FPCN39 CWLW 231431
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 23 July 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      54   20    1300   5    100   27    3200   6
KAMLOOPS     KEL      57   20    1650   5    100   27    3350   6
OKANAGAN     KEL      56   17    1200   5     97   25    2950   6
CASTLEGAR    SPOK     35   15     800   5    100   27    3500   9
CRANBROOK    SPOK      9   18     950   9    100   26    3950  11
REVELSTOKE   KEL      31   16     900   5     74   21    2150   6

*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    W    9   W   20   W   31
CRANBROOK             W   11   W   28

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1400 m         18 C
SPOKANE         1040 m         22 C

TODAY'S VENTING: Fair to poor this morning becoming good
in the afternoon.

VENTING FOR THURSDAY: fair

VENTING OUTLOOK FRIDAY THRU SUNDAY: fair to good in the afternoons
with convection developing with daytime heating.

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.    100   13    2400   7    100   18    3950  15
PR. GEORGE   P.G.    100   14    1900  10    100   19    3700  15
SMITHERS     P.G.     32   13     850   7    100   18    2700  10
WELLS GRAY   P.G.    100   14    4000  15    100   19    4000  21
FT NLSN      F.N.     41   15     500  10     63   18     650  10
FT STJOHN    F.N.     11   15     700  10    100   20    3700  20

*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            W   31   W   44
SMITHERS              W   28   W   44

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      880 m         14 C
FT. NELSON      640 m         18 C

TODAY'S VENTING: good in the central interior by mid morning as
once the inversion breaks and the winds are brought down.
Poor in the Peace becoming good as the winds increase this afternoon.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY: Fair to good in the afternoons
with convection developing with daytime heating.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     68   19    1050   8     82   22    1500   8
FRASER VLY   QUIL     68   19    1050   8     95   26    2000   8
SRN VRISL    QUIL     45   17     750   6     66   21    1150   7
CNTRL VRISL  QUIL     62   19    1000   7     88   25    1850   7
NRN VRISL    HRDY      9   14     100   6     62   17    1150   6
TERRACE      ANT      86   14    1150  13    100   16    1750  15
STEWART      ANT      44   14     450   9     88   16    1150  12

*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    W   17   W   24   W   39
PORT HARDY   W   20   W   26   W   39
SANDSPIT     W   30   W   31   W   39

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1200 m          19 C
PORT HARDY       210 m          15 C
ANNETTE         none m         none

TODAY'S VENTING:  Fair to good on the south coast. Poor over
northern Vancouver Island this morning then becoming good
in the afternoon with daytime heating.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY: Fair to good.

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

END/lm