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Posted at 12:00 PM ET, 05/12/2008

Forecast: Wind-Driven Deluge, Slowly Diminishing

By Jason Samenow

We apologize for this morning's technical difficulties due to a washingtonpost.com blog publishing and comment system outage.

Significant Storm Impacts: Widespread Flooding (do not attempt to cross flooded roadways), Road Closures, Isolated Power Outages from Wind, School Closures

*Flood Warnings continue in effect across the metro area*

Let's call this storm what it is: a late spring Nor'easter of historic proportions. When all is said and done, this storm will have dropped three to six inches of rain, which will rank very high in local spring storm history. But rain is only part of this storm's fury. Winds have gusted over 40 mph in the metro area and 50 mph near the Chesapeake Bay. Sideways blowing sheets of rain will continue today, gradually tapering off this afternoon. Tomorrow, we dry out, but only briefly.

TODAY

Rain, wind, and cold. Highs 50-55. An intense, slow moving coastal storm will continue to plaster the region with rain and wind. Another inch of rain is possible through mid afternoon. After that, rain should begin to diminish in coverage and intensity. A cold north wind will blow at 15-25 mph, with higher gusts. Temperatures will struggle to reach the mid 50s -- that's 20 degrees below average.

Most of the rain should be out of here by dark, and skies will gradually clear overnight. Lows drop down to a chilly 40 in the cooler suburbs to the mid 40s downtown. It will remain breezy, with northerly winds at 15-20 mph. Yes, you are going to need to worry about the wind chill in mid-May!

Confidence: Medium-High

TOMORROW

Welcome relief. Partly sunny. Mid to upper 60s. Tomorrow it will be about 10 degrees cooler than average, but relative to today, a vast improvement. A good deal of sunshine will allow us to dry out. It will remain a bit breezy, with northerly winds at 10-15 mph.

Clear and quite cool tomorrow night, with lows 45-50 (suburbs-city).

Confidence: High

Keep reading for the forecast through the work week and upcoming weekend. Use the comments link below to let us know your rainfall totals and storm stories. Yesterday's record-breaking rain totals, as well as storm totals thus far, are detailed here.

A LOOK AHEAD

Wednesday may be the pick of the week with sunny skies and a high of 70-75. But a cold front approaches at night that may well stall over the region giving us on and off rain chances through the weekend. Confidence: Medium-High

A stalled cold front will be in our vicinity Thursday through Sunday. Waves of rain-producing low pressure will develop along this cold front. The exact position of the cold front and the timing of the waves along it will determine when and how much it rains. It's practically impossible to know these details right now, so the best bet is to call for a 50% chance of rain each day and refine this forecast later. Temperatures should generally be in the 60s to near 70. Confidence: Low-Medium

By Jason Samenow  | May 12, 2008; 12:00 PM ET
Categories:  Forecasts  
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Next: CommuteCast: Cold and Water-Logged

Comments

Shades of May 2003, when the rain just would not stop . . .

Posted by: WSL | May 12, 2008 12:16 PM | Report abuse

Bull Run Regional Park was more like Bull Run Regional Lake this morning, and both Bull and Cub Run's were getting dangerously close to the bottom of the I-66 bridges over them.

At least the resevoirs that were so dangerously low last year should be well back on their way to full status....

Posted by: Kim in Manassas | May 12, 2008 12:20 PM | Report abuse

when is it going to stop????

Posted by: madison | May 12, 2008 12:20 PM | Report abuse

I am in hades with this rain!!! When will it end and we get some actual warm spring weather for more than 2-3 days in a row.

Any long range models/almanacs for memorial day weekend?

Posted by: JS | May 12, 2008 12:24 PM | Report abuse

Pushing 6 inches in the gauge now...add that to the 4 inches from the Thursday to Saturday events and thats 10 inches in 84 hours. NOAA has a site that gives you a frequency of rain events in your area. 10 inches in 4 days occurs in my area once every 100 years. WOW.

Posted by: Dulles ARC | May 12, 2008 12:30 PM | Report abuse

Madison, The rain should wind down between 4 and 6 p.m. and end by 7 or 8 p.m.

