lower chance for severe weather for now.

 Yesterday the Midwest had a deadly derecho. A derecho is a special kind of mesoscale convective system and is a widespread, long-lived windstorm that is associated with a band of rapidly moving showers or thunderstorms. In order to be classified as a derecho, a disturbance needs to stretch at least 250 miles long and be at least 60 miles wide, Tuesday’s derecho traveled 614 miles from start to finish. The derecho started in eastern Iowa and spread through Illinois, Indiana, Ohio and Kentucky, causing widespread damage, a lot of the damaging wind was along a 400-mile path, with winds of 90 to 100 mph. The good news for our region is that this stayed south and west of our region.

Surface Chart, Radar and Satellite.

 

(Why do I always show surface charts, radar, and stuff? To help you visualized what I’m talking about).

The surface chart is showing that stationary front sitting to our south. On the Satellite image we can see that mesoscale convective system well to our east. As the northeastern edge of the heat dome continues to retreat southwestward today, the severe weather is going to shift toward the southwest as well.

Today

with the activity out west, there is a chance some of this could push into western Pennsylvania, so the SPC has a Marginal Risk 

The region will see more sun and average to above average warmth, but there will be clouds here and there. Today, the Northeast will see a partial solar eclipse beginning at about 1:07 p.m. ET, peaking at 1:54 p.m. with about 9% of the Sun covered, and ending at 2:38 p.m.  The percentage of the sun that will be covered depends on your location, (these are rounded) northern Maine (28%), Portland, ME (19%), Burlington, VT (17%), Boston, MA (16%), and New York City (10%). Washington DC ((almost 4%) Pittsburgh will see (around 2%). Never look directly at the Sun through regular sunglasses, binoculars, or a telescope without a proper solar filter.

Tonight the stationary front will be become a warm front and will be moving north. This will increase clouds (these could interfere, with viewing the Perseid meteor shower which peaks tonight) As the front moves north showers and a few thunderstorms will move with it.  We also have a bit of wildfire smoke to deal with. The heat and humidity will continue to advance slowly through the region.

Thursday night and Friday will see a cold front dropping south. This will bring scattered showers and isolated thunderstorms; the severe threat is low. Skies will be clearing north to south as the boundary slides through. By Friday night the front should be down around the Mason Dixon Line.  High Pressure will move in for Saturday into Sunday. On Sunday the high pressure will be starting push away, but most of the day should be dry. Then Sunday night and Monday a frontal system will approach and move through, the leading warm front will bring isolated showers and storms, with the cold front moving through later, bring a better chance for widespread showers and scattered thunderstorms.  High pressure builds in for Tuesday and Wednesday. Then for Wednesday night and Thursday a cold front will move through.

Have a great day!