FPCN39 CWLW 271337
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 MONDAY 27 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      14   14     650   1     84   21    1950   7
KAMLOOPS     KEL      14   13     800   1    100   22    3350   8
OKANAGAN     KEL       9   10     500   0     81   20    2050   7
CASTLEGAR    SPOK     26   12     950   4     70   20    2300   5
CRANBROOK    SPOK     21   11    1250   4     70   19    2550   5
REVELSTOKE   KEL       9   10     550   0     76   18    1950   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 MONDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   W   11   W   17
CRANBROOK             VR   5   NW  17

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1100 m         15 C
SPOKANE         1000 m         14 C

TODAY'S VENTING: Good.


VENTING FOR TUESDAY: GOOD


VENTING OUTLOOK WEDNESDAY THRU FRIDAY: Generally 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.     88    9    2050  12    100   15    3950  12
PR. GEORGE   P.G.     76    9    1500  12    100   14    3700  12
SMITHERS     P.G.     11    7     650   2     82   12    1850   9
WELLS GRAY   P.G.    100   11    4000  12    100   16    4000  12
FT NLSN      F.N.     80    7    2200   7    100   14    4000  12
FT STJOHN    F.N.     80    8    2200  13    100   15    4000  15

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

FORECAST UPPER WINDS FOR MONDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  28   W   43
SMITHERS              SW  33   SW  43

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE     600 m          8 C
FT. NELSON      missing      missing

TODAY'S VENTING: Good.


VENTING FOR TUESDAY: GOOD


VENTING OUTLOOK WEDNESDAY THRU FRIDAY: Good.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     16   12     400   2     54   17    1000   6
FRASER VLY   QUIL     18   14     550   2     81   21    1600   7
SRN VRISL    QUIL     17   12     400   2     55   18    1050   6
CNTRL VRISL  QUIL     16   11     350   2     51   17     950   6
NRN VRISL    HRDY      9   11       0  10     76   13     750  14
TERRACE      ANT      10    6     250  10    100    9    1550  13
STEWART      ANT      50    9     650   8     50    9     650   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 MONDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    VR   5   SW   9   SW  19
PORT HARDY   S   17   SW  20   SW  37
SANDSPIT     SW  24   SW  39   SW  54

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1200m          15 C
PORT HARDY       200 m         11 C
ANNETTE          none          n/a

TODAY'S VENTING: Good.


VENTING FOR TUESDAY: GOOD


VENTING OUTLOOK WEDNESDAY THRU FRIDAY:


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


END/GF