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

Date:  22-Jul-14 Local Time:  07:20 AM Meteorologist:  Branz
Ag Burn Decision Above 3000 ft:  Permissive Burn Day (Fair)    
A.M. Stability (°F) = 4 Wind Speed (mph)  = 14
500 millibar height (decameters) = 584 Average Rainfall (in) = 0
Meteorological (MET) Factor   = 0.85
Air Quality (AQ) Factor (Basinwide 00-06 PST Average PM2.5) = 5.3
Allocation Equation: = 7668
   
ARB REVISED Basinwide Allocation _________________________________________ = 4000
Revised Allocation _________________________________________ = 4000
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 8 1 0.17 540 6 COL
Sutter 6 6 1 0.17 540 9 YUB
Butte 4 3 1 0.17 540 5 CIC-GRD
Yolo/Solano 3 4 1 0.15 500 3 DAV-WOO
Glenn 7 4 1 0.13 460 6 WLW
Sacramento 2 2 1 0.09 380 2 SAC
Yuba 6 6 1 0.07 340 9 YUB
Placer 6 7 1 0.05 300 4 ROS
Tehama 7 4 1 200 acres
unless reduced
by PM
200 6 WLW
Shasta 11 9 1 200 10 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***
Another wave rounding the base of a Pacific NW trough will move northward today, bringing continued onshore flow to the Valley. Some showers and isolated thunderstorms have developed ahead of this feature and will affect the western half of the Valley this morning. Expect mid-level clouds to mix out this afternoon. Overall...expect similar conditions to yesterday with good dispersal and decent southerly flow.

***24 Hour + Outlook****
***Permissive Burn Day****
Onshore flow will continue on Wednesday, leading to similar conditions. AM stability will be a tad higher however as a ridge tries to build northward behind the departing Pacific NW trough. High pressure will start to build for Thursday, and that trend will continue through the weekend. Expect a gradual warming trend for that time period with another possible shot of monsoonal moisture late in the weekend.
Mixing Height Discussion:
Valley: Mixing heights will be over 2000 feet by afternoon.
Winds:
North Valley: South to southeasterly 10-15 mph
South Valley: South to southwesterly 10-15 mph with gusts to 25 mph
Delta: West to southwest 15-20 mph, gusting to 30 mph