FPCN39 CWLW 311428
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 THURSDAY 31 DECEMBER 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.

SOUTHERN INTERIOR

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
FRSR CANYN   KEL      15    3     500   2    100    6    2500  15
KAMLOOPS     KEL      14    3     700   2    100    4    2500  15
OKANAGAN     KEL      14    2     550   2    100    5    2500  15
CASTLEGAR    SPOK     19    3     750   4    100    4    2500  15
CRANBROOK    SPOK      9   -1     950  16      9    1     950  16
REVELSTOKE   KEL       9    0     450   2     12    1     550   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    W   20   W   39   NW  74
CRANBROOK             W   24   W   70

TODAY'S VENTING: BECOMING GOOD THIS AFTERNOON EXCEPT REMAINING
POOR NEAR THE ROCKIES.

VENTING FOR FRIDAY: 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.     10    2     950  17    100    3    2400  20
PR. GEORGE   P.G.      9    0     700  11    100    0    2500  21
SMITHERS     P.G.      9   -2     500   1    100   -2    2500  15
WELLS GRAY   P.G.      9   -3    1100   2    100    3    2500  20
FT NLSN      F.N.     20  -23     750   3     30  -22     950   4
FT STJOHN    F.N.     47  -19    1300   7     48  -18    1350   7


*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            W   65   W   85
SMITHERS              W   46   W   85

TODAY'S VENTING: BECOMING GOOD THIS AFTERNOON EXCEPT REMAINING POOR
IN THE NORTHEAST.

VENTING FOR FRIDAY: POOR TO FAIR.




COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL    100    8    2000  15    100    9    2500  15
FRASER VLY   QUIL    100    7    2000  15    100    9    2500  15
SRN VRISL    QUIL    100    9    2000  15    100    9    2500  15
CNTRL VRISL  QUIL    100    6    2000  15    100    8    2500  15
NRN VRISL    HRDY    100    5    2000  15    100    7    2500  15
TERRACE      ANT     100    1    2000  11    100    3    2500  15
STEWART      ANT     100    0    2000  11    100    3    2500  15


*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    W   37   NW  61   NW  96
PORT HARDY   W   41   W   59   NW  91
SANDSPIT     W   33   W   54   W   82

TODAY'S VENTING: GOOD.




VENTING FOR FRIDAY: FAIR.




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


END/MWSO