To all -- our utmost apologies for the technical difficulties this morning. Let's get the discussion going again. How much rain fell where you live? How has the storm impacted you?

Here are some storm totals from the National Weather Service, but only through 8:30 am or so.

Posted by: Capital Weather Gang | May 12, 2008 12:37 PM | Report abuse

Can you update us on the region's drought situation? With all the rain of late, is it officially over, heading into the summer months?

Posted by: mw | May 12, 2008 12:40 PM | Report abuse

I swear I saw a few snow flurries in Ballston this morning - quite far apart and lasting only a few minutes, but several others saw them as well!

Marina says my boat is fine; I'll see for myself later this afternoon. I am so thankful that the worst I have to worry about is a pleasure boat. Many others are dealing with much more serious damage concerns, I'm sure.

Posted by: ~sg | May 12, 2008 12:42 PM | Report abuse

We'll do a drought update some time this week-- perhaps tomorrow.

Posted by: Capital Weather Gang | May 12, 2008 12:43 PM | Report abuse

My brother, along with a number of others, is making a 115 mile bicycle "ride for the blue" tomorrow as part of Police Week 2008. They leave Richmond in the early morning and arrive in DC in the late afternoon. Any sense of what they can expect? Looks like the storm will have cleared out up here by then. Will the northerly winds give them a little tail wind, or does northerly mean that the wind will be coming from the north?

Posted by: BG | May 12, 2008 12:44 PM | Report abuse

BG: Tomorrow will be nice--sunny and 65-70. But a north wind is a head wind ... i.e. from the north

Posted by: Capital Weather Gang | May 12, 2008 12:52 PM | Report abuse

"or does northerly mean that the wind will be coming from the north" Wow!

Posted by: Anonymous | May 12, 2008 12:59 PM | Report abuse

3.47" so far here in Arnold...we really had some strong winds last night that blew down a lot of trees. I know there were quite a few roads blocked due to this over night and even this morning. Schools went in two hours late in Anne Arundel County because of this and power outage, etc. I think this definitely caught a few people off guard. Nothing like a good soaking.

Posted by: arnoldkh | May 12, 2008 1:07 PM | Report abuse

Our power went out for 30 minutes at 4:30 am. Other than that, my day has been a normal rainy day.

Oh for the sunshine again.

Posted by: Murre (Silver Spring) | May 12, 2008 1:10 PM | Report abuse

Rain amounts in Harpers Ferry about the same as Dulles ARC's. The soil couldn't be soggier, it's squish squish with every footstep across the yard--and I'm on a hill! Now the N wind is predicted to pick up, so I'm eyeing the line of trees on that side of the house. No significant damage yet, thank God. I'm glad to hear ~sg's boat made it through okay.

Posted by: tinkerbelle | May 12, 2008 1:13 PM | Report abuse

Thank you for keeping us up to date, and explaining things. It's helpful.

All's well, right now in northwest DC - but you can almost hear another storm brewing...

Posted by: Captain John | May 12, 2008 1:13 PM | Report abuse

Drought: As of last week, 83% of all VA was abnormally dry and 33% of all VA was in a drought. See http://drought.unl.edu/dm/DM_state.htm?VA,SE for details

Posted by: Jackson | May 12, 2008 1:15 PM | Report abuse

Dulles ARC:
Do you have a link to that NOAA site?

Posted by: CapHill | May 12, 2008 1:21 PM | Report abuse

Thanks, tinkerbelle! And I'm glad to hear you've had no damage as well. Maybe you won't need that Hobbit house after all....

Posted by: ~sg | May 12, 2008 1:23 PM | Report abuse

This was NOT the day for the blog to go down. I really depend on you guys for information and support during major weather events.

Up all night literally bailing out the apartment. Drying out now. I hope I can rent a wet-dry vac somewhere to dry out the carpet quick. It needs to stop raining now, thank you.

Posted by: ep | May 12, 2008 1:37 PM | Report abuse

My total since the latest round started late Sunday morning has been only .79. My total since it all began last Thur. is now 2.20. I would gladly have taken 3-4 additional inches if it would have relieved some of the waterlogged D.C. area, but of course that is not possible.

