FPCN39 CWLW 121400
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 FRIDAY 12 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    2     200   2     36    8    1650   2

KAMLOOPS     KEL      27    5    1300   5     43    8    1700  12

OKANAGAN     KEL      17    4     750   2     38    6    1600   7

CASTLEGAR    SPOK     23    2     950   3     31    5    1300   3

CRANBROOK    SPOK     17   -3    1000   5     40    0    1450   7

REVELSTOKE   KEL       9    2     450   2     24    4    1250   2


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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    S    9   SW  37   SW  70
CRANBROOK             W   17   W   59

TODAY'S VENTING: FAIR TO POOR

VENTING FOR SATURDAY: POOR

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.     23    2    1250  12     58    8    1350  25

PR. GEORGE   P.G.     21    5     700  14     55    6    1000  20

SMITHERS     P.G.     17    3     700   8     36    5    1000  10

WELLS GRAY   P.G.     42    4    1300  15     62    6    1400  25

FT NLSN      F.N.      9    0     400  10     19    4     500  10

FT STJOHN    F.N.     22    3     700  10     59    6    1200  18


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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  91   SW 139
SMITHERS              SW  78   SW 139

TODAY'S VENTING: FAIR TO GOOD.


VENTING FOR SATURDAY: FAIR




COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     20    5     150  20     30   10     200  20

FRASER VLY   QUIL     24    5     150  20     31    9     200  20

SRN VRISL    QUIL     18    5     150   8     22   10     200  12

CNTRL VRISL  QUIL     12    3      50   8     17    5     150  10

NRN VRISL    HRDY     56    9     300  23     62   10     350  25

TERRACE      ANT       9    1     200  43     21    3     250  30

STEWART      ANT       9    3       0  22     16    5       0  10


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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    S   50   SW  72   SW  83
PORT HARDY   S  109   S  132   S  139
SANDSPIT     SW  67   SW  70   SW  78

TODAY'S VENTING: POOR LOCALLY GOOD

VENTING FOR SATURDAY: FAIR TO POOR

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


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