FPCN39 CWLW 131447
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 13 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      23   27     800   2     70   33    2300   4
KAMLOOPS     KEL      15   24     650   2     78   32    2600   5
OKANAGAN     KEL      13   23     550   2     64   31    2200   4
CASTLEGAR    SPOK     27   23     800   6     67   30    1700   7
CRANBROOK    SPOK      9   19     950   6    100   28    3950  14
REVELSTOKE   KEL      10   20     500   2     27   27    1150   3

*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   NW  20   N   30
CRANBROOK             NW   9   NW  24

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          880 m         24 C
SPOKANE         1000 m         25 C

TODAY'S VENTING:
INVERSION HAS WEAKENED FROM YESTERDAY. WINDS IN THE LOW LEVELS
REMAIN GENERALLY LIGHT. EXPECT GOOD VENTING TO DEVELOP BY MIDDAY
ALTHOUGH MIXING HEIGHTS WILL NOT BE HIGH.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY:
LOW LEVEL WINDS INCREASING ON THURSDAY WILL LINGER FRIDAY. GOOD
VENTING SHOULD PREVAIL THROUGH THE PERIOD.

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   22    1950  25    100   28    3950  23
PR. GEORGE   P.G.     81   20    1300  19    100   26    2150  21
SMITHERS     P.G.     37   20     800  11    100   26    1950  19
WELLS GRAY   P.G.    100   19    1700  26    100   28    4000  23
FT NLSN      F.N.      9   21     400  37    100   24    1100  37
FT STJOHN    F.N.     96   21    1100  38    100   26    3700  40

*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            W   33   NW  46
SMITHERS              W   37   NW  46

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       900 m         21 C
FT. NELSON       600 m         22 C

TODAY'S VENTING:
ONLY WEAK INVERSION PRESENT. WINDS IN THE LOW LEVELS HAVE
STRENGTHENED OUT OF THE WEST QUADRANTS. GOOD VENTING EXPECTED MOST
AREAS BEFORE MIDDAY.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY:
LOW LEVEL WINDS INCREASING ON THURSDAY WILL LINGER FRIDAY. GOOD
VENTING SHOULD PREVAIL THROUGH THE PERIOD.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     42   21     650   7     48   24     800   7
FRASER VLY   QUIL     43   21     650   7     52   28     900   6
SRN VRISL    QUIL     36   18     500   6     48   24     750   6
CNTRL VRISL  QUIL     46   23     700   6     63   31    1450   5
NRN VRISL    HRDY     18   18     100  15     85   21     650  19
TERRACE      ANT     100   23    1200  21    100   28    3200  27
STEWART      ANT       9   21     700   0    100   28    1500  17

*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    W   13   N   15   N   30
PORT HARDY   NW  48   N   54   N   61
SANDSPIT     NW  39   NW  59   NW  67

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       900 m         26 C
PORT HARDY       180 m         18 C  INVERSION 670-1600M
ANNETTE          NIL m         ## C

TODAY'S VENTING:
GOOD VENTING IN THE NORTH. ONLY FAIR IN THE SOUTH DUE TO INVERSION
STILL PRESENT.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY:
GOOD VENTING FRIDAY. FAIR TO GOOD ON THE WEEKEND.

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

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