FPCN39 CWLW 011339
SMOKE CONTROL FORECAST FOR COASTAL BC AND THE INTERIOR INCLUDING THE
NORTHEAST ISSUED BY THE MOUNTAIN WEATHER SERVICE OFFICE OF
ENVIRONMENT CANADA AT 7:00 AM PDT FRIDAY 1 MAY 1998 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      26   18     700   4     65   29    1950   4

KAMLOOPS     KEL      23   17     750   4     60   28    2200   4

OKANAGAN     KEL      11   14     500   1     54   26    1800   4

CASTLEGAR    SPOK     21   16     800   4     63   25    1250  10

CRANBROOK    SPOK      9   16     950  15    100   25    3950  12

REVELSTOKE   KEL      17   15     650   4     60   26    2050   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 FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   E   11   SE  20
CRANBROOK             VR   5   SE  15

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1500 m         24 C
SPOKANE         1550 m         25 C

TODAY'S VENTING: POOR THIS MORNING BECOMING FAIR THIS AFTERNOON.
POSSIBLY GOOD FOR A COUPLE HOURS LATE THIS AFTERNOON.

VENTING FOR SATURDAY: FAIR.

VENTING OUTLOOK SUNDAY THRU TUESDAY: THE PASSAGE OF A COLD FRONT
WILL BRING GOOD VENTING.




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   14     950  14    100   25    3950  14

PR. GEORGE   P.G.     20   13     900   6     89   24    1850  12

SMITHERS     P.G.     17   13     800   3     54   24    1350   7

WELLS GRAY   P.G.      9   14    1000  14    100   26    4000  14

FT NLSN      F.N.      9   12     400  10     88   20    2100   8

FT STJOHN    F.N.     17   14     750  10    100   21    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 FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            VR   5   SW  15
SMITHERS              SW  17   SW  15

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1500 m         24 C
FT. NELSON       800 m         18 C

TODAY'S VENTING: POOR BECOMING GOOD FOR A COUPLE HOURS LATE THIS
AFTERNOON.

VENTING FOR SATURDAY: GOOD.

VENTING OUTLOOK SUNDAY THRU TUESDAY: CONTINUING GOOD.




COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     23   16     450   4     27   21     550   4

FRASER VLY   QUIL     29   22     600   4     48   29     900   6

SRN VRISL    QUIL     26   17     450   4     37   25     650   5

CNTRL VRISL  QUIL     27   19     500   4     47   29     850   5

NRN VRISL    HRDY      9   14       0   5     34   21     350   8

TERRACE      ANT      12   14     300   4    100   23    3200  11

STEWART      ANT      15   15     200   3     71   23    1500   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 FRIDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    E   19   E   22   E   24
PORT HARDY   NE  22   NE  17   NE  13
SANDSPIT     NW  26   W   22   SW  35

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE       900 m         30 C
PORT HARDY       750 m         28 C
ANNETTE          250 m         16 C

TODAY'S VENTING: POOR TO FAIR EXCEPT GOOD THIS AFTERNOON ON THE
NORTH COAST.

VENTING FOR SATURDAY: FAIR TO GOOD.

VENTING OUTLOOK SUNDAY THRU TUESDAY: GOOD.




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


END/JDG