FPCN39 CWLW 291437
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 MONDAY 29 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      48   16     900   5     60   21    1700   7
KAMLOOPS     KEL      30   14     700   4     81   21    2150   6
OKANAGAN     KEL      30   13     650   4     53   19    1600   4
CASTLEGAR    SPOK      9   14     500   3     31   18     950   5
CRANBROOK    SPOK      9   10     950   4     70   17    1650   8
REVELSTOKE   KEL       9   12     450   1     11   15     750   1

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

FORECAST UPPER WINDS FOR MONDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    S    9   SW  26   SW  56
CRANBROOK             W   15   W   44

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          800 m         16 C
SPOKANE         1000 m         18 C

TODAY'S VENTING: Fair to poor venting this morning becoming
fair to good except remaining poor in some eastern valleys this
afternoon.

VENTING FOR TUESDAY: FAIR

VENTING OUTLOOK WEDNESDAY THRU FRIDAY: Good as the airmass is
unstable.

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    7    1000   3     90   16    2950   7
PR. GEORGE   P.G.      9    7     700   5     90   17    2700  10
SMITHERS     P.G.      9    6     600   2     65   12    1500   5
WELLS GRAY   P.G.      9    4    1000   7    100   14    4000  16
FT NLSN      F.N.      9    8     400   5    100   13    1250  15
FT STJOHN    F.N.      9    9     700   3     85   16    3700  15

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

FORECAST UPPER WINDS FOR MONDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            S   15   S   24
SMITHERS              SE  11   S   24

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      760 m          8 C
FT. NELSON      600 m         11 C

TODAY'S VENTING: Poor becoming fair to good by the late afternoon.

VENTING FOR TUESDAY: FAIR


VENTING OUTLOOK WEDNESDAY THRU FRIDAY:Good as the airmass is
unstable.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     22   15     300   5     48   18     900   6
FRASER VLY   QUIL     28   15     300   6     55   20    1000   6
SRN VRISL    QUIL     24   15     300   4     52   19     950   6
CNTRL VRISL  QUIL     30   14     300   2     44   18     850   5
NRN VRISL    HRDY     30   15     300   4     66   16     900   9
TERRACE      ANT      15    8     240   3     70   14    2050   5
STEWART      ANT      15    9     300   3     52   14    1550   3

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

FORECAST UPPER WINDS FOR MONDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    S   24   SW  48   SW  67
PORT HARDY   S   39   S   46   SW  59
SANDSPIT     NE  35   E   30   E   24

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1200 m         24 C
PORT HARDY       920 m         17 C
ANNETTE         1200 m         10 C

TODAY'S VENTING: Poor becoming good by mid to late afternoon as
the winds develop.

VENTING FOR TUESDAY: FAIR

VENTING OUTLOOK WEDNESDAY THRU FRIDAY:Fair to good in strong winds.

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


END/lm