FPCN39 CWLW 211448
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 PST SUNDAY 21 DECEMBER 1997 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    1     200   5     55    4    1050   5
KAMLOOPS     KEL       9    2     350   5     60    4    1100   8
OKANAGAN     KEL       9    2     350   5     60    4    1100   8
CASTLEGAR    SPOK     51    2    1200   7     69    4    1350  10
CRANBROOK    SPOK     33   -3    1150  12     80    2    1800  13
REVELSTOKE   KEL       9    1     450   5     17    2     600   5


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

FORECAST UPPER WINDS FOR SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    NW   9   NW  26   NW  43
CRANBROOK             W   11   NW  31

TODAY'S VENTING: BECOMING GOOD THIS AFTERNOON.


VENTING FOR MONDAY: FAIR.



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   -3    1900  31    100   -1    3950  27
PR. GEORGE   P.G.     49   -3     950  19     85   -2    1250  22
SMITHERS     P.G.      9   -8     500   7     49   -4     700   7
WELLS GRAY   P.G.    100   -3    2150  30    100   -1    4000  27
FT NLSN      F.N.     47  -16     650  17     47  -14     700  16
FT STJOHN    F.N.     53   -5     900  24     48   -6     900  24


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

FORECAST UPPER WINDS FOR SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            W   24   W   48
SMITHERS              SW  35   SW  48

TODAY'S VENTING: GOOD IN THE CENTRAL INTERIOR EXCEPT FAIR IN THE
NORTHWEST. FAIR EAST OF THE ROCKIES.


VENTING FOR MONDAY: GOOD


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     53    6     300  23     60    8    1200  14
FRASER VLY   QUIL     25    3     150  23     60    7     600  10
SRN VRISL    QUIL      9    3     150   0     49    6     250   5
CNTRL VRISL  QUIL      9    4     150   0     39    5     200   5
NRN VRISL    HRDY      9    3       0  16     34    4     200  16
TERRACE      ANT       9   -1     200   4      9    0     200   4
STEWART      ANT      11    1      50   4     10    0      50   4


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

FORECAST UPPER WINDS FOR SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    NW   9   NW  19   NW  31
PORT HARDY   S   44   SW  39   W   31
SANDSPIT     S   54   SW  54   SW  57

TODAY'S VENTING: GOOD IN THE LOWER MAINLAND. FAIR TO POOR ELSEWHERE.


VENTING FOR MONDAY: GOOD


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


END/GF