All indications continue to point to a wild night in the Mid-Atlantic region along the I-95 corridor from DC-to-Philly-to-NYC as a powerful cold front barrels towards the east coast.The threat for localized flooding and damaging wind gusts continues with the latest NAM model run at 12Z.
Heavy rainfall in the overnight hours should produce a widespread 1-2 inches along the I-95 corridor, but there can be local amounts of up to 3 inches.The likelihood for localized flooding (e.g. streams, streets) is increased because of the recent frigid spell experienced in the Mid-Atlantic region.The ground has thawed out in the top few inches due to the recent milder temperatures, but not too far below the surface, it is still quite frozen and this will force quite a bit of runoff in the overnight hours as the heavy rain falls in a short period of time. Furthermore, there is some snowmelt upstream that will likely contribute to the higher water levels in the Mid-Atlantic rivers and streams.
As far as winds are concerned, there continues to be a vigorous short wave at 500 mb (below) that takes on a slight negative tilt (orientation from NW to SE) in the overnight hours as it crosses the Great Lakes and Ohio Valley and a widespread strong jet streak of 130+ knots at 250 mb (below) approaching the southern Mid-Atlantic.All of this is in addition to a rapidly intensifying surface low pressure over the Great Lakes and a strong low level jet that has actually been increasing in strength on the latest computer models as the event draws near.Cold air pours in on Thursday behind the frontal system.
Bottom line, prepare for a wild night in the Mid-Atlantic region with localized flooding and strong-to-damaging wind gusts.