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Posted at 6:15 PM ET, 09/30/2010

Second wave of heavy rains advancing north

By Jason Samenow

Another 1" or more possible, DC and east

* Flash Flood Warning extended until 12:15 a.m. *
* Storm impact coverage: PostLocal | Live chat transcript *
* Flash Flood Watch thru tonight | Share photos | Dr. Gridlock *
* Citizen observer rain totals: VA, MD | NWS Mesonet rain totals *
* Outside now? Radar, temperatures & more: Weather Wall *

This isn't over.

Another large area of rain extending southeast through North Carolina and into the Atlantic ocean is headed north and taking aim at the metro region. Rain, sometimes quite heavy (especially from DC and to the east), will again overspread the metro region over the next several hours. Flash flood warnings have been reissued where they were discontinued and extended until 12:15 a.m. for the entire metro region.

Based on current radar trends and model guidance, it looks like another inch or two could fall inside the beltway, around 1" in the north and west suburbs (with amounts decreasing sharply north and west of eastern Loudoun and Montgomery counties) and 1-3" in the eastern suburbs. This rain will be on top of the 2-5" (and isolated 5-9" amounts) which fell earlier today. As was the case this morning, some localized amounts may well be above the "average".

If you are out and about this evening, it is especially important not to attempt to drive through flooded roadways given limited nighttime visibility.

Keep reading for more on this evening's rain threat...

There is a fair amount of uncertainty in the exact rainfall amounts because of a sharp western cutoff with the current batch of rain. As the National Weather Service describes in its afternoon discussion:

LATEST MODEL GUIDANCE CONTINUES TO SHOW ANOTHER WAVE OF LOW PRESSURE MOVING UP THE MID-ATLANTIC COAST THIS EVENING INTO THE OVERNIGHT HOURS. THERE WILL BE A SHARP WESTERN CUTOFF BETWEEN LIGHT PRECIP AND ANOTHER BAND OF HEAVY PRECIP. THEREFORE...ANY SLIGHT SHIFT BETWEEN THE BACK EDGE OF PRECIP WILL MAKE A HUGE DIFFERENCE WITH ADDITIONAL PRECIP ACCUMULATIONS TONIGT. CURRENT THINKING IS THE WESTERN SHORE [OF CHESAPEAKE BAY] IS UNDER THE GUN AGAIN WITH AN ADDITIONAL 1-3 INCHES POSSIBLE WITH THIS ACTIVITY... WHILE AREAS FARTHER TO THE WEST WILL RECEIVE MUCH LESS.

The rain should end in the early morning hours from southwest to northeast. Refer to Ian's PM Update for additional information on Friday's forecast.

By Jason Samenow  | September 30, 2010; 6:15 PM ET
Categories:  Floods, Updates  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   Del.icio.us   StumbleUpon   Technorati   Google Buzz   Previous: Some gusty storms, then possible rain round 2
Next: Torrential rains swamping region

Comments

This will be an interesting evening.
Watching the rain wax & wane here in Centreville. Not very much wind, just rain and a lot of it.
I say stay home tonight if you can.

Posted by: FIREDRAGON47 | September 30, 2010 6:32 PM | Report abuse

so, how about those drought conditions?

Posted by: bdeco | September 30, 2010 6:49 PM | Report abuse

It looks like that large patch of rain that is coming up from NC is going to cover a lot of the area - maybe not just DC and east, but Fairfax too.

Posted by: barbnc | September 30, 2010 7:03 PM | Report abuse

I believe someone asked earlier this week what an "OCM" was.

The answer: On-camera meteorologist. The reason I'm bringing it up is because two of our area OCM's celebrated significant milestones this week; milestones which have gotten "inundated" in the deluge so to speak: Sue Palka [25th anniversary broadcasting on Fox 5, with a nice on-air party last night]; and Kim Martucci & husband [birth of son a couple days ago]; full details are on DCRTV's site. [In addition, I keep trying to figure out why this dratted keyboard occasionally skips a letter; it doesn't need a battery yet because it always warns me with a blinking red light when "battery replacement time" is near!] Anyway, the next wave of rain seems to be moving in; the OCM's keep telling me this is the last one! BTW, still no lightning or thunder, even though we've seen plenty of tropical convective cloudiness.

Posted by: Bombo47jea | September 30, 2010 7:10 PM | Report abuse

We've picked up more than 4" in the Blue Ridge Mtns east of Front Royal... I guess our mountain might have gotten a higher ammt than some nearby locations due to an effect similar to how the Alleghenies wring out clipper systems in the winter? My total doesn't seem to agree with radar precip estimates but is confirmed by a nearby personal weather station.

Bombo47, I saw the celebration for Sue's 25th last night... that was real nice with appearances by Bob Ryan and Doug Hill.

CWG, what kind of winds can we expect tonight?

