FPCN39 CWLW 131336
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 13 AUGUST 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      13   25     550   1     75   37    3200   3
KAMLOOPS     KEL      11   22     500   1     75   35    3350   3
OKANAGAN     KEL      11   22     500   1     75   35    3350   3
CASTLEGAR    SPOK     19   23     750   4     64   36    3500   2
CRANBROOK    SPOK      9   20     950   3     57   33    3950   2
REVELSTOKE   KEL      10   21     500   1     55   33    2200   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   VR   5   W   13
CRANBROOK             W   11   W   13

TODAY'S VENTING: POOR BECOMING GOOD THIS AFTERNOON.


VENTING FOR FRIDAY: 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.     30   17    1200   9    100   28    3950  11
PR. GEORGE   P.G.      9   16     700   2     97   25    2750   8
SMITHERS     P.G.      9   16     550   2     75   23    1950   7
WELLS GRAY   P.G.     59   18    1850   8    100   29    4000  11
FT NLSN      F.N.     25   13     450  20    100   22    2300  21
FT STJOHN    F.N.      9   15     700  20    100   24    3700  20

*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              S   20   SW

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     28   21     400   6     36   27     550   6
FRASER VLY   QUIL     33   23     500   6    100   32    1650  12
SRN VRISL    QUIL     16   18     300   3     27   23     500   4
CNTRL VRISL  QUIL     26   23     500   4    100   33    1750  11
NRN VRISL    HRDY      9   16       0   5     32   20     500   6
TERRACE      ANT      70   16    1000  11    100   22    1750  12
STEWART      ANT      54   17     800   7    100   22    1650  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   15   NW  13   NW  17
PORT HARDY   W   13   W   26   W   39
SANDSPIT     SW  22   SW  30   SW  37

TODAY'S VENTING: GOOD EXCEPT POOR IN AREAS NEAR THE WATER.



VENTING FOR FRIDAY: GOOD



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


END/GF