FPCN39 CWLW 241340
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 FRIDAY 24 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      93   11     850  22    100   13    1500  22
KAMLOOPS     KEL      59   12     850  13    100   15    2150  15
OKANAGAN     KEL     100   13    1450  15    100   16    2400  15
CASTLEGAR    SPOK     48   11     850  13    100   14    1800  17
CRANBROOK    SPOK    100   11    2250  13    100   13    2850  17
REVELSTOKE   KEL      49   11     800  13     94   12    1450  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 FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    W   11   W   26   W   43
CRANBROOK             W   15   W   39

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         2100 m         14 C
SPOKANE         1600 m         11 C

TODAY'S VENTING: GOOD.

VENTING FOR SATURDAY: GOOD TO FAIR

VENTING OUTLOOK SUNDAY THRU TUESDAY: 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   12    3950  14    100   14    3950  14
PR. GEORGE   P.G.    100   11    2200  21    100   13    2650  19
SMITHERS     P.G.    100   11    1950  18    100   13    2250  17
WELLS GRAY   P.G.    100   12    4000  14    100   14    4000  14
FT NLSN      F.N.      9    8    1100   4     29    7     600  10
FT STJOHN    F.N.    100   11    1950  15    100   13    2250  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 FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            W   28   W   31
SMITHERS              W   20   W   31

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      2100 m         11 C
FT. NELSON      1300 m           9 C

TODAY'S VENTING: GOOD LOCALLY POOR

VENTING FOR SATURDAY: GOOD TO FAIR

VENTING OUTLOOK SUNDAY THRU TUESDAY: FAIR

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL    100   12    1850  14    100   14    3100  17
FRASER VLY   QUIL    100   12    1800  13    100   15    3050  17
SRN VRISL    QUIL    100   12    1750  11    100   14    2150  14
CNTRL VRISL  QUIL    100   12    1750  11    100   15    3050  16
NRN VRISL    HRDY     91   10    1450  10     91   10    1450  10
TERRACE      ANT      93   11    2450   7    100   13    3200   7
STEWART      ANT      76   11    2000   5     91   13    2450   6

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

FORECAST UPPER WINDS FOR FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    SW  28   W   33   W   39
PORT HARDY   W   26   W   30   W   35
SANDSPIT     W   26   W   22   W   22

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       130 m          8 C
PORT HARDY       120 m          8 C
ANNETTE          670 m          9 C

TODAY'S VENTING: GOOD

VENTING FOR SATURDAY: GOOD TO FAIR

VENTING OUTLOOK SUNDAY THRU TUESDAY: 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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