The Northeast is going through a warm week (record breaking for some) and is on the verge of a serious threat to start the week.
A negative slant continues eastward this morning. In the immediate future, the temperature is warm and the air is humid. As the lifting mechanism approaches from the west, a strong storm current is expected to erupt.
This is a valid acoustic forecast for 18z near Allentown, PA.
According to this we have:
- An almost untapped atmosphere. It is possible to develop a warm open area – likely multicellular clusters rather than single discrete cells due to lack of cap.
- CAPE decreases in the hail growth zone (-10 C to -30 C). Indicates the possibility of updated winds capable of supporting small hail.
- The lapse rate is weaker. Withdrawals can be difficult to boost.
- Low cutting speed / not much directional cutting force. Supercell is unpopular. The likelihood of tornadoes is low, but backspins are possible where moderate-grade conditions/terrain features allow for enhanced directional shear.
- Some dry air in between levels with ~40 kts winds. There may be damaging winds.
Look for frontline developments in the warm open area of the eastern Appalachians, especially over southeastern PA/NJ/southeastern NY, where a broken cloud cover will allow further instability through the system. daytime heating.
Any storm ahead is likely to be multicellular with the potential to bring hail, wind and heavy rain. When the line arrives later this afternoon, strong winds will become the main threat, along with some heavy rain. The likelihood of tornadoes occurring today is low due to the lack of directional shear. However, it is possible to turn upstream in the stream, especially when the terrain favors low shear strength.
Although the chance of high winds (65+ kts) is low due to low winds high up, consider shelter for a severe thunderstorm warning if there is a severe thunderstorm warning. Winds above 50 mph can still down trees and/or power lines.
Watch the weather this afternoon and evening!