Squall line will deliver 1-2″ of heavy rain Sunday evening

A powerful cold front will push through the Washington Area on Sunday evening. A Squall Line (strong line of thunderstorms with very heavy rain and gusty winds) will likely be accompanied with the passage of the cold front.

A closer look at the current high-resolution North American Model (NAM) model shows the heaviest rain pushing into Metro Washington late Sunday evening, likely after midnight continuing through the pre-dawn hours on Monday morning.

Potential Rainfall Accumulation: Much needed rainfall of one to two inches is possible across the DC Region

I will be watching southern Maryland and the Fredericksburg Area for the potential of Severe Thunderstorms on Sunday evening.  If the backdoor cold front doesn’t make it through these areas and warmer, more humid air prevails, the approaching squall line may have enough CAPE (Convective Available Potential Energy) for stronger updrafts and the threat of an isolated tornado. Otherwise, the most prominent threat on Sunday night will be damaging wind gusts with the arrival of the cold front.