FPCN39 CWLW 091430
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 Friday 9 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      24   16     700   3    100   21    3000  10

KAMLOOPS     KEL      20   16     700   3    100   22    3000  15

OKANAGAN     KEL      18   14     650   3    100   21    3000  12

CASTLEGAR    SPOK     15   13     800   2     80   22    2550  10

CRANBROOK    SPOK      9   10     950   2     39   18    1700   5

REVELSTOKE   KEL      10   11     500   2     90   18    1150   9


*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    VR   5   W   20   W   37
CRANBROOK             W   13   W   31

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1000 m         17 C
SPOKANE         2300 m         22 C

TODAY'S VENTING: Good by the afternoon as the cold front brings
gusty winds and cooler slightly more unstable air. Only fair
conditions persist in the southeast as the cold front doesn't move
through until late this afternoon.

VENTING FOR SATURDAY: GOOD

VENTING OUTLOOK SUNDAY THRU TUESDAY: A strong ridge of high pressure
rebuilds along the coast on Sunday giving stalbe conditions and only
fair venting. The ridge weaken by Thurday allowing more a northerly
flow and more unstable conditions for fair to good venting.


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.     97   11    2450  11    100   17    3950  15

PR. GEORGE   P.G.     74   12    1600  10    100   17    3700  14

SMITHERS     P.G.      9    8     500   3    100   16    3500  12

WELLS GRAY   P.G.    100   13    4000  15    100   17    4000  15

FT NLSN      F.N.     42   10     900   8    100   16    2300  11

FT STJOHN    F.N.     73   12    1600  10    100   16    3700  12


*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   26   W   33
SMITHERS              SW  28   SW  33

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       700 m         15 C
FT. NELSON      1400 m         16 C

TODAY'S VENTING:
VENTING FOR SATURDAY: GOOD

VENTING OUTLOOK SUNDAY THRU TUESDAY: A strong ridge of high pressure
rebuilds along the coast on Sunday giving stable conditions and only
fair venting. The ridge weakens by Tuesday allowing a northerly
flow and more unstable conditions giving fair to good venting.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     61   13     550  15     77   16     750  15

FRASER VLY   QUIL     62   13     500  15     94   19    1100  15

SRN VRISL    QUIL      9   14     550   0     62   18     950   8

CNTRL VRISL  QUIL      9   12     450   0      9   15     600   0

NRN VRISL    HRDY     29   10     450   5     44   12     850   5

TERRACE      ANT     100    9    1150  34    100   15    2950  28

STEWART      ANT     100   11    1100  29    100   15    2400  27


*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    W   17   W   20   W   35
PORT HARDY   W   13   W   19   W   31
SANDSPIT     SW  33   SW  35   SW  41

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1800 m         21 C
PORT HARDY       400 m         10 C
ANNETTE            0 m         none  C

TODAY'S VENTING: Good as the cold front sweeps through the
central interior bringing unstable conditions and gusty winds.

VENTING FOR SATURDAY: fair

VENTING OUTLOOK SUNDAY THRU TUESDAY: A strong ridge of high
pressure rebuilds along the coast providing stable conditions
and possible poor venting conditions.

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

END/lm