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Posted at 6:00 PM ET, 02/28/2009

Update: Mix Tonight, Bigger Snows Tomorrow PM

By Jason Samenow

* Winter Storm Watch Sunday afternoon through Monday morning *

Best accumulation estimate for Sunday p.m. through Monday a.m. remains 3-6", though 6"+ an increasing possibility, especially east of I-95; Not much accumulation tonight.

Our Full Forecast | Radars, Temps & More: Weather Wall

STORM #1: TONIGHT

An area of light rain and sleet has developed to the south and will move northeastward tonight, courtesy Storm #1 in our weekend storm duo. This precipitation will overspread the region between 7 and 10 p.m. After midnight, the rain and sleet will probably change to sleet and snow from northwest to southeast. Most areas shouldn't see much accumulation... although up to a sloppy inch of sleet and snow can't be ruled out -- mainly in the north and west suburbs.

Temperatures will gradually drop to 30-32 by the early morning hours. I'm not expecting major travel difficulties tomorrow morning, although some patchy light snow or sleet may linger along with a few slick spots. So use caution.

STORM #2: SUNDAY P.M.-MONDAY A.M.

Storm #2 remains a significant snow threat for late tomorrow through Monday morning. Snow could begin to accumulate as early as between 4 and 6 p.m. Sunday, with accumulating snow possibly continuing through the overnight.

Keep reading for our latest thoughts on Storm #2 and updated accumulation probabilities.

snowprob2_030109.jpg
CWG snow possibilities for the Sunday-Monday storm.

Some of the guidance which suggested the storm may track too far east to produce accumulating snow has shifted west...so our confidence has increased we will get some shovelable snow.

Still, because the western edge of the substantial snow is so close to our region, just a slight shift to the east would result in significantly lower accumulations. So we cannot rule out a scenario where we receive little, if any snow.

For now, we're sticking with our accumulation projection of 3-6", and 6" or more is an increasing possibility, especially east of I-95.

Our updated probabilities for the full range of possibilities are shown above.

Please comment with what's happening where you live and/or to discuss Storm #1 and Storm #2

By Jason Samenow  | February 28, 2009; 6:00 PM ET
Categories:  Updates  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   Del.icio.us   StumbleUpon   Technorati   Google Buzz   Previous: Sunday-Monday Storm: Significant Snow Possible
Next: Storm Reporting - View Reports

Comments

According to WeatherBug, Damascus is already well below freezing (30.3); can anyone in northern Montgomery County or western Fairfax confirm that temperatures are (close to) or in the low 30s [already]?

At the moment, temperatures area-wide appear to be running several degrees cooler than NAM forecast guidance and more in line with GFS guidance.

I personally think frozen precipitation (in the form of sleet) may be possible (well?) before midnight...

Posted by: Josh-CapitalWeatherGang | February 28, 2009 5:55 PM | Report abuse

36.3 here is centreville

Posted by: heatmiser | February 28, 2009 5:59 PM | Report abuse

Josh, I'm in eastern Loudoun and my weatherbug currently reads 34.

Posted by: natsncats | February 28, 2009 6:00 PM | Report abuse

I called it: NEWS 4 started their forecast at a SALT DOME!

Posted by: stinkerflat1 | February 28, 2009 6:02 PM | Report abuse

Josh: 36.4 here in the Fair Oaks area at 6:05 pm.

Yay snow!

Posted by: CM_in_Fairfax | February 28, 2009 6:06 PM | Report abuse

36.4 in McLean, DP is 20

Posted by: gfp76 | February 28, 2009 6:09 PM | Report abuse

Radar has indicated some precipitation on and off this afternoon, though none has hit the ground here yet.

Current conditions: 28.4F, cloudy

Location: Blue Ridge Mtns, elevation 1900 ft (Eastern Warren County near border with Fauquier Co).

Posted by: spgass1 | February 28, 2009 6:16 PM | Report abuse

A *rough* way to calculate how far the temperature will drop through the process of evaporative cooling -- it is actually precipitating at the moment "upstairs," but this precipiptation is evaporating before it hits the ground (i.e., virga) -- and when water evaporates it releases latent heat is to:

Subtract the DP (20) from the Air-temp (36.2) = 16.2. Then subtract five from this dewpoint depression (16.2-5 = 11.2). Then divide this figure by 3 (11.2/3 = 3.73) and, finally, subtract this number from the current Airtemp (36.2 - 3.73) = 32.47

As I said, this is only a rough measurement with probably only a resolution of +/- 2 to 3 degrees, and there are number of other factors.

Posted by: Josh-CapitalWeatherGang | February 28, 2009 6:17 PM | Report abuse

Current temp. in Burke: 37 exactly with overcast skies.

