FPCN39 CWLW 181423
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 FRIDAY 18 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      52    1     500  18     73   -2    1550  15
KAMLOOPS     KEL      21   -1     500  12     71   -4    1650  11
OKANAGAN     KEL      10   -3     450   8     71   -4    1500   9
CASTLEGAR    SPOK      9   -1     500  13     78   -2    1300  13
CRANBROOK    SPOK     79   -3    1550  17     79   -6    1550  17
REVELSTOKE   KEL      10   -1     500   9     70   -3    1850  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 FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   NE  24   NE  33
CRANBROOK             E   17   E   37

TODAY'S VENTING: GOOD

VENTING FOR SATURDAY: FAIR TO GOOD

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.     24  -13     800  10     40  -15    1200  12
PR. GEORGE   P.G.     22  -14     800  12     48  -16    1250  10
SMITHERS     P.G.     36   -8    1200   3     36   -8    1500   3
WELLS GRAY   P.G.     22  -10    1100   8     45  -12    1200   8
FT NLSN      F.N.      9  -21     400   5     15  -19     550   4
FT STJOHN    F.N.     52  -20    1050  14     52  -20    1050  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 FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            NE  30   N   31
SMITHERS              E   44   NE  31

TODAY'S VENTING: FAIR

VENTING FOR SATURDAY: FAIR TO POOR

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL      9    8     100  11     78    9     1250   9
FRASER VLY   QUIL      9    8      50  11     70    9     1200  10
SRN VRISL    QUIL     12    9     100  10     62   10     1450  12
CNTRL VRISL  QUIL      9    6      50   9     86    8     1450   9
NRN VRISL    HRDY     14    5     100  12     90   7    1200   11
TERRACE      ANT       9    0     200   9     88    2    1150   14
STEWART      ANT       9    0     200   9     71    2      50    8


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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    NE  37   E   44   E   33
PORT HARDY   E   28   E   28   NE  26
SANDSPIT     NE  43   NE  61   NE  61

TODAY'S VENTING: GOOD

VENTING FOR SATURDAY: FAIR

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

END/MWSO