WASHINGTON — If you walked outside on Sunday and just thought “gross,” wait until you get a feel for the heat Monday. Temperatures Monday will be in the lower 90s but with the added humidity it will feel like it’s around 100 degrees.
By the time we get to the afternoon, we are going to want some rain. There is a good threat Monday for severe storms, not just a summer rain shower. So let’s break it down for you so you can be prepared because unfortunately, it looks like most of the activity could be around for the evening commute.
As of 2 p.m., the National Weather Service has placed the entire listening area under a severe thunderstorm watch until 8p.m.
We will have some clouds Monday with a few sunny breaks expected but even that won’t keep the temperatures from going on up. A lee trough is currently over the area with a very strong cold front sitting over the Great Lakes. There will be a few pieces of energy that will float across the region Monday afternoon and into the evening that will kick-start the thunderstorms. Most of the activity — especially the stronger activity — will take place between 4 p.m. and 9 p.m.
A few of the models predict a chance of storms around the D.C. metro area around 5 p.m. While this may not be the exact picture the radar paints at 5 p.m., I do believe we will have storms around the region around that time. Just be sure to leave yourself some extra time and check out the weather radar before you head out the door.
Some heavy downpours are expected around 5 p.m. (Courtesy WeatherBell)
Damaging winds will be the primary threat once these storms get underway. I do expect lots of lightning to be around, so please limit your time outside once these storms start. Lightning can strike from quite a distance, even if the storm is not in your vicinity. We have a small hail threat and a chance for some isolated tornadoes to generate as well.
While there will have a chance to see a tornado warning, the best chance for any to form seems to be around the Baltimore area and to the north and east. We will have to watch the potential for flooding. Considering there is so much moisture in the air, we could get a storm that could produce a few inches of rain per hour. Expect flash flooding through portions of the WTOP listening area.
The Storm Prediction Center outlined the WTOP listening area for a slight risk to exceed our flash flood criteria/excessive rainfall Monday afternoon and evening. (Courtesy NOAA)
It would only take around 2 inches of rain in some parts of region in three hours to reach flash flooding conditions. We could certainly see that in some of the cells that will develop. We will monitor that situation as it evolves, but for now remember to please not drive across any flooded roadway.
It could take 2 inches to 4 inches of rain in just three hours to create flash flooding conditions around the listening area. (Courtesy NOAA)
The main threat should be over around 9 p.m., but we could see some storms linger into late Monday evening and into early Tuesday.
Around the country
The Storm Prediction Center outlined an area that stretches from Boston to Little Rock for expecting a slight risk for severe weather Monday. Unfortunately, several major airports are within this zone. If you are flying out Monday, be sure to factor in the possibility of flight delays.
Tuesday and beyond
Overnight Tuesday will be fairly muggy and warm with temperatures only falling into the lower to mid 70s. Tuesday features another chance of showers and thunderstorms. Again, some of these could be strong to severe as that cold front draped over the Great Lakes makes a run for the D.C. area on Tuesday, eventually crossing the region by late Tuesday night. The best threat right now for severe weather Tuesday will be east of the Blue Ridge Mountains. We will revisit that threat once we get through Monday.
Here’s the placement of the strong cold front that will create thunderstorm chances for Tuesday. The front will eventually move through and clear the area by Wednesday morning leading to more comfortable conditions. (Courtesy NOAA)
The good news is, once we get these two very warm and stormy days out of the way, a much nicer air mass will be with us for the rest of the work week. Starting on Wednesday, temperatures will fall into the lower 80s and upper 70s for daytime highs. You can see the dew points, the measure of moisture in the air, start to drop just after midnight leading into Wednesday morning. Dew points in the 70s make for oppressive humidity, while dew points in the 50s are refreshing.
At 2 a.m. Wednesday, the cold front will cross the region bringing much more comfortable air behind it. Dewpoints will fall from the 70s (oppresive humidity) to the 50s (very refreshing air). (Courtesy WeatherBell)