July outlook: A glimpse at the month ahead
Tuesday, July 2, 2013, 4:06 PM -
June 2013 will be remembered for the Alberta floods. But what else happened across Canada and around the world last month, and how does this set up the July weather pattern?
Overall, June 2013 was warmer than normal across the high latitudes of the northern hemisphere, from Alaska through Nunavut, and from Scandinavia through Siberia. Notable pockets of cooler than normal weather were found in Western Europe (particularly northern Spain) and near the Bay of Bengal in India.
Surface Temperature Anomalies for June 2013. Green/yellow/red indicates areas above normal, blue/purple indicates areas below normal. Courtesy NOAA.
Closer to home, the Western U.S. ended the month on a record-setting streak of hot weather, while the Midwest and Great Lakes saw temperatures at or slightly below normal. If you thought June was a little on the cool side in southern and central Ontario, the stats support your suspicions – while not dramatic by any stretch, the average June temperature was just shy of normal as it was across coastal Labrador. B.C. was generally above normal, while western Nunavut was one of the most abnormally warm locations in the world with temperatures 5 degrees above the June average.
This weather pattern that saw warmer than normal temperatures north of 60 was part of the jet stream setup that gave southern Alberta and parts of the B.C. Interior heavy rainfall and record flooding.
Surface Temperature Anomalies for June 2013. Green/yellow/red indicates areas above normal, blue/purple indicates areas below normal. Courtesy NOAA. Note the broad area of well above normal temperatures north of 60, contrasted with slightly below normal temperatures in Southern Ontario.
July got off to a hot start through much of Western Canada with temperatures eclipsing 40°C in the dry oven of the Fraser Canyon. Meanwhile, it was hardly beach weather in southern Ontario where July has started on a much cooler and more unsettled note than last year.
These extremes will not hold absolutely for the rest of July. Southern Ontario and Quebec will get their share of hot beach days, and the B.C. interior will have some cooler spells. However, most of the seasonal climate models are suggesting that what we have seen so far this summer may be a sign of what’s to come.
Environment Canada’s climate model indicates above normal temperatures are likely across much of the country for July. The one notable exception is southwestern Ontario.
July 2013 temperature anomaly outlook. Red indicates areas likely to be above normal, blue indicates areas likely to be below normal. Courtesy Environment Canada.
Climate models don’t often agree on monthly and seasonal forecasts, but the U.S. climate model shows the same general trend as the Canadian model, giving some more support to the idea of above normal temperatures for most of Canada for July.
July 2013 temperature anomaly outlook. Red indicates areas likely to be above normal, blue indicates areas likely to be below normal. Courtesy NOAA.
Precipitation is a different ballgame altogether. Much of our rainfall in summer is from thunderstorms which are localized in nature and difficult to predict, even the day of! So a monthly or seasonal precipitation forecast certainly needs to be taken with a grain of salt. However, the U.S. climate model shows an interesting trend of drier than normal conditions across B.C. and Alberta, stretching right through into Labrador.
July 2013 precipitation anomaly outlook. Orange/red indicates areas likely to be below normal (dry), green/blue indicates areas likely to be above normal (wet). Courtesy NOAA.
Hot and dry weather would not be good news for the forecast fire season in B.C., which usually ramps up in August. However, other climate models are not indicating the same degree of dryness across this part of the country.
There does appear to be some agreement on the wetter than normal trend continuing in Southern Ontario for July. This doesn't mean that every day will be wet, but it does seem that this summer is shaping up to be notably different than the summer of 2012 which was very hot and generally dry in this part of the country.
What to watch for
These climate model forecasts are averages over a month, and by nature only provide a sketch of the next four weeks. The timing and intensity of individual weather systems will in the end define the month of July for Canadians.
Keep in mind, it was impossible to see the Alberta floods coming at the beginning of June. The exact details of high-impact weather events generally only come into focus a few days in advance. However, it’s safe to say that looking ahead to July (the peak of severe thunderstorm season in Canada) abundant heat and ample moisture mean more weather headlines will be made in the coming weeks. Also, Atlantic Canadians will need to keep a close eye on the ocean as the hurricane season begins to ramp up. Early indications suggest that the jet stream pattern may be more favourable this year for steering storms in our direction.