions in the
interior Bay Area late Wednesday through Thursday
&&
.SHORT TERM...
Issued at 1208 AM PDT Tue Jun 9 2026
(Today and tonight)
Light showers are moving through the Bay Area as an incoming cold
front drags some moisture through the region. These showers have
overperformed a little, and we've gotten reports of a few hundredths
of an inch of rain as far south as the Santa Cruz Mountains. With
continuing bands of precipitation moving through, have added a
chance for coastal and foothill drizzle across the Bay Area and
Santa Cruz County through the night, but accumulations are still
light and won't top a tenth of an inch across most of the Bay Area.
Today will mark the beginnings of a pattern change as an upper level
trough over the Pacific Northwest starts to shift eastwards and
allow a building ridge to come in from the Pacific. Today's highs
will be seasonable to cool, but they will be slightly warmer than
yesterday's with highs in the middle 70s to middle 80s throughout
the inland valleys, up to the upper 80s and near 90 in the warmest
spots of southern Monterey County, the upper 60s to middle 70s near
the bays, and the upper 50s to middle 60s along the Pacific coast.
&&
.LONG TERM...
Issued at 1208 AM PDT Tue Jun 9 2026
(Wednesday through Monday)
The pattern change will continue through Wednesday and Thursday as
the ridge extends into the West Coast while the trough dips a little
south of due east to create an inside slider-like setup, allowing
for a dramatic warming of temperatures for the middle and latter
parts of the week. In addition, strong northerly gusts and low
humidities late on Wednesday into Thursday could result in elevated
to near-critical fire weather conditions across the North Bay
interior mountains, the Diablo range across the interior East Bay,
and the eastern Santa Clara County mountains. For more information
on the expected conditions, see the FIRE WEATHER section.
Hot temperatures on Wednesday and Thursday will contribute to
Moderate HeatRisk across the inland regions, as high temperatures
reach the 90s into the triple digits across the inland valleys,
while temperatures reach the 80s to lower 90s close to the bays and
the 60s to the middle 70s at the Pacific Coast. This corresponds to
a moderate risk of heat-related illnesses, especially for people
sensitive to heat including children, the elderly, pregnant women,
people with chronic health conditions, and people who work or live
outside without adequate cooling or shelter. People spending time
outdoors should take frequent breaks in the shade and drink plenty
of water.
The ridging pattern will persist Friday into the upcoming weekend
with the ridge axis further developing into the northeast Pacific
off British Columbia and the Alaskan panhandle, and the current
forecast depicts a gradual cooling trend during that time persisting
into the early part of next week. Confidence remains low regarding
the time that a marine layer redevelops, but model output hints that
the marine layer stratus could return as soon as Saturday or Sunday.
Conversely, without any major large-scale forcing to move the
general ridging pattern away, temperatures could continue to trend
warmer for Friday and the following weekend. The extended range
outlook has around a 50-50 chance that temperatures remain above the
seasonal average heading into the third week of June.
&&
.AVIATION...
(12Z TAFS)
Issued at 451 AM PDT Tue Jun 9 2026
Expect MVFR/IFR cigs to hold into late morning/early afternoon.
Keeping an eye on drier air mixing to the surface over the North Bay
terminals, that may only be temporary while cigs hover between
VFR/MVFR. Once cigs lift this morning expect VFR conditions to
prevail through the remainder of the TAF period.
Vicinity of SFO...IFR/MVFR cigs expected to lift by early afternoon
with breezy onshore flow by the afternoon easing after sunset. VFR
will prevail through the remainder of the forecast period once cigs
lift this morning.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...IFR cigs expected to become MVFR by mid-
morning and VFR by early afternoon with breezy afternoon onshore
flow easing by sunset. Once cigs lift this morning, VFR conditions
will prevail through the remainder of the TAF period.
&&
.MARINE...
(Today through Sunday)
Issued at 451 AM PDT Tue Jun 9 2026
Fresh to moderate northwest breezes will build seas today
resulting in hazardous conditions for small craft across the
waters through Thursday afternoon. Gale force gusts will spread
across the northern waters Wednesday night into early Thursday.
Wind and seas begin to ease by Thursday evening and are expected
to stay light through the weekend.
&&
.FIRE WEATHER...
Issued at 1208 AM PDT Tue Jun 9 2026
Hot temperatures, gusty north winds, and low humidities across the
North Bay interior mountains into the Diablo Range will raise the
fire weather threats late on Wednesday into Thursday, with a
particular emphasis on the interior mountains of Napa County.
Although the strongest winds will remain within the Sacramento
Valley, gusts of 25 to 35 mph are expected to spread into Napa
County and the Diablo Range south through Santa Clara County, with
stronger gusts of 40-50 mph possible along the Vaca Mountains along
Napa County's eastern edge. Meanwhile, daytime humidity retention
will be very poor with relative humidity values as low as 10-15%,
while overnight recoveries are likewise poor as RH values top out at
20-30%. Thus, fuels are expected to dry rapidly, leading to the
elevated fire weather concerns. Also important to note that even
with the drizzle and light rain coming through the region, wetting
rains (rain totals above 0.1") are not expected, limiting any relief
that will be realized for the midweek period. Elsewhere across the
district, conditions remain hot and dry, but we're not expecting
winds to be as strong as they are across the interior North Bay.
We are continuing to monitor the potential for fire weather products
to be issued for the interior mountains of the North, East, and
South Bays for Wednesday and Thursday. At present, conditions are
right on the edge of critical fire weather criteria, but the
confidence isn't there at this point to pull the trigger on any
warnings. The day shift will reevaluate the fire weather forecast
for Wednesday and Thursday and in collaboration with neighboring
offices, will be in a better position to determine the extent of
necessary products. Regardless of whether any products are issued
across the interior, elevated to near critical fire weather
conditions are still forecast and care must be taken to avoid
starting a fire that could spread rapidly. Remember, one less
spark, one less wildfire.
DialH
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM this morning to 9 PM PDT this
evening for Mry Bay-Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 9 AM to 9 PM PDT Wednesday for Mry Bay.
Small Craft Advisory from 9 AM this morning to 9 AM PDT
Wednesday for Pt Arena to Pt Reyes 0-10 nm.
Gale Warning from 9 AM Wednesday to 3 AM PDT Thursday for Pt
Arena to Pt Reyes 0-10 nm.
Small Craft Advisory from 9 AM this morning to 9 PM PDT
Wednesday for Pigeon Pt to Pt Pinos 0-10 nm-Pt Reyes to
Pigeon Pt 0-10 nm.
Small Craft Advisory from 9 AM this morning to 3 AM PDT Thursday
for Pt Pinos to Pt Piedras Blancas 0-10 nm.
Gale Warning from 9 PM this evening to 3 AM PDT Thursday for Pt
Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 9 AM this morning to 3 PM PDT Thursday
for Pigeon Pt to Pt Pinos 10-60 NM.
&&
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...JM
MARINE...JM
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www.youtube.com/nwsbayareaThe office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 8, 8:34 PM PDT | Small Craft Advisory | MTR | 6 hr | |
| Jun 8, 8:34 PM PDT | Small Craft Advisory | MTR | 36 hr | |
| Jun 9, 1:29 PM PDT | Heat Advisory | MTR | Alameda, Contra Costa, Marin, Napa, City and County of San Francisco, San Mateo and 2 more | 4 days |
Nearby
Red Flag Warnings in California, 2026Every red flag warning in 2026
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.