FPCN39 CWLW 121344
SMOKE CONTROL FORECAST FOR COASTAL BC AND THE INTERIOR INCLUDING THE
NORTHEAST ISSUED BY THE MOUNTAIN WEATHER SERVICE OFFICE OF
ENVIRONMENT CANADA AT 7:00 AM PDT THURSDAY 12 AUGUST 1999 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.

SOUTHERN INTERIOR

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
FRSR CANYN   KEL       9   20     200   6    100   26    2050  10
KAMLOOPS     KEL       9   19     350   6    100   26    3350  12
OKANAGAN     KEL      32   20     650   9    100   27    3350  12
CASTLEGAR    SPOK     83   20    1450  12    100   25    1950  15
CRANBROOK    SPOK     86   19    1650  18    100   22    2400  18
REVELSTOKE   KEL      24   19     650   9    100   24    2150  11

*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
PENTICTON    VR   5   SW  15   SW  19
CRANBROOK             SW  11   W   30

TODAY'S VENTING:  LOCALLY POOR TO FAIR THROUGH SOME VALLEYS EARLY
THIS MORNING OTHERWISE GOOD.




VENTING FOR FRIDAY: GOOD

CENTRAL INTERIOR/NORTHEAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
WILLIAMS L   P.G.    100   18    3950   6    100   21    3950   6
PR. GEORGE   P.G.     98   18    3700   6     98   19    3700   6
SMITHERS     P.G.     44   19    1700   4     84   19    3500   4
WELLS GRAY   P.G.     50   19    1800   7    100   21    4000   6
FT NLSN      F.N.     95   20    1800  11    100   21    2300  11
FT STJOHN    F.N.    100   19    3700  11     93   17    1850  13

*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
PR. GEORGE            N   11   NE   9
SMITHERS              NE  13   E    9

TODAY'S VENTING: GOOD BY LATE MORNING.




VENTING FOR FRIDAY: GOOD

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     71   18     850  11     83   19    1150  11
FRASER VLY   QUIL     82   19    1100  11     82   19    1100  11
SRN VRISL    QUIL     61   18     750   9     74   19    1000  10
CNTRL VRISL  QUIL     62   18     800   9     95   21    1550  10
NRN VRISL    HRDY     32   14     500   4     44   16     650   6
TERRACE      ANT      14   14     250   5     24   19     550   5
STEWART      ANT      12   13     200   3     18   18     300   3

*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    S   11   S   19   SW  22
PORT HARDY   VR   5   VR   5   E   13
SANDSPIT     N   31   N   31   N   31

TODAY'S VENTING: GOOD EXCEPT POOR TO FAIR NORTH ISLAND AND NORTH
COAST.




VENTING FOR FRIDAY: GOOD SOUTH. POOR TO FAIR NORTH.




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

END/TCS