The first step of our step down to a much colder pattern then we have been in for much of October occurred over night as a cold front passed through the area again in response to some pretty big changes in the Pacific this week
Our cold front is suppressing the dominant ridging we have seen to the south and east and will give way to a dominant trough starting today and through the foreseeable future , however it will take some time for the truly chilly/cold and well below average temperatures to get here as we are in a gradual pattern change here and so over the next 5 days or so there will be a bit of a roller coaster ride in temperature for the forecast area, although this roller coaster ride will not feature much in the way of above normal warmth, just back and forth between near average temps and slightly below average.
The reason for this pattern change is a large ridge developing over the east Pacific which is leading to a NW flow from the Arctic to spill down into the Central and eastern US, but the problem is we are entering a amped up and slow moving pattern , and right now the ridge is too far west to allow the truly cold air to make it to our area so we have to wait for this ridge to move east. In response to this we will see several cold frontal passages with brief warm ups ahead of them then colder weather behind them.
So for today and tomorrow highs will generally be in the 60s area wide, upper 50s to low 60s NE PA ,mid to upper 60s along the coast and the vast majority of the area with lows in the mid 30s NE PA to the lower to mid 40s towards the coast
The 2nd piece of this pattern break down comes Saturday night into Sunday as another cold front comes into play this cold front will bring the coldest air mass of the season so far with highs struggling in the lower to mid 50s NE PA , upper 50s to low 60s elsewhere on Sunday and Monday and with a stiff northwest breeze, lows at night will be in the lower 30s NE PA , mid to upper 30s for the Lehigh Valley, North NJ , lower 40s for urban areas and coastal areas, most areas may see the first frost of the season early Monday morning. The cold front will bring a few scattered showers Saturday night as well.
Ahead of the 3rd cold front Monday night and Tuesday will come a brief warm up to near average temperatures, in the mid to upper 50s NE PA, mid to upper 60s along the coast and lows in the upper 30s to low 40s NE PA , upper 40s along the coast, lower to mid 40s in areas in between.
This 3rd cold front will be the final piece to the puzzle with again a chance of isolated showers, this front will likely pass through on Wednesday
By Wednesday and especially Thursday behind this front will come the real chill with temperatures struggling in the mid 40s for highs over NE PA , lower to mid 50s elsewhere with lows probably dipping into the mid to upper 20s for NE PA , upper 30s to around 40 for urban locations and along the coast, lower to mid 30s elsewhere through next weekend. We will see generally dry conditions though besides the isolated to scattered showers with these frontal passages.