FPCN39 CWLW 201334
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 SATURDAY 20 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      65    4     500  15     70    5    1400  15
KAMLOOPS     KEL      19    3     550  10     70    3    1500  15
OKANAGAN     KEL      15    1     450   5     65    3    1500  10
CASTLEGAR    KEL       9    0     495   2     42    2    1500   6
CRANBROOK    SPOK      9   -2     940   3     20    2    1300   8
REVELSTOKE   KEL      12    1     500   5     22    1    1200   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 SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   SW  20   W   48
CRANBROOK             W   15   W   43

TODAY'S VENTING: Poor in the east and fair to good west.

VENTING FOR SUNDAY: 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.     10    0     950  30     10    0     950  30
PR. GEORGE   P.G.     10   -1     700  19     10   -1     700  19
SMITHERS     P.G.      9   -4     500   3      9   -4     500   3
WELLS GRAY   P.G.    100    1    1800  32     94    0    1500  32
FT NLSN      F.N.     16  -17     650   3     17  -16     650   3
FT STJOHN    F.N.      9   -1     700  11      9   -1     700  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 SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            NW  30   NW  30
SMITHERS              NW  33   NW  30

TODAY'S VENTING: Poor locally fair or better at higher elevations.

VENTING FOR SUNDAY: POOR


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     11    8     100  38    100   10    1000  38
FRASER VLY   QUIL     11    5      50  38     11    6      50  38
SRN VRISL    QUIL     38    8     200  16    100   10     850  27
CNTRL VRISL  QUIL      9    7      50  16     40    8     250  16
NRN VRISL    HRDY      9    2     200  15     38    5     400  15
TERRACE      ANT       9    0     200   9      9    1     200   9
STEWART      ANT       9    1       0   1      9    1       0   1

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

FORECAST UPPER WINDS FOR SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   30   W   37   W   39
PORT HARDY   NW  37   NW  39   NW  35
SANDSPIT     NW  33   NW  33   NW  33

TODAY'S VENTING: Poor inner coastal inlets and valleys.
Fair to good along outer coast.

VENTING FOR SUNDAY: Poor south. Fair north.


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


END/KAL