Storms can tend to be random rather than ones that ravage the entire area. While some locations may see little to no precipitation, areas that experience the heaviest downpours may see up to 1 to 2 inches in an hour or two.
The main culprit is the same area of ​​low pressure responsible for major severe weather outbreaks across the Plains and Midwest over the weekend. It brings a cold front through the area that will collide with warm, humid air, causing storms.
The main source of uncertainty in storm coverage and intensity is cloud cover over the region, which can decrease the amount of heating. This could reduce the fuel needed for storms somewhat.
Still, at least scattered strong to severe storms are a good bet into the evening.
- Potential storm schedule: From mid-afternoon until evening. Ending around or just after sunset.
- Chance of rain: About 60 percent for a given location.
- Duration of the storm: Half an hour to an hour, but several storms may pass.
- Most likely effects: Heavy rain, dangerous lightning, isolated damaging wind gusts, one or two brief tornadoes.
- Possible impacts: Multiple tornadoes, isolated large hail and occasional flash floods.
The severe weather pattern includes a vigorous cold front moving in from the west and an atmospheric disturbance that will concentrate air lifting across the DMV later in the afternoon.
There will also be a concomitant increase in wind shear, which is a change in speed and direction with height that helps shape powerful thunderstorms. Meanwhile, near the ground, southerly winds will continue to bring heat and moisture, providing fuel for storms and making the air mass unstable.
A confounding factor is the early morning cloud cover, which is extensive and multi-layered, due to the remnants of a storm complex to the west. Until the clouds clear, the ground will not be heated as much, which could delay full destabilization.
Stronger warming is expected this afternoon, coinciding with increased wind shear. Convective storms are expected to move in as temperatures rise and the front approaches, becoming widespread late this afternoon.
Where these storms are most likely to cluster and their concentration may vary. For example, the NAM weather model favors locations closer to the Bay and southern Maryland. Some of this activity is already underway in southeastern Virginia. Its cousin, the HRRR weather model, begins to trigger storms farther west, including central Maryland and the District.
The storm mode will likely consist of small clusters (multicells) and short curved segments or arcs – a few rotating supercells are also possible. Torrential rain and lightning are likely during any activity. The same goes for strong to severe wind gusts called downbursts and quarter-sized hail. Even one or two brief tornadoes could hit.
CWG will be monitoring the situation closely throughout the afternoon and evening and will provide updates in this article.
Jason Samenow contributed to this report.
News Source : www.washingtonpost.com
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