FPCN39 CWLW 161423
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 16 OCTOBER 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       9   13     500   0     20   15     600   3
KAMLOOPS     KEL       9   13     600  10     19   15     750   3
OKANAGAN     KEL       9   11     500   0     21   16     800   3
CASTLEGAR    SPOK      9   10     800   4     34   14     900   7
CRANBROOK    SPOK      9    8     950   4      9   13     950   8
REVELSTOKE   KEL       9    9     500   0      9    9     500   0

*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   SW  24   SW  50
CRANBROOK             SW  15   W   46

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          850 m         16 C
SPOKANE         1400 m         24 C

TODAY'S VENTING: Poor. Strong inversion and light boundary
layer winds over the area.

VENTING FOR FRIDAY: Poor to fair. Weak frontal zone crossing
the area with give better mixing and improve boundary layer
circulation.

VENTING OUTLOOK SATURDAY THRU MONDAY: Poor as surface ridge
becomes established giving strong inversions and light winds.

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.     30   12    1100  15     50   14    3950  15
PR. GEORGE   P.G.      9   10     700  16      9   11     700  16
SMITHERS     P.G.      9    7     500   8     20   12     650   8
WELLS GRAY   P.G.     30    8    1000   8    100   14    4000  15
FT NLSN      F.N.     29   -1     800   5     31    3     850   5
FT STJOHN    F.N.     28    9    1050   6     34   11    1150   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
PR. GEORGE            W   22   W   44
SMITHERS              SW  31   SW  44

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1000 m         16 C
FT. NELSON      1400 m         19 C

TODAY'S VENTING: Good at elevations above 1000 metres. Otherwise
poor due to the inversion.

VENTING FOR FRIDAY: Fair to good.

VENTING OUTLOOK SATURDAY THRU MONDAY: Poor as surface ridge becomes
established.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     11   14     150   4     17   15     300   4
FRASER VLY   QUIL      9   12      50   4     13   15     150   4
SRN VRISL    QUIL      9   12       0   0      9   15     150   0
CNTRL VRISL  QUIL      9   13     100   0      9   14     100   0
NRN VRISL    HRDY     17   13     150   5     27   14     300   7
TERRACE      ANT      11    9     250  20     11   10     250  20
STEWART      ANT      14   11      50  15      9   10       0  15

*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    SW  24   SW  43   SW  57
PORT HARDY   W   17   W   28   W   39
SANDSPIT     SW  41   SW  46   SW  52

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       350 m         19 C
PORT HARDY      No inversion
ANNETTE         No inversion

TODAY'S VENTING: Poor. Strong inversions in the south and
weak surface heating in the north.

VENTING FOR FRIDAY: Poor as a ridge of high pressure becomes
established over the area.

VENTING OUTLOOK SATURDAY THRU MONDAY: Generally poor.

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


END/DB