Alert archive / California / Red Flag Warnings in 2017
Red Flag Warning 9, NWS San Francisco Bay Area, CA
NWS San Francisco Bay Area, CA issued this red flag warning at Dec 15, 2017, 2:00 AM PST for 5 counties in California. It took effect at Dec 15, 2017, 10:00 PM PST. It was in force for 36 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
- Dec 15, 2017, 2:00 AM PST (10:00 UTC)
- In effect from
- Dec 15, 2017, 10:00 PM PST
- Expired
- Dec 17, 2017, 10:00 AM PST
- In force
- 36 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 09:59 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 00:00Z, 10.0 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
- 3250 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- -21 m²/s²
- 0-3 km storm-relative helicity
- -67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
164 WWUS86 KMTR 151000 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 200 AM PST Fri Dec 15 2017 ...Gusty northerly winds will combine with very low humidity values Friday evening through Sunday morning... .A dry system moving in from the north late on Friday will produce a combination of gusty winds and low humidity values. Due to these factors and the recently long stretch of warm and dry conditions, a very elevated fire weather risk can be expected particularly for higher elevation locations. CAZ507-511-512-517-518-152200- /O.UPG.KMTR.FW.A.0005.171216T0600Z-171217T1800Z/ /O.NEW.KMTR.FW.W.0009.171216T0600Z-171217T1800Z/ 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- 200 AM PST Fri Dec 15 2017 ...RED FLAG WARNING IN EFFECT FROM 10 PM THIS EVENING TO 10 AM PST SUNDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY... The National Weather Service in San Francisco has issued a Red Flag Warning, which is in effect from 10 PM this evening to 10 AM PST Sunday. The Fire Weather Watch is no longer in effect. * WIND...Northerly winds of 15 to 30 mph with local gusts over 50 mph. Strongest gusts will be over the North Bay Mountains and East Bay Hills. * HUMIDITY...Minimum humidity readings of 10 to 20% during the day. Nighttime maximum humidity readings will likely recover early in the night then drop of 25 to 35%. * HIGHEST THREAT...Elevations above 1000 ft, especially the North Mountains and East Bay 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. && $$
5 follow-up statements
188 WWUS86 KMTR 152121 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 121 PM PST Fri Dec 15 2017 ...Gusty northerly winds will combine with very low humidity values Friday evening through Sunday morning... .A dry system moving in from the north late tonight will produce a combination of gusty winds and low humidity values. Due to these factors and the recently long stretch of warm and dry conditions, a very elevated fire weather risk can be expected particularly for higher elevation locations. CAZ507-511-512-517-518-161200- /O.CON.KMTR.FW.W.0009.171216T0600Z-171217T1800Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 121 PM PST Fri Dec 15 2017 ...RED FLAG WARNING REMAINS IN EFFECT FROM 10 PM THIS EVENING TO 10 AM PST SUNDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY... * WIND...Northerly winds of 15 to 30 mph with local gusts over 50 mph. Strongest gusts will be over the North Bay Mountains and East Bay Hills. * HUMIDITY...Minimum humidity readings of 10 to 20% during the day. Nighttime maximum humidity readings will likely recover early in the night then drop of 25 to 35%. * HIGHEST THREAT...Elevations above 1000 ft, especially the North Bay Mountains and East Bay Hills. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
201 WWUS86 KMTR 161201 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 401 AM PST Sat Dec 16 2017 ...Gusty northerly winds will combine with very low humidity values through Sunday morning... .A dry system moving through will produce a combination of gusty winds and low humidity values today and tonight. Due to these factors and the recently long stretch of warm and dry conditions, a very elevated fire weather risk can be expected particularly for higher elevation locations. CAZ507-511-512-517-518-170400- /O.CON.KMTR.FW.W.0009.000000T0000Z-171217T1800Z/ 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- 401 AM PST Sat Dec 16 2017 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 10 AM PST SUNDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY... * WIND...Northerly winds of 15 to 30 mph with local gusts over 50 mph. Strongest gusts will be over the North Bay Mountains and East Bay Hills. * HUMIDITY...Minimum humidity readings of 10 to 20% during the day. Nighttime maximum humidity readings will likely recover early in the night then drop of 25 to 35%. * HIGHEST THREAT...Elevations above 1000 ft, especially the North Bay Mountains and East Bay 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. && $$
