Monday July 21, 2025

7/21/2025

"Maine summer" conditions through midweek

A cool, dry air mass is expected to persist in the region tomorrow, ahead of a ridge building to the west. This ridge will bring warmer temperatures mid-week, with southerly flow bringing more moisture to the area by Thursday. Temperatures will become uncomfortable by the end of the week, with heat indices in the mid-90s in the southern part of the state. A slow-moving cold front may bring storms late this week, although the timing remains uncertain.

Cool and dry conditions stick around on Tuesday

Conditions will remain cool and dry on Tuesday as high pressure builds in Tuesday afternoon. Highs will only reach the mid-70s south of the mountains, and the low 70s up north. Low dew points in the mid-40s to low 50s will keep conditions pleasant across the state. Clear skies are expected, with some scattered clouds. Nighttime temperatures will be cool, ranging from the upper 40s to the low 50s.

Moisture moves into the region midweek
as temperatures heat up

Wednesday 2 PM (18z) to Thursday 8 PM (00z Friday) - With the ridge centered over the region, temperatures are expected to begin heating up on Wednesday. Highs will top out in the mid-to-upper 70s, with an afternoon sea breeze helping to keep the coast cooler. Conditions will become more humid late in the day on Wednesday, as southerly winds bring additional moisture into the region. This will bring increased cloud cover to the state, helping to keep temperatures in the mid-60s Wednesday night into Thursday.

The heat peaks late week

Hot, humid conditions begin to build in during the day on Thursday, with dew points climbing to the mid-to-upper 60s and temperatures inching into the low 90s. Friday will likely be the warmest and most uncomfortable day of the week, with heat indices in the mid-to-upper 90s and dew points in the low 70s. Temperatures are dependent on the timing of an approaching cold front, however, and may be cooler if the cold front moves through early in the day on Friday.

Late week outlook... storm potential?

A slow-moving cold front is expected to move into the region late in the week. The timing of the front is uncertain, with current models indicating that it will push through sometime on Friday. The timing of the cold front will be the determining factor for Friday’s temperatures and any possible storms. If the front doesn’t arrive until late Friday, heat indices may reach the 95-100º range, and more widespread thunderstorms may develop. Another ridge behind the front may bring sunny skies back for late in the weekend into next week, but this is also dependent on the timing of the cold front. Confidence remains extremely low regarding the timing of the front, so stay tuned for more information as we approach the end of the week.

Temperature outlook through Sunday

Today's update prepared by Michigan State student intern
Harry Fuess

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