Wide spread clouds and showers this Friday limiting the severe weather risk thus SPC (Storm Prediction Center) has lowered the risk to Marginal (less of a risk than a slight risk) this is also the start of some damp and cooler times for the eastern half of the US as cool Canadian high Pressure settles in over the nations mid section.
Friday morning the jet stream pattern shows a strong upper level anti cyclone (also known as a high pressure system) over the central Plains keeping things HOT in that region. Notice in the next image of the jet stream we’ll see a dip allowing cooler more dry air to settle in throughout the weekend.
By Friday night we see the jet stream begin to take a dive south east over the eastern US this will signal the start of cooler times but notice in the next jet stream image we will see this dip become more pronounced.
When we see two jet stream maxes (noticed off the North East Coast and again from the upper Plains into the South East, we will likely get a low pressure system to spin up and deepen (become stronger, lowering pressure) this kind of set up may lead to enhanced rainfall somewhere in the Mid Atlantic states and indeed the rainfall forecast for the next 2 days goes with quite a bit of rain which cloud lead to some flooding issues in that region. If you live in North Carolina or south ward I don’t believe rainfall will hang around long enough to cause these issues as the main low pressure will be more north over Norther VA and around the DC metro.
Computer model forecast like the one above also point to the Mid Atlantic getting pounded by rounds of heavy rain through Sunday evening.
Saturday mornings surface map shows an area of High Pressure over the western Great Lakes but extending its influence into the northern New England and much of the central Mid West with time that will extend into the south east but not before flooding parts of the Mid Atlantic.
Saturday afternoon temps and dew points will be much lower and very refreshing compared to what most of July has been.
I’ve drawn a line showing the cut off between moist air (first image) and the dry air moving in. Also in the right image (Saturday afternoon temps) you can see where much cooler air will be (thanks in part to not only lower moisture but rainfall)
By Sunday we should being to see the low pressure over the Mid Atlantic move on off over the ocean and allow that sprawling high pressure to take control. Check the next two images for Sunday below.
In the first image (dew point values) are much lower over the interior parts of the New East and into Appalachia which (in the second image) will allow for much cooler days and evenings. Second image is Sunday morning around 5 Am eastern which shows very refreshing numbers 60s, to 50s, perhaps some 40s in the Higher terrain ?? possible!
That concludes this blog for the weekend, though check back by Sunday evening for the upcoming weekly update.