FPCN39 CWLW 131400
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 THURSDAY 13 MAY 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      51   11    1550  11     75   14    2100  15
KAMLOOPS     KEL      45   10    1850   5     93   16    3350   8
OKANAGAN     KEL      40    8    1650   5     95   15    3350  10
CASTLEGAR    SPOK     30    5    1200   5     80   14    3200  12
CRANBROOK    SPOK     20    6    1400   5    100   13    3000  10
REVELSTOKE   KEL      42   10    1350   5     75   13    2400   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    W    9   W   11   VR   5
CRANBROOK             VR   5   VR   5

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

VENTING FOR FRIDAY: 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.     42    7    2000   8    100   12    3950  13
PR. GEORGE   P.G.     42    6    1100  10    100   10    2150  15
SMITHERS     P.G.     38    7     950  11    100   12    2250  13
WELLS GRAY   P.G.     20    4    1500  10    100   12    4000  13
FT NLSN      F.N.      9    6     400   5     13    7     450   5
FT STJOHN    F.N.      9    4     700  15     30    8    1250   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            W   13   NW  17
SMITHERS              NW  20   N   17

TODAY'S VENTING: POOR TO FAIR THIS MORNING RISING TO GOOD THIS
AFTERNOON. EXCEPT REMAINING POOR OVER NORTHEAST BC.

VENTING FOR FRIDAY: GOOD

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     40   11     500   9    100   14    2500  16
FRASER VLY   QUIL     34   10     450  10    100   14    2500  11
SRN VRISL    QUIL     32   10     550   8    100   14    2550   8
CNTRL VRISL  QUIL     35   10     600   8    100   14    2600  15
NRN VRISL    HRDY     27    6     250   8     95   12    2050   8
TERRACE      ANT      27    8    1150   2    100   14    3200   7
STEWART      ANT      25    9     850   2     74   14    2050   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   13   W    9   VR   5
PORT HARDY   NW  13   VR   5   E   11
SANDSPIT     NW  19   N   20   NE  15

TODAY'S VENTING: POOR TO FAIR THIS MORNING INCREASING TO GOOD OVER
ALL AREAS THIS AFTERNOON.

VENTING FOR FRIDAY: GOOD

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


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