More Rain on the way for the Mid Atlantic

Hello Everyone,
It looks as if a model consensus has hit us supporting a increased chance for higher QPF amounts up and down the Mid Atlantic Coasts. Looking at the current observations and radar, you can distinctively see 3 separate systems, all of which will effect our weather in some way tomorrow.

Models have came together to agree on developing a secondary coastal low with the energy situated on the South Eastern US coast. You can see all three pieces of energy very easy on the NAM 500mb chart. With the approaching cold front to the east. The developing coastal low can easily maneuver up the east side of the trough, and use with the energy associated with the cold front to the west. Were the energy from the cold front and the coastal low interact, will form a thin line of the heaviest convection were the heaviest QPF axis will form. 

Most models agree that this 3 piece system will drop heavy amounts of precipitation. Were the heaviest will drop is not completely known. Lets take a look at what 3 different models are showing. Lets start with the GEM

The 12z GEM came in quite wet for the I-95 corridor and much drier for out viewers outside. The GEM really wants the Secondary Coastal low to gain strength rapidly. Doing so will sap the other pieces of energy and weaken the cold front of their convection and keep the area they move over drier. 

You can easily see the weak cold front over Central NY, Eastern PA, down to Maryland. Also look how the secondary Low centered near North Carolina is strengthening in convection. 

Now the cold front has phased with the Coastal Low an the convection from the Main LP is dissipated. The Coastal Low is throwing heavy DBZ bands back over the area with enhanced moisture feed from the SST. With this solution the I-95 corridor would be the area with the most QPF totals. 

Most of the NAM runs today agree with this situation. Looking at the 18z 12Km NAM, its very similar to the GEM, but it wants to keep the initial cold front and pieces of energy to the north stronger than the GEM. Take a look at the simulated 12Km radar.

This is hour 21. See how the coastal low is still situated in North Carolinia, yet the cold front has reached NJ. The LLJ associated with the cold front has allowed the convection to stay stronger. 

Now the cold front moves more through the area and the coastal low is now throwing back more precipitation. Were the Cold front and coastal low interact on this run ends up being in Eastern PA and Western Jersey  down all the way to Maryland. With that the heaviest QPF axis will extend in that region. The NAM also want s to give heavy QPF amounts to Upstate and Western NY. 

With this solution, the QPF maximum axis would be more west than the GEM

The GFS is the outlier at the moment. It dos not really energize the developing coastal low, and is also weaker with the front. It also displaces the heaviest QPF axis into Maryland then into Connecticut. I don't agree with this output map. The GFS isn't close to the consensus so i must count is as the improbable solution right now.

Looking at the current observations and seeing a increasing in convection blow up to the system to the north and east, and the secondary low to the South, i believe most area in the Mid Atlantic are in for a soaking tomorrow. I think a solution a little less amplified than the GEM is showing is the right way to think right now. Widespread 1.5" plus in the I-95, about .5 -1.00 outside the I-95 with a chance for more precipitation in Western NY and Upstate NY in the Adirondacks.  Check your States tab for Rainfall forecasts and a much shorter individual blog.

Have a great day

Ryan Remondelli