A push of cool air and warm, moist air will clash over the northeastern United States to end this week and the first weekend of May, AccuWeather meteorologists say. In addition to a strong temperature contrast from east to west, conditions will range from sunny to rainy and even thundery, all in a span of 100 miles.
Thursday may very well be the best day of the week for outdoor plans for the Northeast region as a whole.
A high pressure area will first nose southward over the Maritime Provinces of Canada to end the week. This will force a flow of cool ocean air across New England and the mid-Atlantic region.
“The pattern will create cool, damp and likely drizzly conditions in parts of southern and western New England and the mid-Atlantic coast on Friday,” AccuWeather Senior Meteorologist Tom Kines said. “But at some point in northern New England, the weather may turn out rather nice with dry air and sunshine.”
Farther west, warm air will surge over the Ohio Valley and into the Appalachians Friday and set the stage for trouble this weekend.
The setup could result in the eastern slopes of the Appalachian spine being quite cool, with temperatures peaking within a few degrees of 60. Meanwhile, on the western slopes, temperatures may climb into the 80s.
Aside from the pockets of drizzle in the Northeast Friday, no widespread areas of heavy, soaking rain are likely. That will change during the weekend, however.
The moisture from the Atlantic will be joined by moisture from the Gulf of Mexico as a front approaches from the Midwest this weekend.
An eruption of showers and thunderstorms will result and expand eastward from the Appalachians to the mid-Atlantic and New England during the weekend.
“Some areas will turn out really miserable this weekend with clouds, episodes of rain and cool conditions much of the time,” Kines said.
Even though an all-out washout is not likely due to a mosaic of moisture, temperatures during the day may be no better than the 50s where the sky remains cloudy and rain falls off and on, and highs in some places could even hover in the 40s at times.
“Conditions this weekend will be far less than ideal for outdoor plans ranging from graduations to picnics and ball games,” Kines said. “People are encouraged to keep checking on the forecast for details on the timing of the rain for their location of interest.”
Where warm air holds on and expands eastward or even gets close enough, drenching and locally gusty thunderstorms may develop. These are most likely to occur from the Appalachians on west into the Ohio Valley during the second half of the weekend. A few thunderstorms may also erupt in parts of Virginia, Maryland and Delaware.