Alert archive / California / Red Flag Warnings in 2017
Red Flag Warning 3, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this red flag warning at Aug 30, 2017, 12:00 PM PDT for 5 counties in California. It took effect at Aug 31, 2017, 9:00 PM PDT. It was in force for 48 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
- Aug 30, 2017, 12:00 PM PDT (19:00 UTC)
- In effect from
- Aug 31, 2017, 9:00 PM PDT
- Expired
- Sep 2, 2017, 9:00 PM PDT
- In force
- 48 hr
- Issued by
- NWS San Francisco Bay Area, CA
Counties Monterey County, CA, San Benito County, CA, San Mateo County, CA, Santa Clara County, CA, Santa Cruz County, CA
The radar
The San Francisco radar (KMUX), 33 km from the middle of the area, began a volume at 19:00 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, 7.0 hours before the alert went out and 102 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
- 1917 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- -31 m²/s²
- 0-3 km storm-relative helicity
- 123 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
630 WWUS86 KMTR 301900 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 1200 PM PDT Wed Aug 30 2017 ...HOT AND DRY CONDITIONS WILL IMPACT THE REGION THURSDAY NIGHT INTO THE WEEKEND ALONG WITH LOCALLY GUSTY WINDS IN THE HILLS... .Strong high pressure currently over the Desert Southwest will build over California resulting in a prolonged period of hot and dry weather. Poor to very poor humidity recoveries will occur in the hills above 1000 feet overnight and daytime relative humidity values will drop as low as the single digits and teens. Overnight temperatures will remain mild and in the 70s and 80s with daytime temperatures exceeding 100 degrees. In addition, locally gusty north to northeast winds will develop in the hills at night and become northwesterly during the day. These weather factors will result in the potential for rapid fire spread in the warned area. CAZ507-511-512-517-518-310430- /O.NEW.KMTR.FW.W.0003.170901T0400Z-170902T1500Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 1200 PM PDT Wed Aug 30 2017 ...RED FLAG WARNING IN EFFECT FROM 9 PM THURSDAY TO 8 AM PDT SATURDAY FOR HOT AND DRY CONDITIONS WITH POOR OVERNIGHT HUMIDITY RECOVERIES FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... The National Weather Service in San Francisco has issued a Red Flag Warning, which is in effect from 9 PM Thursday to 8 AM PDT Saturday. * AFFECTED AREA...Fire weather zones 507, 511, 512, 517, and 518. This includes elevations above 1000 feet in the North and East Bay Hills, the Santa Cruz Mountains, the Diablo Range, the Santa Lucia Range, and the interior mountains of Monterey and San Benito Counties. * WIND...North to Northeast winds 5 to 10 mph with gusts 20 mph during the night and North to Northwest winds 5 to 10 mph with gusts 20-25 mph during the day. * HUMIDITY...Humidity recovery at night will generally be 20-30% and dropping to 10-20% during the day. * IMPACTS...any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$ MM
7 follow-up statements
662 WWUS86 KMTR 310426 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 926 PM PDT Wed Aug 30 2017 ...HOT AND DRY CONDITIONS WILL IMPACT THE REGION THURSDAY NIGHT INTO THE WEEKEND ALONG WITH LOCALLY GUSTY WINDS IN THE HILLS... .Strong high pressure will build over California Thursday and Friday, resulting in a prolonged period of hot and dry weather through the Labor Day weekend. Poor to very poor humidity recoveries will occur in the hills above 1000 feet overnight and daytime relative humidity values will drop as low as the single digits and teens. Overnight temperatures will remain quite warm in the 70s and 80s with daytime temperatures exceeding 100 degrees across most inland areas. In addition, locally gusty north to northeast winds will develop in the hills at night and become northwesterly during the day. These weather factors will result in the potential for rapid fire spread in the warned area beginning late Thursday and continuing through at least Saturday morning. CAZ507-511-512-517-518-312300- /O.CON.KMTR.FW.W.0003.170901T0400Z-170902T1500Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 926 PM PDT Wed Aug 30 2017 ...RED FLAG WARNING REMAINS IN EFFECT FROM 9 PM THURSDAY TO 8 AM PDT SATURDAY FOR HOT AND DRY