FPCN39 CWLW 201434
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 Wednesday 20 August 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   21     500   0     37   28    1200   3
KAMLOOPS     KEL      19   22     800   2     42   28    1450   3
OKANAGAN     KEL       9   19     500   0     42   28    1450   3
CASTLEGAR    SPOK     22   20     850   4     42   28    1150   6
CRANBROOK    SPOK      9   19     950  14    100   27    3950  10
REVELSTOKE   KEL       9   17     500   0     26   24    1050   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    E    9   SE  20   S   33
CRANBROOK             VR   5   S   22

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1400 m         28 C
SPOKANE         1250 m         28 C

TODAY'S VENTING: POOR BECOMING FAIR IN THE AFTERNOON.

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY:GOOD AS UNSETTLED CONDITIONS
LIE OVER THE PROVINCE AS NUMEROUS UPPER TROUGHS SWING THROUG.


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   17     950   6     98   24    3950   6
PR. GEORGE   P.G.     16   16     850   5     75   25    2500   5
SMITHERS     P.G.     17   16     800   3     62   25    1950   5
WELLS GRAY   P.G.      9   17    1000   6     98   26    4000   6
FT NLSN      F.N.     29   15     650   8     75   22    1850   7
FT STJOHN    F.N.     43   16    1150   9    100   22    3700   7

*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            E   19   SE  20
SMITHERS              E   15   S   20

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       980 m          23 C
FT. NELSON      1000 m          19 C

TODAY'S VENTING: POOR IN THE MORNING BECOMING GOOD BY MID
AFTERNOON.

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY:GOOD AS UNSETTLED CONDITIONS
LIE OVER THE PROVINCE AS NUMEROUS UPPER TROUGHS SWING THROUGH.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     15   19     250   4     34   23     600   6
FRASER VLY   QUIL     15   18     200   4     45   24     700   7
SRN VRISL    QUIL     15   17     200   4     25   22     350   5
CNTRL VRISL  QUIL     16   18     200   4     42   24     650   6
NRN VRISL    HRDY     18   15     350   3     20   19     450   3
TERRACE      ANT      27   20     450   8     76   25    1500   8
STEWART      ANT      22   18     200   8     68   25    1000   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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   11   S   13   SE  28
PORT HARDY   S   17   SE  30   SE  33
SANDSPIT     N   13   E    9   SE  19

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1070 m         27 C
PORT HARDY       800 m         27 C
ANNETTE          250 m         20 C

TODAY'S VENTING: POOR TO FAIR IN THE SOUTH BECOMING GOOD
ON THE NORTH COAST IN THE AFTERNOON.

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY:GOOD AS A SOUTHWESTERLY FLOW
LIES OVER THE PROVINCE.


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

END/LM