Based on the latest interpretation of long range forecast information analyzed by Accuweather’s Brett Anderson, the prospect of a high number of severe weather outbreaks in the southeastern U.S. during May are projected.
It appears that there will be an unusually strong jet stream passing over the region during extended periods of the month, which will add a lot more energy to fronts and thunderstorms.
The extended range forecast for May in our region looks like more of the same of what we’ve been having - the cool weather is expected to continue through May.
As of the third week of April, a weak La Nina existed in the equatorial Pacific. La Nina is projected to weaken slowly, and we should be looking at near-neutral conditions by mid-May, according to the International Research Institute (IRI) for Climate and Society.
The consensus is for near-neutral conditions this summer and fall; however, strong easterlies, which are associated with La Nina, remain across the region, and the SOI is still well above normal, which means that despite neutral conditions in the equatorial Pacific, La Nina-type influences on global weather patterns will likely persist into early summer, according to the IRI.
Based on current modelling and La Nina projections it looks like there will be a continuation of cooler weather across much of southern Canada for the rest of this spring, while severe weather will be widespread from the Mississippi Valley to the Middle Atlantic and Southeast U.S. into early June.
The persistence of La Niña conditions into the spring period may affect the continued accumulation and melt of the snow pack through the spring freshet period.
Weather during the April to June period will affect the specific flood risk in snow melt driven rivers of the province. A delayed melt of the snow pack will mean that more snow may be present when we enter into the late spring-early summer period (where there is an increased likelihood of hot weather), and therefore flood risk may increase. The River Forecast Centre will continue to monitor the snowpack and weather conditions throughout the snow melt period, and will revise our assessment of runoff and flood potential accordingly.
Okanagan
Snow pack levels are variable in the Okanagan basin, and range from 84 per cent of normal (Islaht Lake) to 135 per cent of normal (Summerland Reservoir). Overall basin index for the Okanagan-Kettle is 107 per cent.
Similkameen
Snow pack levels in the Similkameen basin are variable, ranging from 83 per cent of normal at Hamilton Hill, to 120 per cent at Lost Horse Mountain. Overall basin index is 101 per cent.