CONDITIONS WITH POOR OVERNIGHT HUMIDITY RECOVERIES FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... * AFFECTED AREA...Fire weather zones 507, 511, 512, 517, and 518. This includes elevations above 1000 feet in the North and East Bay Hills, the Santa Cruz Mountains, the Diablo Range, the Santa Lucia Range, and the interior mountains of Monterey and San Benito Counties. * WIND...North to Northeast winds 5 to 10 mph with gusts 20 mph during the night and North to Northwest winds 5 to 15 mph with gusts 20 to 25 mph during the day. * HUMIDITY...Daytime relative humidity values in the single digits and teens. Nighttime humidity recoveries very poor with humidity values remaining below 30 percent for locations in the hills. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
886 WWUS86 KMTR 311949 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 1249 PM PDT Thu Aug 31 2017 ...HOT AND DRY CONDITIONS WILL IMPACT THE REGION THURSDAY NIGHT INTO THE WEEKEND ALONG WITH LOCALLY GUSTY WINDS IN THE HILLS... .Strong high pressure will build over California Thursday and Friday, resulting in a prolonged period of hot and dry weather through the Labor Day weekend. Poor to very poor humidity recoveries will occur in the hills above 1000 feet overnight and daytime relative humidity values will drop as low as the single digits and teens. Overnight temperatures will remain quite warm in the 70s and 80s with daytime temperatures exceeding 100 degrees across most inland areas. In addition, locally gusty north to northeast winds will develop in the hills at night and become northwesterly during the day. These weather factors will result in the potential for rapid fire spread in the warned area beginning late Thursday and continuing through at least Saturday morning. CAZ507-511-512-517-518-011500- /O.CON.KMTR.FW.W.0003.170901T0400Z-170902T1500Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 1249 PM PDT Thu Aug 31 2017 ...RED FLAG WARNING REMAINS IN EFFECT FROM 9 PM THIS EVENING TO 8 AM PDT SATURDAY FOR HOT AND DRY CONDITIONS WITH POOR OVERNIGHT HUMIDITY RECOVERIES FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... * AFFECTED AREA...Fire weather zones 507, 511, 512, 517, and 518. This includes elevations above 1000 feet in the North and East Bay Hills, the Santa Cruz Mountains, the Diablo Range, the Santa Lucia Range, and the interior mountains of Monterey and San Benito Counties. * WIND...North to Northeast winds 5 to 10 mph with gusts 20 mph during the night and North to Northwest winds 5 to 15 mph with gusts 20 to 25 mph during the day. * HUMIDITY...Daytime relative humidity values in the single digits and teens. Nighttime humidity recoveries very poor with humidity values remaining below 30 percent for locations in the hills. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
866 WWUS86 KMTR 011058 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 358 AM PDT Fri Sep 1 2017 ...HOT AND DRY CONDITIONS WILL IMPACT THE REGION FRIDAY INTO THE WEEKEND ALONG WITH LOCALLY GUSTY WINDS IN THE HILLS... .Strong high pressure will build over California through the Labor Day weekend, resulting in a prolonged period of hot and dry weather. Poor to very poor humidity recoveries will occur in the hills above 1000 feet overnight and daytime relative humidity values will drop as low as the single digits and teens. Overnight temperatures will remain quite warm in the 70s and 80s with daytime temperatures exceeding 100 degrees across most inland areas. In addition, locally gusty north to northeast winds will develop in the hills at night and become northwesterly during the day. These weather factors will result in the potential for rapid fire spread in the warned area through at least Saturday morning. CAZ507-511-512-517-518-012200- /O.CON.KMTR.FW.W.0003.000000T0000Z-170902T1500Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 358 AM PDT Fri Sep 1 2017 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 AM PDT SATURDAY FOR HOT AND DRY CONDITIONS WITH POOR OVERNIGHT HUMIDITY RECOVERIES FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... * AFFECTED AREA...Fire weather zones 507, 511, 512, 517, and 518. This includes elevations above 1000 feet in the North and East Bay Hills, the Santa Cruz Mountains, the Diablo Range, the Santa Lucia Range, and the interior mountains of Monterey and San Benito Counties. * WIND...North to Northeast winds 5 to 10 mph with gusts 20 mph during the night and North to Northwest winds 5 to 15 mph with gusts 20 to 25 mph during the day. * HUMIDITY...Daytime relative humidity values in the single digits and teens. Nighttime humidity recoveries very poor with humidity values remaining below 30 percent for locations in the hills. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
