Frightening weather forecast for Halloween in Montreal

Dark skies and showers early in the week gave way to sunshine and typical October weather on Tuesday and Wednesday. Unfortunately, the fair weather will not hold for Halloween, with strong low pressure expected to bring Montreal a damp, breezy and cool night for Trick or Treating. (Valley Weather)

Expect a cool, breezy and damp Halloween night in Montreal.

After a rather chilly but fair weather week in Montreal, low pressure will move into the region unfortunately bringing with it a wet Halloween forecast. High pressure will dominate our weather Wednesday, with sunny skies, light winds and a seasonable high around 10 (50F).

Clouds will increase overnight as low pressure begins to organize in the Tennessee Valley. This system will deepen as it move along the spine of the Appalachians into southern New England. A surge of moisture ahead of the storm will push rain into the St. Lawrence Valley on Thursday. 

Meanwhile a secondary area of low pressure will develop along the middle Atlantic coast and become the stronger storm as it lifts into northern Maine by Saturday. Deep Atlantic moisture will stream into southern Quebec on Friday. Combined both these storms will deliver a soaking rain from late Thursday into Friday. In all, 25-50mm is possible in the Montreal region.

The hope is that the steady rain will taper to a more showery situation by Trick or Treating time Friday night, but the weather will still be damp, breezy and cool regardless. Temperatures will be cool throughout the period, with lows around 5C (41F) and daytime highs in the upper single digits. Sunday turns even colder with lows near freezing and a high around 6C (43F). Gusty northwest winds will make it feel even colder.

Saturday will remain cold and damp with scattered showers and even a snowflake or two across the higher elevations of the Eastern Townships, Adirondacks and Green Mountains.