FPCN39 CWLW 281430
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 Thursday 28 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      12   16     500   1     60   21    1200   7
KAMLOOPS     KEL      12   16     600   1     97   22    2550   7
OKANAGAN     KEL      12   16     600   1     86   21    2200   7
CASTLEGAR    KEL      30   16     800   8     90   23    2500   9
CRANBROOK    KEL      25   14    1350   4     90   20    2950   9
REVELSTOKE   KEL      11   15     600   1     60   19    1550   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
PENTICTON    VR   5   SW  17   SW  31
CRANBROOK             W    9   W   30

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          760 m         17 C
SPOKANE          MISSING

TODAY'S VENTING: BECOMING GOOD BY THE AFTERNOON.


VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY: FAIR TO GOOD SATURDAY.
POOR ON SUNDAY AND MONDAY AS A LOW PRESSURE CENTRE CROSSES THE
REGION.

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   10     950  15     90   16    2950  10
PR. GEORGE   P.G.     37   13    1000  10    100   16    2350  15
SMITHERS     P.G.     23   12     750   6     85   16    1650  11
WELLS GRAY   P.G.    100   13    2350  17    100   17    4000  20
FT NLSN      F.N.     65   15    1000  12    100   20    2450  13
FT STJOHN    F.N.     94   13    1850  13    100   15    2200  14

*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            W   30   W   43
SMITHERS              W   28   W   43

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1040 m         15 C
FT. NELSON       980 m         15 C

TODAY'S VENTING: BECOMING GOOD BY NOON.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY: GOOD ON SATURDAY. BECOMING
FAIR TO GOOD SUNDAY AND MONDAY.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     51   17     500  12     90   20    1250  12
FRASER VLY   QUIL     69   18     700  13    100   22    1850  11
SRN VRISL    QUIL     23   16     250   7     84   20    1100  11
CNTRL VRISL  QUIL     17   14     150   7     58   17     850  10
NRN VRISL    HRDY      9   14     200   0     48   17    1350   4
TERRACE      ANT      47   15     950   6     94   18    1850   9
STEWART      ANT       9   15     400   0     60   18    1350   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    S   11   SW  17   SW  30
PORT HARDY   VR   5   VR   5   SW   9
SANDSPIT     SW  13   W   11   W   11

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      240 m         16 C
PORT HARDY      670 m         16 C
ANNETTE         NONE          NONE

TODAY'S VENTING: BECOMING GOOD BY THE AFTERNOON EXCEPT
FAIR NORTHERN VANCOUVER ISLAND

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY:FAIR TO GOOD SATURDAY.
FAIR TO POOR ON SUNDAY AND MONDAY AS A LOW PRESSURE CENTRE
CROSSES THE REGION.

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

END/LM