FPCN39 CWLW 251430
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 Friday 25 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      67   18    1450   6    100   26    3200   9
KAMLOOPS     KEL      93   19    2300   8    100   25    3350   9
OKANAGAN     KEL      93   19    2300   8    100   26    3350   9
CASTLEGAR    SPOK     24   19    1000   3     72   27    3500   3
CRANBROOK    KEL     100   18    3950  10    100   25    3950  10
REVELSTOKE   KEL      70   16    1750   7    100   21    3450   9

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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   W   13   W   19
CRANBROOK             W    9   W   19

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         NONE
SPOKANE         1500 m         22 C

TODAY'S VENTING: GOOD.

VENTING FOR SATURDAY: GOOD.

VENTING OUTLOOK SUNDAY THRU TUESDAY: DECREASING TO FAIR BY TUESDAY.


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.     76   12    1650  14    100   18    3950  15
PR. GEORGE   P.G.     44   13    1200   8    100   18    3700  13
SMITHERS     P.G.     35   14    1100   5    100   18    2350  10
WELLS GRAY   P.G.    100   15    4000  15    100   20    4000  15
FT NLSN      F.N.     36   17     550  18    100   22    3400  17
FT STJOHN    F.N.      9   14     700  17    100   20    3700  16

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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            W   20   W   22
SMITHERS              W   17   W   22

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1300 m         15 C
FT. NELSON       600 m         18 C

TODAY'S VENTING: GOOD.

VENTING FOR SATURDAY: GOOD.

VENTING OUTLOOK SUNDAY THRU TUESDAY: GENERALLY GOOD.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    HRDY     87   17    1100  13    100   21    1900  13
FRASER VLY   HRDY     87   17    1100  13    100   24    2400  12
SRN VRISL    HRDY     77   16     900  12    100   22    2000  13
CNTRL VRISL  HRDY     87   17    1050  13    100   22    2000  13
NRN VRISL    HRDY     63   15     700  11     92   18    1150  13
TERRACE      ANT      51   15    1250   5     83   18    2150   6
STEWART      ANT      35   15     700   4     61   18    1500   5

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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   17   W   19   NW  22
PORT HARDY   W   19   NW  20   NW  28
SANDSPIT     W   20   W   19   W   22

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      MISSING
PORT HARDY      NONE
ANNETTE         NONE

TODAY'S VENTING: GOOD.

VENTING FOR SATURDAY: GOOD.

VENTING OUTLOOK SUNDAY THRU TUESDAY: GOOD EXCEPT BECOMING
FAIR IN THE SOUTH BY TUESDAY.

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

END/DSL