FPCN39 CWLW 311440
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 PST WEDNESDAY 31 DECEMBER 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    5     200   3    100    8    1050  20
KAMLOOPS     KEL       9    3     350   3     16    5     550   3
OKANAGAN     KEL       9    4     350   3     70    6     900  15
CASTLEGAR    SPOK     29    3     900   6     30    4     900   6
CRANBROOK    SPOK      9    0     950  19     61    5    1300  19
REVELSTOKE   KEL       9    2     450   3      9    2     450   3

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

FORECAST UPPER WINDS FOR WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    SW   9   W   30   W   72
CRANBROOK             W   24   W   67

TODAY'S VENTING: Fair in western valleys otherwise poor.

VENTING FOR THURSDAY: Fair.


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.      9    1     950  23      9    3     950  23
PR. GEORGE   P.G.      9    3     700  20      9    3     700  20
SMITHERS     P.G.      9   -1     500   8      9    0     500   8
WELLS GRAY   P.G.     10    2    1000  23     10    3    1000  23
FT NLSN      F.N.     63  -21     750  19      9  -22     400  18
FT STJOHN    F.N.     89  -16    1700  14     90  -15    1700  14

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

FORECAST UPPER WINDS FOR WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            NW  20   W   28
SMITHERS              NW  11   W   28

TODAY'S VENTING: Poor except good east of the Rockies.

VENTING FOR THURSDAY: Fair.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     10    5     150   2     13    7     250   2
FRASER VLY   QUIL      9    4      50   2     12    6     200   2
SRN VRISL    QUIL     11    6     150   1     11    7     250   1
CNTRL VRISL  QUIL     11    7     250   1     12    8     300   1
NRN VRISL    HRDY      9    8       0   4      9    8       0   4
TERRACE      ANT      72    0    1300   8     72    0    1300   8
STEWART      ANT      89    4    1750   8     10    0      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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    SW  39   SW  63   W   76
PORT HARDY   SW  33   W   43   W   50
SANDSPIT     N   43   N   41   N   37

TODAY'S VENTING: Poor locally good outer north coast.

VENTING FOR THURSDAY: Fair to poor.


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


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