FPCN39 CWLW 251405
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 PST THURSDAY 25 MARCH 1999 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       9    9     200   4     56   13    1650   4
KAMLOOPS     KEL      51   11    1600   4     63   15    2150   4
OKANAGAN     KEL      26    9     800   4     57   13    1850   4
CASTLEGAR    SPOK      9    8     500   3     19   12     850   3
CRANBROOK    SPOK      9    9     950  17    100   12    2250  21
REVELSTOKE   KEL       9    6     450   4     10    7     500   4

*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    SW   9   SW  20   SW  41
CRANBROOK             SW  19   SW  56

TODAY'S VENTING: FAIR TO GOOD.

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.    100    5    1750  25    100   10    3950  29
PR. GEORGE   P.G.     85    5    1300  21    100   10    3700  28
SMITHERS     P.G.     12    4     650   3     87    8    1550  13
WELLS GRAY   P.G.    100    5    1800  25    100   10    4000  29
FT NLSN      F.N.     41    7     650  13     84   11    1100  17
FT STJOHN    F.N.     29    6     750  30    100    9    1250  33

*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            S   44   SW  61
SMITHERS              S   48   SW  61

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    100    8    1300  17    100   11    2050  18
FRASER VLY   QUIL     56    7     500  13    100   11    2000  18
SRN VRISL    QUIL     78    8     800  14    100   11    1900  17
CNTRL VRISL  QUIL    100    9    1450  16    100   11    1950  17
NRN VRISL    HRDY     31    6     600   4     55    9    1450   4
TERRACE      ANT      10    2     200  15    100    5     950  30
STEWART      ANT      10    2      50  12     70    5     450  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
VANCOUVER    S   35   S   46   SW  54
PORT HARDY   SW  37   SW  50   SW  65
SANDSPIT     SW  46   SW  52   SW  52

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: GOOD.


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


END/MWSO