From Mt. Holly:
 
NEAR TERM /UNTIL 6 PM THIS EVENING/...
Its been an interesting couple of hours this morning as the warm
frontal rainfall generally fell east of where we had anticipated
it. We`ve seen generally 0.5-1" of rainfall east of the I-95
corridor and across DelMarVa. Based on forecast RFC Flash Flood
Guidance, and DOT reports have confirmed, this has been causing
the potential for some ponding of water over roads and areas of
poor drainage. The pressing issue is that right behind the
rainfall fall we`ve seen significant increases in reports of
stronger winds. Looking at one hour pressure changes in the HRRR
and from obs in the area we`ve seen all the signatures of a
gravity wave propagating through the Mid-Atlantic. We`ve issued
an SPS to highlight this threat.
Moving forward into today, SPC has expanded the SLGT just a bit
further north and we think that today`s set up to be an impact
day with regards to convection. The timing of the threat should
run from around noon through 8pm on the late side. Based on
our mesoanalysis forecasters thoughts, we should see initially
discrete cells moving through before coalescing into a line of
storms. All of the typical steering flow indicators, deep layer
shear, bunkers-right, and storm relative flow all is oblique to
the boundary. This should mean that as the storms approach the
I-95 corridor we`ll be looking at a QLCS event with the
potential for rotation along the line.