176 TABLE 63. SrratiricaTion TaBuLaTion Prepiction TEcHNIQUE BanpDs FOR Wixp Direction AND Hour or Day | | number Winddirection, degrees I iI 55-105 205-355 5-15 115-195 2 15-135 275-355 145-265 5 | 914! 1-8 15-24 3 355 5-195 205-345| , 220) 1 21-24 4 5-135 145-265 275-325; 1-4 165-205 245-255 45-95 135-155 5-45 105-125 1-3 5-6 15-55 5 145-285 295-325 335-345 355 65-135 1 6 7 8 335-355 215-235 265-355 | III Hour (CST) or TAM station 25-45 1 | ou | III 1-2 t-17 18-24 | j 9-10} 12-24 APPLICATION OF 5-35 75-125 | 315-355 TABULATION 1-6 11-15; 17-24 PREDUCTION used because of the developmental nature of this work; but a municipality may use this form as a guide in tailoring one to its own needs. The symbol Prb stands for the probability estimate of the forecast verification. | 17-24 4 7-8 After the forecast values are received, a clerk may use the 50 percentile entry of the Tabulation Preduction Scheme Tables to enter the predicted SOs concentration or those of another pollutant of interest and present these to the meteorologist. Ordinarily, municipal air pollution control agencies 1 1-7 14-22) 23-24 5-65 225-265 75-215) 24 275-325 335-345 355 | 45-65 135-305 5-16 3-5 in Figure 138, This form has been in use in test operations with Murray and Trettel, Inc. providing the hourly forecasts and the Argonne National Laboratory and the City of Chicago Department of Air Pollution Control adapting the forecasts for operational use, More variables are indicated than were actually will find it uneconomical to employ a complete forecasting staff. Hourly forecasts will, therefore, be ob- 8-13 of one or two meteorologists employed by the air pollu- 1 10-16 5-9 19-22 17-18 23-24 7-10 16 SCHEME tained from an organization like the U. 8. Weather Bureau or a private meteorological firm. The services TO tion control agency would be used to interpret the forecasts of both the weather and pollutant concen- tration for action by appropriate officials. The municipal meteorologist would determine whether an air pollution incident was probable within the forecast period. His access to the latest upper air and surface weather charts enables him to judge whether (1) a land-sea breeze will develop, (2) a thunderstorm is likely, (3) precipitation or fog will appear, (4) a frontal system will pass, or (5) DAILY OPERATIONS Since the variables used in the Tabulation Pre- diction Scheme are wind direction, wind speed, temperature, ceiling heights, and hour of day, these are the variables (except of course the hour of day) for which forecasts are required. The forecasts should be made for each hour and the range of the group interval, e.g., a wind speed forecast over the range of 4-7 miles per hour, should correspond to the ranges in the Tabulation Prediction Scheme. The forecast for the day should preferably be made between 0700 and 0800 so that the severity of the early morning pollution peak will be covered. Forecasts for 12 to 24 hours are reasonably routine. These forecasts may be issued every 6, 12, or 24 hours, depending on the local needs. Of course, during potential or actual severe pollution conditions, constant surveillance is necessary. A format for recording the forecasts and the com- puted and observed pollution concentrations is shown TABLED 64. Units anp Group INTERVALS FOR VARIABLES USED IN THE TABULATION PREDICTION SCHEME 1. Wind speed Unit: miles per hour Group interval: 0-3, 4—7, 8—12, 13—18, 19—24, >24 2. Wind direction Unit: degrees Group interval: 10-degree grouping : 5—14, 15—24, 25—35, ete., or aceording to band widths of Table 63. 3, Temperature Unit: °F Group interval: —20— —11, —10—-—1, 0—-9, 10—19, 20-29, 30-39, 40—49, 50—59, 60—69, 70—79, 80-89, 90—-99 4. Ceiling height Unit: feet Group interval: 0—-999, 1000—2499, 2500—6999, > 7000 5. Hour of day Unit: one hour Group interval: one hour intervals centered on the hour; or according to band width of Table 63.