FPCN39 CWLW 181328
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 SATURDAY 18 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      95   13     800  25    100   16    1450  25

KAMLOOPS     KEL      13   11     800  10    100   17    3350  12

OKANAGAN     KEL      11    7     500   1    100   16    3350   6

CASTLEGAR    SPOK     18    9     800   3     97   17    3500   5

CRANBROOK    SPOK      9    6     950   7    100   15    3950   6

REVELSTOKE   KEL      10    7     550   1    100   15    3450   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 SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    S    9   S   28   SW  44
CRANBROOK             VR   5   SW  19

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          940 m         12 C
SPOKANE          870 m         10 C

TODAY'S VENTING: GOOD

VENTING FOR SUNDAY: GOOD

VENTING OUTLOOK MONDAY THRU WEDNESDAY: FAIR MONDAY THEN 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.     10    9     950  25    100   13    3950  25

PR. GEORGE   P.G.      9    8     700  11     81   12    1350  17

SMITHERS     P.G.     15    9     750   3     28   11     900   5

WELLS GRAY   P.G.    100   10    4000  25    100   14    4000  25

FT NLSN      F.N.     19   10     550   6    100   18    2000  11

FT STJOHN    F.N.      9   10     700   6    100   16    2200  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 SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            S   41   S   43
SMITHERS              S   20   SW  43

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       800 m          9 C
FT. NELSON       830 m         15 C

TODAY'S VENTING: GOOD EXCEPT POOR IN THE SOUTHWEST

VENTING FOR SUNDAY: GOOD

VENTING OUTLOOK MONDAY THRU WEDNESDAY: GOOD

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     69   11     750  13    100   14    1300  18

FRASER VLY   QUIL     68   11     700  13    100   14    1250  18

SRN VRISL    QUIL     50   11     600   8     94   14    1100  14

CNTRL VRISL  QUIL     59   11     650  10     88   13    1000  14

NRN VRISL    HRDY     60    9     400  18     89   11     700  20

TERRACE      ANT      78    7     900  16     97    9    1150  17

STEWART      ANT      71    8     750  12     78    9     850  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 SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    S   35   SW  48   SW  52
PORT HARDY   W   30   W   33   SW  37
SANDSPIT     SW  31   SW  33   SW  31

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       180 m         10 C
PORT HARDY       460 m         10 C
ANNETTE         NONE

TODAY'S VENTING: GOOD

VENTING FOR SUNDAY: GOOD

VENTING OUTLOOK MONDAY THRU WEDNESDAY: GOOD

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


END/PJS