FPCN39 CWLW 231339
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 23 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      16   14     500   2     89   20    1300  15
KAMLOOPS     KEL      14   15     700   2     86   20    1400  12
OKANAGAN     KEL      12   11     500   2     77   18    1200  12
CASTLEGAR    SPOK      9   12     500  15     72   16    1100  15
CRANBROOK    SPOK     10   12     950  23     76   16    1600  15
REVELSTOKE   KEL      10   11     500   2     54   15    1000  10

*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   S   13
CRANBROOK             SE   9   SE  24

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1600 m         22 C
SPOKANE         1700 m         21 C

TODAY'S VENTING: GOOD

VENTING FOR FRIDAY: FAIR

VENTING OUTLOOK SATURDAY THRU MONDAY: FAIR

CENTRAL INTERIOR/NORTHEAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
WILLIAMS L   KEL       9   10     950   4    100   17    3500  12
PR. GEORGE   F.N.     34   10     900  13    100   17    3700  11
SMITHERS     ANT      51    8    1700   4    100   15    3500  12
WELLS GRAY   F.N.     98   10    2600  10    100   18    4000  10
FT NLSN      F.N.      9    6     400  13     53   11     800  13
FT STJOHN    F.N.     28    9     850  13    100   12    2250  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
PR. GEORGE            S    9   S   22
SMITHERS              S   11   S   22

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      MISSING
FT. NELSON      1200 m         14 C

TODAY'S VENTING: GOOD LOCALLY FAIR

VENTING FOR FRIDAY: FAIR

VENTING OUTLOOK SATURDAY THRU MONDAY: FAIR

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     67   13     800  11     71   15     850  11
FRASER VLY   QUIL     68   13     800  11     73   16     900  11
SRN VRISL    QUIL     59   13     800   9     64   16     900   9
CNTRL VRISL  QUIL     57   12     750   9     64   16     900   9
NRN VRISL    HRDY     51    8     550  10     77   11     950  11
TERRACE      ANT      26    9    1100   2    100   14    2700   9
STEWART      ANT      16   10     700   1     95   14    2450   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   19   W   19   SW  26
PORT HARDY   W   19   W   17   SW  22
SANDSPIT     W   13   VR   5   S   11

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1600 m         22 C
PORT HARDY      1100 m         12 C
ANNETTE         1200 m         12 C

TODAY'S VENTING: GOOD

VENTING FOR FRIDAY: FAIR TO POOR

VENTING OUTLOOK SATURDAY THRU MONDAY: FAIR

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


END/