FPCN39 CWLW 281331
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 TUESDAY 28 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      26   15     700   4     53   24    1800   3
KAMLOOPS     KEL      22   14     750   4     57   23    1900   4
OKANAGAN     KEL      11   12     600   1     57   23    1900   4
CASTLEGAR    SPOK     19   14     850   3     49   23    2100   3
CRANBROOK    SPOK     30   12     850   4     60   22    2400   3
REVELSTOKE   KEL      19   13     750   4     54   22    1900   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 TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PENTICTON    VR   5   SW  17   SW  22
CRANBROOK             VR   5   SW  19

           INVERSION HT    BREAKTHRU TEMP
KELOWNA         1400 m         23 C
SPOKANE         1000 m         21 C

TODAY'S VENTING: FAIR TO GOOD.


VENTING FOR WEDNESDAY: FAIR.


VENTING OUTLOOK THURSDAY THRU SATURDAY: FAIR THURSDAY. BECOMING GOOD
FRIDAY AND SATURDAY.

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.     29    9    1200   8    100   17    3950  16
PR. GEORGE   P.G.     15   10     850   4     94   15    2150  10
SMITHERS     P.G.     11    8     600   2     23   12     950   4
WELLS GRAY   P.G.     36    9    1350   8    100   17    4000  16
FT NLSN      F.N.     30   10    1500   4    100   16    3200  10
FT STJOHN    F.N.     45    9    1500   8    100   15    3200  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 TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
PR. GEORGE            SW  26   SW  46
SMITHERS              SW  31   SW  46

           INVERSION HT    BREAKTHRU TEMP
PR. GEORGE        600 m         13 C
FT. NELSON      MISSING        MISSING

TODAY'S VENTING: GOOD EXCEPT POOR IN THE NORTHWEST.


VENTING FOR WEDNESDAY: GOOD


VENTING OUTLOOK THURSDAY THRU SATURDAY: GENERALLY GOOD.


COAST

           UPPER      ***** MORNING ******    ***** AFTERNOON ****
             AIR      VI  Tmp  MXG HT  Wnd    VI  Tmp  MXG HT  Wnd
                               (mASL)  (kt)            (mASL)  (kt)
VANCOUVER    QUIL      9   13     200   0     12   18     600   1
FRASER VLY   QUIL      9   14     250   0     56   24    1850   3
SRN VRISL    QUIL      9   12     200   0     12   19     600   1
CNTRL VRISL  QUIL     10   15     350   0     44   23    1650   3
NRN VRISL    HRDY      9   10       0  12     54   16     950  10
TERRACE      ANT      10    6     250  11     10    8     250  11
STEWART      ANT       9    6       0   6     20    8     200   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 TUESDAY AFTERNOON (WINDS IN KM/H):
             900m     1800m    2700m
VANCOUVER    VR   5   VR   5   SW  17
PORT HARDY   VR   5   SW  19   SW  31
SANDSPIT     SW  20   SW  33   SW  46

           INVERSION HT    BREAKTHRU TEMP
QUILLAYUTE      900 m          26 C
PORT HARDY      1000 m         16 C
ANNETTE         NONE           N/A

TODAY'S VENTING: FAIR TO POOR.


VENTING FOR WEDNESDAY: POOR TO FAIR.



VENTING OUTLOOK THURSDAY THRU SATURDAY:  POOR TO FAIR THURSDAY.
BECOMING GOOD FRIDAY AND SATURDAY.




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


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