At Little Chute, Wisconsin, the Great Wisconsin Cheese Festival starts today. Temperatures there may drop to the 40s tonight. That's not teeth-cheddaring, but it sure won't feel like Monterrey, Jack.
Before the front went through, we saw a parade of clouds with some showers and thunderstorms moving from southwest to northeast (left to right in the time lapse movie). As soon as the front arrived, dense, cool air moved in from the northeast.
Since yesterday, a high pressure area has expanded into New England. If you trace the flow using the isobars, you can see that the previous flow from the ocean has largely weakened. This means warmer afternoons for New England but causes cold nights.
The current surface pattern clearly shows the flow that is bringing ocean-cooled air in from the east. If the high pressure area to the north expands southward as expected by tomorrow, this flow will be weakened and perhaps cut off.
The cold front is embedded in a large area of clouds, showers and thunderstorms covering the middle of the country. It will advance past the Northeast coast by the end of the day Sunday. The frontal zone is shown on this picture from late morning Friday.
When weather systems are relatively weak, small scale variations cause forecast uncertainty because several different weather types (such as showers, sunshine, cloudiness, etc.) can coexist in the same region and change constantly. This map shows such a pattern:
Some of the thunderstorms can become severe, with damaging wind and brief cloudbursts of rain. The greatest chance for locally severe storms should be in the "S" areas highlighted on this map (based on the NWS Storm Prediction Center's guidance).
There is a slight risk for severe thunderstorms later today from north-central Tennessee up across Indiana and Ohio to Michigan and eastern Wisconsin (shown by the "S" area on the map below. Thunderstorms are not predicted for areas near the coast from Delaware to New England.
It is not going to snow any time soon, but in any type of weather the flag is a symbol of freedom. This holiday weekend we celebrate the contributions of those who were there to defend the freedoms we enjoy in these times.
Once again, the rain will miss much of central and northern New England. The region has been in a dry spell, as evidenced by its appearance on this U.S Drought Monitor map.