FPCN39 CWLW 231418
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 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      40    9    1100  13    100   15    2400  17
KAMLOOPS     KEL      44    8    1250  15    100   13    2300  15
OKANAGAN     KEL      40    8    1250  15    100   12    2050  17
CASTLEGAR    SPOK     26    7     950  15     78   11    1200  15
CRANBROOK    SPOK     10    6     950  18     89   10    1900  14
REVELSTOKE   KEL       9    6     450  15     86    8    1400  12

*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    NW  11   NW  26   N   39
CRANBROOK             N    9   N   26

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         No inversion
SPOKANE         1450 m         11 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   P.G.     83    4    1750  15    100    8    2850  17
PR. GEORGE   P.G.     61    5    1300  11    100    8    2250  14
SMITHERS     P.G.     28    5     800   7     62    6    1400   8
WELLS GRAY   P.G.     90    4    1950  15    100    7    2800  17
FT NLSN      F.N.     42   -2     700  12     49    0     850  10
FT STJOHN    F.N.     37    0    1100   8     54    2    1300   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            N   15   N   13
SMITHERS              VR   5   W   13

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      No inversion
FT. NELSON      1500 m          7 C

TODAY'S VENTING: Good.

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      9    9     100   9     75   11     200  15
FRASER VLY   QUIL     17   10     150   9     76   12     650  17
SRN VRISL    QUIL     11    9     100   2     40   12     300  10
CNTRL VRISL  QUIL     11    9     100   2     39   12     350  11
NRN VRISL    HRDY      9    8       0  13     61   11     550  13
TERRACE      ANT       9    7     250   5      9    9     250   5
STEWART      ANT       9    7      50   0      9    9     100   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
VANCOUVER    NW  15   N   17   N   26
PORT HARDY   NW  11   N   11   NW  17
SANDSPIT     S   20   S   19   SW  17

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       250 m         11 C
PORT HARDY       100 m          9 C
ANNETTE          150 m          8 C

TODAY'S VENTING: Fair to good.

VENTING FOR FRIDAY: 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/DB