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Posted at 5:00 AM ET, 11/29/2010

Forecast: Wild week - Sun, storms & winter's return

By Jason Samenow

* Outside now? Radar, temps & more: Weather Wall *

Today's Daily Digit
 
A somewhat subjective rating of the
day's weather, on a scale of 0 to 10.

 

Placid, pleasant start to volatile week
 
Get the 'Digit' on Twitter

EXPRESS FORECAST

Today: Sunny. 50-54. | Tonight: Clouds increase. 37-42. | Tomorrow: Cloudy, slight chance of showers. Low 50s. | A Look Ahead | Get Express Forecast by E-mail

FORECAST IN DETAIL

The weather word of the week is volatility as a midweek front brings big, abrupt changes. Today marks the calm before the storm and even tomorrow is relatively tranquil before the front unleashes its fury Tuesday night into Wednesday with heavy rain, gusty winds and possible thunder. Behind the front, it turns colder for the second half of the week. By late in the weekend, we have to keep an eye on the very slight possibility of a little winter weather.

Temperatures: Latest D.C. area temperature map powered by iMapWeather (base map by Google). Click and hold on map to pan. Double-click to zoom. Refresh page to update. See larger map on our Weather Wall.

Today (Monday): It's probably the nicest day of the week if you don't like cold, wind or precipitation. Sunshine is dominant, with highs heading up into the low 50s. Winds are from the southeast at around 10 mph. Confidence: High

Tonight: Skies are clear early followed by increasing high and mid-level clouds as the night wears on. Lows range from upper 30s in the suburbs to the low 40s downtown. Confidence: Medium-High

Keep reading for the forecast through next weekend...

Tomorrow (Tuesday): Clouds further increase as we await the passage of a warm front to the south. Some spotty light rain is possible (30% chance), but I think the bulk of the day is dry. A bit of a cool wedge may linger as cold high pressure retreats to the northeast. Until the warm front lifts to our north in the afternoon or early evening, highs may struggle to reach the mid-50s. Winds are primarily from east early shifting to more out of the south late in the afternoon. Confidence: Medium

Tomorrow Night: After the warm front passes us by, southerly winds become quite gusty (up to 30 mph or so). The chance of showers and even thunderstorms significantly increases after midnight as the cold front draws closer. The showers/storms likely produce heavy rain and a few could be severe with damaging winds. Temperatures probably rise overnight to near 60 or so. Confidence: Medium

A LOOK AHEAD

Showers and thunderstorms, potentially heavy, continue Wednesday morning as a powerful cold front drives through the region. Rainfall totals may reach 1-2" or so. By afternoon, the rain subsides but we'll contend with winds from the northwest at 15-25 mph with higher gusts. Morning high temps near 60 remain more or less steady until the late afternoon when colder air begins to spill into region. Wednesday night is breezy and cold with lows 26-32 (suburbs-city). Confidence: Medium

Cold high pressure grips the region Thursday through Saturday. Skies are sunny with highs each day in the mid 40s or so and overnight lows in the 20s to near 30. Confidence: Medium-High

A weak disturbance may approach the region around Sunday offering a slight (20-30%) chance of snow or rain. There's conflicting guidance on this disturbance but if it develops, it doesn't look like a big storm. Remarkably, this precipitation chance is appearing on December 5th when we've had snow five times in the last eight years. High temps on Sunday would be in the 40s if this disturbance doesn't materialize and probably in the 30s if it comes through. Confidence: Low

By Jason Samenow  | November 29, 2010; 5:00 AM ET
Categories:  Forecasts  
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Next: A look into early December: cold likely

Comments

It's pretty amazing that DCA is hanging in at 34 when it is low 20's in the valley and 21 in Manassas. This should be the morning that the last fig by the house freezes along with the unwanted house plant under the deck.

Posted by: eric654 | November 29, 2010 5:30 AM | Report abuse

Eric, we're at 29F up at 1900 ft east of Front Royal.

Interesting about the chance of snow on the 5th again...

Since it's Cyber Monday, if interested, I thought I'd share my review of a weather clock radio.

Posted by: spgass1 | November 29, 2010 5:57 AM | Report abuse

spgass1--thx for the weather radio review. Very helpful. I've been looking for a good one for a couple of years.

Another nice frosty a.m. in Harpers Ferry. I'm enjoying the calm before the storm. An 8-pointer is strolling through my meadow right now. He knows exactly where his safety boundaries are!

