FPCN39 CWLW 151504
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 15 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      13   22     600   1    100   29    3200  10

KAMLOOPS     KEL      12   21     600   1     43   29    1150   5

OKANAGAN     KEL      11   20     550   1     43   28    1150   5

CASTLEGAR    SPOK     19   19     750   4     34   27    1150   4

CRANBROOK    SPOK      9   17     950   5     31   25    1150   4

REVELSTOKE   KEL      10   17     500   2     48   25    1450   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   W   11   W   17
CRANBROOK             VR   5   W   20

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1150 m         28 C
SPOKANE         1100 m         27 C

TODAY'S VENTING: Poor to Fair.  Good above 1200 metres.

VENTING FOR FRIDAY: Fair.

VENTING OUTLOOK SATURDAY THRU MONDAY: Good as a cold front sweeps
through the region and bringing gusty strong winds and
destabilizing the airmass.

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   17    2450  27    100   25    3950  20

PR. GEORGE   P.G.    100   18    2050  20    100   23    3700  20

SMITHERS     P.G.     21   16     700   8    100   23    3500  20

WELLS GRAY   P.G.    100   18    4000  27    100   26    4000  20

FT NLSN      F.N.    100   17    1850  32    100   28    3400  32

FT STJOHN    F.N.    100   17    3700  33    100   24    3700  33


*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            SW  26   SW  35
SMITHERS              SW  33   SW  35

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       700 m         18 C
FT. NELSON       700 m         17 C

TODAY'S VENTING: Becoming good by mid morning in the Central
Interior. Becoming good in the afternoon in the Peace District.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY: Good as a cold front sweeps
through the region and bringing gusty strong winds and destabilizing
theairmass.

COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL      9   16     900   5     61   20    1250   8

FRASER VLY   QUIL      9   16     900   2     90   25    2100   5

SRN VRISL    QUIL      9   13     350   0     49   20    1000   5

CNTRL VRISL  QUIL      9   17     700   0     43   22    1300   2

NRN VRISL    HRDY     25   13     150  13     39   18     850   5

TERRACE      ANT      34   14    1050  11     57   19    1550   7

STEWART      ANT      34   14     700   8     57   19    1550   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
VANCOUVER    W   15   SW  19   SW  28
PORT HARDY   S   22   S   30   S   37
SANDSPIT     SW  24   SW  31   SW  39

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1400 m         25 C
PORT HARDY       700 m         20 C
ANNETTE         1800 m         22 C

TODAY'S VENTING: Generally fair except good inland in the afternoon
 where temperature rise to the mid Twenties.

VENTING FOR FRIDAY: GOOD

VENTING OUTLOOK SATURDAY THRU MONDAY:Good as a cold front sweeps
through the region destabilizing the airmass.

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

END/lm