Apex Weather

St. John Valley weather for June 16-22, 2021

Short-term outlook — Wednesday-Friday

The 500-millibar upper-level trough associated with the cold front and low pressure that brought last evening’s thunderstorms will slowly move over the Valley today and Thursday with a chance for scattered showers and an isolated thunderstorm or two across the Valley this afternoon. 

An upper-level low pressure just north of the region will keep a chance for scattered showers across the SJV Thursday into the afternoon before precipitation wanes as the system moves east.

High pressure will build into the Valley Thursday evening with mostly clear skies through early Friday morning. Partly cloudy skies develop Friday as a frontal system moves east from the Great Lakes with increasing chances for showers across the SJV Friday afternoon into Saturday.

Today & Tonight 

Mostly clear early then becoming mostly cloudy in the afternoon with a 50 percent chance for showers and a slight chance for isolated afternoon thunderstorms. Rainfall totals less than 1/10-inch. High near 65 with northwest winds 5 to 10 mph becoming west in the afternoon.

Tonight, partly cloudy with a 30 percent chance for scattered showers. Rainfall amounts less than 1/10-inch. Low near 45 with west-southwest winds 0 to 5 mph.

Thursday, June 17
Mostly cloudy in the morning then becoming partly cloudy in the afternoon with a 40 percent chance for scattered showers. Rainfall totals less than 1/10-inch. High around 67 with west winds 5 to 10 mph.

Thursday night, mostly clear with a 5 percent chance for showers. Low near 49 with southwest winds 0 to 5 mph. 

Friday, June 18

Partly cloudy with a 20 percent chance for isolated afternoon showers. High around 80 with southwest winds 5 to 10 mph.

Friday night, mostly cloudy with a 50 percent chance for showers. Low near 55 with south winds 0 to 5 mph.

Medium-Range Outlook: Saturday – Tuesday 

A cold front approaches from the west Saturday bringing showers and a chance for afternoon/evening thunderstorms. Showers and a chance for thunderstorms continue overnight into Sunday morning. 

Showers are likely Sunday as surface front followed by the associated upper-level low/trough moves across the region. Another frontal system approaches later Monday with a chance for afternoon showers. Showers are likely Tuesday as the front moves across the Valley and exits into the Maritimes Tuesday night.

Saturday, June 19

Mostly cloudy in the morning then cloudy in the afternoon with an 80 percent chance for showers, especially in the afternoon along with a chance for scattered afternoon thunderstorms. High near 75 with south winds 5 to 10 mph.

Saturday night, cloudy with a 70 percent chance for showers and a chance for scattered thunderstorms. Low around 54 with south winds 0 to 5 mph.

Sunday, June 20, 2021 / Summer Solstice at 11:32 pm ET

Cloudy with a 70 percent chance for showers and a slight chance for isolated afternoon thunderstorms. High near 74 with west winds 5 to 10 mph.

Sunday night, mostly cloudy in the evening with showers likely then becoming partly cloudy with a 20 percent chance for isolated showers. Low near 51 with west winds 0 to 5 mph.

Monday, June 21

Partly cloudy with a 40 percent chance for scattered showers, mainly in the afternoon. High around 81 with southwest winds 5 to 10 mph.

Monday night, considerable cloudiness with a 60 percent chance for showers. Low around 59 with south winds 0 to 5 mph.

Tuesday, June 22

Mostly cloudy in the morning then overcast in the afternoon with showers likely. Chance for precipitation 60 percent. High around 78 with south winds 5 to 10 mph.

Tuesday night, becoming partly cloudy with a 50 percent chance for showers. Low near 55 with west winds 5 to 10 mph.

Long-Range Trends: Wed. June 23 –  Tue. June 29
Above normal temperatures   / Near normal precipitation

Note: Computer model precision diminishes the further into the week the forecast projects. Check the Fiddlehead Focus for weather updates with more current information.

The Week Ahead is the work of UMFK Professor Joseph E. Becker based on personal weather station data, various computer forecast models, and information that the National Weather Service, NOAA, and other weather resources provide.

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