FPCN39 CWLW 231400
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 FRIDAY 23 APRIL 1999 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      24   13     800   3     85   21    3200   4
KAMLOOPS     KEL      22   12     900   3     85   21    3350   4
OKANAGAN     KEL      19   10     750   3     85   21    3350   4
CASTLEGAR    SPOK     31   11     850   7    100   20    3500  12
CRANBROOK    SPOK     19    9    1000  15    100   18    3950  13
REVELSTOKE   KEL      18   10     800   3     85   19    3450   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 FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   N    9   N   20
CRANBROOK             VR   5   N   11

TODAY'S VENTING: GOOD

VENTING FOR SATURDAY: GOOD

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    9     950  14    100   17    3950  18
PR. GEORGE   P.G.     51   11    1000  17    100   15    2000  16
SMITHERS     P.G.      9   6      550   8     44   12     950  10
WELLS GRAY   P.G.      9    9     950  14    100   17    4000  18
FT NLSN      F.N.      9   10     400   3     13   14     500   3
FT STJOHN    F.N.     28   13     850  12     90   16    1750  13

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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  28   W   54
SMITHERS              SW  37   W   54

TODAY'S VENTING: GOOD EXCEPT FAIR IN THE SMITHERS AREA AND POOR IN
 THE FORT NELSON AREA.

VENTING FOR SATURDAY: GOOD

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     34   11     350  10     48   16     550  10
FRASER VLY   QUIL     43   14     450  10    100   23    1900  10
SRN VRISL    QUIL     15   11     300   2     37   17     650   5
CNTRL VRISL  QUIL     17   14     450   2     57   19    1250   5
NRN VRISL    HRDY     10    6     150   1     29   12     450   5
TERRACE      ANT      34    8     400  15    100   12    1500  18
STEWART      ANT       9    7       0  10    100   12    1500  18

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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    N   11   N   22   N   31
PORT HARDY   VR   5   W   20   W   37
SANDSPIT     S   30   SW  59   SW  94

TODAY'S VENTING: GOOD NORTH. GOOD TO FAIR SOUTH LOCALLY POOR ON
 VANCOUVER ISLAND.

VENTING FOR SATURDAY: FAIR TO GOOD

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


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