FPCN39 CWLW 241432
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 Thursday 24 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      39   19     950   4    100   27    3200   6
KAMLOOPS     KEL      48   19    1250   5    100   25    3350   6
OKANAGAN     KEL      38   18    1100   4    100   26    3350   6
CASTLEGAR    SPOK     37   20     950   7    100   27    2650  19
CRANBROOK    SPOK     33   19    1100  15    100   26    3950  22
REVELSTOKE   KEL      24   16     850   4    100   22    3450   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    W    9   W   17   W   24
CRANBROOK             W   11   W   24

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          600 m         15 C
SPOKANE         1200 m         22 C

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: GOOD.

VENTING OUTLOOK SATURDAY THRU MONDAY: DECREASING TO FAIR BY MONDAY.


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   12    2050  20    100   18    3950  17
PR. GEORGE   P.G.     90   13    1550  17    100   17    3700  16
SMITHERS     P.G.     12   12     650   3    100   17    2350  13
WELLS GRAY   P.G.    100   15    4000  17    100   20    4000  17
FT NLSN      F.N.      9   14     400  22    100   20    2450  22
FT STJOHN    F.N.      9   14     700  23    100   19    3700  22

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

FORECAST UPPER WINDS FOR THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            W   26   W   31
SMITHERS              W   24   NW  31

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       900 m         14 C
FT. NELSON       700 m         18 C

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: GOOD.

VENTING OUTLOOK SATURDAY THRU MONDAY: GOOD.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    HRDY     64   18    1350   6    100   22    2550   8
FRASER VLY   HRDY     68   19    1500   6    100   25    2700   8
SRN VRISL    HRDY     27   16     650   3     86   21    1900   7
CNTRL VRISL  HRDY     63   18    1300   6    100   24    2650   8
NRN VRISL    HRDY     12   15     200   2     63   18    1250   6
TERRACE      ANT      86   16    1450  11    100   21    3200  13
STEWART      ANT      72   17    1100   8    100   21    3000  11

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

FORECAST UPPER WINDS FOR THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   20   W   26   W   33
PORT HARDY   NW  26   NW  31   NW  37
SANDSPIT     W   30   W   33   NW  35

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      missing
PORT HARDY       200 m         16 C
ANNETTE          100 m         14 C

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: GOOD.

VENTING OUTLOOK SATURDAY THRU MONDAY: GOOD.

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

END/DSL