FPCN39 CWLW 211430
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 21 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      24   13    1100   2    100   18    4000   4
KAMLOOPS     KEL      44   13    1700   3    100   18    4000   5
OKANAGAN     KEL      23   12    1200   2    100   17    4000   4
CASTLEGAR    SPOK     21   11     800   4    100   17    4000  10
CRANBROOK    SPOK     50   10    1600   8    100   17    4000  15
REVELSTOKE   KEL      19   10    1050   2    100   15    4000   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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   VR   5   S   11
CRANBROOK             VR   5   S   19

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1200 m         12 C
SPOKANE          900 m         12 C

TODAY'S VENTING: THE AIRMASS REMAINS UNSTABLE SO GOOD VENTING
IS EXPECTED THIS AFTERNOON.

VENTING FOR THURSDAY: GOOD.

VENTING OUTLOOK FRIDAY THRU SUNDAY: CONTINUING GOOD DURING THE
AFTERNOON.




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    7    2850  27    100   13    3950  27
PR. GEORGE   P.G.    100    8    1950  28    100   14    3700  26
SMITHERS     P.G.    100    9    1650  26    100   17    3500  25
WELLS GRAY   P.G.    100    9    4000  27    100   14    4000  27
FT NLSN      F.N.     52    9    1500   5    100   17    3400   7
FT STJOHN    F.N.     47    6    1550   5    100   11    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 WEDNESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            NE  30   E   24
SMITHERS              E   26   E   24

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE       750 m          6 C
FT. NELSON       750 m          9 C

TODAY'S VENTING: GUSTY WINDS AND AN UNSTABLE AIRMASS AT LOW
LEVELS WILL RESULT IN GOOD VENTING TODAY. NORTHEAST BC WILL
HAVE POOR TO FAIR VENTING THIS MORNING.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY: CONTINUING GOOD.




COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     93   14    1150  14    100   17    1750  13
FRASER VLY   QUIL     79   13     850  14    100   17    1700  13
SRN VRISL    QUIL     57   13     700   9    100   17    1600  12
CNTRL VRISL  QUIL     58   13     750   9    100   17    1600  12
NRN VRISL    HRDY      9   13       0   1     64   18    1750   4
TERRACE      ANT      10   13     250  11    100   21    3200  14
STEWART      ANT      11   14      50   4    100   21    2800  13

*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    VR   5   S   11   S   19
PORT HARDY   VR   5   E   13   E   26
SANDSPIT     NE  41   NE  37   NE  46

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       200 m         12 C
PORT HARDY       700 m         17 C
ANNETTE          200 m         18 C

TODAY'S VENTING: OVER THE SOUTH COAST VENTING WILL BECOME GOOD
BY THIS AFTERNOON. THE NORTH COAST VENTING WILL NOT BE GOOD UNTIL
MID AFTERNOON.

VENTING FOR THURSDAY: GOOD

VENTING OUTLOOK FRIDAY THRU SUNDAY: CONTINUING GOOD.




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

END/JDG