- Issued at
- 04:00 PDT/PST
- Created by
The HEAT Continues
A continuation of hot and dry weather with an increase in daily high temperatures is anticipated.
Expect freezing levels to reach 4000 m over extreme southern B.C. and up to 3500 m over North Thompson and surrounding regions. Temperatures over B.C. will also range from 5-10 degrees above seasonal values for today and Monday. In some places, the combination of recent rain followed by increased runoff due to warming will lead to rising streams and rivers. On the other hand, on the outer periphery of the ridge, the Liard Basin will remain vulnerable to more precipitation today followed by mild (but not dramatically warm) conditions on Monday. Be sure to check the B.C. River Forecast Centre website for the latest flood warnings and advisories.
Another transition will occur Monday night and Tuesday with a return to cool and wet conditions, at least for the southern half of B.C.
The 500 mb animation above shows an upper ridge firmly anchored over British Columbia. The resulting warming trend is shown by the rising partial thicknesses (orange dashed lines) which reflect the overall composition of the airmass above any given point across our region at a given time. For B.C. overall, with the exception of the northeast, we see a range from 558-570 dam on Sunday and Monday. There is a second extension of the ridge into the western Yukon that morphs into its own high-pressure centre by Monday. This upper high-pressure should persist through mid-week.
Meanwhile, further south, the ridge will be eroded by an approaching cold upper low off Vancouver Island Monday evening. This new system thoroughly replaces the ridge and banishes it well to the east by Tuesday morning. The model consensus is fairly strong and overall has been trending faster on this transition, so we are now more confident that this will occur by early Tuesday at the latest, with a push of cooler marine air onto the coast. Widespread instability will also develop and should trigger showers and possibly thunderstorms across a broad southern half of the province. Details will be refined with time, but it will definitely be much cooler and potentially wet for most of British Columbia on Tuesday... except for the north, which will remain warm and dry along with the Yukon.