A stormy afternoon, or nocturnal noise? Dueling forecasts are on display Thursday for the Lehigh Valley

BETHLEHEM, Pa. – Most meteorologists would agree that summer is the most challenging time of year to forecast the chance of rain and severe weather, and Thursday is a showcase on the probability of precipitation — or lack thereof.

Scattered severe thunderstorms are possible across parts of the region, according to the Storm Prediction Center, with the Lehigh Valley on the border of a marginal to slight risk for severe weather.

• The Storm Prediction Center has the Lehigh Valley on the edge of a slight risk for severe weather Thursday
• EPAWA meteorologist Bobby Martrich disagrees with the risk area for afternoon storms
• The National Weather Service is also questionable on the storm threat, saying some models show the area devoid of storms this afternoon

But a local meteorologist doesn't quite share that outlook.

It comes days after storms pounded the Lehigh Valley and dropped 3 to 5 inches of rain across the area, with some locations receiving even more.

Priming the atmosphere

“It’s going to be hot and humid today. Very hot and humid, in fact,” EPAWA meteorologist Bobby Martrich said in his daily video forecast.

Temperatures will be in the 90s across most areas, and Martrich said it’s just the start.

“We’re going to have more humidity coming back into the region in the next couple of days.”

According to the National Weather Service, dew points increased overnight and were settling into the 65 to 70 degree range in the early morning hours. They’re only expected to rise higher, especially into the evening.

A dew point of 70-75 is considered “oppressive,” while dew point numbers between 66-70 feel “uncomfortable.”

The storm threat

“I don’t think most of the area is going to see thunderstorms during the day today,” Martrich said, though he did highlight a northern portion of the area as having some potential for storms.

But more of his focus was on the Lehigh Valley’s window “on either side of midnight” and into the overnight hours.

That’s at odds with the Storm Prediction Center and the NWS forecast office in Mount Holly, New Jersey, which said areas from Allentown to Reading northwestward “will be worth watching for at least isolated showers and thunderstorms this afternoon.”

That could come from the “tail” of a line of storms along a cold front in central New York that’s expected to progress eastward during the mid-to-late afternoon. Wind damage could be the primary threat.

“The greater threat is to our northwest,” the weather service forecast discussion said, flagging the slight risk of severe thunderstorms by the Storm Prediction Center and saying it “appears warranted.”

“Wind looks to be a greater threat than hail. Tornado threat appears very low, but not non zero.”

But the forecast discussion did acknowledge that some CAMs (convection-allowing models) show even the northwest areas of the Lehigh Valley and counties to the north “devoid of [storms] this afternoon.”

The loss of daytime heating and a more stable environment should mean any storms overnight won’t be severe, Martrich said.

The threat continues Friday

“Expect that there will be showers and storms around Friday afternoon with the chance for flooding and severe [weather],” the NWS forecast discussion said.

The Storm Prediction Center has the entire area in a marginal (1/5) risk for severe thunderstorms on Friday and the Weather Prediction Center has most of New Jersey and far eastern Pennsylvania in a slight (2/5) risk and marginal (1/5) risk elsewhere for excessive rainfall.