**An important note on the weather web site: there will be some big news tomorrow as Vencore Weather is moving to a new home...stay tuned**
It has been a hard year to cut the grass. The I-95 corridor has had five weekends in a row with rain and this upcoming one will become the sixth. Tropical moisture is entrenched in the eastern US and multiple disturbances in the upper atmosphere will head our way from the Midwest over the next few days and “squeeze out” this abundant moisture in the atmosphere likely resulting in some tropical downpours.
The combination of high pressure riding along the Northeast US coastline and low pressure over the Midwest has resulted in an influx of tropical moisture in our area riding northward from the Caribbean Sea and Gulf of Mexico. Meanwhile, upper-level trough will shift eastward from the Great Lakes over the next few days and this will “squeeze” out the deep moisture in the atmosphere likely resulting in some downpours in DC, Philly and NYC. The upper-level trough may actually close off for a time this weekend enhancing the possibility of heavy rainfall in parts of the I-95 corridor; especially, south of the PA/MD border. The result of a cut-off low this weekend will likely be the formation of surface low pressure and this could lead to downpours in the Saturday-Sunday time frame.
Grounds are already well saturated in parts of the Mid-Atlantic region from recent rains and additional downpours over the next five days can lead to flash flooding issues. Flash flood watches have been already posted for the DC metro region and other areas south of the PA/MD border and may eventually be required north of the Mason-Dixon Line. On the back side of the surface low pressure system, it’ll turn noticeably cooler on Sunday and Monday and much of next week looks cooler-than-normal in the Northeast US.
Meteorologist Paul Dorian