FPCN39 CWLW 251336
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 SATURDAY 25 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     100   13    2400   9    100   20    3200   9
KAMLOOPS     KEL      36    9     800   7    100   18    3350   9
OKANAGAN     KEL      36    9     800   7    100   20    3350   9
CASTLEGAR    SPOK     48   10    1450   5    100   16    3500   8
CRANBROOK    SPOK    100    9    3950   9    100   14    3950   9
REVELSTOKE   KEL      27    8     800   6    100   14    3450   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 SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   W   19   W   28
CRANBROOK             VR   5   W   24

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          920 m         10 C
SPOKANE          880 m          7 C

TODAY'S VENTING: GOOD

VENTING FOR SUNDAY: GOOD

VENTING OUTLOOK MONDAY THRU WEDNESDAY: 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.    100    5    3950  25    100   13    3950  25
PR. GEORGE   P.G.    100    7    2800  22    100   14    3700  22
SMITHERS     P.G.     31    5     900   7    100   12    3500  20
WELLS GRAY   P.G.    100    5    4000  25    100   14    4000  25
FT NLSN      F.N.     51    5     900  10    100    9    1600  19
FT STJOHN    F.N.     44    7    1100  10    100   15    2800  21

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

FORECAST UPPER WINDS FOR SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  37   SW  46
SMITHERS              S   46   SW  46

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       760 m          5 C
FT. NELSON      3600 m         20 C

TODAY'S VENTING: GOOD

VENTING FOR SUNDAY: GOOD

VENTING OUTLOOK MONDAY THRU WEDNESDAY: GOOD TO FAIR

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     71   10    1250   7    100   14    2200   9
FRASER VLY   QUIL     92   11    1900   8    100   14    2150   9
SRN VRISL    QUIL     36    9     550   6     96   14    2100   8
CNTRL VRISL  QUIL     14    7     150   4     92   12    1950   8
NRN VRISL    HRDY     20    7     150   8    100   10    1350  14
TERRACE      ANT     100    7    1100  23    100   11    2000  25
STEWART      ANT      84    8     700  18    100   11    1700  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 SATURDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    S   26   SW  39   W   39
PORT HARDY   S   72   SW  78   SW  70
SANDSPIT     SW  52   SW  59   SW  70

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       200 m          9 C
PORT HARDY       130 m          8 C
ANNETTE         1890 m         13 C

TODAY'S VENTING: GOOD

VENTING FOR SUNDAY: GOOD

VENTING OUTLOOK MONDAY THRU WEDNESDAY: GOOD TO FAIR

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


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