FPCN39 CWLW 221433
SMOKE CONTROL FORECAST FOR COASTAL BC AND THE INTERIOR INCLUDING THE
NORTHEAST ISSUED BY THE MOUNTAIN WEATHER SERVICE OFFICE OF
ENVIRONMENT CANADA AT 8:00 AM PDT Thursday 22 May 1997 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      42   13    1000   5     66   18    1900   5
KAMLOOPS     KEL      50   13    1400   5     74   18    2200   5
OKANAGAN     KEL      41   12    1150   5     74   18    2200   5
CASTLEGAR    SPOK     17   11     750   3    100   18    3500  10
CRANBROOK    SPOK      9    9     950   9    100   16    3950  13
REVELSTOKE   KEL      38   11    1150   5     62   16    1950   5


*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             VR   5   S   22

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         NO INVERSION
SPOKANE          915 m         14 C

TODAY'S VENTING: BECOMING GOOD THIS AFTERNOON.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THROUGH MONDAY: GOOD IN THE AFTERNOONS.

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.     79    7    1600  16    100   13    3950  11
PR. GEORGE   P.G.     83    8    1300  19    100   14    3700  13
SMITHERS     P.G.     56    7     950  14    100   16    3500  12
WELLS GRAY   P.G.     83    7    1850  14    100   15    4000  11
FT NLSN      F.N.     28   10     650   8    100   20    3400  10
FT STJOHN    F.N.      9    6     700   7     94   10    2350   9


*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            NE  15   E   11
SMITHERS              NE  20   NE  11

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      NO INVERSION
FT. NELSON       640 m         10 C

TODAY'S VENTING: GOOD IN THE INTERIOR.  BECOMING GOOD THIS AFTERNOON
IN THE INTERIOR.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THROUGH MONDAY: GOOD IN THE AFTERNOONS.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     83   13    1050  12    100   17    2100  13
FRASER VLY   QUIL     74   13     900  11    100   17    2000  13
SRN VRISL    QUIL     21   12     250   6    100   17    1850  13
CNTRL VRISL  QUIL     21   12     250   6    100   16    1700  12
NRN VRISL    HRDY     30   12     550   4    100   17    2150  15
TERRACE      ANT       9   13     250   6    100   21    3200   9
STEWART      ANT      12   14     100   4    100   21    3000   9


*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    VR   5   S   11   S   20
PORT HARDY   N   15   NE  15   E   28
SANDSPIT     N   39   NE  33   NE  41

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       250 m         11 C
PORT HARDY      NO INVERSION
ANNETTE          150 m         12 C

TODAY'S VENTING: BECOMING GOOD BY LATE MORNING.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THROUGH MONDAY: GOOD IN THE AFTERNOONS.

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

END/PLJ