FPCN39 CWLW 121442
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 Tuesday 12 August 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      20   26     900   2     36   32    1500   2
KAMLOOPS     KEL      14   22     650   2     32   30    1450   2
OKANAGAN     KEL      11   21     600   1     32   30    1450   2
CASTLEGAR    SPOK     15   21     800   2     62   30    1750   6
CRANBROOK    SPOK      9   20     950   8     95   27    3950   5
REVELSTOKE   KEL      10   19     550   1     24   27    1200   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 TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   NW  11   NW  19
CRANBROOK             VR   5   W   19

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1280 m         28 C
SPOKANE         1040 m         26 C

TODAY'S VENTING: A strong inversion will preclude good venting
from developing at all but the highest elevations.

VENTING FOR WEDNESDAY: Fair to poor.

VENTING OUTLOOK THURSDAY THRU SATURDAY:
Fair to good venting as nocturnal inversion becomes weaker.

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   21     950  11    100   28    3950  14
PR. GEORGE   P.G.     13   19     750   8    100   26    2550  11
SMITHERS     P.G.     13   19     700   2     56   26    1300   8
WELLS GRAY   P.G.     10   19    1000  11    100   28    4000  14
FT NLSN      F.N.     53   19     600  24    100   26    2200  20
FT STJOHN    F.N.     ##   ##     ###  ##    100   26    3700  18

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

FORECAST UPPER WINDS FOR TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            W   20   NW  26
SMITHERS              W   19   W   26

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       945 m         24 C
FT. NELSON       850 m         24 C

TODAY'S VENTING:
The inversion is shallow enough to allow breathrough to occur
in the afternoon. Low level winds from the northwest will also
aid in the venting.

VENTING FOR WEDNESDAY: Fair to good.

VENTING OUTLOOK THURSDAY THRU SATURDAY:
Generally good.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     54   20     600  11     63   25     750  11
FRASER VLY   QUIL     55   20     600  11     68   28     800  11
SRN VRISL    QUIL     23   19     500   3     51   26     750   7
CNTRL VRISL  QUIL     45   22     650   7     53   28     800   7
NRN VRISL    HRDY      9   16       0   8     42   20     400  10
TERRACE      ANT      60   21     700  14    100   27    2350  14
STEWART      ANT      19   19     150   7    100   27    2100  12

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

FORECAST UPPER WINDS FOR TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   11   NW  13   NW  17
PORT HARDY   N   37   NW  30   NW  24
SANDSPIT     NW  30   NW  31   NW  33

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       910 m         29 C
PORT HARDY      1130 m         29 C
ANNETTE          400 m         22 C

TODAY'S VENTING:
Over northern areas, a weak inversion and moderate northwesterly
winds will allow for good venting. To the south the inversion is
stronger and this will allow for mostly fair venting today.

VENTING FOR WEDNESDAY: Fair to poor.

VENTING OUTLOOK THURSDAY THRU SATURDAY:
Fair to poor Thursday. Fair to good Friday and Saturday.

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

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