Posted by: Yellowboy | February 28, 2009 6:18 PM | Report abuse

35.8 here in Sterling. Is there any chance that the storm could shift westward? (I'm selfish when it comes to snow)

Posted by: Sterlingva | February 28, 2009 6:18 PM | Report abuse

*sniff* I am actually in Richmond right now, not Manassas, so I can't be of any help other than to say it is raining here right now and 38.

Posted by: ksrgatorfn1 | February 28, 2009 6:19 PM | Report abuse

Even though the temperature was above freezing in Stafford about a half hour ago, some very light ice pellets were falling when I ventured outside.

Posted by: david_in_stafford | February 28, 2009 6:28 PM | Report abuse

39.4 on the water in Annapolis at 6:30. Are we in the zone for snow or too far east, as usual?

Posted by: thecrawfords | February 28, 2009 6:29 PM | Report abuse

I just heard the NEWS 4 dude say the latest model runs show the storm shifting east! What's up with this team?

Posted by: stinkerflat1 | February 28, 2009 6:29 PM | Report abuse

Model discussion: NAM continues to leave us precipitation-free tomorrow night. Disquieting feature for snow-lovers is that the storm apparently moves rapidly away on Monday. Earliest model runs had storm moving SLOWLY up the coast and possibly giving us snow until Tuesday AM. [Too darned much dry air feeding in as of now!]

Two unusual features on current NOAA map. 1. Highest pressure in Northern Hemisphere is currently over Central Pacific between Aleutians and Hawaii. [Normally it should be over Siberia/Mongolia.] 2. There is low pressure directly over the North Pole. [Normally a polar high should be feeding the "polar easterlies" this time of year.] An intense low pressure system sits W of the Pacific Coast between California and the intense Central Pacific high.

Posted by: Bombo47jea | February 28, 2009 6:31 PM | Report abuse

temp South of Damascus near Butler's orchard at 6:30P is 34. Come on snow ! :-)

Posted by: RicknearButlers | February 28, 2009 6:32 PM | Report abuse

Where's the Snowcam?

Posted by: Bitter_Bill | February 28, 2009 6:34 PM | Report abuse

I just checked my outside temp thermometer in Montgomery Village and it said 30 degrees. However, I am not sure how accurate it is. It does feel cold...

Posted by: soleil2000 | February 28, 2009 6:35 PM | Report abuse

@stinkerflat1

There's been no eastward shift in the models. With the exception of the NAM which shifted a bit west early on, they've basically stayed constant today. Could they still shift -- east or west? Sure...

Posted by: Jason-CapitalWeatherGang | February 28, 2009 6:36 PM | Report abuse

I'm surprised at how many seasoned DC vets are buying into this storm. The rule over the years has been that if the storm can miss us, it will.

Posted by: jaydreb1 | February 28, 2009 6:37 PM | Report abuse

Holding at 33.6 deg F here between Laytonsville and Olney in Montgomery County. Nothing falling yet.

Bring It!

Posted by: uncledak | February 28, 2009 6:40 PM | Report abuse

CWG - Any validity to the rumors of the storm shifting east? We are 20 hours out - how usual is it for the models to waffle this close to the storm.

Posted by: snowlover | February 28, 2009 6:40 PM | Report abuse

Jason - you basically answered my questions in your post above - thx!

Posted by: snowlover | February 28, 2009 6:42 PM | Report abuse

Historical note:
While significant March snows are not impossible, they are extremely rare:
Not the March of the Penguins.
Anything over 2.1" after midnight Sunday would be a record for Mar. 2.

Posted by: CapitalClimate | February 28, 2009 6:49 PM | Report abuse

Burke, VA, 37 degrees F, no precipitation

Posted by: nadya77 | February 28, 2009 6:50 PM | Report abuse

Records are made to be broken!!

Posted by: snowlover | February 28, 2009 6:52 PM | Report abuse

@jaydreb1

I think this one will happen since I saw a landscape company actually using lawnmowers on a property off Mass Ave. on Thursday. That is a major weather jinx if ever I saw one. A lawn mower on Feb 26th? Come On.

Posted by: uncledak | February 28, 2009 6:53 PM | Report abuse

37 in Shirlington. Tonight's forecast: dark.

Posted by: jochpo | February 28, 2009 7:00 PM | Report abuse

. . . with widely scattered light toward morning . . .

Posted by: uncledak | February 28, 2009 7:08 PM | Report abuse

As I had thought, the NAM mos guidance is running too warm. Here are 7pm comparisons.

For DCA:
NAM predicted 41
GFS predicted 38
Actual temp was 38

For IAD:
NAM predicted 39
GFS predicted 35
Actual temp was 35

For both airports, the GFS MOS guidance forecast temp for 7pm (0Z) was exactly right while the NAM MOS guidance temp was 3 degrees too warm at DCA and 4 degrees too warm at IAD; it will be very interesting to see if this trend continues. Especially since the NAM is typically better with low-level temperatures due to its higher resolution.

