Although a fair weather dome of high barometric pressure is cresting over New England today, locking in dry air for plenty of sunshine mixed only with a few high altitude clouds, the big storm making headlines in our nation’s midsection will have an impact on our weather, even as it moves into Canada. The counter-clockwise flow of air around the major Central U.S. storm has already scooped up a wealth of warmth responsible for record high temperatures in the South-Central U.S., and while that air will moderate on its way to New England, we still expect pronounced warming this weekend. In the transition from cool, dry air to warmer air, we’ll find clouds increasing overnight Thursday night, cloudy skies with sprinkles and highs in the 50s Friday, and rain showers overnight Friday night into Saturday morning. The biggest factor in Saturday’s weather is how quickly rain showers depart…with showers expected to slowly sag southeast Saturday morning to midday, likely allowing sun to break out for all but Cape Cod and the Islands, meaning all but the Cape should also be poised to rise to the 70s by day’s end. Sunday will start dry but the next approaching storm center will be moving east into New England with rain developing by late day and evening, continuing into Patriots Day and the Marathon. It seems quite likely rain will continue into the marathon, with our exclusive NBC10 Boston/NECN Forecast System showing a 75% chance of rain Monday, though it’s likely the heaviest would be focused during the morning and if luck is on our side, perhaps the heaviest could slide through before the starting gun, but right now it’s too early to say if that hope will hold merit. The biggest question Monday is temperature right now, which is especially important if it’s wet, but right now our First Alert Team expects 50s. The middle of next week will hold the best days for outdoor plans during school vacation week before the chance of showers and rain rises again toward the end of the week in the exclusive First Alert 10-day.