FPCN39 CWLW 171547
SMOKE CONTROL FORECAST FOR COASTAL BC AND THE INTERIOR INCLUDING THE
NORTHEAST ISSUED BY THE MOUNTAIN WEATHER SERVICE OFFICE OF
ENVIRONMENT CANADA AT 7:50 AM PST THURSDAY 17 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      77    9    1000  12    100    9    2000  12
KAMLOOPS     KEL       9    3     350   7    100    5    2650  10
OKANAGAN     KEL      19    4     500   7    100    5    2650  10
CASTLEGAR    SPOK     17    3     750   3    100    4    2800  13
CRANBROOK    SPOK     42    3    1100  27    100    4    2100  27
REVELSTOKE   KEL      12    3     500   7    100    3    2500  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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    NW  11   NW  30   NW  48
CRANBROOK             W   20   W   48

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: 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.     87   -2     300  15    100  -12    1500  12
PR. GEORGE   P.G.     72    0     300  13    100  -13    1500  10
SMITHERS     P.G.      9   -3     500   6    100  -12    1500  10
WELLS GRAY   P.G.      9   -3     500   8    100  -10    1450   9
FT NLSN      F.N.     78  -15     850  23     78  -15    1850  23
FT STJOHN    F.N.    100   -5    1500  33    100   -2    1800  31

*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            N   35   N   37
SMITHERS              NW  30   N   37

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: FAIR TO GOOD.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL      9    8     100  19     38    9     250  19
FRASER VLY   QUIL      9    8      50  19     30    9     200  19
SRN VRISL    QUIL     12    9     100   4     62   10     450  17
CNTRL VRISL  QUIL      9    6      50   4     86    8     750  19
NRN VRISL    HRDY     14    5     100   8    100    7    1200  21
TERRACE      ANT       9    0     200   9     88    2    1150  14
STEWART      ANT       9    0     200   9     11    2      50   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
VANCOUVER    W   39   NW  57   NW  65
PORT HARDY   NW  48   NW  67   NW  70
SANDSPIT     NW  52   NW  61   N   70

TODAY'S VENTING: POOR BECOMING GOOD BY EARLY AFTERNOON.

VENTING FOR FRIDAY: GOOD.

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

END/JDG