FPCN39 CWLW 201433
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 Sunday 20 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      32   26     950   3     75   36    3200   3
KAMLOOPS     KEL      23   24     900   3     75   34    3350   3
OKANAGAN     KEL      14   22     700   2     60   32    2300   3
CASTLEGAR    SPOK     34   23    1000   5    100   33    3500   9
CRANBROOK    SPOK     59   22    1350  15    100   30    3950  10
REVELSTOKE   KEL      13   21     700   2     58   31    2300   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 SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   VR   5   SW   9
CRANBROOK             VR   5   VR   5

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1700 m         31 C
SPOKANE         1500 m         27 C

TODAY'S VENTING: good.

VENTING FOR MONDAY: good.

VENTING OUTLOOK TUESDAY THRU THURSDAY: good.


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.     22   21    1050  11    100   29    3950  12
PR. GEORGE   P.G.     17   20     900   4    100   28    3700  10
SMITHERS     P.G.     10   17     650   1    100   28    3700  10
WELLS GRAY   P.G.      9   19    1000  11    100   29    4000  12
FT NLSN      F.N.     32   18     550  15    100   25    3400   8
FT STJOHN    F.N.     59   20    1250  11    100   27    3700   7

*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   22   S   31
SMITHERS              SW  19   SW  31

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1400 m         28 C
FT. NELSON      1500 m         25 C

TODAY'S VENTING: good.

VENTING FOR MONDAY: good.

VENTING OUTLOOK TUESDAY THRU THURSDAY: good.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     43   20     550   8     44   24     600   8
FRASER VLY   QUIL     44   20     550   8     47   25     650   8
SRN VRISL    QUIL     40   17     550   7     44   23     600   7
CNTRL VRISL  QUIL     42   20     550   7     55   26     900   7
NRN VRISL    HRDY     57   16     550  12     62   19     700  11
TERRACE      ANT      10   14     250  14     85   17    1200  13
STEWART      ANT      43   15     400  10     68   17     750  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 SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    SW   9   SW  19   S   24
PORT HARDY   VR   5   S   22   S   33
SANDSPIT     SW  17   S   22   S   33

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1500 m         33 C
PORT HARDY      1500 m         30 C
ANNETTE         none

TODAY'S VENTING: only fair near water.

VENTING FOR MONDAY: good.

VENTING OUTLOOK TUESDAY THRU THURSDAY: generally good.

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

END/dsl