We are in the midst of a January thaw , (although there really has not been much to thaw out from!) Over the next several days we will see the warmth very slowly back off after peaking on Monday .
So far while its been well above normal, the true warmth HAS NOT made it east of the Appalachians , this is because of cold air damming , this happens a lot during winter warm ups, warm air comes in aloft but cold air from previous cold weather gets trapped in the valley of the Appalachians and east to the coastal plain at the surface due to cold air sinking , warm air rising, so while areas west of the Appalachians have been in the 60s the last 4 days areas east of the mountains have struggled in the mid to upper 40s . There is also a light SE wind off the chilly Atlantic waters which is transporting ow level moisture, overcast skies with lack of sun to help warm us up.
I do expect cold air damming to give way tonight and tomorrow as a cold front very slowly comes our way and winds increase out of the south , which should scour out any cold air that is trapped in the region with slowly rising temperatures over night , however there will still be mostly cloudy skies with maybe some peeks of sun so highs tomorrow will likely be in the low to mid 50s for most, some upper 50s possible if we get decent sunshine.
We see clearly a ridge is dominating the eastern US , and it’s not going to give way easily . We see a deep trough out west entering the Midwest , however as expected by yours truly, the SE ridge will be stubborn and will force the best dynamics and the truly cold air with this trough north before it enters the Northeast and Mid Atlantic .
So instead of having Arctic air and a deep trough sweep through this week , we will see the trough lift North and east and the region will be impacted by the base of the trough with seasonable temperatures to slightly above normal instead of well below normal , you can thank the stubborn southeast ridge .
The cold front will slowly come through tomorrow afternoon with isolated showers but with the dynamics with this trough moving north and away from the area the front will weaken rapidly moving east
Tuesday through Thursday this weak cold front will be forced to stall , again because of the southeast ridge over the Mid Atlantic, weak disturbances will form and ride this front bringing the threat of periods of scattered rain/snow showers each day , with the best chance Tuesday morning and Wednesday morning and the best chance to see precipitation will be over southern NJ , southeast PA Delaware, Maryland and Virginia with the precipitation isolated and light for the NYC metro. Highs will be in the mid 30s interior to low to mid 40s along the coast lows in the low to mid 2os NE PA to upper 20s to low 30s along the coast, which is slightly above normal
You can see above what I mean by the trough and the cold air lifting NE away from our area, the first image is Monday the next is Wednesday , and you can clearly see the trough lift NE and take a majority of the cold air with it
The front will dissipate to our south by Thursday leading to clearing skies and continued temperatures around average through the weekend with conditions, highs in the low to mid 30s interior to upper 30s to low 40s along the coast , lows in the lower 20s NE PA to mid to upper 20s along the coast. A brief moderation Sunday into Monday is possible ahead of another cold front.