169 WWUS86 KMTR 012110 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 210 PM PDT Fri Sep 1 2017 ...HOT AND DRY CONDITIONS WILL CONTINUE TO IMPACT THE REGION INTO THE WEEKEND...ALONG WITH LOCALLY GUSTY WINDS IN THE HILLS... .Strong high pressure over California will continue to produce very hot and dry weather across the entire district through Saturday. Very poor humidity recoveries will occur in the hills above 1000 feet overnight, and daytime relative humidity values will drop as low as the single digits and teens. Overnight temperatures will remain quite warm in the 70s and 80s with daytime temperatures exceeding 100 degrees across most areas and up to 110 to 115 in the hottest inland areas. In addition, moderate and locally gusty north to northeast winds are expected in the hills at night, becoming northwesterly during the day. These weather factors will result in the potential for rapid fire spread in the warned area through at least Saturday evening. CAZ507-511-512-517-518-021300- /O.EXT.KMTR.FW.W.0003.000000T0000Z-170903T0400Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 210 PM PDT Fri Sep 1 2017 ...RED FLAG WARNING NOW IN EFFECT UNTIL 9 PM PDT SATURDAY FOR HOT AND DRY CONDITIONS WITH POOR OVERNIGHT HUMIDITY RECOVERIES FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... * AFFECTED AREA...Fire weather zones 507, 511, 512, 517, and 518. This includes elevations above 1000 feet in the North and East Bay Hills, the Santa Cruz Mountains, the Diablo Range, the Santa Lucia Range, and the interior mountains of Monterey and San Benito Counties. * WIND...North to Northeast winds 5 to 10 mph with gusts 20 mph during the night and North to Northwest winds 5 to 15 mph with gusts 20 to 25 mph during the day. * HUMIDITY...Daytime relative humidity values in the single digits and teens. Nighttime humidity recoveries very poor with humidity values remaining below 30 percent for locations in the hills. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
911 WWUS86 KMTR 021137 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 437 AM PDT Sat Sep 2 2017 ...HOT AND DRY CONDITIONS WILL CONTINUE TO IMPACT THE REGION INTO THE WEEKEND...ALONG WITH LOCALLY GUSTY WINDS IN THE HILLS... .Strong high pressure over California will continue to produce very hot and dry weather across the entire district through Saturday. After very poor humidity recoveries overnight, daytime relative humidity values will drop as low as the single digits and teens. Daytime temperatures will also once again exceed 100 degrees across most areas and up to 110 to 115 in the hottest inland areas. In addition, moderate and locally gusty northerly winds are forecast through at least this evening. These weather factors will result in the potential for rapid fire spread in the warned area through at least Saturday evening. CAZ507-511-512-517-518-022200- /O.CON.KMTR.FW.W.0003.000000T0000Z-170903T0400Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 437 AM PDT Sat Sep 2 2017 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM PDT THIS EVENING FOR HOT AND DRY CONDITIONS WITH POOR OVERNIGHT HUMIDITY RECOVERIES FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... * AFFECTED AREA...Fire weather zones 507, 511, 512, 517, and 518. This includes elevations above 1000 feet in the North and East Bay Hills, the Santa Cruz Mountains, the Diablo Range, the Santa Lucia Range, and the interior mountains of Monterey and San Benito Counties. * WIND...North to Northeast winds 5 to 10 mph with gusts 20 mph during the night and North to Northwest winds 5 to 15 mph with gusts 20 to 25 mph during the day. * HUMIDITY...Daytime relative humidity values in the single digits and teens. Nighttime humidity recoveries very poor with humidity values remaining below 30 percent for locations in the hills. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
