FPCN39 CWLW 031431
SMOKE CONTROL FORECAST FOR COASTAL BC AND THE INTERIOR INCLUDING THE
NORTHEAST ISSUED BY THE MOUNTAIN WEATHER SERVICE OFFICE OF
ENVIRONMENT CANADA AT 8:00 AM PDT Wednesday 3 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      16   20     500   2     48   28    1550   3
KAMLOOPS     KEL      14   19     600   2     47   27    1700   3
OKANAGAN     KEL      14   19     600   2     47   27    1700   3
CASTLEGAR    SPOK     25   20     750   6     43   27    1300   5
CRANBROOK    SPOK      9   20     950   4     56   26    2500   4
REVELSTOKE   KEL      18   19     750   3     38   24    1350   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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   W   13   W   20
CRANBROOK             VR   5   SW  13

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1500 m         25 C
SPOKANE         1500 m         26 C

TODAY'S VENTING: Becoming fair to good in the late afternoon.

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY: Fair to good in the
afternoons.

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   14     950   5    100   23    3950   9
PR. GEORGE   P.G.      9   11     700   3     31   21    1300   4
SMITHERS     P.G.     14   12     750   2     35   19    1700   3
WELLS GRAY   P.G.      9   15    1000   5    100   24    4000   9
FT NLSN      F.N.      9   13     400  17     59   20     750  17
FT STJOHN    F.N.      9   15     700  17    100   21    3700  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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW   9   SW  20
SMITHERS              S   19   S   20

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1300 m         22 C
FT. NELSON       820 m         21 C

TODAY'S VENTING: Becoming fair to good in the mid afternoon.

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY: Generally fair in the
afternoons.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     50   18     700   8     63   22    1250   6
FRASER VLY   QUIL     50   18     700   8     70   24    1500   6
SRN VRISL    QUIL     43   18     650   6     62   23    1350   5
CNTRL VRISL  QUIL     36   17     600   5     62   23    1400   5
NRN VRISL    HRDY      9   14       0   5     46   20     850   6
TERRACE      ANT      11   15     250  39    100   19    1700  36
STEWART      ANT       9   14       0  17    100   19    1200  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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    SW  11   W   13   SW  24
PORT HARDY   S   26   S   37   S   43
SANDSPIT     S   33   S   39   S   46

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1500 m         23 C
PORT HARDY       425 m         17 C
ANNETTE          none          none

TODAY'S VENTING: Becoming good in the late afternoon except
only fair over northern Vancouver Island.

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY: Good as a trough moves
through on the weekend.

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

END/lm