Sunday, April 22, 2012

Late-Season Noreaster

Get ready for a late-season Noreaster as its going to be a very wet and windy day.   Temperatures across the area are in the lower 50's in New Jersey and Delaware to the upper 40's in Eastern PA.  They will stay pretty steady throughout the day, only rising a few degrees.  Currently there are light showers over Southern NJ and Delaware, moving from south to north.  The heavier rains that we'll see later on are down in Southeastern VA and the Carolinas at the present time.

Through the morning, the rain will be light, but as we go into the afternoon, conditions will go downhill rapidly.  The rain will become heavy at times and the winds will also increase.  It will vary by location, but brunt of the storm will be from noon today till 10pm tonight.  Again, the timing will vary by location.  Points furthest south will see the worst of it more in the afternoon and early evening, whereas northern most areas will see the brunt later tonight.  With the heavy rainfall, Flood Watches are also up for some counties, mainly in Eastern PA.  We are down several inches of rainfall for the year, the soaker we'll get is much needed.  General rainfall amounts will be in the 1.5 to 2.5 inch range, with some areas, especially closer to the mountains in Northeastern PA and parts of Northern NJ seeing amounts as high as 4 inches.

Coastal Flood Advisories are up for all counties in Southern NJ, as areas along the Delaware River/Bay and Atlantic Ocean could see some minor tidal flooding during high tide.  Dangerous rip currents and high surf are also likely.  Winds will also be a factor, especially down the shore.  A light North to Northeasterly wind this morning, will rapidly increase and turn more easterly this afternoon and evening.  Winds 20-30 mph will be likely.  Winds along the coast will be stronger and gusts could reach as high as 45-50 mph.

This will be quite a significant system for this late in the season.  We have a deep trough that is digging south from Canada.  This combined with a shortwave embedded within it, will help to intensify a low-pressure system at the surface.  The low is currently off the coast of South Carolina and Georgia.  It will drive straight north along the coast, even possibly moving a bit west of North as it gets closer to the NJ coast and will travel  right into New York City and take a track up the Hudson River in New York State.  Normally, we see Noreaster track that parallels the coast and travels in a NNE to NE direction.  But there are types where the low starts offshore and then travels North and even North-North Westerly  direction that goes inland.  These are more rare and sometimes can be referred at "Southeasters".  Its an old term that you rarely ever hear anymore.  If the storm tracks a bit further west than expected and goes inland over New Jersey, some places could see the winds shift to the Southeast, and this could cause more problems with flooding down the shore. 

This system is a quick mover and things will clear out by tomorrow and the rain will be over.  But it will be unseasonably cool the next few days as this deep trough is over the area.