FPCN39 CWLW 291400
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 29 APRIL 1999 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       9   10     550   0    100   20    3200   5
KAMLOOPS     KEL       9   10     800   0    100   20    3350   5
OKANAGAN     KEL       9    8     550   0    100   19    3350   5
CASTLEGAR    SPOK     11   10     900   0    100   19    3500   7
CRANBROOK    SPOK     10    7     950   2    100   14    3950   7
REVELSTOKE   KEL       9   10    1050   0     81   18    3450   5

*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    N    9   NE  15   E   17
CRANBROOK             E   19   E   44

TODAY'S VENTING: GOOD.


VENTING FOR FRIDAY: FAIR.




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.     31    6    1400   5    100   14    3950   8
PR. GEORGE   P.G.     42    5    1050  10    100   14    3700   8
SMITHERS     P.G.     40    8    1100   6    100   14    3500   7
WELLS GRAY   P.G.     30    4    1100   6    100   16    4000   8
FT NLSN      F.N.     20    5     600   5     83   12    2150   7
FT STJOHN    F.N.      9    3     700  10    100   10    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 THURSDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SE  11   S   19
SMITHERS              S   33   S   19

TODAY'S VENTING: GOOD.


VENTING FOR FRIDAY: GOOD.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL     26   11     300   8     98   16    1400  13
FRASER VLY   QUIL     32   12     300  10    100   21    3050  13
SRN VRISL    QUIL     22   10     250   6    100   17    2100  12
CNTRL VRISL  QUIL     31   13     350   7    100   20    2250  12
NRN VRISL    HRDY     11    7     200   1     77   14     600   8
TERRACE      ANT      10    8     200  20    100   15    3200  32
STEWART      ANT       9    8       0  10    100   15    2300  26

*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    N   15   NE  17   NE  15
PORT HARDY   S   19   S   30   SW  33
SANDSPIT     S   61   S   59   S   57

TODAY'S VENTING: GOOD.

VENTING FOR FRIDAY: FAIR.


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


END/MWSO
$$$$^^