FPCN39 CWLW 201423
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 SUNDAY 20 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  -11     500   2     70   -9    1800  12
KAMLOOPS     KEL      35  -12     850   6     70  -10    1950  13
OKANAGAN     KEL      98  -11    1700  12     70   -9    1950  14
CASTLEGAR    SPOK    100  -12    2050  22    100   -9    2400  12
CRANBROOK    SPOK     10  -20     950  25    100  -17    2050  15
REVELSTOKE   KEL      94  -12    1650  12     70   -9    1850  14

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

FORECAST UPPER WINDS FOR SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   NW  20   N   46
CRANBROOK             N   13   N   43

TODAY'S VENTING: GOOD.



VENTING FOR MONDAY: 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  -21     950   6     28  -18    1300   6
PR. GEORGE   P.G.     14  -18     950   2     27  -16    1250   3
SMITHERS     P.G.     15  -16     950   2     16  -15    1000   2
WELLS GRAY   P.G.     15  -20     950   4     31  -17    1400   6
FT NLSN      F.N.     10  -23     400   1      9  -21     400   1
FT STJOHN    F.N.     10  -22     700  17      9  -19     700  17

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

FORECAST UPPER WINDS FOR SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            NW  24   N   54
SMITHERS              NW  48   NW  54

TODAY'S VENTING: POOR DUE TO THE PRESENCE OF A STRONG INVERSION.


VENTING FOR MONDAY: FAIR.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL    100   -4    1450  32    100   -1    1850  24
FRASER VLY   QUIL     10   -6      50  27    100   -5    1300  22
SRN VRISL    QUIL    100   -2    1650  31    100    0    1900  22
CNTRL VRISL  QUIL    100   -2    1700  31    100    0    1900  19
NRN VRISL    HRDY     14   -2     150   4     57    0     950   7
TERRACE      ANT      10  -10     200   8      9   -8     200   8
STEWART      ANT      10  -11     200   8      9   -8     200   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 SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    VR   5   N   31   N   48
PORT HARDY   NW  26   NW  43   N   59
SANDSPIT     N   41   N   54   NW  56

TODAY'S VENTING: GOOD IN THE SOUTH. POOR IN THE NORTH.



VENTING FOR MONDAY: GOOD


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


END/GF