FPCN39 CWLW 141500
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 Wednesday 14 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      32   21     800   4     71   29    1600  10
KAMLOOPS     KEL      28   20     850   4     67   30    3350   5
OKANAGAN     KEL      21   19     750   3     49   28    1650   4
CASTLEGAR    SPOK     22   17     750   5     66   27    1900   6
CRANBROOK    SPOK      9   16     950   7     64   26    3950   5
REVELSTOKE   KEL      10   16     600   1     43   26    1550   4

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

FORECAST UPPER WINDS FOR WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   SW   9   W   17
CRANBROOK             VR   5   W   17

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1645 m         27 C
SPOKANE         1500 m         26 C

TODAY'S VENTING: fair in some valleys but good in the Fraser
Canyon in the afternoon as the winds develop. Good above 1600 metres.

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY: Fair to good as the air cools
and the ridge rebuilds.

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   17     950  14     48   25    1450  10
PR. GEORGE   P.G.     22   15     850   8     52   25    1450  12
SMITHERS     P.G.     22   15     800   5     40   23    1100   6
WELLS GRAY   P.G.      9   15    1000  14     40   26    1400  13
FT NLSN      F.N.     59   14     900   5     40   24    3400   5
FT STJOHN    F.N.     53   16    1100   5     40   24    3700   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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  28   SW  39
SMITHERS              SW  26   SW  39

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1500 m         28 C
FT. NELSON      1430 m         26 C

TODAY'S VENTING: fair

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY: Becoming good on friday through
 the weekend as a trough tracks across the region destabilizing the
 airmass.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     46   17     400  10     61   21     700  10
FRASER VLY   QUIL     58   20     550  10     68   25     950  10
SRN VRISL    QUIL     16   15     150   6     49   19     500  10
CNTRL VRISL  QUIL     48   19     500  10     51   25     950  11
NRN VRISL    HRDY     14   14     100   5     30   18     350   9
TERRACE      ANT     100   16    1050  12     70   21    1750  11
STEWART      ANT      91   16     900  11     70   21    1450  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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    SW  13   SW  19   SW  31
PORT HARDY   S   22   S   31   S   35
SANDSPIT     NW  13   SW  15   SW  22

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1300 m         24 C
PORT HARDY      1700 m         27 C
ANNETTE         1700 m         27 C

TODAY'S VENTING: Poor over northern Vancouver Island  fair to
good elsewhere. Good above 1600 metres.

VENTING FOR THURSDAY: FAIR

VENTING OUTLOOK FRIDAY THRU SUNDAY: fair to good as a trough
swings through the region.

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

END/lm