FPCN39 CWLW 221337
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 22 APRIL 1998 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   12     500   0     68   20    1400   7
KAMLOOPS     KEL       9   11     500   0     65   20    1600   6
OKANAGAN     KEL       9   11     500   0     65   20    1600   6
CASTLEGAR    SPOK     28   12     750   8     60   20    1600   6
CRANBROOK    SPOK      9   12     950   9     69   20    1900   9
REVELSTOKE   KEL       9   10     500   0     57   17    1350   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
PENTICTON    VR   5   S   20   S   46
CRANBROOK             S    9   S   28

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1600 m         20 C
SPOKANE         1036 m         20 C

TODAY'S VENTING: GOOD

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY: GOOD TO 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.     35    7    1150  14    100   17    3950  12
PR. GEORGE   P.G.     35    7     950  12    100   16    3700  12
SMITHERS     P.G.     21    6     750   5     95   13    1950  11
WELLS GRAY   P.G.     54    7    1400  14    100   17    4000  12
FT NLSN      F.N.      9    6     400  12    100   12    2100  15
FT STJOHN    F.N.      9    7     700  14    100   12    3700  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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SE  15   S   22
SMITHERS              SE  20   S   22

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1036 m         10 C
FT. NELSON       650 m         11 C

TODAY'S VENTING: GOOD

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY: GOOD TO FAIR

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     30   12     500   5     37   16     800   4
FRASER VLY   QUIL     30   12     500   5     49   17    1100   5
SRN VRISL    QUIL     27   12     450   4     37   16     800   4
CNTRL VRISL  QUIL     27   12     450   4     46   17    1050   4
NRN VRISL    HRDY     17    8     150   8     86   12    1150  11
TERRACE      ANT      10    6     250  20    100   11    2100  25
STEWART      ANT       9    7       0  11    100   11    1550  22

*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    VR   5   S   11   S   33
PORT HARDY   NW   9   S    9   S   26
SANDSPIT     S   22   S   30   S   37

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1160 m         18 C
PORT HARDY       150 m          9 C
ANNETTE          350 m          8 C

TODAY'S VENTING: FAIR SOUTH TO GOOD NORTH

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY: GOOD TO FAIR

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


END/MWSO