FPCN39 CWLW 211336
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 TUESDAY 21 APRIL 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   15     600   2     75   20    1550   7

KAMLOOPS     KEL      43   17    1050   6    100   21    3350  11

OKANAGAN     KEL      12   12     500   2     75   19    1700   7

CASTLEGAR    SPOK     19   10     750   4     68   17    1700   4

CRANBROOK    SPOK      9    9     950  13    100   17    2350  13

REVELSTOKE   KEL      10   10     500   2     38   16    1000   6


*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   SW  15   SW  30
CRANBROOK             SW  11   SW  28

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          820 m         15 C
SPOKANE         1005 m         16 C

TODAY'S VENTING: GOOD EXCEPT FAIR IN THE COLUMBIAS

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY: 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.      9    5     700   5     60   13    1200   7

PR. GEORGE   KEL       9    9     700   7     55   14    1200   7

SMITHERS     P.G.      9    5     700   5     50    9    1200   7

WELLS GRAY   KEL       9    9    1000   7    100   15    4000  15

FT NLSN      F.N.      9    5     400   1     65   12    2600   3

FT STJOHN    F.N.     63    9    2600   4     88   13    3700   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 TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  20   SW  31
SMITHERS              S   22   SW  31

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      MISSING
FT. NELSON       530 m          9 C

TODAY'S VENTING: GOOD EXCEPT ONLY FAIR IN THE NORTHWEST

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY: GOOD

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     77   12     700  16    100   15    1300  18

FRASER VLY   QUIL     89   13     850  17    100   17    2000  18

SRN VRISL    QUIL     63   12     600  12     99   15    1150  15

CNTRL VRISL  QUIL     22   10     300   5     90   14    1000  15

NRN VRISL    HRDY     25    9     200  10    100   12    1400  13

TERRACE      ANT      10    7     250  23    100   11    1850  25

STEWART      ANT      25    8     100  15    100   11    1450  23


*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    VR   5   S   13   SW  33
PORT HARDY   S   15   S   20   S   33
SANDSPIT     S   48   S   52   S   54

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      NONE
PORT HARDY       130 m          9 C
ANNETTE           60 m          8 C

TODAY'S VENTING: GOOD

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY:GOOD

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


END/PJS