FPCN39 CWLW 191432 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 Thursday 19 June 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 33 17 1350 2 100 22 3200 6 KAMLOOPS KEL 54 16 1950 4 100 22 3350 6 OKANAGAN KEL 59 17 2150 4 100 22 3350 6 CASTLEGAR SPOK 56 14 950 13 100 20 3500 16 CRANBROOK SPOK 100 14 3950 18 100 20 3950 18 REVELSTOKE KEL 18 14 1050 2 100 18 3450 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 THURSDAY AFTERNOON (WINDS IN KM/H): 900m 1800m 2700m PENTICTON W 9 W 17 W 24 CRANBROOK W 9 W 26 INVERSION HT BREAKTHRU TEMP KELOWNA nil m ## C SPOKANE 940 m 12 C TODAY'S VENTING: Little sign of an inversion this morning. Venting should reach good values before noon over most areas. VENTING FOR FRIDAY: FAIR TO GOOD VENTING OUTLOOK SATURDAY THRU MONDAY: Low pressure system moving eastward will maintain unstable conditions. Expect good venting during the afternoon hours through the period. 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 11 2000 27 100 19 3950 24 PR. GEORGE P.G. 100 13 1800 23 100 18 3700 22 SMITHERS P.G. 73 12 1200 14 100 18 3500 20 WELLS GRAY P.G. 100 13 4000 24 100 18 4000 24 FT NLSN F.N. 64 14 750 19 100 18 1700 19 FT STJOHN F.N. 47 12 950 19 100 16 2150 19 *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 W 28 W 28 SMITHERS W 20 W 28 INVERSION HT BREAKTHRU TEMP PR. GEORGE nil m ## C FT. NELSON nil m ## C stable to 800m TODAY'S VENTING: No signs of significant inversion in the interior. Furthermore, winds in the low levels appear to be quite strong. Good venting will develop over most areas before midday. VENTING FOR FRIDAY: FAIR TO GOOD VENTING OUTLOOK SATURDAY THRU MONDAY: Low pressure system moving south of the regions will mean light flow over the this region. Expect generally fair venting to prevail. Short period of good venting possible in some areas during the afternoon. COAST UPPER ***** MORNING ****** ***** AFTERNOON **** AIR VI Tmp MXG HT Wnd VI Tmp MXG HT Wnd (mASL) (kt) (mASL) (kt) VANCOUVER QUIL 100 16 2050 10 100 20 2300 10 FRASER VLY QUIL 96 15 1800 9 100 19 2150 10 SRN VRISL QUIL 58 14 1050 6 100 20 2150 9 CNTRL VRISL QUIL 59 14 1100 6 100 17 2050 9 NRN VRISL HRDY 9 11 0 5 85 15 1750 7 TERRACE ANT 49 13 1950 3 70 17 2550 4 STEWART ANT 18 12 600 2 62 17 2300 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 VANCOUVER W 19 W 19 W 17 PORT HARDY NW 17 W 9 W 13 SANDSPIT W 11 W 11 W 11 INVERSION HT BREAKTHRU TEMP QUILLAYUTE nil m ## C near surface inversion PORT HARDY nil m ## C near surface inversion ANNETTE nil m ## C TODAY'S VENTING: Only a very shallow inversion near the surface shows up on morning soundings. Surface ridge over the coast has lead to diminishing winds. Generally good venting forecast despite the lighter winds. VENTING FOR FRIDAY: FAIR. VENTING OUTLOOK SATURDAY THRU MONDAY: Fair venting on Saturday improving to good Sunday with stronger low level flow developing. VENTILATION GUIDELINES: 0-33.....POOR 34-54.....FAIR 55-100.....GOOD. VENTILATION INDICES NORMALLY DROP TO POOR AFTER SUNSET. END/BJS