Posted by: Josh-CapitalWeatherGang | February 28, 2009 7:10 PM | Report abuse

Jason - what's the latest on tonight's weather? Think my kids will have Hebrew School tomorrow AM in North Potomac?? Keep up the good work.

Posted by: someonelikeyou | February 28, 2009 7:11 PM | Report abuse

Capital Cimate, you are incorrect when you say that significant March shows here are extremely rare. That is DEFINITELY not the case. I have seen a number of them over the years here, ranging from 4" to the 12" Superstorm of March 11-12, 1993. I have also seen a number of smaller, 1" storms in March.

In fact, I have actually seen more March snowfalls around here than I have seen March thunderstorms. (I've lived here since 1962, as a young boy)

Posted by: MMCarhelp | February 28, 2009 7:13 PM | Report abuse

About 35 degrees right now in Potomac (near Great Falls & MacArthur Blvd.)

Posted by: someonelikeyou | February 28, 2009 7:13 PM | Report abuse

WeatherBug at Chantilly HS reads 32.3

Posted by: Ebbi88 | February 28, 2009 7:24 PM | Report abuse

CWG - Are we going to see another update around midnight, or is it going to be tomorrow morning? Thx!

Posted by: snowlover | February 28, 2009 7:33 PM | Report abuse

This is a good spot for snowlovers! (The forum, not the DC area this year)
My kids are doing the snow dance! We want snow!!

Posted by: celestun100 | February 28, 2009 7:39 PM | Report abuse

37.4 & very light rain in NW Spotsy. Remember 12" snow in Roanoke on March 28-29, 1970, I was finishing up my last yr at Tech. Some parts of Va got 18-24" from that storm. On the 30th in was grilling outside with temps close 2 70. May be a few days off on that storm, but my b,day is the 29th & I think that's when it occurred. Don't believe the DC area got much of anything from it. Also washed & waxed our car the day b4. It had been a fairly snowless winter until then.

Posted by: VaTechBob | February 28, 2009 7:47 PM | Report abuse

5 inches would be heaven. My kids are forgetting what snow is. I teach school and the middle school kids said that it "Looked like Alaska" on the one day this year that we had what looked like less than a 1/4 inch of big, blowing flakes.

Posted by: celestun100 | February 28, 2009 7:52 PM | Report abuse

The only March daily snowfalls over 4" since 1929:
3 29 1942 11.5
3 9 1999 8.4
3 7 1941 8
3 3 1960 7.1
3 13 1993 6.5
3 30 1964 4.8
3 3 1978 4.1

Average number of March thunderstorms:
1.2 PER YEAR.

Posted by: CapitalClimate | February 28, 2009 7:54 PM | Report abuse

Does that mean you think this will turn to rain like all the other storms have this year?

Posted by: celestun100 | February 28, 2009 7:56 PM | Report abuse

Snow/sleet here in Culpeper Va.

Posted by: clintonportis17 | February 28, 2009 8:09 PM | Report abuse

Finally precip entering the DC area. Just started to sleet in Lake Ridge - temp at 36 degrees.

Posted by: ZmanVA | February 28, 2009 8:12 PM | Report abuse

Celeste, turing to rain is doubtful. Cold air will only be reinforced as the storm moves along. So once it starts snowing, It should stay that way.

Posted by: Brian-CapitalWeatherGang | February 28, 2009 8:17 PM | Report abuse

How often does the NWS update their snow information? How likely are we to get snow in central Montgomery County? Does it all depend on if this band of snow is wide enough to include us?

Posted by: celestun100 | February 28, 2009 8:23 PM | Report abuse

VaTechBob--I was born on that 29th! I wasn't born in Roanoke, but a bit upstream of the storm, and there was a warm snap afterwards. The storm came out of nowhere--my folks were caught unawares and were lucky to make it to the hospital in time!

Posted by: jkuchen | February 28, 2009 8:30 PM | Report abuse

I was actually around for 5 of those March storms. Had about 10" at Fountainhead Park from the 93 storm. National usually has lower totals.

Posted by: VaTechBob | February 28, 2009 8:33 PM | Report abuse

8:30:
Moderate to heavy snow falling; Ground getting white. 32 degrees.

Posted by: AugustaJim | February 28, 2009 8:38 PM | Report abuse

@someonelikeyou

I think your kids better prep for Hebrew school... don't think it will be inclement enough to cancel.

Posted by: Jason-CapitalWeatherGang | February 28, 2009 8:38 PM | Report abuse

AugustaJim, where are you that you see snow?

