Fantastic first week of fall weather; season predictions

A block in the jet stream and high pressure has the Maritimes setup for a very sunny first week of autumn.

The blocking pattern is known as a Rex Block. This occurs when high pressure sits north of low pressure at the height of the jet stream, which is about 10 kilometres above the surface. The block will stagnate our weather for the next several days, allowing high pressure to prevent much in the way of cloud or precipitation developing.

A developing block in the jet stream is likely to keep high pressure in place for the Maritimes over the next several days. (CTV/Kalin Mitchell)

It looks likely the block will last into next week which means we are looking at early October before our next chance at widespread rain or showers.

Clear sky at night does increase our risk of frost. Frost Advisories are in place for Monday night/early Tuesday morning for the province of New Brunswick with the exception of Charlotte County. Frost Advisories have also been issued for parts of northern and eastern mainland Nova Scotia.

High temperatures this week are expected to be at and above the climate averages for late September which are in the mid-to-high teens.

Frost Advisories in effect for the province of New Brunswick Monday night into Tuesday morning.

SEASON PREDICTIONS

The Canadian seasonal prediction system run by Environment Canada indicates a higher likelihood of above normal temperatures for Fall 2023. The same system indicating equal probabilities of precipitation being above or below normal.

Seasonal outlooks produced by the National Ocean and Atmospheric Association (NOAA) out of the U.S. end toward the Canadian border. If, however, we extend the predicted conditions for New England into the Maritimes it shows above normal temperatures and equal chances of above or below normal precipitation for the season. In other words, very similar to the prediction from Environment Canada.

The probability of above normal temperatures through October-November-December per Environment Canada.

We are now past the climatological peak of the Atlantic hurricane season. The frequency of development of tropical storms and hurricanes historically slows through the Fall. The season does extend all the way through the end of November.