FPCN39 CWLW 201431 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 Friday 20 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 72 16 950 12 99 20 2300 8 KAMLOOPS KEL 82 16 1700 9 100 22 3350 8 OKANAGAN KEL 88 17 2000 8 100 22 3350 8 CASTLEGAR SPOK 58 14 1000 12 100 20 3500 12 CRANBROOK SPOK 92 13 1950 14 100 19 3950 12 REVELSTOKE KEL 29 13 750 7 96 18 2400 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 PENTICTON VR 5 W 15 W 19 CRANBROOK W 9 W 24 INVERSION HT BREAKTHRU TEMP KELOWNA nil m ## C SPOKANE 1000 m 14 C TODAY'S VENTING: Still only a weak inversion over the southern interior. Generally good venting will develop this morning as the airmass remains unstable. VENTING FOR SATURDAY: GOOD VENTING OUTLOOK SUNDAY THRU TUESDAY: Cool unstable pattern through the weekend. Fair to good venting expected although winds will be light. Some ridging late Monday...forecasting good venting Tuesday. 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. 91 12 1800 17 100 18 3950 13 PR. GEORGE P.G. 84 13 1550 14 100 18 3700 13 SMITHERS P.G. 55 12 1150 9 100 18 3500 12 WELLS GRAY P.G. 81 11 1700 17 100 18 4000 13 FT NLSN F.N. 58 15 750 17 100 21 1850 19 FT STJOHN F.N. 19 12 750 17 44 14 950 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 FRIDAY AFTERNOON (WINDS IN KM/H): 900m 1800m 2700m PR. GEORGE W 17 W 13 SMITHERS NW 13 NW 13 INVERSION HT BREAKTHRU TEMP PR. GEORGE 670 m 11 C FT. NELSON 1000 m 19 C TODAY'S VENTING: Some indication of stabilizing over the interior in the next 12 hours. However, it should not be enough to hinder venting today. In the northeast, an inversion is present and will make for fair to poor venting in most areas. VENTING FOR SATURDAY: FAIR TO GOOD VENTING OUTLOOK SUNDAY THRU TUESDAY: Generally weak flow pattern through outlook. Airmass will be cool and still unstable enough to provide a few hours of good venting in the afternoon. COAST UPPER ***** MORNING ****** ***** AFTERNOON **** AIR VI Tmp MXG HT Wnd VI Tmp MXG HT Wnd (mASL) (kt) (mASL) (kt) VANCOUVER QUIL 34 15 1100 3 65 20 2100 4 FRASER VLY QUIL 33 15 1100 3 74 21 2200 4 SRN VRISL QUIL 34 15 1000 3 64 20 1950 4 CNTRL VRISL QUIL 23 13 500 3 46 17 1450 3 NRN VRISL HRDY 9 10 0 3 50 15 1250 4 TERRACE ANT 9 12 250 6 66 17 2200 4 STEWART ANT 11 11 150 2 62 17 2050 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 FRIDAY AFTERNOON (WINDS IN KM/H): 900m 1800m 2700m VANCOUVER W 15 W 17 W 15 PORT HARDY SW 9 S 13 SW 11 SANDSPIT VR 5 VR 5 VR 5 INVERSION HT BREAKTHRU TEMP QUILLAYUTE 300 m 11 C PORT HARDY #### m ## C near surface ANNETTE 180 m 11 C TODAY'S VENTING: Only a weak inversion present over the coast this morning. Mixing heights however will not be very high and winds are expected to be generally light. Overall, fair to good venting is anticipated today. VENTING FOR SATURDAY: GOOD VENTING OUTLOOK SUNDAY THRU TUESDAY: Fair to good venting. VENTILATION GUIDELINES: 0-33.....POOR 34-54.....FAIR 55-100.....GOOD. VENTILATION INDICES NORMALLY DROP TO POOR AFTER SUNSET. END/BJS