Posted by: celestun100 | February 28, 2009 8:41 PM | Report abuse

About the current temps...would it already be down to freezing in Charlottesville this soon? A friend called who's driving and she felt like the roads were getting icy. The current radar looks like rain, and I thought the freezing bit was to start later tonight.

Posted by: manassasmissy | February 28, 2009 8:41 PM | Report abuse

Just got back from an afternoon out, light sleet/rain falling in Arlington.

Posted by: JJones-CapitalWeatherGang | February 28, 2009 8:42 PM | Report abuse

I am amazed, given the current seeming strength of radar returns (at least over some areas) that the air temperature has barely dropped at all over the past few hours and, even more surprisingly, that the dew point hasn't come up; the vast majority of precipitation is still evaporating

Posted by: Josh-CapitalWeatherGang | February 28, 2009 8:45 PM | Report abuse

Do you still think 3-7? I sure hope so. Im alright with hebrew tomorrow but whats the schoolcast for mon? Likely for school? Likely for closing? What do you think?

Posted by: hoyafan516 | February 28, 2009 8:47 PM | Report abuse

Current temp. in Burke: 36.7 with light sleet.

Posted by: Yellowboy | February 28, 2009 8:47 PM | Report abuse

Sleeting pretty good, and has been, since about 8 p.m. Temp holding at 33 for the past hour in New Baltimore.

Posted by: weathergrrl | February 28, 2009 8:47 PM | Report abuse

I am 100 miles w.s.w. of D.C.

1300 ft. elev. above sea level.

Posted by: AugustaJim | February 28, 2009 8:51 PM | Report abuse

Snow scenarios in the greater Washington area are like the "Peanuts" cartoons in which Lucy takes away the football just as Charlie Brown goes to kick it--hopes are dashed every time!

Make that kick, Charlie Brown!

Posted by: le_rod | February 28, 2009 8:55 PM | Report abuse

Very light sleet falling now. I didn't see it at first, but could hear it. 28.2F

Posted by: spgass1 | February 28, 2009 8:58 PM | Report abuse

Down to 30 degrees with snow and sleet falling.

Posted by: AugustaJim | February 28, 2009 8:59 PM | Report abuse

Praise God! Snow falling here in McLean.
But if there weren't any snow, well, God be praised regardless.

Posted by: KBurchfiel | February 28, 2009 9:04 PM | Report abuse

Holy crap.

The NAM has just become my new best friend!

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/00/images/nam_pcp_030l.gif

Posted by: JTF- | February 28, 2009 9:13 PM | Report abuse

32.5 in northwest Montgomery.

Posted by: MKadyman | February 28, 2009 9:16 PM | Report abuse

Mixed prec. in NW`Spotsy, 35.5. It's a know fact that people born on March 29 r the most intelligent people on the planet.

Posted by: VaTechBob | February 28, 2009 9:17 PM | Report abuse

100% snow, pavement beginning to cover.

1/4 inch acc.

Posted by: AugustaJim | February 28, 2009 9:23 PM | Report abuse

Wow, sounds like a lot of you are indeed turning wintry tonight. Still 37 and barely anything to report here in downtown DC.

Also, I would caution against getting too attached to one weather model on one isolated model run! It is just one "voice" for us to consider in this whole forecast thing!

Posted by: Camden-CapitalWeatherGang | February 28, 2009 9:24 PM | Report abuse

Winter 2009: Meet Spring 2009. I think i like spring more already....

Posted by: JJones-CapitalWeatherGang | February 28, 2009 9:24 PM | Report abuse

Moderate sleet in Culpeper Va.

Posted by: clintonportis17 | February 28, 2009 9:26 PM | Report abuse

CWG - Why is the NWS Sterling being so conservative on this? They have ot updated their 3pm forecast and, as it stands, it looks like all they predict is a few inches of wintry mix. Consensus is that is flat wrong - why the delay in updating their forecasts?

Posted by: worldtraveler | February 28, 2009 9:27 PM | Report abuse

Taking Amtrak from BWI to NYC on Monday 11:30 am arriving 2pm

Will we be OK getting to train station? travelling? arriving?

Stressing . . .

Posted by: Post43 | February 28, 2009 9:31 PM | Report abuse

@worldstraveler

It is about building on the forecast. Even though it seems right now that this forecast is a solid lock, that was not the case even 18 hours ago. With almost a full 24 hours before the onset of this sucker, there is still plenty of time for Sterling to get their detailed forecast to what we will eventually see. I'd expect to see a much stronger forecast from Sterling this evening if things continue to trend the way they are now.

Posted by: JJones-CapitalWeatherGang | February 28, 2009 9:32 PM | Report abuse

worldtraveler:

They are still at 12z. The Gov. is always slow to react.

