wpostServer: http://css.washingtonpost.com/wpost2

Most Read: Local

Posted at 11:15 PM ET, 09/07/2011

PM Update: More heavy rain, flooding possible overnight

Flood warning & Flash Flood Warnings for much of region this evening | Hurricane Tracking Center

Latest on road closures and traffic impacts: Dr. Gridlock

11:10 p.m. update: Rain should let up after around 3 a.m., but plan for plenty of flooding issues in the morning except for Loudoun and northern Prince William counties and points west (the rain looks to continue missing those areas to the east). See map below for the exact areas covered by Flash Flood Warnings, and follow the latest updates in our live Twitter feed above. More showers tomorrow but shouldn’t be nearly as heavy. Phew.

10:40 p.m. update: Flash Flood Warnings extended east to include Prince George’s, Anne Arundel, northwestern Calvert, eastern Charles, northwestern St. Mary’s and southeastern Baltimore counties until 4:30 a.m. Pretty much the entire eastern two-thirds of the metro area is under a Flash Flood Warning. Not included is Frederick, western Montgomery, western Fairfax, Prince William and Stafford counties and points west.

10:15 p.m. update: Flash Flood Warnings now stretch from King George County in Virginia all the way north through D.C. and north/northeast past Baltimore. A steady south-to-north stream of often heavy rain covers the warned area. Extreme rainfall rates of 1-2”/hr or a little more are possible across these areas. Flooding is likely so be very careful if you have to be out. Never try to cross a flooded road. Some good news - no Tornado Warnings are currently in effect.

Monitor severe warnings issued by the National Weather Service and radar on our Severe Weather Tracking Station below. Also, comment below with conditions where you are.

9:20 p.m. update: A train of moderate to heavy rain is moving south to north through the heart of the metro area and has prompted a Flash Flood Warning until midnight for most areas inside the Beltway including the District, and southward through Alexandria, Falls Church, Arlington, and eastern Fairfax and western Charles counties. Rain rates of 1-2”/hr are possible in these areas, which is likely to cause some flooding. Meanwhile, to the south, a Tornado Warning is in effect until 9:45 p.m. for eastern Charles and northwestern St. Mary’s counties. Follow the latest developments in our live update feed above. [9:50 p.m.: TORNADO WARNING until 10:15 p.m. for southeast Prince George’s, northeast Charles and northwest St. Mary’s counties.]

8:15 p.m. update: More rain has arrived from the south across much of the area, while a t’storm cell possibly containing a tornado has been passing north through central St. Mary’s and southern Calvert counties. As this latest batch of rain passes through, watch out for more flooding, especially re-flooding of roads that flooded earlier today. If you are out and about, be mindful that it’s hard to see flooding in front of you at night. When in doubt, turn around don’t drown.

5:25 p.m. update: Radar shows more narrow bands of heavy showers and thunderstorms developing to the south. Especially along and east of I-95, periods of heavy rainy and flash flooding may resume. Even to the west of the heaviest rain, creeks and streams are rising and a flood warning has been posted for a large part of the region through 11:15 p.m.

From 3:30 p.m.: What a morning into early afternoon! Hope you like rain, and you’ve dodged all the inconveniences, including some significant flash flooding across the area. The good news is the big batch of precipitation that’s tormented the area has headed north, but the runoff will continue, and more activity is likely to pass through as the big area of low pressure continues to spin to our west. At least temperatures remain “cool,” with muggy highs only near 70 most spots.

Through Tonight: Additional waves of showers and heavy rain mixed with thunder are likely during the evening and overnight, especially along and east of I-95. There’s even a slight risk of severe weather before dark. It won’t rain all the time, and most activity probably won’t be as intense or widespread as earlier, but heavy rainfall rates remain possible as well “training” (showers repeatedly passing over the same area). Any additional rain will only exacerbate current flooding issues. Lows are pretty similar to evening temperatures, mainly upper 60s to near 70.

Remember: turn around, don’t drown. This is particularly important at night when judging water depth is nearly impossible.

Tomorrow (Thursday): More periods of rain, some heavy, are possible throughout the day. The heaviest activity may tend to focus in the northeast section of the area (think Potomac river and east/north) as low pressure lingers. Totals are probably not as intense as today, but another 1-2”+ is possible in places which see the most rain. Highs should reach the mid-70s to near 80, depending on sunshine or lack thereof.

See Dan Stillman’s forecast through the weekend. And if you haven’t already, join us on Facebook and follow us on Twitter .


Rainfall totals late this morning through afternoon estimated by doppler radar (National Weather Service)
Too much rain: Just today, National Airport has picked up over 1.5”, with event totals now past 3 inches. BWI is closer to 1.25” today, while Dulles is still between .5” and 1” since midnight. Big ‘winners’ on the day are generally just to the east of D.C. and west of Baltimore, particularly in places like Prince George’s, eastern Howard, and Charles counties where 3-5”+ rain have fallen since this morning. Radar estimated totals for the entire event are now as high as 5-8” in a band just east of D.C., with the highest spots in that band centered south of La Plata.

Tropics: Besides the remnants of Lee that we’re dealing with locally, the tropics remain quite active. Hurricane Katia’s winds are now down to 85 mph as it begins its curve back out to sea between the U.S. and Bermuda. Maria is struggling on its trek westward through the open Atlantic and it is now expected to remain a tropical storm through the next five days, but it will need to be watched as it heads west toward the southeast U.S. coast. Another disturbance in the Bay of Campeche remains relatively unorganized, though computer guidance suggests it will become Nate and eventually impact someone from northern Mexico toward the central Gulf coast, perhaps as a hurricane.

By and  |  11:15 PM ET, 09/07/2011

Categories:  Forecasts

 
Read what others are saying
     

    © 2011 The Washington Post Company