[conspire] Donner und blitzen

[Tim Utschig]

On Sat, Sep 12, 2009 at 05:51:11AM -0700, Rick Moen wrote:
> I've been up in the middle of the night on account of 24x7 on-call
> sysadmin duties, and -- wow! -- there's thunder and lightning out
> there.  What is this, September in Ohio?


Over here in south Fremont we were woken by same.  My wife said, "If it
was thunder, there'd be rain.  Must have been a plane."  A few louder
batches of rolling thunder soon followed.


> Looking out at my back porch, where CABAL meets during dry weather,
> I see dry pavement.  So, if it rained at all, it must have been
> light and brief -- and then evaporated already.  
> 
> National Weather Service has, at the moment, an almost perfectly
> useless forecast for our address:  "Slight chance of showers and
> thunderstorms (20%), high of 29 degrees C / 29 degrees C / 84
> degrees F.  Some of the storms could produce small hail.  Mostly
> cloudy.  West wind between 8 and 21 km/h (5 and 13 mph)."
> 
> Gee, thanks, NWS.


I visited the NWS web site last night as well and saw a red swath
painted from Oregon to the bay area on the map of the US.  I clicked it
and read the following (this is an older version of the warning which
was current last night):

  http://www.wrh.noaa.gov/total_forecast/getprod.php?prod=XXXRFWMTR&wfo=mtr&version=4

  "WWUS86 KMTR 120546
  RFWMTR
  
  RED FLAG WARNING
  NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
  1046 PM PDT FRI SEP 11 2009
  
  ...RED FLAG WARNING FOR DRY LIGHTNING TONIGHT THROUGH SATURDAY MORNING...
  
  CAZ505>507-511-512-517-121800-
  /O.CON.KMTR.FW.W.0002.000000T0000Z-090912T1800Z/
  COASTAL NORTH BAY...INCLUDING POINT REYES NATIONAL SEASHORE-
  NORTH BAY INTERIOR VALLEYS-NORTH BAY MOUNTAINS-
  EAST BAY HILLS AND DIABLO RANGE-SANTA CRUZ MOUNTAINS-
  SANTA LUCIA MOUNTAINS AND LOS PADRES NATIONAL FOREST-
  1046 PM PDT FRI SEP 11 2009
  
  ...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT SATURDAY...
  
  A RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 AM PDT SATURDAY. 
  
  THE RED FLAG WARNING IS IN EFFECT FOR THE COASTAL HILLS OF
  MONTEREY COUNTY...THE SANTA CRUZ MOUNTAINS...THE EAST BAY HILLS
  AND DIABLO RANGE OF SANTA CLARA COUNTY AND THE ENTIRE NORTH BAY
  INCLUDING POINT REYES NATIONAL SEASHORE AND THE INTERIOR VALLEYS.
  
  MOISTURE AND INSTABILITY WILL CONTINUE TO INCREASE ACROSS THE
  REGION. LATEST DATA INDICATES A HIGH POTENTIAL FOR LIGHTNING
  STRIKES TO DEVELOP OVER THE OCEAN LATER THIS AFTERNOON OR EVENING.
  THEN THE MAINLY DRY THUNDERSTORMS ARE FORECAST TO TRACK OVER MUCH
  OF THE SAN FRANCISCO BAY AREA. THE LOWER ATMOSPHERE IS EXPECTED TO
  REMAIN FAIRLY DRY WITH ANY LIGHTNING STRIKES BRINGING AN INCREASED
  LIKELIHOOD OF NEW FIRE STARTS GIVEN THE VERY DRY FUEL BEDS.
  
  THE THREAT OF DRY THUNDERSTORMS IS EXPECTED TO DEVELOP WEST OF
  BIG SUR AND THEN SPREAD NORTHWARD OVER THE SANTA CRUZ MOUNTAINS
  AND INTO THE NORTH BAY OVERNIGHT INTO EARLY SATURDAY MORNING. BY
  MIDDAY SATURDAY ANY THREAT OF DRY LIGHTNING IS EXPECTED TO BE
  NORTH OF THE AREA.
  
  PRECAUTIONARY/PREPAREDNESS ACTIONS...
  
  A RED FLAG WARNING MEANS THAT CRITICAL FIRE WEATHER CONDITIONS
  ARE EITHER OCCURRING NOW...OR WILL SHORTLY. A COMBINATION OF DRY
  LIGHTNING...LOW RELATIVE HUMIDITY...AND WARM TEMPERATURES WILL
  CREATE EXPLOSIVE FIRE GROWTH POTENTIAL."


-- 
   - Tim Utschig <tim at tetro.net>