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Posted at 5:00 AM ET, 12/21/2010

Forecast: Partly sunny with persistent cold

By Matt Rogers

Christmas snow chance hangs tough

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

 

Less breezy (i.e., wind chill), but we are still cold, cold, cold.
 
Get the 'Digit' on Twitter

EXPRESS FORECAST

Today: Partly sunny and cold. 34-38. | Tonight: Mostly cloudy. 22-29. | Tomorrow: Partly sunny, still chilly. 35-40. | A Look Ahead | Get Express Forecast by E-mail

FORECAST IN DETAIL

Our balance-of-week weather is being driven by two factors: consistent cold flow from the northwest and intermittent cloud cover from Pacific disturbances. The result is consistent colder-than-normal temperatures right up to Christmas Eve and variable sky conditions (but no precipitation is expected). We continue to monitor the chance of snow around Christmas.

Snow Potential Index: 5 (→) - Holiday weekend snow chances holding steady just above 50%, but devil remains in details.

 
The SPI is a daily assessment of the potential for accumulating snow for the next week on a 0-10 scale. Get the 'SPI' on Twitter
 

Today (Tuesday): Weakening weather systems and associated cloud debris from the current and recent West Coast storm onslaught is spreading across the country and offer us mainly complicated skies at times over the next few days. Cold weather that arrived last week is being subtly reinforced by prevailing winds from the north and west (5 to 10 mph today). Highs today should again be in the mid-to-upper 30s with partly sunny sky conditions. Confidence: High

Tonight: Cloudy skies are expected as a fading weather system tracks through the area. There is a very slight chance of a passing flurry (~15%). Clouds could keep our low temperatures from falling as much, but we still expect 20s throughout the area with the warmest readings downtown (upper 20s). Confidence: Medium-High

Keep reading for the forecast through the Christmas weekend...

Tomorrow (Wednesday): Partly sunny skies again, but temperatures may actually (get ready for it...) touch 40 degrees in spots! Other areas still see highs in the upper 30s. Everyone should be at least slightly warmer than the last couple of days. Light winds mainly come from the north again. Confidence: Medium-High

Tomorrow Night: Partly cloudy skies overnight with light winds and lows ranging from the near 20 in the colder suburbs to the mid-to-upper 20s downtown. Confidence: Medium-High

A LOOK AHEAD

Thursday and Friday are your final shopping days leading up to the Christmas holiday. The weather is cold, but not frightful. Mostly sunny skies Thursday and partly sunny skies Friday as high temperatures again mainly range in the mid-to-upper 30s. Lows Thursday night should range widely through the 20s (coldest in the outer 'burbs). Confidence: Medium-High

Christmas Eve (Friday Night) is forecast to see increasing clouds, but still cold conditions and light winds. Lows should drop into the 20s yet again with just a 20% chance of snow toward morning. Confidence: Medium-High

The Christmas weekend is focused on a possible White Christmas story. Recent guidance is split between having a storm come up the coast with moderate snow for the mid-Atlantic versus having the storm pass more out to sea with just a chance of light snow. So we keep snow chances in the 50-60% range Saturday into Saturday night with low odds of heavy snow (20%). High temps both days are in the low 30s, but higher winds on Sunday make it feel worse. We just can't get enough of these wintertime winds, right? Confidence: Low

By Matt Rogers  | December 21, 2010; 5:00 AM ET
Categories:  Forecasts  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   Del.icio.us   StumbleUpon   Technorati   Google Buzz   Previous: Mammoth snow: 13+ feet in four days
Next: Christmas snow statistics for the D.C. area

Comments

Best article! Best place to find and print coupons of major brands during holidays is "Printapons" search online and find.

Posted by: janeejkurtz | December 21, 2010 6:02 AM | Report abuse

Printapons? Really?

Posted by: MattRogers1 | December 21, 2010 6:43 AM | Report abuse

The latest 6z GFS operational gives us an estimated 4-8" (closer to the 4 side) on Christmas.

Posted by: MattRogers1 | December 21, 2010 6:46 AM | Report abuse

NWS has been underforecasting the high temperatures lately: it was only supposed to stay around 32 yesterday, yet the actual high was 38.

Posted by: HenryFPotter | December 21, 2010 6:50 AM | Report abuse

Morning, Matt...while understanding that this X-mas situation is very complicated and fluid at this point, someone told me that they'd heard a predicition for 12" of snow on Christmas Eve/Christmas...the most I've even heard of so far is 4"...any comment?

