10:11 AM

One disturbance has already raced through the forecast area early this morning with a steady moderate rainfall throughout much of the region, however there is a lot more rain on the way over the next 24 to 36 hours that will bring much needed relief to the drought stricken Mid Atlantic.  Unforunantly, this will have to occur on the weekend, but I guess it’s best to get into this pattern before the summer months.  

The disturbance that brought the rain this morning will continue to move off the coast with generally party cloudy skies throughout the forecast area by this afternoon.  More breaks in the clouds are expected over the Hudson Valley and Connecticut than points to the south, while southern New Jersey will likely remain mostly cloudy as moisture at the mid levels continues to stream into the southern and central Mid Atlantic.

ecw11A picture can sometimes tell you a lot about the pattern better than any model guidance and this morning’s water vapor image is no exception.  Of course, the first thing that stands out is the bright colors over the Southeast, however that’s not what is important here.  Those bright colors are the direct result of convective development or thunderstorms.  The warm, moist air is rapidly rising in these locations as the thunderstorms intensify.  The Southeast is in for a stormy afternoon with a chance of severe thunderstorms.  However, the key here are two important features.  The first is the well developed upper low over Oklahoma, which by the way has produced basically a blizzard over the western two-thirds of that state and Kansas.  Side note, after living there for six years, those guys are in shut down mode and I wonder how many actually where able to watch Oklahoma take out Syracuse last night.  Anyway, that upper low is quickly tracking towards the central Great Lakes, which is starting to produce any environment of rapidly divergence air current over the Mid Atlantic, which by the way is enhancing the lifting over the Southeast and Mid Atlantic.  I think the strength of this upper low and divergent wind current over the East coast is what enhanced the rainfall from early this morning and will likely continue to do so through tomorrow afternoon.  The trough is also setting up into a negative tilt along the East coast, which will slow down the progression of the cold front tonight and produce an environment of strong moist air advection at 700 and 850 MB over the Mid Atlantic from the Atlantic.  

The other feature that stands out is the upper level flow out of the Gulf of Mexico up into the Mid Atlantic.  We have an established flow at 500 MB of strong moisture advection, which will support a highly saturated atmosphere over the forecast area through tomorrow afternoon.  

So let’s combine everything!  We have an environment favorable for rising air throughout the Mid Atlantic, a slowing of the entire progression of the storm from southwest to northeast, and plenty of moisture at all levels of the atmosphere that will entire the forecast area from this evening through much of Sunday morning.  Obviously, this should all lead to some impressive rainfall by Sunday morning.  Combine these factors with the evolution of an occluded front (discussed last night in this post), and the set up is prime to produce heavy rainfall over the forecast area with the potential for some minor small stream and urban flooding.  Rainfall amounts of an inch to two inches will be possible by Sunday afternoon as the cold front clears the forecast area.  The heaviest rainfall is expected tomorrow morning between the hours of 4 AM and 11 AM as the cold front enhances the lifting over the entire region which will be seen as an elevated line of heavy showers and thunderstorms.  Wind damage may be an isolated threat with these storms.  

High pressure will build into the region on Sunday night and Monday with windy conditions and partly cloudy skies.  Temperatures through the period will average near  normal.