FPCN39 CWLW 041432
SMOKE CONTROL FORECAST FOR COASTAL BC AND THE INTERIOR INCLUDING THE
NORTHEAST ISSUED BY THE MOUNTAIN WEATHER SERVICE OFFICE OF
ENVIRONMENT CANADA AT 8:00 AM PDT Monday 4 August 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      26   28    1050   2     98   36    2600   7
KAMLOOPS     KEL      16   24     700   2     58   34    2650   4
OKANAGAN     KEL      16   24     700   2     58   33    1950   5
CASTLEGAR    SPOK     20   23     750   4     32   33    1150   4
CRANBROOK    SPOK      9   23     950   8    100   33    3950   9
REVELSTOKE   KEL      12   21     550   2     33   29    1550   2

*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   VR   5   S   11
CRANBROOK             VR   5   VR   5

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         2880 m         33 C
SPOKANE         1100 m         25 C

TODAY'S VENTING: Poor this morning becoming fair by mid morning and
 briefly good in the late afternoon as temperatures finally break
through the inversion.  Remaining poor in the Columbia and West
Kootenays.

VENTING FOR TUESDAY: FAIR

VENTING OUTLOOK WEDNESDAY THRU FRIDAY: Fair becoming good on
Thursday as a trough of low pressure destabilizes the airmass.

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.      9   22     950  19    100   28    3950  19
PR. GEORGE   P.G.      9   20     700  10    100   27    1850  15
SMITHERS     P.G.     11   16     650   2     14   21     800   2
WELLS GRAY   P.G.      9   21    1000  19    100   28    4000  19
FT NLSN      F.N.     27   19     550  10    100   26    2300  11
FT STJOHN    F.N.      9   18     700  11    100   25    3700  11

*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            S   11   S   30
SMITHERS              S    9   S   30

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1200 m         28 C
FT. NELSON       700 m         24 C

TODAY'S VENTING: Poor this morning becoming good in the mid afternoon
except poor in the northwest.

VENTING FOR TUESDAY: FAIR

VENTING OUTLOOK WEDNESDAY THRU FRIDAY:Fair becoming good on
Thursday as a trough of low pressure destabilizes the airmass.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     21   20     800   2     37   25    1050   5
FRASER VLY   QUIL     24   21     850   2     47   28    1150   5
SRN VRISL    QUIL     18   19     500   2     39   23     950   5
CNTRL VRISL  QUIL     25   21     850   2     54   28    1200   4
NRN VRISL    HRDY      9   16     150   4     35   19     450   6
TERRACE      ANT      17   18     550   3    100   22    3200  23
STEWART      ANT       9   17     150   0    100   22    3000  20

*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   S   17   S   41
PORT HARDY   S   11   S   22   S   35
SANDSPIT     S   35   S   37   S   39

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1100 m         25 C
PORT HARDY       600 m         20 C
ANNETTE         none           none

TODAY'S VENTING:  Poor this morning becoming fair by the afternoon
except poor over northern Vancouver Island. Becoming good
over the north coast.

VENTING FOR TUESDAY: FAIR

VENTING OUTLOOK WEDNESDAY THRU FRIDAY: Good as a trough
of low pressure swings through and destabilizes the airmass.

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

END/lm