Technical Discussion

Synopsis

 A trough in the south will bring moisture associated with tropical storm Nicole up toward the state for late Wednesday night into the day on Thursday. The models are still a little off for the placement of this low pressure coming up the coast. Heavy rain is associated with this system and the mixture of rain and clouds will keep temperatures down for Thursday. A weak cold front will push the disturbance out of the way but a trough will linger into the weekend. This will also bring a shot of cooler air in the region and also keep the chance for a lingering shower to occur.

Short-term(Thursday-Friday)

The moisture from tropical storm Nicole will arrive overnight and last into the day on Thursday. The models are still unclear of the exact track of the system. The 12z run of the NAM has the storm more towards the east, bringing the heaviest rains towards more of the eastern parts of PA. The GFS has the storm more inland over central PA, with the heaviest rains over central and eastern PA.  Im leaning towards the NAM, but I kept the chance for heavy rain across the state. Wherever the placement the rainfall totals will be great with GFS totals up to 3-4 inches over some parts of the state. This means the possibility for small stream and street flooding is there. A weak cold front will pass through and push out the tropical system for the day on Friday. Cool air will move in behind this front bring below average temperatures to the region.

Long-term(Saturday-Sunday)

A trough will build in and stick around for the weekend. This will also filter even cooler air to the region, as temperatures this weekend will have a hard time getting out of the 50s. The GFS shows the chance for an isolated shower for both days. I put it in for the day on Sunday as the greatest divergence will be over us that day which could produce a few showers. Otherwise overnight temperatures will be very chilly as some of the cooler, northern spots could even get down to freezing.  These northern spots could easily see frost especially on Sunday night, with low temperatures dipping down close to freezing.