FPCN39 CWLW 301331
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 THURSDAY 30 APRIL 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      17   17     700   2     65   29    2250   4
KAMLOOPS     KEL      15   16     750   2     61   27    2250   4
OKANAGAN     KEL      13   14     600   2     55   26    2100   3
CASTLEGAR    SPOK     19   16     850   3    100   27    3500   8
CRANBROOK    SPOK      9   15     950   5    100   25    3950  10
REVELSTOKE   KEL      13   14     700   2     48   24    1800   3

*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   NE   9   VR   5
CRANBROOK             VR   5   NE   9

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1500 m         24 C
SPOKANE         1000 m         22 C

TODAY'S VENTING: Poor this morning becoming good in the afternoon.


VENTING FOR FRIDAY: FAIR.


VENTING OUTLOOK SATURDAY THRU MONDAY: Good.


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.     20   13    1050   9    100   23    3950   6
PR. GEORGE   P.G.     32   13     950  10    100   21    3700   7
SMITHERS     P.G.     16   11     750   3     64   20    1700   6
WELLS GRAY   P.G.     26   13    1200   9    100   24    4000   6
FT NLSN      F.N.      9   10     400  13    100   19    2350  17
FT STJOHN    F.N.      9   10     700  13    100   18    2550  18

*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            S    9   SW  15
SMITHERS              S   19   S   15

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE      1000 m         17 C
FT. NELSON       800 m         14 C

TODAY'S VENTING: Good.



VENTING FOR FRIDAY: GOOD



VENTING OUTLOOK SATURDAY THRU MONDAY: Good.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     10   15     150   1     11   20     250   1
FRASER VLY   QUIL     11   19     250   1     15   26     600   1
SRN VRISL    QUIL     12   15     150   3     17   22     300   3
CNTRL VRISL  QUIL     13   17     150   3     25   26     550   3
NRN VRISL    HRDY     14   11     100   6     36   17     350   9
TERRACE      ANT       9   11     200   3     49   16     850   8
STEWART      ANT      15   11     100   5     28   16     500   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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    E   15   SE  17   SE  11
PORT HARDY   SE  22   S   41   S   46
SANDSPIT     VR   5   S   24   S   35

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      1000 m         28 C
PORT HARDY       800 m         23 C
ANNETTE         1200 m         19 C

TODAY'S VENTING: Poor.


VENTING FOR FRIDAY: POOR.


VENTING OUTLOOK SATURDAY THRU MONDAY: Fair to good.


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


END/GF