WEATHER BLOG: Cold Snap Coming

A secondary surface cold front has pushed through the region this morning, ushering in the coolest air of the season thus far. 850 mb level temperatures falling to -3 to -4 C today should translate to highs in the middle 50s across the region today, 8-10 degrees below the normal high for October 17.

-There will be some instability shower activity popping in the afternoon again today but at this point we think it remains north and west of the region.

-A large upper level trough will linger today through Monday, meaning this cold air mass will stick around. Tonight, we will likely see our first widespread freeze across the region away from Baltimore-Washington metro.

-Sunday will be the day that the core of the cold upper level trough swings right through the northeastern US with the coldest temperatures at the surface and aloft. We may manage to see some sunshine for the first few daylight hours Sunday but the stratocu cloud cover should develop earlier and will likely dominate over any sun the rest of the day.

-It will be another breezy and chilly mid-November like day Sunday. 850 mb level temperatures are forecast to bottom out Sunday around -5 or -6 C. This combined with all the clouds will make it very tough for surface temperatures to struggle back into the 50s.

-Sunday night will see clearing again as the center of the cold Canadian surface high builds into the Northeast. It should be the coldest night with temperatures reaching down into the 20s by daybreak Monday leading to a hard killing freeze in much of the region. Even BWI metro will get close to 32!

-With the surface high overhead Monday, we should start next week with more in the way of sunshine but it will remain well-below normal with highs only in the low to mid 50s (10 below normal.)

-By Tuesday through the middle of the week, the high will move off the coast, allowing temperatures to warm into the 60s. It would not surprise me if one day toward the end of the week we reach 70!