Low pressure is crossing the Great Lakes, with an attendant cold front stretched from western N.Y. to the Ohio River. Ahead of the cold front breezes from the southwest were continuing to direct unseasonably mild air across the Northeast Seaboard. Temperatures were still in 30s to low 40s in many places, 15-20 degrees above normal for this time of day. We reached 54 at BWI Marshall Saturday and 57 at the Science Center.
The Great Lakes low will track to near Quebec City by Sunday night which will allow the aforementioned cold front to cross the region Sunday afternoon. Despite the cold frontal passage, it will remain rather mild as very gusty winds from the west cause air to subside/sink from the Appalachian mountains, compress and warm…an effect called “compressional warming”…which will essentially slow the arrival of the cold air until later Sunday afternoon. The aforementioned moisture-starved front will be accompanied by some afternoon clouds, but no precipitation is expected. As mentioned, temperatures will then quickly fall Sunday night, reaching the mid 20s by Monday morning.
Monday will start with a little sunshine as a weak zone of high pressure crosses the region ahead of a jet stream disturbance moving east from the Great Lakes/Ohio Valley, it will then cloud over by late morning.
The disturbance will cross our area later in the afternoon and evening accompanied by clouds and a few snow showers. Enough snow may fall to coat the ground. Blustery winds from the northwest will direct the coldest air so far this winter into the viewing area late Monday night into Tuesday … which will persist through the remainder of the week. Indeed, temperatures will struggle to reach 30 from Tuesday through at least Thursday, and we should stay below freezing through next weekend …. certainly colder than any weather we experienced last winter! The good news is that the gusty winds will subside on Wednesday as Canadian high pressure moves across the East …. so Wednesday and Thursday will be partly to mostly sunny, frigid with mainly light breezes.