FPCN39 CWLW 211400
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 WEDNESDAY 21 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      29   10     500   6    100   16    3200  11
KAMLOOPS     KEL      60   11    2200  10    100   15    3350  11
OKANAGAN     KEL      55   11    2200   8    100   15    3350  11
CASTLEGAR    SPOK     89   10    1800  11    100   15    3500  10
CRANBROOK    SPOK     28    4    1900   9    100    7    3950  11
REVELSTOKE   KEL      99   10    2200  10    100   15    3450  11

*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    NW   9   NW  17   N   22
CRANBROOK             VR   5   N    9

TODAY'S VENTING: FAIR TO GOOD EXCEPT POOR OVER THE FRASER CANYON
AND CRANBROOK THIS MORNING.

VENTING FOR THURSDAY: 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.     30    6    2000   4    100   12    3950  12
PR. GEORGE   P.G.     31    8    1950   5    100   13    2850  11
SMITHERS     P.G.     19    6    1050   3    100   12    2250  11
WELLS GRAY   P.G.     20    4    2000  10    100   12    4000  21
FT NLSN      F.N.      9    6     400   0     66   14    1550   7
FT STJOHN    F.N.      9    8     700   3     98   13    2550   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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            VR   5   E    9
SMITHERS              W    9   S    9

TODAY'S VENTING: GENERALLY POOR THIS MORNING RISING TO FAIR TO
GOOD THIS AFTERNOON.

VENTING FOR THURSDAY: GOOD


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     83    9    1250  10    100   14    2450  10
FRASER VLY   QUIL     72    8    1000  10    100   14    2400  10
SRN VRISL    QUIL     81   10    1350   8    100   14    2300   9
CNTRL VRISL  QUIL     82   10    1400   8    100   15    2550   9
NRN VRISL    HRDY     40    5     650   6     89   10    1800   8
TERRACE      ANT      57    6     900   9     80   12    2900   4
STEWART      ANT      13    5     150   3     77   12    2200   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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    NW  11   NW   9   VR   5
PORT HARDY   NW  11   VR   5   N   15
SANDSPIT     VR   5   NW   9   NW  17

TODAY'S VENTING: FAIR TO GOOD EXCEPT POOR THIS MORNING AT STEWART.

VENTING FOR THURSDAY: GOOD

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


END/
$$$$^^