*Flash Flood Watch for the entire area until midnight*
Had enough yet? After a good 3 to 7-plus inches of rain fell across the region on Saturday, breaking the daily rainfall records at all three major airports, we’re back at it again today. This time, the driving force behind storm development is more typical of our normal summer regimen. Unstable air, fueled by spots of sunshine and a strong upper-level low to our west will continue to pump in batches of heavy rain and thunderstorms for the rest of the day. With the ground already oversaturated from Saturday’s rains, it won’t take much more precipitation to cause flooding, hence the area-wide flash flood watch. We are quickly reaching the point where folks really need to remember the oft-mentioned: “Turn around, don’t drown.”
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Through tonight: Showers and embedded thunderstorms will continue to rotate through the region in batches for the rest of the evening and into the part of the overnight period. Guidance suggests areas along and east of Interstate 95 stand the greatest chance at seeing additional heavy rainfall. Some of the storm cells that do develop will contain gusty winds and lightning, but the biggest hazard by far will be the threat of flash floods, especially east of the District, where sopping-wet soil can’t hold any more water. (Some spots there received upward of 7 inches of rain Saturday.)
Elevated chances (60 percent) of scattered showers and thunderstorms exist through midnight, before storm coverage should begin to wane. It will be warm and quite muggy overnight, with a 50-percent chance of scattered showers or even an isolated thunderstorm. Low temperatures will range from 68 to 73 degrees, with a southeast wind at 10 mph.
View the current weather at The Washington Post.
Tomorrow (Monday): Scattered showers are likely to form early in the morning, with an outside chance at a pre-dawn rumble of thunder or two. Our shower and thunderstorm chances will only increase as the day progresses. Patches of heavy rain and thunderstorms will continuously rotate in from the south, possibly becoming “trained” over the same locations, increasing the probabilities of flash floods. Don’t expect much if any sunshine Monday, with high temperatures only reaching the low 80s. Humidity values will be oppressive: Dew points will rise into the low 70s, with only some aid from a moderate (10 to 15 mph) southeast wind. Expect more showers and thunderstorms Monday night, as we stay warm and muggy with lows in the low 70s.
Time for an arc? Saturday’s deluge was not the best way to kick of a week’s long stretch where we will probably be under the treat of heavy rain every day.
Thanks to an unusually strong (for late July) upper-level low and huge blocking high over the North Atlantic, we are stuck in an extremely favorable pattern for heavy rain. And this could go beyond just causing us a nuisance or ruining our summer vacation plans.
Last week, we mentioned the historic D.C. rainfall from June 2006 as a potential analogous event to our current wet pattern, and that comparison is looking pretty good at the moment. With such an efficient environmental setup for heavy precipitation, some areas could (including totals from Saturday) end up with close to a foot of rain by the end of the week.
With totals like that in the realm of possibilities, flood reports and incidents will easily be on the rise as the week continues.
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