FPCN39 CWLW 221400
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 22 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      18   12    1100   1     76   20    3200   8
KAMLOOPS     KEL      19   11    1350   1     86   18    3350   8
OKANAGAN     KEL      19   11    1350   1     69   17    2500   6
CASTLEGAR    SPOK     33   10    1450   8    100   17    3500  12
CRANBROOK    SPOK     30    6    2850   9    100    9    3950  15
REVELSTOKE   KEL      24   12    2050   1     36   17    3450   1

*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    VR   5   NE   9   E   17
CRANBROOK             E   11   E   22

TODAY'S VENTING: GENERALLY POOR THIS MORNING INCREASING TO FAIR TO
GOOD LATER THIS MORNING.

VENTING FOR FRIDAY: POOR

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.     37    8    1400   7    100   16    3950   9
PR. GEORGE   P.G.     32    7     950   9    100   14    3700   9
SMITHERS     P.G.     13    5     750   2     60   13    1700   6
WELLS GRAY   P.G.     26    3    1500   4    100   16    4000   9
FT NLSN      F.N.      9    8     400   5    100   17    2850   8
FT STJOHN    F.N.      9    8     700   8    100   16    3700   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  15   SW  24
SMITHERS              SW  31   SW  24

TODAY'S VENTING: GENERALLY POOR THIS MORNING RISING TO GOOD OVER ALL
AREAS THIS AFTERNOON.

VENTING FOR FRIDAY: POOR


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     28   10     450   7    100   16    3100  12
FRASER VLY   QUIL     33    9     400   4    100   17    3050  11
SRN VRISL    QUIL     28    9     350   5    100   16    3000  12
CNTRL VRISL  QUIL     32   10     400   8    100   16    3050  12
NRN VRISL    HRDY     48    8     550   9     86   13    1000  13
TERRACE      ANT      18    3     300   3    100   13    3200   8
STEWART      ANT      10    6     150   1     65   13    1450   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    NW   9   N    9   NE  15
PORT HARDY   W    9   SW  13   W   20
SANDSPIT     S   72   SW  72   SW  78

TODAY'S VENTING: GENERALLY POOR THIS MORNING WITH FAIR OVER NORTHERN
VANCOUVER ISLAND. RATES BECOMING GOOD OVER ALL AREAS BY EARLY
AFTERNOON.

VENTING FOR FRIDAY: POOR


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


END/
$$$$^^