Red Flag Warning 4, NWS San Francisco Bay Area, CA

Issued

Sep 5, 2012, 10:46 AM PDT (17:46 UTC)

In effect from

Sep 5, 2012, 5:00 PM PDT

Expired

Sep 6, 2012, 2:58 AM PDT

In force

10 hr

Issued by

NWS San Francisco Bay Area, CA

Counties Alameda County, CA, Contra Costa County, CA, Marin County, CA, Napa County, CA, Sonoma County, CA

The Sacramento radar (KDAX), 73 km from the middle of the area, began a volume at 17:49 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.

455 
WWUS86 KMTR 051746
RFWMTR

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
1046 AM PDT WED SEP 5 2012

...RED FLAG WARNING IN EFFECT FOR WEDNESDAY AFTERNOON THROUGH
THURSDAY MORNING...

.AMPLE UPPER LEVEL MOISTURE COMBINED WITH INCREASING INSTABILITY
WILL PROVIDE A CHANCE FOR HIGH BASED THUNDERSTORMS WEDNESDAY
AFTERNOON THROUGH THURSDAY MORNING FOR PORTIONS OF THE NORTH AND
EAST BAY. ANY DEVELOPED STORMS WILL BE CAPABLE OF PRODUCING NUMEROUS
CLOUD TO GROUND LIGHTNING STRIKES. ADDITIONALLY...A VERY DRY AIRMASS
REMAINS IN PLACE AND STORM MOTION WILL BE RATHER QUICK THUS
LIMITING THE CHANCE FOR A WETTING RAIN. THEREFORE...GUSTY OUTFLOW
WINDS WILL BE POSSIBLE WITH DEVELOPED STORMS.

CAZ506-507-510-511-060600-
/O.NEW.KMTR.FW.W.0004.120906T0000Z-120906T1800Z/
NORTH BAY INTERIOR VALLEYS-NORTH BAY MOUNTAINS-
EAST BAY INTERIOR VALLEYS-EAST BAY HILLS AND DIABLO RANGE-
1046 AM PDT WED SEP 5 2012

...RED FLAG WARNING IN EFFECT FROM 5 PM THIS AFTERNOON TO 11 AM
PDT THURSDAY FOR THUNDERSTORMS WITH DRY LIGHTNING FOR THE NORTH
BAY VALLEYS AND MOUNTAINS AND EAST BAY INTERIOR VALLEYS AND MOUNTAINS...

THE NATIONAL WEATHER SERVICE THE SAN FRANCISCO BAY AREA HAS
ISSUED A RED FLAG WARNING...WHICH IS IN EFFECT FROM 5 PM THIS
AFTERNOON TO 11 AM PDT THURSDAY. 

* AFFECTED AREA: FIRE ZONE 506 NORTH BAY INTERIOR VALLEYS...
  FIRE ZONE 507 NORTH BAY MOUNTAINS...FIRE ZONE 510 EAST BAY 
  INTERIOR VALLEYS...FIRE ZONE 511 EAST BAY HILLS AND DIABLO 
  RANGE.

* TIMING: WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING.

* THUNDERSTORMS: ISOLATED SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH
  WEDNESDAY AFTERNOON INCREASING IN COVERAGE WEDNESDAY EVENING
  THROUGH THURSDAY MORNING.

* OUTFLOW WINDS: GUSTY OUTFLOW WINDS UP TO 40 MPH WILL BE POSSIBLE
  WITH THE STRONGEST STORMS.

* IMPACTS:THE COMBINATION OF DRY LIGHTNING STRIKES AND LOW
  RELATIVE HUMIDITY IN THE NORTH AND EAST BAY WILL CREATE
  CRITICAL FIRE WEATHER CONDITIONS. 


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 WILL
CREATE EXPLOSIVE FIRE GROWTH POTENTIAL.

&&

$$


HTTP://WEATHER.GOV/SANFRANCISCO

585 
WWUS86 KMTR 060958
RFWMTR

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
258 AM PDT THU SEP 6 2012

CAZ506-507-510-511-061100-
/O.CAN.KMTR.FW.W.0004.000000T0000Z-120906T1800Z/
NORTH BAY INTERIOR VALLEYS-NORTH BAY MOUNTAINS-
EAST BAY INTERIOR VALLEYS-EAST BAY HILLS AND DIABLO RANGE-
258 AM PDT THU SEP 6 2012

...RED FLAG WARNING IS CANCELLED FOR ZONES 506...507...510 AND
511...

THE NATIONAL WEATHER SERVICE THE SAN FRANCISCO BAY AREA HAS
CANCELLED THE RED FLAG WARNING. 

THUNDERSTORMS HAVE GREATLY DECREASED OVERNIGHT AND ONLY A SLIGHT CHANCE
OF SHOWERS OR THUNDERSTORMS REMAINS FOR OUR AREA. THEREFORE...THE
RED FLAG WARNING HAS BEEN CANCELLED.

$$


HTTP://WEATHER.GOV/SANFRANCISCO

Red Flag Warnings in California, 2012Every red flag warning in 2012

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.