If the 00z models concur, expect a big change with the morning package.

Posted by: AugustaJim | February 28, 2009 9:33 PM | Report abuse

Camden, I meant to preface that with the fact that the NAM was, until recently, my arch nemesis.

As you can see, I am a fair weather friend (pun very much intended). :)

Posted by: JTF- | February 28, 2009 9:33 PM | Report abuse

Thanks folks.

Posted by: worldtraveler | February 28, 2009 9:34 PM | Report abuse

Light sleet and 32.5 degrees in Great Falls, VA.

Posted by: dwljr | February 28, 2009 9:37 PM | Report abuse

Understood RE: NAM model :)

also, Amtrak should not have any delays with this storm. Only 8"+ will delay rail line traffic. And that hasn't happened--to my knowledge--in the Metro Area since 1996.

Posted by: Camden-CapitalWeatherGang | February 28, 2009 9:38 PM | Report abuse

@Post43.

I'd like to see yes, but the northeast corridor will be an absolute mess on Monday afternoon, even if the snow is done here by noon, it will likely still be going on in the NYC area. Would it be possible to travel on Tuesday instead?

Anyone have any experience with Amtrak in the snow?

Posted by: JJones-CapitalWeatherGang | February 28, 2009 9:38 PM | Report abuse

Can't travel Tuesday - family event, hotel etc. reservations made.

I, too, would like to hear of Amtrak experience in the snow. Even if it's OK here, I'm concerned about travelling up to NYC.

I think once we're actually in NYC, we'll be fine.

All thoughts appreciated!!

Posted by: Post43 | February 28, 2009 9:41 PM | Report abuse

Before anybody goes crazy (might be too late for that) keep in mind that it got up to 66 Friday afternoon. Ground is warm, and with the higher sun angle of late winter it's going to be difficult to get a lot of accumulating snow on area roadways.
Even if we get several inches of snow this is looking more like a "snow on the grass, just slush on the streets" type of storm.

Posted by: Curmudgeon4 | February 28, 2009 9:44 PM | Report abuse

@Curmudgeon4

I wouldn't assume that this will not impact roads. The bulk of the snow will fall overnight when the sun angle is not an issue and temperatures will be falling into the 20s.

Posted by: Jason-CapitalWeatherGang | February 28, 2009 9:47 PM | Report abuse

Sleet/snow mix now in Lake Ridge, however looks like snow is predominant form of precip.

Posted by: ZmanVA | February 28, 2009 9:48 PM | Report abuse

Pavement is now white, snow continuing to fall. 29 degrees

Posted by: AugustaJim | February 28, 2009 9:49 PM | Report abuse

correction.. predominant form in Lake Ridge still appears to be sleet.

Posted by: ZmanVA | February 28, 2009 9:50 PM | Report abuse

Curmudgeon:

Much of the heavy precipitation looks like it will be overnight Sunday into Monday, so the sun angle won't matter then. Also, the roads are quite cool at the present time (30s, some low 40s) and will have time and cold air above (and cold precip hitting it right now) to cool further before the main event:

http://www.chart.state.md.us/travInfo/weatherStationData.asp

Posted by: JTF- | February 28, 2009 9:52 PM | Report abuse

Nothing: Zero, zip, zilch. Merrifield is dry as a bone.

Posted by: --sg | February 28, 2009 9:53 PM | Report abuse

One day of 60+ weather will do little to stop accumulation. Especially when today didn't make it much north of 40.

Posted by: Brian-CapitalWeatherGang | February 28, 2009 9:53 PM | Report abuse

My point about the sun angle is that even though Sunday will be a cloudy day, the higher sun angle will help warm the roads after tonight's precip event. I still think that major roadways will only be slushy, especially with the salt treatemnt they are receiving right now.

Shady secondary roads...different story.

Posted by: Curmudgeon4 | February 28, 2009 9:57 PM | Report abuse

--sg: Merrifield should be getting the mix pretty soon.

Posted by: ZmanVA | February 28, 2009 9:59 PM | Report abuse

It's not just one day of 60+. It was also fairly mild Thursday, with some areas topping out near 60 in the afternoon.

Posted by: Curmudgeon4 | February 28, 2009 9:59 PM | Report abuse

So back to my Amtrak anxiety (sorry):

Better to take beltway to 95 Monday morning? We were going to leave at 9:00 for an 11:20 train. Should we go earlier? If so, how much? (from Boyds)

Many thanks

Posted by: Post43 | February 28, 2009 10:01 PM | Report abuse

Issued by The National Weather Service
Baltimore/Washington, MD
10:03 pm EST, Sat., Feb. 28, 2009

... WINTER STORM WATCH REMAINS IN EFFECT FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING...