Posted by: spgass1 | September 30, 2010 7:22 PM | Report abuse

I posted about Sue's 25th anniversary fete last night, just after 11 p.m. in this thread http://voices.washingtonpost.com/capitalweathergang/2010/09/the_calm_before_the_rainstorm.html#comments and yes, it did (not unsurprisingly) get lost in the deluge. Didn't know about know about Kim Martucci's new motherhood.

An interesting point in the Palka Tribute (http://www.myfoxdc.com/dpp/weather/sue-palka-celebrates-25-years-at-fox-5-wttg) is that Bob Ryan has been a D.C. OCM for 30 years, Doug Hill for 27 yrs, and Sue for 25 years. That's 82 combined years of OCM experience amongst three top-notch OCMs, surely something few U.S. metro areas can match.

Looking at the latest Mosaic Radar loop, unless the precip coming up through central Virginia veers sharply NE, much of the DC area is about to get hammered again.

A question for later: is today's rain too late to save this year's fall color? In 1966, a day-long, four-inch-plus rain in early (?) September ended a drought and we had what is still regarded as one of the most colorful falls in memory hereabouts.

Posted by: JerryFloyd1 | September 30, 2010 7:28 PM | Report abuse

Wilmington, NC rain update: 22.5" as of late in the day Thursday. Down there, the gators really may be swimming in the streets.

Posted by: JerryFloyd1 | September 30, 2010 7:35 PM | Report abuse

Really, JerryFloyd1? That is very interesting about the Fall leaves saturated in color from a September soaking. I would love to know thoughts on whether this rain could possibly do the same.

Posted by: Snowlover2 | September 30, 2010 7:37 PM | Report abuse

Somebody out there did one heck of a rain dance...

Posted by: Brian-CapitalWeatherGang | September 30, 2010 7:48 PM | Report abuse

It's pretty cool on radar right now, you can see the front pushing into the advancing moisture and the two combining for an enhanced area of rainfall going through D.C. etc.

Posted by: Ian-CapitalWeatherGang | September 30, 2010 7:55 PM | Report abuse

based on the radar, the rain line looks like its pushing winchester, not loudoun...but what do I know.

Posted by: rocotten | September 30, 2010 7:57 PM | Report abuse

@rocotten

Yes--Rain is pushing a bit further west than we expected-- all that means is more areas getting heavy rain. May update a little later.

Posted by: Jason-CapitalWeatherGang | September 30, 2010 8:03 PM | Report abuse

@Brian -- for real!!

We've topped 3" of rain today in Ashburn, according to my local weatherbug station.

Posted by: natsncats | September 30, 2010 8:03 PM | Report abuse

I'm curious as to why these 2 radars seem to not agree. They both show rain streaming up from the south, but one shows the western suburbs getting light rain, while the other shows the same area in yellows/reds (i.e., moderate to heavy rain). Which one should I trust to be right?

http://www.weather.gov/ridge/Conus/full_loop.php

http://www.wunderground.com/radar/mixedcomposite.asp?region=b5&size=2x&ID=LWX19

Posted by: FH59312 | September 30, 2010 8:07 PM | Report abuse

@Snowlover, that 1966 deluge was earlier in September (on registration day at the Univ. of Maryland which in those days was usually just after Labor Day).

I remember asking a colleague if the heavy rain would save the fall and she said "no, it's too late, the growing season has ended."

Fortunately, that turned out not to be the case. A climatalogist/botanist might be able to say whether this year's rains came too late or just in the nick of time.

Posted by: JerryFloyd1 | September 30, 2010 8:09 PM | Report abuse

they both show the same thing to me...the heaviest rain stretches from Anne Arundel in the northeast towards Charlottesville in the south west and it appears to be moving north northwest

Posted by: rocotten | September 30, 2010 8:11 PM | Report abuse

Wow, in the last few frames there seems to be a very heavy band of rain setting up from Fredericksburg north through PWC toward DC. I bet driving through that would not be fun.

Posted by: barbnc | September 30, 2010 8:17 PM | Report abuse

One thing to keep in mind further northwest even if it's raining there now is the drier air filtering in. The heaviest totals should be nearest the front and then back in the warm sector to the east.

Posted by: Ian-CapitalWeatherGang | September 30, 2010 8:19 PM | Report abuse

NOAA radar http://www.goes.noaa.gov/ECIR4.html is showing a plume at least as far south as Hispanola.

How much of this stuff is going train over our area?

Meanwhile the on the NHC site, the Caribbean and western/central Atlantic still look active.

Posted by: JerryFloyd1 | September 30, 2010 8:22 PM | Report abuse

Is it me or is that line of heavy rain and storms south of the city riding right up 95?

Posted by: SkywalkerSS | September 30, 2010 8:25 PM | Report abuse

Heaviest rain now appears to be west of 95.

Posted by: rwalker66 | September 30, 2010 8:30 PM | Report abuse

link to tomorrow's weather is broken

fix or update

am bike commuter who tends to not miss a day but my goodness, may hit low lying places in Hyattsville/College Park/Silver Spring area.

