FPCN39 CWLW 181430
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 18 June 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      58   19    1050   7    100   24    3200  14
KAMLOOPS     KEL     100   19    2200  11    100   23    3350  14
OKANAGAN     KEL      39   17     850   7    100   22    3350  14
CASTLEGAR    SPOK     36   15     850   9    100   20    2350  19
CRANBROOK    SPOK     ##   ##     ###  ##    100   20    3950  24
REVELSTOKE   KEL      13   15     550   3    100   18    2200  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
PENTICTON    W   13   W   26   W   35
CRANBROOK             W   11   W   31

           INVERSION HT    BREAKTHRU TEMP
KELOWNA          580 m         16 C
SPOKANE          950 m         16 C

TODAY'S VENTING: Weak inversion will erode before midday. This will
allow for good venting through the afternoon for most areas.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY:
Airmass will remain unstable through the period. Winds however should
be generally light. Expect good venting in the afternoon hours.

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.     90   14    2600   8    100   19    3950   8
PR. GEORGE   P.G.     76   14    1800   9    100   18    3700   8
SMITHERS     ANT      80   12    1550  11    100   18    3500  11
WELLS GRAY   P.G.     90   14    2750   8    100   18    4000   8
FT NLSN      F.N.     31   14     800   6     50   18    1250   6
FT STJOHN    F.N.     26   14    1050   5     69   18    2400   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            W   33   W   41
SMITHERS              W   22   W   41

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      #### m         ## Cinversion between 700-1200m /16C
FT. NELSON      #### m         ## Cinversion between 650-1000m /19C

TODAY'S VENTING: Good over the Central Interior. In the northeast,
generally fair venting expected. Temperatures need to approach the 20
degree mark here for good venting here.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY:
Airmass will remain moist and unstable through the period. Winds
should be generally light. Expect generally fair venting conditions
to prevail.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL    100   17    1550  17    100   20    2550  17
FRASER VLY   QUIL    100   16    1250  17    100   20    2450  17
SRN VRISL    QUIL     95   16    1150  14    100   20    2300  16
CNTRL VRISL  QUIL     61   14     700  10     96   16    1200  14
NRN VRISL    HRDY     44   13     350  13    100   16    1300  22
TERRACE      ANT      66   13    1000  10    100   17    2000  11
STEWART      ANT      53   14     700   8     91   17    1550   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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    W   24   W   30   W   31
PORT HARDY   W   22   W   24   W   30
SANDSPIT     W   31   W   28   W   30

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

TODAY'S VENTING: Little or no signs of inversion along the coast.
This should allow for good venting for most of the day.

VENTING FOR THURSDAY: FAIR TO GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY:
Fair 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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