FPCN39 CWLW 011430 AAA
REVISED SMOKE CONTROL FORECAST FOR COASTAL BC AND THE INTERIOR
INCLUDING THE NORTHEAST ISSUED BY THE MOUNTAIN WEATHER SERVICE OFFICE
OF ENVIRONMENT CANADA AT 7.27 AM PDT THURSDAY 1 OCTOBER 1998 FOR
TODAY.

VENTILATION INDICES (TEMPERATURE) AND MIXING HEIGHTS.
MIXING HEIGHTS IN METRES ABOVE SEA LEVEL.
AVERAGE WINDS IN KNOTS.

SPOT INDICES ARE DETERMINED BY THE ASPECT AND ELEVATION OF THE SITES.
COMPARE WINDS, TEMPERATURES AND ELEVATION WITH THE SITES HERE
TO DETERMINE THE INDEX IN ANY OTHER AREA.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     54   13     450  16     87   16     900  16
FRASER VLY   QUIL     53   13     400  16     90   17     950  16
SRN VRISL    QUIL      9   12     200   0     30   16     900  10
CNTRL VRISL  QUIL      9   13     350   0     30   16     900  10
NRN VRISL    HRDY     15   12     150   4     24   14     350   5
TERRACE      ANT      81   11    1350  10     97   13    1700  11
STEWART      ANT      17   11     200   4     80   13    1300   8

*SUBTRACT 20 FROM THE VENTILATION INDEX IN VALLEYS IF THE MIXING
HEIGHT IS BELOW THE HEIGHT OF THE LOCAL HILLS.

FORECAST UPPER WINDS FOR THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    SW  28   SW  44   SW  52
PORT HARDY   SW  19   W   24   W   31
SANDSPIT     SW  35   SW  33   SW  31

TODAY'S VENTING: POOR

VENTING FOR FRIDAY: POOR

VENTILATION GUIDELINES:
          0-33.....POOR
          34-54.....FAIR
          55-100.....GOOD.
VENTILATION INDICES NORMALLY DROP TO POOR AFTER SUNSET.


END/LEC