356 WWUS86 KMTR 021918 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 1218 PM PDT Sat Sep 2 2017 ...HOT AND DRY CONDITIONS WILL CONTINUE TO IMPACT THE REGION INTO THE WEEKEND...ALONG WITH LOCALLY GUSTY WINDS IN THE HILLS... .Strong high pressure over California will continue to produce very hot and dry weather across the entire district through Saturday. After very poor humidity recoveries overnight, daytime relative humidity values will drop as low as the single digits and teens. Daytime temperatures will also once again exceed 100 degrees across most areas and up to 110 to 115 in the hottest inland areas. In addition, moderate and locally gusty offshore winds are forecast into this evening. These weather factors will result in the potential for rapid fire spread in the warned area through at least Saturday evening. CAZ507-511-512-517-518-030400- /O.CON.KMTR.FW.W.0003.000000T0000Z-170903T0400Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 1218 PM PDT Sat Sep 2 2017 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM PDT THIS EVENING FOR HOT AND DRY CONDITIONS FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... * AFFECTED AREA...Fire weather zones 507, 511, 512, 517, and 518. This includes elevations above 1000 feet in the North and East Bay Hills, the Santa Cruz Mountains, the Diablo Range, the Santa Lucia Range, and the interior mountains of Monterey and San Benito Counties. * WIND...North to Northeast winds 5 to 10 mph with gusts 20 mph during the night and North to Northwest winds 5 to 15 mph with gusts 20 to 25 mph during the day. * HUMIDITY...Daytime relative humidity values in the single digits and teens. Nighttime humidity recoveries very poor with humidity values remaining below 30 percent for locations in the hills. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
655 WWUS86 KMTR 030357 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 857 PM PDT Sat Sep 2 2017 CAZ507-511-512-517-518-030500- /O.EXP.KMTR.FW.W.0003.000000T0000Z-170903T0400Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 857 PM PDT Sat Sep 2 2017 ...RED FLAG WARNING WILL EXPIRE AT 9 PM PDT THIS EVENING FOR HOT AND DRY CONDITIONS FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... Even though the Red Flag Warning will expire this evening, fire weather concerns will continue through at least Sunday evening. Temperatures will be trending downward starting on Sunday, but inland areas and the hills will remain hot and dry. Also, southerly winds will begin to increase across the far southern portion of the district late Sunday and then across most of the rest of the district on Sunday night. Moderate and gusty southerly winds are expected in the hills and locally in the valleys on Sunday night. However, relative humidity values are forecast to increase significantly on Sunday night. Also, increasing moisture from the remnants of Tropical Storm Lidia will result in a slight chance of showers and thunderstorms beginning in the southern portion of the district by Sunday afternoon. These chances will remain across the south through Monday morning. Shower and thunderstorm chances will then advance northward into at least the southern half of the San Francisco Bay Area by Monday afternoon and evening. When thunderstorm chances first develop late on Sunday, the sub-cloud layer will still be very dry and so conditions could be favorable for dry lightning across Monterey and San Benito Counties. But with time the lower levels should moisten and any thunderstorms that develop from Sunday night onward will most likely be accompanied by wetting rains. $$
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 29, 9:02 PM PDT | Small Craft Advisory | MTR | 36 hr | |
| Aug 30, 1:27 PM PDT | Excessive Heat Warning | MTR | Alameda, Contra Costa, Marin, Monterey, Napa, San Benito and 5 more | 4 days |
| Aug 30, 1:27 PM PDT | Heat Advisory | MTR | Alameda, Contra Costa, Marin, Monterey, Napa, San Benito and 2 more | 32 hr |
| Aug 30, 1:27 PM PDT | Heat Advisory | MTR | Marin, Monterey, City and County of San Francisco, San Mateo, Santa Cruz, Sonoma | 47 hr |
Nearby
Red Flag Warnings in California, 2017Every red flag warning in 2017
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.