FPCN39 CWLW 121446
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 SUNDAY 12 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    6     500   0     77   11    2100   5
KAMLOOPS     KEL       9    5     500   0    100   11    2950   9
OKANAGAN     KEL      11    7     800   1    100   12    3350  10
CASTLEGAR    SPOK     33    6     800   9    100   11    3500  14
CRANBROOK    SPOK     10    4     950  15    100    9    3950  14
REVELSTOKE   KEL       9    5     550   0     94    9    2450   8

*SUBTRACT 20 FROM THE VENTILATION INDEX IN VALLEYS IF THE MIXING
HEIGHT IS BELOW THE HEIGHT OF THE LOCAL HILLS.

FORECAST UPPER WINDS FOR SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    W   11   W   30   NW  50
CRANBROOK             W   20   W   54

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          550 m          6 C
SPOKANE          940 m          6 C

TODAY'S VENTING: Good. The airmass is still somewhat unstable
with moderate northwest winds in the boundary layer.

VENTING FOR MONDAY: Fair. Stable airmass as ridge builds over
the interior.  However good southerly winds expected through
the valleys.

VENTING OUTLOOK TUESDAY THRU THURSDAY: Poor to fair as a strong
ridge of high pressure becomes centered over the interior.

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.     47    0    1400  10     80    6    3950  15
PR. GEORGE   P.G.     26    1    1000   6     87    4    1950  10
SMITHERS     P.G.     26    1     900   5     72    5    1700   8
WELLS GRAY   P.G.     87    1    1950  13     70    5    1550  11
FT NLSN      F.N.      9   -8     382   2      9   -2     382   5
FT STJOHN    F.N.      9   -7     695   3     10   -1     800   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 SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            W   11   W   52
SMITHERS              S   33   SW  52

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1000 m          3 C
FT. NELSON      1500 m          2 C

TODAY'S VENTING: Good in the south. Poor in the Peace.

VENTING FOR MONDAY: Fair to good.

VENTING OUTLOOK TUESDAY THRU THURSDAY: Fair to good.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL      9    9     100   4     45   12     750   6
FRASER VLY   QUIL      9    8      50   4     41   12     650   6
SRN VRISL    QUIL      9    9     100   0     56   13     950   6
CNTRL VRISL  QUIL      9    9     150   0     25   12     500   4
NRN VRISL    HRDY     37    9     450   8     56   11     800   8
TERRACE      ANT      11    3     200  10     11    5     200  15
STEWART      ANT      14    6     150   4     11    5      50   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 SUNDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    SW  22   W   41   W   52
PORT HARDY   SW  52   W   50   W   57
SANDSPIT     SW  74   SW  72   W   76

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       3 0 m         11 C
PORT HARDY           No inversion
ANNETTE          150 m          6 C

TODAY'S VENTING: Poor to fair as overrunning warm air pushes in
aloft creating stable conditions.

VENTING FOR MONDAY: Poor to fair. A ridge of high pressure in the
south will give stable conditions and poor venting. Strong winds
in the north will be offset by limited surface heating giving
low mixing heights.

VENTING OUTLOOK TUESDAY THRU THURSDAY: Fair to good. The ridge
remains over the south while frontal systems move onto the
north coast.

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


END/DB