Posted by: NorthFork1 | December 21, 2010 6:50 AM | Report abuse

Morning, Matt...while understanding that this X-mas situation is very complicated and fluid at this point, someone told me that they'd heard a predicition for 12" of snow on Christmas Eve/Christmas...the most I've even heard of so far is 4"...any comment?

Posted by: NorthFork1 | December 21, 2010 6:51 AM | Report abuse

Sorry for the double post...you had already answered my question by the time I posted...

Posted by: NorthFork1 | December 21, 2010 6:53 AM | Report abuse

Hi Henry, yeah, I saw that too- I don't know why they have been so cold on forecast high temperatures. This air mass is pretty steady-state with mid-to-upper 30s.

NorthFork1, there are unfortunately huge model differences on this storm. That massive complicated complex hitting California right now has been difficult to handle on the models. The one thing I can say is that the Christmas Eve timing looks less and less likely. In fact, most guidance starts stuff around here anywhere from late morning to late day on Christmas Day. I'd lean toward your number or lower at this point...but you're right...it's a tricky situation.

Posted by: MattRogers1 | December 21, 2010 6:54 AM | Report abuse

Hey Matt, I also saw that this storm is being predicted by many as a 12+ inches our area. Why are you predicting 4-8......? I'm confused now. lol

Posted by: lll1424 | December 21, 2010 7:06 AM | Report abuse

matt, you said,
"...most guidance starts stuff around here anywhere from late morning to late day on Christmas Day."

well, this should make the snow-is-inconvenient crowd less unhappy.

presumably the later it happens the more people will be where they're going - i.e., not have to travel too much in it. i've been saying for a few days now how snow starting late on the 25th and continuing all night would be perfect timing.

1)but...does this "late start" mean less snow for MFY?

2)is there a scenario where we get a "late start" AND high accumulations?

Posted by: walter-in-fallschurch | December 21, 2010 7:18 AM | Report abuse

If you remember, the December Storm of 2009 was predicted originally to be around 10 inches a day or two before the storm arrived. We ended up with 16+ in the area. The models are coming into agreement and the storm is also slowing meaning a later onset to the storm with us seeing the snow start more on Christmas Day into the 26th. The key for us will be where and when does the low get cranking? We want to see this happen further South around the OBX. Right now (from what I have seen) it does not "bomb out" until it is on the same latitude as D.C./M.D. giving the Northeast states (N.J., N.Y., Mass., ME) a major snow. I like the 4-8" early estimate and believe that this may be upped to 5-10" in the coming day. They is is a further track South and for it to bomb and stall! Should be an interesting holiday weekend.

Posted by: greg2010 | December 21, 2010 7:19 AM | Report abuse

111424, who are these "many" of which you speak who are forecasting 12+ on this storm?

Walter, the timing of the storm will not affect accumulations as much as the actual track. I think Greg's assessment is a good one for the time being. I am still concerned that like last weekend, this storm will ultimately track farther offshore. So I tend to lean to the low end of the possible range. Hopefully, by tomorrow, we'll be able to get a better handle on this system.

Posted by: MattRogers1 | December 21, 2010 7:25 AM | Report abuse

I should be careful with using "many" but just as the user Northfolk heard...I heard a prediction of 12+ inches.

Posted by: lll1424 | December 21, 2010 7:36 AM | Report abuse

@MattRogers1 - What model do you guys put most faith in? It appears that you are basing your forecast off of the GFS. From what I have heard the Euro has us getting much more than 4". I am kind of a model noob so I am only familiar with the GFS and NAM. I agree with about 4" based on the GFS, and I quess we will have to wait another day or so for the NAM, but what is your assesment of the Euro?

Posted by: snowlover | December 21, 2010 7:40 AM | Report abuse

thanks matt.

predictions of 12".... hmmm... that sounds familiar.

so did anyone catalog jb/accuweather's predictions for TODAY's east coast snow storm? looks like dc to ny and boston is getting 0.0" today.

how 'bout the "big one" on dec 19th? MFY (my front yard) got 0.0" from that one.

how 'bout the thursday one that gave us

to be fair, once we find jb's prediction, we've got to compare it to CWGs from the same day.

Posted by: walter-in-fallschurch | December 21, 2010 7:43 AM | Report abuse

Can we send the spammer to someplace where it never snows?

Posted by: wiredog | December 21, 2010 7:45 AM | Report abuse

Hi Snowlover! The European model is MUCH slower with a start late Christmas night maybe and then most of the activity on Sunday instead. It is heaviest toward the Delmarva, but from what I could tell, it still seems to have DC area in maybe a 4-8" range.

