FPCN39 CWLW 231323
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 THURSDAY 23 JULY 1998 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      17   26     550   2    100   37    3200  15
KAMLOOPS     KEL      13   23     550   2     57   36    3350   2
OKANAGAN     KEL      13   23     550   2     45   35    2400   2
CASTLEGAR    SPOK     17   23     750   3     96   33    3500   5
CRANBROOK    SPOK      9   19     950   2    100   31    3950   6
REVELSTOKE   KEL      10   21     500   2     34   32    1800   2

*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    VR   5   SW   9   SW  13
CRANBROOK             VR   5   W   11

TODAY'S VENTING: FAIR TO GOOD.

VENTING FOR FRIDAY: FAIR.




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   18     950   8    100   29    3950  12
PR. GEORGE   P.G.     12   19     750   4     82   27    2300   7
SMITHERS     P.G.     11   19     700   1     56   27    1550   6
WELLS GRAY   P.G.      9   20    1000   8    100   31    4000  12
FT NLSN      F.N.     17   19     600   4     57   26    1600   5
FT STJOHN    F.N.     11   19     750   4    100   25    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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE
SMITHERS              W   20   W

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: GOOD.




COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     67   18     650  14     75   23     750  14
FRASER VLY   QUIL     72   21     700  14     97   30    1650  10
SRN VRISL    QUIL     24   16     550   3     29   22     750   3
CNTRL VRISL  QUIL     28   21     700   3     88   30    1550   9
NRN VRISL    HRDY     30   15     400   6     54   18     750   9
TERRACE      ANT      38   17     800   6     95   23    1950   9
STEWART      ANT      22   17     450   3     80   23    1650   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   13   W   15   W   19
PORT HARDY   W   11   W   15   W   20
SANDSPIT     SW  31   SW  35   SW  41

TODAY'S VENTING: FAIR TO GOOD.

VENTING FOR FRIDAY: FAIR.




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


END/JDG