Tuesday 8 a.m.
While it will be generally mild to warm, a frontal zone will cause changes as it moves southeastward today, stalls tomorrow in Maryland or Virginia, then moves back north on Thursday and Thursday night. Some showers and thunderstorms will affect the area from the Ohio Valley into the Northeast today (west) and tonight (east).
All the computer models show heavy rain during the Thursday to early Friday period in the area surrounding Lake Michigan. Racine, Wis., and Kalamazoo, Mich., have had close to average rainfall for all of April even though the month is barely half over.
The storm that brings rain farther south will cause more snow in the upper Great Lakes. It may get cold enough to allow snow showers in western Michigan by Friday night then in western New York by Saturday morning.
This video deals with Northeast weather for the rest of the week and into the weekend.
This map highlights the pressure pattern and resulting flow from the Ohio Valley eastward this morning.
The upper-air flow forecast for this evening shows the trough that helps to support rainfall ahead of the cold front.
After reaching the 80s today from NYC to Boston, it might not be that warm again through much of next week.
A noticeable push of cooler air will spread southward from Ontario and Quebec into the eastern Great Lakes and New England between tomorrow and Saturday.
A cold front from eastern Canada will slide southward along the East coast between late Friday and the end of the weekend. For the area from Philadelphia to Boston, where temperatures will reach the summery 80s each day through Friday, it will mean a noticeable change to cooler weather.
Average high temperatures in Chicago and New York City are in the mid-70s now, but for the next several days, temperatures will run 8-15 degrees above those long-term averages. Supporting this warmth is a flow aloft that originates over the Southwest:
Rain was common in the Northeast this morning, though Boston was still waiting as of 9 a.m. Their summer dry spell has continued.