242 WWUS86 KMTR 170351 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 751 PM PST Sat Dec 16 2017 ...Gusty northerly winds will combine with very low humidity values through Sunday morning... .A dry system moving through will produce a combination of gusty winds and low humidity values today and tonight. Due to these factors and the recently long stretch of warm and dry conditions, a very elevated fire weather risk can be expected particularly for higher elevation locations. CAZ507-511-512-517-518-171200- /O.CON.KMTR.FW.W.0009.000000T0000Z-171217T1800Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 751 PM PST Sat Dec 16 2017 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 10 AM PST SUNDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY... * WIND...Northerly winds of 15 to 30 mph with local gusts over 50 mph. Strongest gusts will be over the North Bay Mountains and East Bay Hills. * HUMIDITY...Minimum humidity readings of 10 to 20% during the day. Nighttime maximum humidity readings will likely recover early in the night then drop to 25 to 35%. * HIGHEST THREAT...Elevations above 1000 ft, especially in the North Bay Mountains and East Bay Hills. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Red Flag Warning means that critical fire weather conditions are either occurring now...or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. && $$
434 WWUS86 KMTR 171018 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco Bay Area 218 AM PST Sun Dec 17 2017 ...Gusty northerly winds will continue to combine with low humidity values through Sunday morning... .High pressure rapidly building into the Great Basin this morning is resulting in a strong offshore pressure gradient and a combination of gusty winds and low humidity values. Due to these factors and the recent long stretch of warm and dry conditions, a very elevated fire weather risk exists particularly for higher elevation locations. CAZ507-511-512-517-518-171800- /O.CON.KMTR.FW.W.0009.000000T0000Z-171217T1800Z/ 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- 218 AM PST Sun Dec 17 2017 ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 10 AM PST THIS MORNING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY... * WIND...Northerly winds of 15 to 30 mph with local gusts over 50 mph. Strongest gusts will be over the North Bay Mountains and East Bay Hills. * HUMIDITY...Overnight maximum humidity readings will likely be confined to the 20 to 30% range. * HIGHEST THREAT...Elevations above 1000 ft, especially in the North Bay Mountains and East Bay 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. && $$
944 WWUS86 KMTR 171754 RFWMTR URGENT - FIRE WEATHER MESSAGE National Weather Service San Francisco CA 954 AM PST Sun Dec 17 2017 ...Red Flag Warning will expire at 10 am PST... CAZ507-511-512-517-518-171900- /O.EXP.KMTR.FW.W.0009.000000T0000Z-171217T1800Z/ North Bay Mountains-East Bay Hills and the Diablo Range- Santa Cruz Mountains- Santa Lucia Mountains and Los Padres National Forest- Mountains Of San Benito County And Interior Monterey County Including Pinnacles National Park- 954 AM PST Sun Dec 17 2017 ...RED FLAG WARNING WILL EXPIRE AT 10 AM PST THIS MORNING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 507, 511, 512, 517, AND 518... Northerly winds will continue to decrease through the rest of the day across the higher elevations of the San Francisco Bay Area. This will help to improve fire weather conditions throughout the area. Despite the decreasing winds, relative humidity values will remain low this afternoon. Residents should remain mindful of the continued dry conditions, and to report new fires immediately to law enforcement. $$
The office that day
Everything else NWS San Francisco Bay Area, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 14, 8:56 PM PST | Gale Warning | MTR | 54 hr | |
| Dec 15, 2:17 PM PST | Small Craft Advisory | MTR | 36 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.