Posted by: MattRogers1 | December 21, 2010 7:46 AM | Report abuse

dang...supposed to read:

how 'bout the thursday one that gave us less than 1.5" at MFY (my front yard).

---------------
hhmmm... wonder if the "less than" symbol "erased" the rest of my comment?

Posted by: walter-in-fallschurch | December 21, 2010 7:48 AM | Report abuse

Where can one find the Euro model output? The American models are pretty easy to find.

Posted by: JTF- | December 21, 2010 7:49 AM | Report abuse

Good Morning Matt.

What kind of effect will the storm presently bringing precip to New York and New England have on the weekend storm? That present storm seems to be doing a loop in that area--just hanging out.

Posted by: retroace | December 21, 2010 7:52 AM | Report abuse

snowlover, I also heard it would be a lot more then 4 inches here in the DCA but I will trust CWG and the forecasting they provide.

walter, I have to say I agree. accuweather hypes things way too much but NOAA is on alert with this storm warning of a potential storm..but not discussing accumalations.

My main question is I suppose...isn't it too early to announce accumalations?

Posted by: lll1424 | December 21, 2010 7:58 AM | Report abuse

I love the smell of meteorological blog banter in the morning.

Posted by: casa_wasabi | December 21, 2010 8:04 AM | Report abuse

I have to say I prefer the current European model for pushing most activity into Sunday.

Posted by: Finn1917 | December 21, 2010 8:14 AM | Report abuse

Happy Solstice everyone!
A 4 - 8 inch snow over the holiday weekend sounds terrific to me.

Posted by: FIREDRAGON47 | December 21, 2010 8:41 AM | Report abuse

Yes, it is way too early to announce accumulation forecasts- we do not have an official one. I have quoted some raw model guidance in the comments here, but did not make an official forecast yet on those numbers.

Posted by: MattRogers1 | December 21, 2010 8:45 AM | Report abuse

I watched the lunar eclipse in Harpers Ferry from about 2:15 to 3:15. Frustratingly, clouds rolled into a clear sky at almost the exact moment of total eclipse. There were some excellent views but I had to monitor the sky constantly for breaks in the clouds. The moon didn't appear as deep a red as I've seen it in eclipse photos, and it seemed equidistant between Gemini and Orion. A memorable event.

Posted by: tinkerbelle | December 21, 2010 8:52 AM | Report abuse

Understood Matt.....it's all pie-in-the-sky speculation right now.
But I'm giddy from holiday cookies & interrupted sleep, so I'm going to enjoy the buildup before the bust.

Posted by: FIREDRAGON47 | December 21, 2010 8:54 AM | Report abuse

has there ever been a Dec that never reached 40 degrees?

Posted by: silencedogoodreturns | December 21, 2010 9:03 AM | Report abuse

i hate the way some mets often times word things. ive heard bob ryan say we may get a little snow on xmas day like 10 times this morning on wtop.

no one knows if its going to be a little, alot or none at all. but yet heres bob saying a little. i could so be a meteorologist!

Posted by: KRUZ | December 21, 2010 9:04 AM | Report abuse

DCA is 33 right now at 9 a.m. but NWS still predicts a high of 36! I'm thinking 45.

Posted by: HenryFPotter | December 21, 2010 9:05 AM | Report abuse

I used to spend a lot of time on In-Accuweather and the Eastern boards, but I've got to tell you that since last winter this is where I go for good, reasoned weather discussion--aside from the "ha-ha it's snowing, there's no global warming" trolls.

I'm a snow lover, but I've got to say that I'd be happy if the East Coast got nothing more than TV-like Christmas snow showers from this one. Going to be with my family in NY for Christmas, have to drive back on the 27th AND our two cats will be in trouble if the cat sitter can't get over in bad weather!

Posted by: concepcion611 | December 21, 2010 9:06 AM | Report abuse

k just woke up a bit ago after waking up at 1:38 am and sitting in my sun (moon) room wrapped in a blanket with a cup of tea and watched the lunar eclipse till 4 am. It was beautiful and here south of Hamilton VA I had a perfect view. Clouds were to the south of me and I looked to the west where I saw shooting stars and the moon get swallowed up and turn to an amber. Fantastic and worth the loss of sleep!! Once in a lifetime event.

Posted by: worldtraveler83 | December 21, 2010 9:08 AM | Report abuse

I have been viewing multiple sites over the past week and haven't seen one forecast this weekend for 12+ from ANYONE...even JB, mr. snowstorm monster lover himself. Not sure where that talk is coming from...think its in some snowlover-wishful-thinking heads. this thing will most likely be too far OTS and we'll probably get a max of 4'' like we've been hearing from the CWG...but obviously it's early to even say that.

