California Air Resources Board - Meteorology Section
Basinwide Ag-Burn Acreage Allocation - Sacramento Valley Air Basin

Date:  25-May-15 Local Time:  07:22 AM Meteorologist:  Mims
Ag Burn Decision Above 3000 ft:  Permissive Burn Day (Fair)    
A.M. Stability (°F) = 8 Wind Speed (mph)  = 7
500 millibar height (decameters) = 573 Average Rainfall (in) = 0
Meteorological (MET) Factor   = 0.5
Air Quality (AQ) Factor (Basinwide 00-06 PST Average PM2.5) = 8.2
Allocation Equation: = 6487
   
ARB REVISED Basinwide Allocation _________________________________________ = 3000
Revised Allocation _________________________________________ = 3000
District Yesterday's
24-Hr Avg
PM2.5
Yesterday's
PM2.5
(0-6 PST)
Reduction
Factor
Proration Final
Allocation
(Acres)
Avg PM2.5
(0-6 PST)
Conc Stn
Colusa 12 12 1 0.17 370 11 COL
Sutter 10 10 1 0.17 370 0 YUB
Butte 8 7 1 0.17 370 8 CIC-GRD
Yolo/Solano 0 0 1 0.15 350 0 DAV-WOO
Glenn 7 9 1 0.13 330 6 WLW
Sacramento 9 9 1 0.09 290 9 SAC
Yuba 10 10 1 0.07 270 0 YUB
Placer 8 7 1 0.05 250 7 ROS
Tehama 7 9 1 200 acres
unless reduced
by PM
200 6 WLW
Shasta 11 11 1 200 8 AND
When any district's 0-6 am average PM2.5 is >= 27 ug/m increasing concentrations will result in a reduction
in allocation acres (e.g. 27-28 : 20%, 29-30 : 40%, 31-32 : 60%, 33-34 : 80%)
ARB Comments
Cautionary Comments:
***Permissive Burn Day ***
Subtle changes again as a transitory low pressure system deepens the marine layer and returns southerly flow to the valley. Temperatures and mixing will lower a bit in response to this marine push. Thunderstorms remain in forecast as the low pressure system spins up activity.

24hr Outlook
***Permissive Burn Day***
Not much change over the next 24 hours as the main large scale features stay put. By midweek models are forecasting the ridge to expand, which will help shut down the onshore flow and produce the some of the warmest afternoon temps we’ve seen this spring…..
Mixing Height Discussion:
Valley: Mixing heights over 2,000 feet by early afternoon.
Winds:
Valley: South-Southeasterly early 5-12 mph gusting to 15 mph, turning South-Southwesterly 5-10 mph this afternoon.
Delta: Breezy Southwesterlies 10-25 mph.