Winter's last hurrah: Chilly, wet and windy, with warm temperatures to follow
Thursday, April 2, 2015, 9:33 AM - Warmer weather is on the way for mid-April, but don’t expect a quiet transition. Before spring-like temperatures finally take hold in eastern Canada, we’ll have a period of cold followed by active weather lasting through the Easter long weekend and into next week.
The forecast for Easter weekend is still complex, but the latest data helps brings the details into better focus. Beginning with Good Friday, a mild afternoon across Southern Ontario will give way to falling temperatures and northwest winds as a cold front pushes across the region.
At the same time, a disturbance developing across the Ohio River Valley will track northeastward along the front. The most significant precipitation is likely to remain south of the U.S. border. Enough moisture will push north, however, for some light snow Friday night across Southern Ontario and Quebec, highlighted in blue on the following image.
Messy Saturday for the Maritimes
As this weather system strengthens, it will bring widespread precipitation to the Maritimes on Saturday. The rain to snow transition continues to be a forecasting challenge, but it is looking more likely that New Brunswick will see mostly snow, while Nova Scotia will see predominantly rain briefly changing over to snow on Saturday evening.
Widespread cold for Easter
In the wake of this system, we will see a cold air mass descend across Canada, which will mean a chilly Easter from coast to coast. This image shows the temperature anomaly (departure from normal) for Sunday April 5. Areas in green are more than 3C below seasonal, while areas in purple are more than 10C below seasonal.
Active spring weather after Easter
Looking beyond Easter, confidence is increasing that we will be moving into a much milder period for mid-April. This image for Sunday, April 12, shows how the warm air will begin to take hold. Notice the distinct contrast with the Easter image.
However, pattern changes of this magnitude rarely happen quietly. Somewhere in between cold and warm there will have to be period of transition, and these transitions can cause a clash of air masses that often bring about periods of active spring weather.
This next image falls in the middle of the previous two, and shows the temperature pattern for early next week. Notice the sharp boundary between warm and cold (red next to blue) across the Great Lakes. These boundaries are breeding grounds for storm systems, and this type of pattern tells us to keep a close eye out for developing storm systems early next week.
As this next image shows, some of the long range forecast guidance is already highlighting the potential for a significant storm system for next week.
These powerful spring systems are capable of producing everything from severe weather and heavy rain in the south to a band of significant snow in the north, often with a messy transition including freezing rain and ice pellets in between. It is important to note that the image below is just one of many possible forecast scenarios at this point, and the key to focus on the overall picture rather than the specifics (such as the rain/snow line) at this stage.
The Forecast Centre will closely monitor the data for next week to determine exactly how this period of expected active weather will play out.
Warmth finally arrives for the east
Once we make it through this active period however, warm temperatures will finally take hold in a persistent fashion for Eastern Canada. This last image shows below the forecast temperature pattern once we reach mid-April. Widespread warmer-than-seasonal temperatures are expected, which is certainly a welcome sight after a cold start to spring.