A WINTER STORM WATCH REMAINS IN EFFECT FROM SUNDAY AFTERNOON THROUGH MONDAY MORNING.

LOW PRESSURE OVER NEBRASKA WILL TRACK SOUTHEAST TOWARD GEORGIA ON SUNDAY... AND THEN TURN UP THE COAST SUNDAY NIGHT. THE LOW WILL STRENGTHEN AS IT MOVES NORTH ALONG THE COAST.

TEMPERATURES WILL BE SUB FREEZING SUNDAY NIGHT. DEPENDING ON THE TRACK OF THE LOW SEVERAL INCHES OF SNOW ARE POSSIBLE SUNDAY NIGHT AND MONDAY MORNING... ESPECIALLY ALONG AND EAST OF I-95. THE LOW WILL TRACK NORTHEAST OF THE AREA MONDAY... BRINGING AN END TO THE PRECIPITATION BY MIDDAY MONDAY.

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT SNOW... SLEET... OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL. CONTINUE TO MONITOR THE LATEST FORECASTS.

Posted by: someonelikeyou | February 28, 2009 10:06 PM | Report abuse

After an afternoon of spotty sleet, finally getting the flakes in Charlottesville, and 31 degrees.

CWG - what are the ingredients necessary to make a coastal storm stall and are any present? Even better, what's needed to focus every ounce of moisture onto Charlottesville (just on my house would be fine to spare everyone else)?

@Post43, Re: Amtrak - can you take a northbound MARC train to the station? Avoid the Beltway & 95 at all cost.

Posted by: cvilleSnowMan | February 28, 2009 10:07 PM | Report abuse

They are still sticking to the forecast of "several inches". It seems like the only place reporting a BIG storm is the Post.

Posted by: justin1013471 | February 28, 2009 10:09 PM | Report abuse

A light dusting of mainly sleet and a bit of snow on cars here in Lake Ridge. Coming down at a good clip.

Posted by: ZmanVA | February 28, 2009 10:11 PM | Report abuse

Annapolis, MD: 10:10 PM, 38.8F, and the sleet started recently. The temp has not varied by more than a few degrees all day, and I'm hoping that will continue. Bah humbug on the snow forecast! Time for spring!

Posted by: ceblakeney | February 28, 2009 10:11 PM | Report abuse

NWS update (west trend) which would be good for me.


HAVE UPDATED THE GRIDS FOR LATER SUNDAY AND SUNDAY NIGHT WITH THE
NEXT STORM SYSTEM. CUT OFF UPPER-LEVEL LOW WILL TRACK THROUGH THE
SOUTHEASTERN CONUS SUNDAY AND TOWARDS THE MID-ATLANTIC COAST SUNDAY
EVENING. AS THE UPPER-LEVEL LOW APPROACHES THE BAROCLINIC ZONE ALONG
THE SOUTHEAST COAST...LOW PRESSURE WILL DEEPEN AS BOTH SYSTEMS TRACK
UP THE MID-ATLANTIC COAST SUNDAY NIGHT. GIVEN THE FACT THAT THIS
SYSTEM WILL BE CUT OFF AND DIGGING...THIS MAY PULL DOWN SOME
NORTHERN BRANCH ENERGY AS IT TRACKS UP THE COAST SUNDAY NIGHT. THIS
MAY ALLOW FOR THE SYSTEM TO TRACK FURTHER WEST THAN WHAT PREVIOUS
GUIDANCE WAS INDICATING. LATEST GUIDANCE HAS ALSO TRENDED A BIT
FURTHER WEST WITH THE TRACK OF THE LOW. HAVE BUMPED UP POPS FOR THE
METROPOLITAN AREAS SOUTH AND EAST WITH AN INCREASING LIKELIHOOD FOR A
BAND OF SNOW TO DEVELOP LATER SUNDAY AFTERNOON THROUGH SUNDAY NIGHT
ACROSS THESE AREAS.

WILL KEEP THE WATCH UP FOR NOW...AND HAVE THE NEXT SHIFT TAKE
ANOTHER LOOK AT IT WITH THE LATEST 00/06Z GUIDANCE. ONE THING TO
NOTE IS THAT THERE WILL BE A TIGHT GRADIENT BETWEEN HEAVIER SNOW AND
LITTLE OR NO SNOW. A SHIFT EITHER WAY WITH THE TRACK OF THE LOW WILL
HAVE A SIGNIFICANT IMPACT ON THE FORECAST.-- End Changed Discussion --

Posted by: clintonportis17 | February 28, 2009 10:13 PM | Report abuse

Pavement is now white, snow continuing to fall. 29 degrees

Posted by: AugustaJim | February 28, 2009 9:49 PM


-------------------------------------------

Jim - You're a tease and making us crazy!