Posted by: parksndc | December 21, 2010 9:32 AM | Report abuse

Woke up at 2:20 and went to the sliding glass door (faces SW). The moon had a nice chunk bitten out of it, but unfortunately there were wispy clouds covering most of the sky so I threw another log in the wood stove and went back to bed.

Posted by: eric654 | December 21, 2010 9:37 AM | Report abuse

has there ever been a Dec that never reached 40 degrees?

Posted by: silencedogoodreturns | December 21, 2010 9:03 AM | Report abuse
**************************************

December 1 of this year was in the mid-60s. Seems like so long ago...

Posted by: thepostischeap | December 21, 2010 9:45 AM | Report abuse

The 00z ECMWF and GGEM are trending toward more phasing and amplitude in the long wave pattern which gives areas especially I95 and east a more significant storm.....but this is only one run....

As I suggested last night at 8:52 in Wes's post, some of the synoptics are troubling for those wishing for a major snowstorm. The large lp over the north Atlantic (50/50 hybrid) is too strong and too far west, with no trigering hp over northern New England to the Lakes to help funnel Atlantic moisture into the system. Wes confirmed without reference at 10:18 pm when he commented about the lack of 850mb easterly winds to help tap Atlantic moisture.

The 00z ECMWF and GGEM weaken and shift the 50/50 hybrid a little out of the way, allowing more amplitude and a closer to the coast track.

It will be interesting to see if the 12z runs sustain and if the GFS climbs on board.......

Posted by: AugustaJim | December 21, 2010 9:46 AM | Report abuse

@worldtraveler83
I also enjoyed the eclipse over a cup of tea - stayed up until it reached maximum totality at 3:17 am. The starry sky, light winds, and passing clouds over the high moon made for a very wintry experience...especially with the moonlight reflecting off the remaining snow on my deck. Definitely worth it, considering it's been 372 years since the last winter solstice eclipse, and I won't be alive 84 years from now!

Posted by: meteorolinguist | December 21, 2010 9:49 AM | Report abuse

meteorolinguist, wow you stayed up? very impressive. I am jealous too. I just couldn't make it! Glad you had some tea to keep you awake though.

Any others enjoy the eclipse last night?

Boy was it cold this morning for my walk to work. Walk-commuters out there with me on this one? Brrrr. Scarf had to go over most of my face! haha

AugustaJim - we too are watching those model trends. It will have to be a steady progression .. make a real discernible CONSISTENT pattern... for me to get excited/on-board.

Posted by: Camden-CapitalWeatherGang | December 21, 2010 10:24 AM | Report abuse

Camden:

You express intelligence with that attitude.

Posted by: AugustaJim | December 21, 2010 10:46 AM | Report abuse

AugustaJim - haha, why thank you ;) and yes, I want some snow too. But chaos theory is in full (non-theory?) effect with the atmosphere's mathematical output this winter...

Posted by: Camden-CapitalWeatherGang | December 21, 2010 10:55 AM | Report abuse

Yes, my wife set the alarm for 3:17 am. She jumped up threw on a coat and ran outside. The dog and I did not. However I did rouse for a moment and look at the moon. Very beautiful, glad I got up for those 30 seconds...

BTW my parents took me to Nova Scotia for the total solar eclipse back in about '72. Saw the last moon launch at Cape Kennedy in about '73. I do enjoy this stuff - thought we'd be cruising the planets by now.

Posted by: CCCinNaptown | December 21, 2010 10:57 AM | Report abuse

has there ever been a Dec that never reached 40 degrees?

Posted by: silencedogoodreturn
********************************

Not if Snow Miser is in charge!!

I never want to see a day
That's over forty degrees
I'd rather have it thirty,
Twenty, ten, five and let it FREEEEEEEZE!!!

Posted by: wadejg | December 21, 2010 11:15 AM | Report abuse

CCCinNaptown - was the moon a copper-orange color as predicted it would be around 3:17am? I bet it was spectacular! and yes, so much for space travel, eh? ;)

Not positive about the 40 degrees in December.. I have started researching though. But my gut tells me we have always hit 40, at least once, during every December on record.

Posted by: Camden-CapitalWeatherGang | December 21, 2010 11:30 AM | Report abuse

Yes it was a beautiful copper-orange as predicted. I actually thought the moon would be darker but the color was very pleasant. The cold, clear night made it very vivid - in a pale wintery sort-of way.

Posted by: CCCinNaptown | December 21, 2010 11:36 AM | Report abuse

@CCCinNaptown: "BTW my parents took me to Nova Scotia for the total solar eclipse back in about '72. ..."