Thanks.

Posted by: CollegeQuaParkian1 | September 30, 2010 8:31 PM | Report abuse

@CollegeQuaParkian1

Link fixed.

Posted by: Jason-CapitalWeatherGang | September 30, 2010 8:41 PM | Report abuse

Thanks, Jason. LOVE THE SITE.

Posted by: CollegeQuaParkian1 | September 30, 2010 9:07 PM | Report abuse

Time sensitive but you can really see the front causing intense rains here.. 1 hr radar estimated totals.

Posted by: Ian-CapitalWeatherGang | September 30, 2010 9:09 PM | Report abuse

Man this prediction was botched pretty bad. We are getting hammered here in Manassas Park. At least 4" has fallen since 4:00 today and it's still raining hard. This on top of at least 3" we got lastnight into today. I saw something like 1-2" forecast here for the day and it ending by 5pm when I checked yesterday. Right....Think again. Another FAIL on this one guys.

Posted by: j0nx | September 30, 2010 9:11 PM | Report abuse

So far my little part of Holmes Run Creek has stayed in its bank. I am thankful for the drier slot we are apparently in here in Falls Church. I will hold my breath through the night and not put things back until tomorrow. Thanks CWG for all the good information throughout the day.

Posted by: erbele | September 30, 2010 9:14 PM | Report abuse

Why have these recent rain events been so unpredictable and hard to predict?

Closing in on 7 inches here in Burke.

Posted by: Yellowboy | September 30, 2010 9:24 PM | Report abuse

Heading off to bed, but we gotta' do this again when it's snow, not rain.

Although I realize the atmospheric setup won't be the same as today's, I want to see a 20-inch plus accumulation at DCA, even if means hauling in snow by the "train"load.

Posted by: JerryFloyd1 | September 30, 2010 9:28 PM | Report abuse

@j0nx,
I believe the CWG were calling for a general 2-4" with locally higher amounts of 5+". You seem to have fallen into that category of 5"+.
If radar is to be taken literally, we could be in the soup for at least another 5 to 6 hours. I hope not. We have had enough rain for one day. Come back another day.

Posted by: pjdunn1 | September 30, 2010 9:30 PM | Report abuse

@CWG -- Is this another sort of perfect storm setup, with its combination of phenomena?

Raining moderately hard in Michigan Park for the past 2 hours.

Posted by: kperl | September 30, 2010 9:38 PM | Report abuse

Finally getting heavy rain in Spotsy. Now getting ready 2 eat crow 4 thinking the rain amounts forecast were over stated.
This Sept will end up as the 4th warmest on record, +5.

Posted by: VaTechBob | September 30, 2010 9:44 PM | Report abuse

We're getting a nice sustained rain for the past two hours here in Georgetown. It's somewhere between a drizzle and a downpour. A drenching rain is what I'd call it.

I have a question.

I put a mop bucket in my garden yesterday which now has 4.5 inches of rainfall in it. It's underneath my cherry tree's canopy though.

Does placing it under a tree void the measurement? And if so, did I get more or less rain?

Posted by: Georgetwoner | September 30, 2010 9:45 PM | Report abuse

Some thoughts

Drought is getting dented pretty darn good.

CWG called for beaucoup rain and we're getting beaucoup rain. So what if they are off by some? What did you plan to do in the 2 to 4 inch forecast?

It is not fair to ask these guys questions like -- will I be ok driving such and such time? Big rain event equals big rain event, not easy to know when it will and won't rain, don't drive unless you have to.

Funny how no one is trying to come up with a name for this event (course I might have missed that discussion).

Train of Rain 2010?

Posted by: jaybird926 | September 30, 2010 9:48 PM | Report abuse

Mother nature plays a little joke on us.
Withold water rations all during record breaking heat, then deliver a summer's worth of rain in one day. More freaky stuff for freak year 2010.
VaTechBob, you'll only get 3-4 inches total while everyone else gets 5-10.

Posted by: FIREDRAGON47 | September 30, 2010 9:56 PM | Report abuse

@JerryFloyd1, I'm not a professional, but I'd guess that in my area at least (western Ffx co), this rain is too late to provide fall color. Many trees have already started to shed leaves in response to the drought, so I'd say that color will be spotty at best.

A species that colors late, in a location that hasn't been TOO dry, might get a boost from this rain. I'll be watching the trees near my office, since in addition to maples, I have tulip poplar, sour gum, sweet gum, redbud, and dogwoods.

Posted by: fsd50 | September 30, 2010 10:19 PM | Report abuse

I don't think this event deserves a name.

Snowmageddon & Snowpocalypse definitely did.

It's just a rainy day.

Posted by: Georgetwoner | September 30, 2010 10:20 PM | Report abuse

The comments to this entry are closed.

 
 
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