FPCN39 CWLW 181407
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 18 SEPTEMBER 1997 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      30   13     500   8     68   18    2250  15
KAMLOOPS     KEL      65   10     900  18     70   18    2550  18
OKANAGAN     KEL      40    8     400   7     60   16    2200  10
CASTLEGAR    SPOK     35    9     500   4     60   15    1800  12
CRANBROOK    SPOK     40    8     400   5     60   14    2650  12
REVELSTOKE   KEL      30   10     500   5     60   13    1300   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
PENTICTON    VR   5   VR   5   W   13
CRANBROOK             VR   5   VR   5

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          700 m         11 C
SPOKANE         NO INVERSION

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: POOR TO FAIR.

VENTING OUTLOOK SATURDAY THRU MONDAY: POOR.




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.     22    5    1000   5     60   14    3950   8
PR. GEORGE   P.G.     22    3     700   3     62   13    3700   8
SMITHERS     P.G.     24    3     700   4     60   14    2900   7
WELLS GRAY   P.G.     25    1    1100   7     80   14    4000   8
FT NLSN      F.N.     19    2     800   2     85   12    2250   7
FT STJOHN    F.N.     23    3     500   3     78    9    2300   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            NW   9   NW  15
SMITHERS              VR   5   W   15

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      NO INVERSION
FT. NELSON       700 m          7 C

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: POOR TO FAIR.

VENTING OUTLOOK SATURDAY THRU MONDAY: POOR TO FAIR.




COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     22   14     800   5     60   19    1550  13
FRASER VLY   QUIL     14   11     800   5     60   19    1500  13
SRN VRISL    QUIL     33   13     700   5     68   19    1450  12
CNTRL VRISL  QUIL     12   12     500   5     58   19    1450  12
NRN VRISL    HRDY     10   12     500   5     69   16     950  12
TERRACE      ANT      33    6     700   5     38   17    1200   6
STEWART      ANT      33    6     800   5     38   17     550   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    VR   5   VR   5   VR   5
PORT HARDY   VR   5   NE  15   N   24
SANDSPIT     SW  26   W   30   W   31

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      NO INVERSION
PORT HARDY      1800 m         21 C
ANNETTE          800 m         17 C

TODAY'S VENTING: FAIR TO GOOD.

VENTING FOR FRIDAY: FAIR TO POOR.

VENTING OUTLOOK SATURDAY THRU MONDAY: POOR.




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


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