This was a very intense and compact storm. For a cold core system to be this compact regarding qp is very unusual. The immediate D.C. area seems to have been the sweetspot. 90 miles to the s.w. or 90 miles to the n.e. of D.C. very little rain fell compared to the amount dumped on the Capital area. It dumped on this area then moved out to sea.

If this had been 3-4 months ago, many would have received an historic winter storm. Parts of central Pa. had an inch of snow on the grass this morning.

We can all remember as we head into next winter, the dramatic impact possible from a negative NAO and AO. Our weather has been impacted a great deal during the past six weeks from this anomoly. We were positive most of the winter but have averaged negative since late March.

Posted by: Augusta Jim | May 12, 2008 1:45 PM | Report abuse

Storm total through 1:30 Pm on South side of Rockville + 2.85"

Posted by: rob | May 12, 2008 1:46 PM | Report abuse

Too bad we did not have this setup in January, February and March. Let's hope this trend continues into the winter (I know----seven months away) and we could get blasted. The rain is nice considering how dry we have been the past several years.

Posted by: Greg | May 12, 2008 1:52 PM | Report abuse

ep -- hope you dry out quickly. we're glad you depend on us for info, and are just as disappointed as you are about today's technical difficulties.

Posted by: Capital Weather Gang | May 12, 2008 2:08 PM | Report abuse

I posted something similar once before, so forgive me of repeating - but I think our soils must have been severely damaged by the three-year drought pattern we are now hopefully coming out of. I'm seeing ponding in my yard where I never saw it before. It just seems like the hard clay soils around here are having even more trouble soaking up moisture. Granted, this rain came very quickly, but still.

Anyone a hydrologist that can explain? I'm sure not.

Posted by: Southside FFX | May 12, 2008 2:18 PM | Report abuse

Too bad we can't bottle this Nor'easter for use next winter. Just think, with the current cold temperature anomalies in mid-January we'd be looking at a couple feet or more of blowing and drifting snow. Hope springs eternal, but daydreaming usually winds up the only "reality".

Posted by: Steve Tracton, Capital Weather Gang | May 12, 2008 2:19 PM | Report abuse

This is the link to the page that shows the rainfall amount frequencies - http://hdsc.nws.noaa.gov/hdsc/pfds/index.html - just click on your state and go from there...

Posted by: Dulles ARC | May 12, 2008 2:32 PM | Report abuse

You guys are good. Technical difficulties and all - everyone had a few early this morning.

I used to watch the weather by looking out the window. Now I know to keep doing that, but also checking with you guys too.

Keep up the good work.

Posted by: Captain John | May 12, 2008 2:37 PM | Report abuse

Fauquier Co./New Balitmore rain totals:

Thursday-Saturday total: 4 inches
Sunday: 4.75 inches.
Monday low: 39 at 7:30 a.m.

Yard's starting to look like a swimming hole. Just imagine what it would look like with the equivalent of snow!

Posted by: weathergrrl | May 12, 2008 3:04 PM | Report abuse

Southside FFX:

I am not a retired hydrologist, but I know enough about water percolation into various soils to confirm some of your suspicions.

To begin, you mention "clay soils". Clay is resistant to efficient percolation under the best of conditions because the porosity is too fine. This can be compounded when it is too dry. This effect can be noticed with some "water resistant" fabrics, if wearing in the rain. You may stay dry for 15 minutes, but once the rain begins to percolate through the pores in the fabric, you can become soaked rather quickly.

Depending on soil type, some folks in the water logged D.C. area would be surprised to find rather dry soil a few feet below the surface.The most efficient percolation is through a very coarse soil. 6-10 inches of rain should have been evenly dispersed over a 4 week period vs. a 4 day period for greatest benefit.

Unfortunately, a tremendous amount of water that may be desperately needed later this summer in the D.C. area has been lost through runoff.

The greatest benefit is to reservoirs within the watershed area of the heavy rainfall that could catch and hold the water.

Posted by: Augusta Jim | May 12, 2008 3:33 PM | Report abuse

The comments to this entry are closed.

 
 
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