FPCN39 CWLW 211433
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 SUNDAY 21 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       9   15     650   0      9   24    1400   0
KAMLOOPS     KEL       9   16     900   0      9   25    1500   0
OKANAGAN     KEL       9   15     800   0      9   24    1450   0
CASTLEGAR    SPOK     14   15     800   2     30   23    1150   3
CRANBROOK    SPOK      9   12     950   9     42   20    1350   9
REVELSTOKE   KEL       9   10     500   0      9   20    1300   0

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

FORECAST UPPER WINDS FOR SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   SE   9   SE   9
CRANBROOK             VR   5   E    9

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1600 m         27 C
SPOKANE         1600 m         24 C

TODAY'S VENTING: POOR


VENTING FOR MONDAY: POOR



VENTING OUTLOOK TUESDAY THRU THURSDAY: 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   15     950  17    100   22    2200  16
PR. GEORGE   P.G.     21   13     800  10     67   20    1300  13
SMITHERS     P.G.     14   12     700   3     50   18    1200   7
WELLS GRAY   P.G.      9   14    1000  17     98   21    2000  17
FT NLSN      F.N.      9   10     400  12     89   15    1650  11
FT STJOHN    F.N.     82   13    1900   9    100   20    3700   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 SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            S   15   SW  20
SMITHERS              S   26   S   20

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1200 m         19 C
FT. NELSON       500 m         13 C

TODAY'S VENTING: GENERALLY GOOD.




VENTING FOR MONDAY: FAIR TO POOR.




VENTING OUTLOOK TUESDAY THRU THURSDAY: FAIR TUESDAY AND WEDNESDAY.
GOOD THURSDAY.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     13   16     200   4     27   21     500   5
FRASER VLY   QUIL     15   17     200   4     37   25     800   4
SRN VRISL    QUIL     15   15     150   4     30   22     550   4
CNTRL VRISL  QUIL     15   16     200   4     33   24     650   4
NRN VRISL    HRDY     13   14     400   1     14   18     550   1
TERRACE      ANT      78   14     800  19    100   20    1950  15
STEWART      ANT      66   15     600  13    100   20    1900  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 SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    SE  17   S   30   S   24
PORT HARDY   SE  24   S   43   S   41
SANDSPIT     S   46   S   61   S   61

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1300 m         28 C
PORT HARDY      1000 m         23 C
ANNETTE         NONE           N/A

TODAY'S VENTING: POOR IN THE SOUTH. GOOD IN THE NORTH.



VENTING FOR MONDAY: POOR IN THE SOUTH. GOOD IN THE NORTH.



VENTING OUTLOOK TUESDAY THRU THURSDAY: REMAINING POOR IN THE SOUTH.
CONTINUING 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