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

Date:  21-Sep-20 Local Time:  06:46 AM Meteorologist:  Mims
Ag Burn Decision Above 3000 ft:  Marginal Burn Day    
A.M. Stability (F) = 13 Wind Speed (mph)  = 7
500 millibar height (decameters) = 584 Average Rainfall (in) = 0
Meteorological (MET) Factor   =
Air Quality (AQ) Factor (Basinwide 00-06 PST Average PM2.5) = 43.2
Allocation Equation: =
   
ARB/SMPC REVISED Basinwide Allocation _________________________________________ = 0
District Yesterday's
24-Hr Avg
PM2.5
Yesterday's
PM2.5
(0-6 PST)
Reduction
Factor
Yesterday's
PM2.5
MAX
Hour of
Yesterday's
MAX
Avg PM2.5
(0-6 PST)
Conc Stn
Colusa 42 28 0 73 13 47 COL
Butte 46 25 0 88 17 53 CIC-GRD
Glenn 51 57 0 77 19 59 WLW
Placer 38 30 0 98 19 35 ROS
Sacramento 41 29 0 92 17 39 SAC
Sutter 37 35 0 53 22 43 YUB
Yolo/Solano 25 21 0.4 39 8 32 DAV-WOO
Yuba 37 35 0 53 22 43 YUB
Tehama - - 1 - - - RBL
Shasta 23 15 0 50 21 42 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:
*** No Burn Day ***
Not much change early as we close out summer 2020. Light winds and weak ridging continues the high PM 2.5 numbers and no burn conditions. Winds shift to an onshore gradient this afternoon, pushing some of the smoke eastward. But, the hazy conditions with impacts close to the fires should continue since we have so much smoke in the valley to start with.

24hr Outlook
*** No Burn Day***
Even more of a delta influence tomorrow as another weak trough moves towards California. This is part of a larger system hat will bring some much needed rain north of the region later. Not expecting much in the valley, but any moisture should help firefighters. The warm up that follows by this weekend should start our fall, north winds season.
Mixing Height Discussion:
Valley: Mixing heights will reach 2500 feet.
Winds:
Valley: Light and Variable to 5 mph early, the Southerly 5-15 mph.
Delta: Southwesterly 5-15 mph, gusting to 20 mph by afternoon.
Complaints: Col Sut But Yol Gle Sac Yub Pla Teh Sha Total
18-Sep-20 0 0 0 0 0 0 0 0 0 0 0
19-Sep-20 0 0 0 0 0 0 0 0 0 0 0
20-Sep-20 0 0 0 0 0 0 0 0 0 0 0







Data Table
21-Sep-20 Date
06:46 AM Local Time
Mims Meteorologist
Marginal Burn Day Ag Burn Decision Above 3000 ft
13 A.M. Stability (F)
7 Wind Speed (mph)
584 500 millibar height (decameters)
0 Average Rainfall (in)
Meteorological (MET) Factor
43.2 Air Quality (AQ) Factor (Basinwide 00-06 PST Average PM2.5)
Allocation Equation:
0 ARB/CCO REVISED Basinwide Allocation