Posted by: waterfrontproperty | February 28, 2009 10:13 PM | Report abuse

Light sleet, 37, in Falls Church. Slushy looking streaks and flakes under the parking lot lights.

Posted by: MiltonWaddams | February 28, 2009 10:13 PM | Report abuse

Can't do Marc- different line.

So what's the best way to get to BWI Amtrak Mon morning? Usually, we take back roads, but I'm afraid to do that in slippery weather.
Please help!

Posted by: Post43 | February 28, 2009 10:14 PM | Report abuse

39.2 on the water in Annapolis at 10:20, spitting tiny bits of rain and slush.

Posted by: thecrawfords | February 28, 2009 10:16 PM | Report abuse

Sleet now falling in downtown DC. Not sure when it started.

Posted by: elizqueen | February 28, 2009 10:18 PM | Report abuse

Update:

Current Observations: Deck is coated
Sleeting and snowing, 26.8F

Location: east of Front Royal

Posted by: spgass1 | February 28, 2009 10:19 PM | Report abuse

Do you think a winter storm warning will be issued for this storm?

Posted by: PeterBethesda | February 28, 2009 10:19 PM | Report abuse

@ZManVA: Yep, sleet just started coming down in Merrifield a few minutes ago, thanks! All I had to do was post my little whine to bring it on, I guess. :-)

Posted by: --sg | February 28, 2009 10:20 PM | Report abuse

Peter: absolutely, especially for DC and I-95 eastwards. That is unless there is a major shift in the models over night.

Posted by: JTF- | February 28, 2009 10:20 PM | Report abuse

Light snow with some sleet here in upper NW DC. Good to see NWS has upped totals to 4-6 here now.. early trends tonight suggest that could still be low.

Posted by: Ian-CapitalWeatherGang | February 28, 2009 10:26 PM | Report abuse

00z NAM shifts a little to the east.

STOP!!

Posted by: AugustaJim | February 28, 2009 10:28 PM | Report abuse

Current temp. in Burke: 35.4 with sleet mixing with snow.

Here is the NWS forecast for my are thru Monday night:

Overnight: Rain, snow, and sleet before midnight, then snow and sleet. Low around 31. North wind around 11 mph. Chance of precipitation is 80%. Total nighttime snow and sleet accumulation of less than one inch possible.

Sunday: Snow and sleet, mainly after 3pm. High near 37. North wind between 9 and 11 mph. Chance of precipitation is 90%. New snow and sleet accumulation of 1 to 2 inches possible.

Sunday Night: Snow. Low around 26. Blustery, with a north wind between 16 and 21 mph. Chance of precipitation is 90%. New snow accumulation of 4 to 6 inches possible.

Monday: A chance of snow, mainly before 1pm. Cloudy, with a high near 31. Blustery, with a north wind between 15 and 20 mph. Chance of precipitation is 40%.

Posted by: Yellowboy | February 28, 2009 10:28 PM | Report abuse

33.5 in NW Spotsy. with snow & sleet, some accum. on ground & truck. Temps been dropping all evening, 3 degrees since 7:45.

Posted by: VaTechBob | February 28, 2009 10:29 PM | Report abuse

Yeah they just updated the totals for Alexandria as well...


Sunday: Snow and sleet, mainly after 3pm. High near 39. North wind around 10 mph. Chance of precipitation is 90%. New snow and sleet accumulation of 1 to 2 inches possible.

Sunday Night: Snow. Low around 27. Blustery, with a north wind between 17 and 22 mph. Chance of precipitation is 90%. New snow accumulation of 3 to 7 inches possible.

Sounds good to me!!

Posted by: justin1013471 | February 28, 2009 10:30 PM | Report abuse

Light sleet here in Chevy Chase at the moment. I am amazed that it's precipitating yet there's still a 16 degree dewpoint depression. Current temp = 35.8; Current dewpoint = 20. Now that precipitation has reached the ground I would expect the temperature to begin to drop a bit and the dewpoint to come up (but they haven't been acting too "rationally" over the past few hours so I wouldn't be surprised if they don't).

Posted by: Josh-CapitalWeatherGang | February 28, 2009 10:30 PM | Report abuse


Post 43
I used to take Amtrak from Milwaukee to Detroit in the snow. Also from Albany to Toldedo. I don't remember any problems at all. Seems like it would be an ok way, and safer than driving.

Ice could be dangerous, but I don't think snow matters. Can you call Amtrak?

Posted by: celestun100 | February 28, 2009 10:30 PM | Report abuse

Post43 regarding Amtrak, I would say to take the main roads to the station and allow a lot of extra travel time. Good chance they will be running. You can check your train's status at amtrak.com

Of course, keep monitoring the situation (WTOP 103.5 fm has traffic/weather every 10 minutes) and use good judgment.

