FPCN39 CWLW 181442
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 18 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      18    2     500   3     20    4     550   3
KAMLOOPS     KEL      14    1     500   3     20    4     650   4
OKANAGAN     KEL      13    0     450   3     20    4     650   4
CASTLEGAR    SPOK     38    1     900   8     43    2    1000   8
CRANBROOK    SPOK     30   -1    1050  21     38    0    1100  21
REVELSTOKE   KEL      12    1     550   3     12    2     550   3

*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   N   11   NW  15
CRANBROOK             NW   9   NW  20

TODAY'S VENTING: Poor.

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.      9   -7     950  10      9   -3     950  10
PR. GEORGE   P.G.      9   -5     700   6      9   -4     700   6
SMITHERS     P.G.     10   -7     600   1     12   -2     750   1
WELLS GRAY   P.G.     48   -3    1450  10     48   -3    1450  10
FT NLSN      F.N.      9  -20     400  10     17  -18     450  10
FT STJOHN    F.N.      9   -9     700  10      9   -8     700  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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  13   W   15
SMITHERS              S   35   S   15

TODAY'S VENTING: Poor.

VENTING FOR FRIDAY: Fair.




COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     45    6     450  11     98    8    1350  13
FRASER VLY   QUIL     31    5     250  11     96    8    1250  13
SRN VRISL    QUIL     16    4     200   4     71    8    1000   9
CNTRL VRISL  QUIL     13    3     150   4     18    5     250   4
NRN VRISL    HRDY      9    3       0   2     15    6     350   2
TERRACE      ANT       9    0     200  12      9    1     200  12
STEWART      ANT       9    0       0   5      9    1       0   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
VANCOUVER    VR   5   VR   5   NW  11
PORT HARDY   S   41   S   39   SW  28
SANDSPIT     S   96   S   93   S   78

TODAY'S VENTING: Good on the outer coast otherwise poor.

VENTING FOR FRIDAY: Good.


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


END/kal