FPCN39 CWLW 201456
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 PDT SATURDAY 20 SEPTEMBER 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      29   14     800   4     50   22    1600   4
KAMLOOPS     KEL      29   14    1000   3     51   23    1800   4
OKANAGAN     KEL      26   13     900   3     49   22    1700   4
CASTLEGAR    SPOK     38   14     900   8     90   22    2150   9
CRANBROOK    SPOK      9   11     950  10     83   20    2200  10
REVELSTOKE   KEL      23   12     900   3     43   19    1600   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 SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   VR   5   SE  13
CRANBROOK             VR   5   E   15

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         2000 m         25 C
SPOKANE         1400 m         19 C

TODAY'S VENTING: FAIR IN THE SOUTHWEST BECOMING GOOD IN THE
SOUTHEAST.


VENTING FOR SUNDAY: FAIR


VENTING OUTLOOK MONDAY THRU WEDNESDAY: 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   11     950  11    100   19    3950  16
PR. GEORGE   P.G.     19   12     850   6     75   18    1750   9
SMITHERS     P.G.     11   10     650   2     65   16    1600   4
WELLS GRAY   P.G.      9   11    1000  11    100   19    4000  16
FT NLSN      F.N.     34    9    1000   8     90   18    2000  13
FT STJOHN    F.N.     65   11    1000  15    100   16    2500  18



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

FORECAST UPPER WINDS FOR SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  22   W   39
SMITHERS              SW  28   SW  39

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1000 m         16 C
FT. NELSON      MISSING        MISSING

TODAY'S VENTING: FOOD.




VENTING FOR SUNDAY: FAIR




VENTING OUTLOOK MONDAY THRU WEDNESDAY: 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   14     100   4     23   20     550   3
FRASER VLY   QUIL     15   16     200   4     68   26    1350   4
SRN VRISL    QUIL     17   15     200   5     37   22     850   4
CNTRL VRISL  QUIL     17   16     200   5     55   24    1300   4
NRN VRISL    HRDY     14   12     150   4     25   17     350   5
TERRACE      ANT      11   11     250  37    100   16    1200  34
STEWART      ANT       9   11       0  17    100   16     850  29


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

FORECAST UPPER WINDS FOR SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    VR   5   SE  17   S   11
PORT HARDY   S   11   S   19   SW  20
SANDSPIT     S   39   S   46   SW  54

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1600 m         23 C
PORT HARDY      2500 m         35 C
ANNETTE          N/A           N/A

TODAY'S VENTING:  POOR IN THE SOUTH EXCEPT GOOD IN INLAND AREAS
IN THE AFTERNOON. GOOD ON THE NORTH COAST.


VENTING FOR SUNDAY: FAIR



VENTING OUTLOOK MONDAY THRU WEDNESDAY: POOR IN THE SOUTH AND GOOD IN
THE NORTH.


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


END/GF