Plain-language summary:
A storm very similar to Friday's storm will bring southerly winds followed by a period of rain, heavy at times, today before turning much colder for Monday and Tuesday. A swath of snow, locally heavy, is likely from eastern Ontario to southern Maine Monday night into Tuesday morning. After a cold Tuesday, it rapidly warms up through Thursday, before a cold front bring some showers and temporarily cooler air late Friday into Saturday. Despite some uncertainty afterward, the weather starting next weekend looks rather mellow and relatively warm though perhaps on the cloudier side with rain chances, though it could turn cooler later the following week.
Meteorological discussion:
Today brings similar storm to Friday with southerly winds followed by a period of rain, heavy at times
It has been a rather active week across our region, though without the wintry precipitation that looked likely earlier due to the mid-week storm being stronger and tracking much farther north than previously expected, eliminating what was likely the last chance of widespread decent snowfall for our region. Instead, light rain fell for most before the warm front and most of the precipitation passed to the north, leading to southerly winds and warmer temperatures on Friday, except for Maine which remained more in the cold air, with northern areas receiving some ice pellets and freezing rain. Yet another similar storm is tracking through a similar region of central Quebec today, just two days later, with another round of southerly winds, but this time, with most of the rain (heavy at times) falling along the cold front.
Turns chilly Monday and Tuesday with snow likely from eastern Ontario to southern Maine, locally heavy in a narrow zone
Behind the cold front, a rather chilly though certainly not record cold air mass for early April will push into the region tonight into Monday, accompanied by some snow showers, especially in higher elevations, though accumulations will be none or minimal. This cooldown is occurring as the extreme upper-level ridge to the south and west that was dominant in March, causing many places to our southwest to experience the warmest March on record, is finally weakening, with broad temporary upper-level ridging in the western U.S. promoting an upper-level trough temporarily over eastern North America. A moisture-starved disturbance in the west-northwest flow will enter southern parts of the region, from eastern Ontario to southern Maine, Monday night into Tuesday. With the cold air in place, precipitation will fall as snow. Given that the disturbance is relatively weak and moisture-starved, precipitation will be much lighter and less widespread than with the storms this past week. However, it being April, the low-levels are warmer and more unstable than they would be for a cold air mass in the middle of winter, which will promote convective snow showers and bands that could bring locally heavy snow in a narrow area.
 |
| Source: TropicalTidbits |
 |
| Source: Climate Prediction Center |
Cold Tuesday before quickly turning warmer through Thursday
Unseasonably cold air will be reinforced behind the disturbance later Tuesday, but will not last long as an upper-level trough entering western Canada (-PNA) will promote some upper-level ridging in the eastern U.S. later in the week. The cold surface high-pressure system that will bring an unseasonably cold night Tuesday night will move southeastward into the western Atlantic later in the week, promoting southwesterly flow, sunshine, and quickly warming temperatures through Thursday. While the record heat of March to the southwest is gone, the persistent arctic air to the north during March, with parts of central and northern Canada experiencing the coldest March on record, is also weakening. This is leading to a large decrease in the temperature gradient and weakening of the baroclinic zone, with the wild March weather becoming much more mellow as we head deeper into April, in contrast to some other Aprils with wild weather. The continued positive NAO and AO also does not favor arctic air plunging southward deep into the U.S.
 |
| Source: Patrick Duplessis and PRISM |
 |
| Source: TropicalTidbits |
Some showers likely late Thursday into Friday before temporarily cooler through Saturday, then likely mellow and relatively warm with occasional rain chances
A low-pressure system passing to the north will likely bring some showers late Thursday into Friday before briefly turning colder again behind a slow-moving cold front later Friday and Saturday, though the air mass does not appear especially cold like it did in March. Given the overall upper-level ridge in the eastern U.S. likely to be present for most of the following week, storms will likely track to the north or northwest of our region, leading to cooldowns being relatively brief and our region being in the warm sector of the storms, leading to mostly above average temperatures with rain likely along the warm and cold fronts. Unlike the warmups in March, the upper-level ridge axis near the U.S. East Coast favors a deep south-southwesterly flow of moisture from the Gulf of Mexico, likely leading to a "dirtier" warmup with more clouds and showers, especially in northern areas closer to the low-pressure track and baroclinic zone. However, if the upper-level ridge is weaker, that would allow for cold (even if not as cold as in March) surface high-pressure systems to sneak from the north and resist any real push of warmth, which would also lead to a farther south storm track that would bring longer-lasting periods of colder rain and cloudiness to our region. That is still a possibility, albeit not the most likely scenario, though that is a bit more likely later the following week as the AO becomes somewhat less positive and the eastern U.S. ridge weakens.
 |
| Source: TropicalTidbits |
No comments:
Post a Comment