FPCN39 CWLW 201433
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 Tuesday 20 May 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      16   13     850   1    100   18    4000  10
KAMLOOPS     KEL      30   13    1450   2    100   18    4000  10
OKANAGAN     KEL      34   14    1750   2    100   18    4000  10
CASTLEGAR    KEL      28   12     750   8    100   15    4000  10
CRANBROOK    SPOK     10   11     950  25    100   17    4000  20
REVELSTOKE   KEL      18   11    1150   1    100   15    4000  10

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

FORECAST UPPER WINDS FOR TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   SW  15   SW  20
CRANBROOK             S   13   S   30

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          600 m         12 C
SPOKANE         1300 m         17 C

TODAY'S VENTING: THE AIRMASS IS UNSTABLE TODAY SO BY LATE
AFTERNOON VENTING WILL BECOME GOOD.

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY: VENTING WILL REMAIN
GOOD DURING THE AFTERNOONS.




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    8    3950  34    100   13    3950  34
PR. GEORGE   P.G.    100    9    3700  34    100   13    3700  34
SMITHERS     P.G.     87    9    1000  27    100   18    3500  32
WELLS GRAY   P.G.    100   10    4000  34    100   15    4000  34
FT NLSN      F.N.     15    8     700   2    100   12    3400   7
FT STJOHN    F.N.      9    5     700   3    100   11    3700   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 TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            NE  50   E   56
SMITHERS              NE  35   NE  56

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       970 m          9 C
FT. NELSON       700 m          9 C

TODAY'S VENTING: A STRONG NORTHERLY FLOW AND AN UNSTABLE AIRMASS
AT LOW LEVELS WILL RESULT IN GOOD VENTING TODAY.

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY: GOOD DURING THE AFTERNOONS
DUE TO AN UNSTABLE AIRMASS.



COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     55   13    1250   5     89   16    2200   6
FRASER VLY   QUIL     52   13    1150   5     99   17    2500   7
SRN VRISL    QUIL     61   14    1350   5     93   17    2350   6
CNTRL VRISL  QUIL     62   14    1400   5     93   17    2400   6
NRN VRISL    HRDY      9   12       0   5     64   17     600  12
TERRACE      ANT      10   14     200  19    100   21    3200  17
STEWART      ANT      11   14      50   7    100   21    3000  16

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

FORECAST UPPER WINDS FOR TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    S   13   SW  11   W   11
PORT HARDY   N   20   NE  20   NE  22
SANDSPIT     N   59   NE  46   NE  54

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       100 m         10 C
PORT HARDY       600 m         17 C
ANNETTE          500 m         19 C

TODAY'S VENTING: GOOD MOST OF THE DAY SOUTHERN SECTIONS DUE TO
A VERY UNSTABLE AIRMASS. ELSEWHERE VENTING WON'T BE GOOD UNTIL
MID AFTERNOON.

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY: GOOD DURING THE AFTERNOONS
DUE TO AN UNSTABLE AIRMASS.




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

END/JDG