Posted by: tinkerbelle | November 29, 2010 6:47 AM | Report abuse

spgass1,
saw your web page. love that picture of the deer w/john lennon glasses... (Buck at Night in the Fall)

all,
looks like we're setting that days-btwn-freezing-temps record (even though it's 29 here). add another record to the list. i suppose there's probably some weather geek type keeping track of all these 2010 records? should be quite a list.

Posted by: walter-in-fallschurch | November 29, 2010 6:55 AM | Report abuse

First real hard frost of the year for us ... and yet, still some protected spots are green!

Posted by: weathergrrl | November 29, 2010 8:08 AM | Report abuse

Did someone say S-N-O-W on December 5th?!?!?! Let's flashback to last year...
http://www.youtube.com/watch?v=dUi_4cg_XEs.

Greg

Posted by: greg2010 | November 29, 2010 8:10 AM | Report abuse

walter, we are planning some sort of records wrap up around the end of the yr. and yes, it seems DCA missed freezing again (shows most recent 6 hr low of 33 this a.m.).

Posted by: Ian-CapitalWeatherGang | November 29, 2010 8:34 AM | Report abuse

ian,
boy that low of 33 goes a long way toward explaining dca's horrible snowfall totals. had it been snowing/accumulating everywhere else all night it might not have been at dca.

can you say how much of that 33 degree reading - the highest i've seen for any areas around here - is the product of:

1)urban heat island
2)location next to a moderating river
3)low elevation

Posted by: walter-in-fallschurch | November 29, 2010 9:08 AM | Report abuse

Walter here's a limited view of one of those factors http://waterdata.usgs.gov/nwis/dv?cb_00010=on&format=gif_default&begin_date=2008-11-28&end_date=2010-11-28&site_no=01646500&referred_module=sw

If the URL doesn't show it, it is basically a chart showing a lot warmer water starting this past spring compared to the previous year. So that could be a factor in keeping DCA warm although it is circumstantial.

Posted by: eric654 | November 29, 2010 9:40 AM | Report abuse

I love you December 5th! Come on, don't let me down!

Posted by: MaltyCharacter | November 29, 2010 9:59 AM | Report abuse

eric,
interesting data. what i see is a mean water temp of

1) 4.8C for 28 nov 08
2) 8.7C for 28 nov 09
3) 7.3C for 28 nov 10

first, i'm kind of surprised there's that much variation. and second, as far as last night goes, the water was colder than it was last year on this date. last night the river was warmer than the air. anyway, i'm wondering how much that affects air temps at dca?

Posted by: walter-in-fallschurch | November 29, 2010 10:16 AM | Report abuse

Walter you are right about variability after looking at year by year data since 1988. So I guess the answer to your question is probably not a lot since we would see a stronger correlation if it did.

Posted by: eric654 | November 29, 2010 10:19 AM | Report abuse

eric,
i think it would require a complex analysis that's probably not realistic - unless you could get a computer program to do the "grunt work".

i guess you'd have to correlate the differences btwn the daily water and air temps at dca with the difference btwn the air temps at dca and say dulles.

also, the effect probably reverses itself in the summer: the river would have a cooling effect. this difference might be a way to "tease out" the UHI effect?

Posted by: walter-in-fallschurch | November 29, 2010 11:50 AM | Report abuse

The forecast charts appear to show a low developing on the front over western NC then passing directly over our area at ca. 12 Zulu [7:00 AM] Wednesday [early morning].

As things stand, my Tuesday evening dance looks okay [normal rain or showers, if anything, but with a generally southerly/southwesterly breeze], but my Wednesday morning Safeway errand could be rather adversely impacted. Lows which pass directly overhead may often give us nastier weather than those passing to the west and north. There does seem to be a thunderstorm threat roughly between 3 AM and noon Wednesday. Severe weather is possible but may be worse to our south.

Posted by: Bombo47jea | November 29, 2010 12:02 PM | Report abuse

Walter that makes sense. We would have to show that the "difference" between National and surrounding stations can be correlated in some way to the water temperature mainly in spring and fall when the water temperature lags the air temperature the most.

Posted by: eric654 | November 29, 2010 12:48 PM | Report abuse

Where are we likely to see the greatest amount of rain Tuesday night into Wednesday?

Posted by: wzitlau | November 29, 2010 2:08 PM | Report abuse

Interesting comments about the heat island of DCA. I have a similar question on the opposite effect. Up here nr Ft Meade, MD, they often use Tipton Airport as the official weather station for Ft Meade. The thermometer is constantly 5 degrees, sometimes 10 degrees colder than surrounding places such as BWI Airport, Baltimore, Glen Burnie, etc.. What gives?

Posted by: OdentonMike | November 29, 2010 4:03 PM | Report abuse

The comments to this entry are closed.

 
 
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