FPCN39 CWLW 171432
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 17 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      21   21     800   2     65   26    1400   3
KAMLOOPS     KEL      20   20     900   2     66   26    1850   4
OKANAGAN     KEL      12   18     600   1     66   26    1850   4
CASTLEGAR    SPOK     23   19     750   6     64   27    1300   5
CRANBROOK    SPOK      9   19     950   3     72   26    3950   3
REVELSTOKE   KEL       9   17     600   0     57   23    1350   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   W   13   W   13
CRANBROOK             VR   5   SW  11

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1400 m         24 C
SPOKANE         1200 m         27 C

TODAY'S VENTING: POOR THIS MORNING BECOMING GOOD
BY THE AFTERNOON WITH DAYTIME HEATING AND AS THE TROUGH
OF LOW PRESSURE MOVES THROUGH.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY:RIDGE BUILDS INTO THE INTERIOR
POOR TO FAIR EXCEPT GOOD FOR A FEW HOURS IN THE AFTERNOONS.


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.     23   14    1100   9    100   20    3950   9
PR. GEORGE   P.G.      9   12     700   6    100   20    2950   9
SMITHERS     P.G.     11   13     750   1    100   21    2850   8
WELLS GRAY   P.G.     33   14    1300   9    100   21    4000   9
FT NLSN      F.N.     70   16    1400   9    100   20    3400   9
FT STJOHN    F.N.     70   15    1700   5    100   19    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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            W   11   W   13
SMITHERS              VR   5   SW  13

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1050 m         19 C
FT. NELSON       800 m         14 C

TODAY'S VENTING: POOR THIS MORNING BEOCMING GOOD BY NOON.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY:FAIR TO GOOD AS
AS A RIDGE OF HIGH PRESSURE BUILDS BUT A SOUTHWESTERLY FLOW
REMAINS.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     20   19     450   3     55   22     750   7
FRASER VLY   QUIL     19   18     400   3     59   23     850   5
SRN VRISL    QUIL     16   18     400   2     51   22     650   7
CNTRL VRISL  QUIL     17   19     450   2     72   24    1300   7
NRN VRISL    HRDY     76   15     700  15    100   18    1100  12
TERRACE      ANT      44   15    1200   4     65   20    1500   5
STEWART      ANT      42   16     950   4     60   20    1350   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   17   W   17   W   20
PORT HARDY   NW  24   NW  19   W   19
SANDSPIT     SW  19   SW  17   SW  22

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       700 m         22 C
PORT HARDY       200 m         15 C
ANNETTE         NONE m         NONE

TODAY'S VENTING: GOOD IN THE NORTH POOR IN THE SOUTH
BECOMING FAIR IN THE AFTERNOON.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY:POOR TO FAIR
BECOMING FAIR IN THE AFTERNOONS IN THE SOUTH.
FAIR TO GOOD IN THE NORTH AS CONDITONS REMAIN UNSETTLED.

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

END/LM