BLOG: Cold April Morning
By: Justin Drabick
Yesterday's cold front with spawned some strong thunderstorms with gusty winds ushered in a cold air mass behind it. Ahead of the front, temps were in the 60s and then dropped about 15 degrees in an hour after the front passed. A trough or dip in the jet stream developed over the Ohio Valley and then moved over the mid-Atlantic and Northeast. This allowed for cold temperatures to return early this morning.
Low temperatures this morning bottomed out in the upper 20s and 30s around the Delaware Valley. A frost advisory was also in effect for central and southern Delaware. However, the wind never died down last night keeping the temperatures from dropping even further. The wind keeps the air mixed up which does not allow the cold dense air to settle to the surface. The wind also kept frost from developing in the advisory area, which resulted in canceling the frost advisory earlier.
Here are some morning low temperatures:
Allentown: 27
Mt. Pocono: 28
Millville: 28
Doylestown: 31
Philadelphia: 35, the record low is 24 set in 1982
Notice how the temperature in Allentown was colder than Mt. Pocono. This happened because the wind was stronger in the mountains keeping the temperature warmer than the valley. The colder and denser air was able to settle into the valley near the ground in Allentown. This is why wind forecasts are very important for temperature forecasting.
The good news is that this cold air mass is short lived as the jet stream trough has lifted out. Temperatures should remain near average over the next few days with some showers chances as this active weather pattern continues. A ridge in the jet stream looks like it will develop late in the weekend and early next week allowing for a warm-up. Highs should reach into the 70s during this time period, before another cold front makes its way through the Delaware Valley.
