FPCN39 CWLW 041342
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 4 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    0     200   3     33    3    1050   3
KAMLOOPS     KEL       9   -1     500   3     31    3    1150   3
OKANAGAN     KEL       9    0     550   3     31    3    1150   3
CASTLEGAR    SPOK     20    1     850   3     23    3     950   3
CRANBROOK    SPOK      9   -5     950   4     11   -4     950   4
REVELSTOKE   KEL       9   -1     550   5     36    0    1050   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   VR   5   VR   5
CRANBROOK             VR   5   VR   5

TODAY'S VENTING: POOR

VENTING FOR FRIDAY: 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.      9   -4     950   6      9    1     950   7
PR. GEORGE   P.G.     18   -5     850   5     22   -2     900   7
SMITHERS     P.G.     22   -2     850   4     22   -2     850   4
WELLS GRAY   P.G.      9   -2    1000   7      9    1    1000   7
FT NLSN      F.N.      9  -10     400   4      9   -8     400   4
FT STJOHN    F.N.      9   -6     700   4      9   -3     700   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  20   SW  30
SMITHERS              SW  33   SW  30

TODAY'S VENTING: POOR

VENTING FOR FRIDAY: POOR

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL      9    6     100   6     15    9     150   8
FRASER VLY   QUIL      9    7      50   6     16   10     150   8
SRN VRISL    QUIL      9    6       0   6     19    9     150   8
CNTRL VRISL  QUIL      9    6      50   6     17    8     100   9
NRN VRISL    HRDY     30    8     250  10     46    9     450  10
TERRACE      ANT      13    2     250  12     12    3     250   9
STEWART      ANT      10    2      20  10     12    4      50   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
VANCOUVER    E   20   SE   9   VR   5
PORT HARDY   S   26   S   19   S   22
SANDSPIT     VR   5   S   19   S   33

TODAY'S VENTING: POOR

VENTING FOR FRIDAY: POOR

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


END/mwso