FPCN39 CWLW 101434
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 10 July 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      74   17    1100  10    100   21    2500   8
KAMLOOPS     KEL      47   15     750  11     96   19    2450   8
OKANAGAN     KEL      77   16    1650   8    100   21    2900   7
CASTLEGAR    SPOK    100   17    1650  25    100   22    3500  22
CRANBROOK    SPOK    100   17    3950  22    100   21    3950  22
REVELSTOKE   KEL      35   14     750  10     88   17    2200   7

*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    W   11   W   20   W   33
CRANBROOK             VR   5   SW  22

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         nil  m         ## C
SPOKANE         1050 m         13 C

TODAY'S VENTING:
Generally good. Surface heating will be limited over northwestern
sections but this should not restrict mixing heights significantly.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY:
Fair to good.

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.     40   12    1200  13    100   17    3950  11
PR. GEORGE   P.G.     34   13    1050   8    100   19    3700  10
SMITHERS     P.G.     29   13     950   5    100   20    3500   8
WELLS GRAY   P.G.    100   14    4000  11    100   18    4000  11
FT NLSN      F.N.     70   19    1250  10    100   24    3400  10
FT STJOHN    F.N.     37   15    1000  10    100   21    3700  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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            NW  24   N   30
SMITHERS              NW  15   NW  30

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1150 m         18 C
FT. NELSON       970 m         18 C

TODAY'S VENTING:
Good venting expected to develop by early afternoon.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY:
Fair to good.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     67   16    1400   6     87   20    2100   7
FRASER VLY   QUIL     65   16    1300   6     87   20    2050   7
SRN VRISL    QUIL     54   16    1150   5     83   20    2000   6
CNTRL VRISL  QUIL     55   16    1200   5     83   20    2000   6
NRN VRISL    HRDY     44   14     500   9     92   17    1250  12
TERRACE      ANT      70   16    1000  11    100   21    2600  11
STEWART      ANT      44   16     650   6    100   21    2250   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   24   W   30   NW  30
PORT HARDY   NW  22   NW  22   NW  22
SANDSPIT     W   17   NW  15   NW  17

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       200 m         12 C
PORT HARDY       nil m         ## C
ANNETTE          nil m         ## C

TODAY'S VENTING:
Moderate low level winds and a weak inversion will mean generally good
venting over coastal sections.

VENTING FOR FRIDAY: FAIR TO GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY:
Fair to good.

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

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