Was this the same total solar eclipse that passed over Va Beach? 7 March 1970. I remember it like yesterday. 3 minutes totality, perfect weather, high altitude rocket launches from Wallops Island. Heck, it even inspired Carly Simon to write a song:

"Then you flew your Lear jet to Nova Scotia,
to see the total eclipse of the sun..."

Posted by: ennepe68 | December 21, 2010 11:38 AM | Report abuse

CCCinNaptown - very neat! yes the clear "crisp winter" sky was great for the event last night!

wadejg - I found a couple useful links for you to look at. Nothing as definitive as I want, but you can glance at the data to at least partially satisfy your curiosity. I doubt that any December, even the coldest December of 1880, failed to hit 40 at least once. The mean of the Dec 1880 month is 29.0. Statistically speaking, I believe that mean to be several degrees too high to indicate a failure to hit 40F for a high temperature during even that coldest December. Here is what I have been reading:

http://www.erh.noaa.gov/lwx/climate/dca/dcatemps.txt
http://www.erh.noaa.gov/lwx/climate/dca/Dcadec.txt

Posted by: Camden-CapitalWeatherGang | December 21, 2010 11:46 AM | Report abuse

@Camden-CapitalWeatherGang

You're right about 40 in Dec. In fact, Ian's blurb in yesterday's PM Update lays it all out: "There was a question about the record for most days with highs below 40 degrees. So far this month we've had 12 such days. The most sub-40 degree days occurred in December, 1876 before the official observing station moved to Reagan National Airport (DCA). After the station move, the most such days at DCA occurred in 1989 with 22. So we have a ways to go to reach a meaningful record. That said, the long-range forecast suggests 2010 could challenge for a high spot on that list. 2009 had just 10."

Posted by: Jason-CapitalWeatherGang | December 21, 2010 11:48 AM | Report abuse

I set my alarm for 3:00am and stayed outside until about 3:45. Unfortunately, a cold came and joined me- I hope it leaves by the 23rd. Here in Alexandria, there was cloud cover at times, but the moon was visible for the most part and beautiful. It was a copper orange color as predicted.

Posted by: Snowlover2 | December 21, 2010 11:48 AM | Report abuse

@ennepe68: Yes, it must have been the very same one you saw in VA Beach. They are so infrequent it had to be.

We went to Nova Scotia because that was the place where 'totality' was best viewed on the planet, so we really got the treatment. We pulled our Airstream trailer up there and tooled around quite a while before the big event.

Even as a kid I imagined how primative societies would have been scared witless by a solar eclipse - it got very dark, but in a weird coppery light. It could get you worshipping trees, fish, stars...

Posted by: CCCinNaptown | December 21, 2010 11:49 AM | Report abuse

I'm not sure if this has anything to do with the lunar eclipse (which I was waaaay too tired to stay up for), but I was startled awake at just after 5am by the moonlight through my window and it was BRIGHT. I don't think I have ever seen the moon shining so brightly. Perhaps it was the clear sky as well. It was casting shadows from the trees and even into my apartment. We had to close the blinds to get back to sleep. Quite eerie, and spectacular.

Posted by: amandap2986 | December 21, 2010 11:54 AM | Report abuse

I'm not sure if this has anything to do with the lunar eclipse (which I was waaaay too tired to stay up for), but I was startled awake at just after 5am by the moonlight through my window and it was BRIGHT. I don't think I have ever seen the moon shining so brightly. Perhaps it was the clear sky as well. It was casting shadows from the trees and even into my apartment. We had to close the blinds to get back to sleep. Quite eerie, and spectacular.

Posted by: amandap2986 | December 21, 2010 11:55 AM | Report abuse

I got up at 3 to check out the eclipse too. Hoped I'd be able to just step out on the balcony but couldnt quite see it from there. Once I got out into the parking lot a little ways it was quite vivid. Very deep copper. Well worth losing 20 min of sleep.

Posted by: Brian-CapitalWeatherGang | December 21, 2010 12:15 PM | Report abuse

The 6-12-inch forecast for Christmas seems to be from a Euro run. Four to eight inches on the GFS forecast seems reasonable.

Recent Euro runs seem to be delaying the storm into the Saturday/Sunday time frame.

At least my dance schedule is light--tonight at the Clarendon Ballroom, and possibly New Year's Eve at Glen Echo. There's also a dance Monday night at Chevy Chase--Metro issues might rule that out for me. They're actually starting random bag checks on Metro today.

Posted by: Bombo47jea | December 21, 2010 12:32 PM | Report abuse

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