FPCN39 CWLW 131432
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 Tuesday 13 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      30   22     750   4    100   31    3200   6
KAMLOOPS     KEL      23   20     700   4    100   30    3350   6
OKANAGAN     KEL      20   19     650   4     87   28    2350   7
CASTLEGAR    SPOK     27   17     750   8     71   27    1300  11
CRANBROOK    SPOK      9   16     950  14     90   25    3950  12
REVELSTOKE   KEL       9   16     550   0     73   25    1850   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 TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   VR   5   W   13
CRANBROOK             VR   5   W   15

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1500 m         24 C
SPOKANE         1320 m         27 C

TODAY'S VENTING: Becoming good by the early afternoon

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY: Good as the airmass
becomes unstable.

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   16     950   8     60   25    1950  10
PR. GEORGE   P.G.     19   15     900   5     70   25    1900  10
SMITHERS     P.G.     18   15     900   3     58   25    2700   5
WELLS GRAY   P.G.      9   15    1000   8     80   26    3000  10
FT NLSN      F.N.     10   12     400  17     81   17    1150  12
FT STJOHN    F.N.     48   13    1050  13    100   20    3700   8

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

FORECAST UPPER WINDS FOR TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            VR   5   W   13
SMITHERS              S   11   S   13

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1160 m         23 C
FT. NELSON      1250 m         18 C

TODAY'S VENTING: good

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY:Good as the airmass
becomes more unstable as the ridge weakens.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     51   16     500  12     70   20     750  13
FRASER VLY   QUIL     60   18     600  12     79   25    1300   7
SRN VRISL    QUIL     40   15     400   9     63   20     700  11
CNTRL VRISL  QUIL     47   17     550   9     40   23     850   4
NRN VRISL    HRDY     11   12     250   1     35   18     400   5
TERRACE      ANT       9   15     200   5     39   23    1650   2
STEWART      ANT      18   15     150   8     49   23    1250   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 TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    VR   5   S   11   SW  19
PORT HARDY   S   24   S   28   S   26
SANDSPIT     S   37   S   37   S   41

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       980 m         24 C
PORT HARDY       800 m         24 C
ANNETTE          550 m         21 C

TODAY'S VENTING: Fair on the coast due to a stable marine layer.
Good inland and above 800 metres.

VENTING FOR WEDNESDAY: GOOD

VENTING OUTLOOK THURSDAY THRU SATURDAY:The airmass
becomes more unstable as the ridge weakens giving good venting.

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

END/lm