BETHLEHEM, Pa. — As severe weather rakes the East Coast, the National Weather Service has issued a special weather statement for the Lehigh Valley effective Wednesday afternoon.
“Isolated strong easterly wind gusts near 40 to 50 mph have developed this afternoon, as strong low pressure begins to approach from the south,” the statement said.
The weather service attributed the strong — and perhaps damaging — gusts to a wake low passing across the area.
A wake low is an area of low pressure developing behind a complex system of rain and storms. It forms by air sinking on the back side of the area of rain.
As that sinking air warms and becomes less dense, it causes a pressure gradient to develop between the low pressure and rain/storms.
A Nor’easter ahead
EPAWA meteorologist Bobby Martrich said he wouldn’t attribute the strong wind totally to a wake low, but more to a secondary low-pressure system that’s set to redevelop off the coast — a classic "Miller B" system typically seen in the winter.
“Maybe even a little snow."
EPAWA meteorologist Bobby Martrich
Along with a flood watch that remains in effect for the Lehigh Valley through Thursday afternoon, Martrich said a true no’reaster is on the doorstep as that low reforms.
It will be classified as a nor’easter "as soon as it exits the coast,” Martrich said.
He predicted the Lehigh Valley could see sleet and grauple mixed in with rain showers on Thursday.
“Maybe even a little snow,” he said.
Power outages, flooding a concern
The weather service said strong wind gusts will continue and are likely to result in some isolated instances of tree damage or power outages.
About 1:30 p.m. Wednesday, outages had ticked up across the region. PPL Electric had 35,000 customers without power across its service area, including more than 3,000 in Lehigh County and more than 1,100 in Northampton County.
“During the higher rainfall rates, local flash flooding cannot be ruled out. Excessive runoff may continue to cause rivers, creeks, and streams to rise through the end of the week even when the rain has ended.”
National Weather Service flood watch
Met-Ed reported more than 12,000 customers without power in its service area, with nearly 200 out in Lehigh County and 229 out in Northampton.
The weather service said that in addition to strong winds, additional rainfall amounts of 1 to 3 inches are expected across the watch area into Thursday.
About two dozen river points are forecast to approach flood stage, with several exceeding flood stage, forecasters said.
“The rain will be heavy at times, with hourly rates reaching or exceeding an inch, with the more widespread and heaviest rain expected to fall this afternoon and early this evening,” the flood watch states.
“During the higher rainfall rates, local flash flooding cannot be ruled out. Excessive runoff may continue to cause rivers, creeks, and streams to rise through the end of the week even when the rain has ended.”