10/29 Coastal Storm…Wild Sunday, then Big Changes!

Big changes in store over the next 24-36 hours! We’re going from Jeans & T-Shirt weather to grab the sweatshirts & jackets (and the umbrella) and it’s all thanks to a very strong & complex system. This storm actually has two parts. The first is a cold front that is pushing east across the eastern US through Sunday which is bringing the cold. This front will provide support that will help generate a coastal low Sunday (part 2) that will bring wind & rain to the area and help to really pull cold air into the area.

The Satellite/Radar picture from Saturday Evening doesn’t show a tremendous amount of moisture with the front, but by Sunday morning that will start to change as the front starts to pick up moisture from Tropical Storm Philippe in the Caribbean/Bahamas and the coastal low starts to form. The storm will maintain this ‘tropical moisture’ connection as it works up the coast so the storm has plenty of moisture. The upper level system will also “absorb” Philippe which will aid the system in strengthening. Now you see why I said it’s a complex system. 🙂

Expect rain most of the day, and areas of heavy rain are possible, especially along & east of I-95. There is a question as to whether or not a dry slot will develop and allow a few dry hours, but this still remains to be seen. Regardless, rain will still likely wrap around late Sunday evening before pulling out overnight into Monday morning.

It’s not shown below, but the mountains will see some snowfall Sunday into Monday. 1-3″ is expected in spots.

Future Radar Saturday Night through Monday Morning

In addition, the initially warm temperatures, high moisture, and strong wind shear over the area could spin off a weak/brief tornado or two across portions of southern Maryland and the lower Delmarva Sunday morning. This threat will decrease quickly as the colder air is brought in and stabilizes the atmosphere.

In terms of rainfall amounts. I’m expecting a general 1″ – 1.5″ region wide. Highest totals will be in the mountains and along & east of I-95. Higher totals will be found across New England where the NWS is forecasting 3-5 inches across portions of Northern Pennsylvania and western New York.

 

National Weather Service Rainfall prediction Sunday – Monday

 

As the low moves up the coast, it will undergo rapid intensification, and we’ll see winds increase through the day on Sunday. The strongest winds for our area look to be between 6PM Sunday and 6AM Monday, where gusts 40-50+MPH will be possible. It would be advisable to be prepared for scattered power outages in parts of the area and to make sure you don’t have any loose objects in your yard that could get blown away.  Winds will remain gusty through Monday, but will die off some by the afternoon.

Future Wind Gusts from Hi-Res NAM model valid Sunday Evening through Monday afternoon

As mentioned, it will turn COLD with a strong NW wind on Sunday. Temps will likely peak earlier in the day and fall as the cold air is pulled in.  Areas N&W will see the quickest drop in temps, while areas closer to the coast will see a delay thanks to the warmer ocean air that will initially be over eastern areas. By late Sunday, much of the area is in the 40s, and by Monday morning, everyone is waking up to temps in the 30s/40s.

Future temps from Hi-Res NAM model valid Sunday through Monday morning

 

Behind this system, highs Mon & Tue will be in the mid/upper 50s. The wind will stay up enough that morning lows will have trouble dipping back into the 30s, but it will still be cold. Wind chills Monday morning will be in the upper 20s and low 30s, something to keep in mind for the bus stop on Monday! Conditions will clear out quickly Monday, so while it will be cold to start the week, expect a lot of sunshine to aid in that.

-Andrew