Posted by: spgass1 | February 28, 2009 10:36 PM | Report abuse

its crazy, 2 days ago noone thought this storm would happen and yesterdays crystal ball said a 30% chance but now noaa says 90 % chance sunday night

Posted by: samdman95 | February 28, 2009 10:36 PM | Report abuse

Since it sounds like this storm is going to be better for those east of 95, what does the forcast look like for Ashburn, Leesburg, Dulles ?

Have my ice cubes ready the the pj's inside out

Posted by: jmudave | February 28, 2009 10:37 PM | Report abuse

Dry here in Sandy Spring. No snow... yet...
Would anyone remind reviewing what the dew point has to with this?

Posted by: celestun100 | February 28, 2009 10:39 PM | Report abuse

Snow here in Silver Spring... Looking forward to a fun 24-36 hours!

Posted by: SkywalkerSS | February 28, 2009 10:40 PM | Report abuse

Snowing in Potomac!

Posted by: someonelikeyou | February 28, 2009 10:44 PM | Report abuse

Sleet significant right now in DC @ 10:44pm Sat. night. Accumulating on side streets and trying to accumulate on more traveled streets.

Posted by: jweinrieb | February 28, 2009 10:45 PM | Report abuse

Posted by: justin1013471 | February 28, 2009 10:46 PM | Report abuse

Light sleet mixed with very light snow at the Vienna Metro. Current temp 30.2

Posted by: Ebbi88 | February 28, 2009 10:47 PM | Report abuse

Sleet is accumulating on typically colder surfaces here in Chevy Chase -- i.e., grass, mulch, outside table covers, etc.

Temperature now down to 33.8 with dew point up to 23.0; finally behaving as expected. The gap between the two will continue to decrease over the next hour.

Posted by: Josh-CapitalWeatherGang | February 28, 2009 10:48 PM | Report abuse

Moderate snow and sleet here in Sterling, with a temperature of 32.2 degrees. There is a light coating already on the grass, but pavement temperatures are currently too warm for accumulation. However, I feel that tomorrow night will be a different story: think of what a coating of snow from tonight will do to ground temps!

I've got my fingers crossed for a westward shift. Sorry, DC, but I deserve more snow than you. :-)

The new 0Z GFS run has 0.75" of liquid for my area.

Posted by: Sterlingva | February 28, 2009 10:49 PM | Report abuse

So that red means 15-18 inches of snow?? I doubt that will be anywhere near here. I still can't believe we're going to get anything significant.

Posted by: celestun100 | February 28, 2009 10:52 PM | Report abuse

What model runs are the FOX 5 people using? They just made it out to be a small snow/sleet event for Monday...didn't even give a predicted total...

Posted by: HistoryTchr | February 28, 2009 10:53 PM | Report abuse

Looks like all snow now in Lake Ridge.

Posted by: ZmanVA | February 28, 2009 10:54 PM | Report abuse

Why sn't accuweather making a big deal out of this? They are usually the ones that get into it?

Posted by: celestun100 | February 28, 2009 10:55 PM | Report abuse

Light snow in Olney

Posted by: celestun100 | February 28, 2009 10:58 PM | Report abuse

Agreed, history teacher...the fox five lady didn't even mention accumulating snow, let alone totals. She made it sound like nothing..."trending to the south and east"...based on what? Would Sue have been so wishy washy?

Posted by: manassasmissy | February 28, 2009 10:59 PM | Report abuse

Did you hear the woman on fox 5??? Capital weather....seriously would you guys give them some weather training and how to read models?????

Posted by: clintonportis17 | February 28, 2009 10:59 PM | Report abuse

Gwen Tolbert of Channel 5 must be smoking something. Very conservative NO-CASTING. Hard to believe that she is in a major market. What a lame lack of info forecast.

Posted by: stinkerflat1 | February 28, 2009 11:00 PM | Report abuse

Yah, Fox 5 said heavier accumulations esp. East. Not even a stab or hint at snowfall amounts...

Posted by: mchristinaw | February 28, 2009 11:02 PM | Report abuse

mix of snow and sleetish in Arlington, light accumulation on the ground...

Posted by: JJones-CapitalWeatherGang | February 28, 2009 11:02 PM | Report abuse

NBC 4 -----

A light coating tonight.

3-6 inches of snow....a little more than less. The fun begins!

WUSA -

More Snow---Bigger Storm for Sunday Night Monday. 4-5 inches of snow not out of the question.

Posted by: stinkerflat1 | February 28, 2009 11:03 PM | Report abuse

NWS forecast for Olney is still showing only 1-2" tomorrow night:

Windy with snow showers in the evening evolving to a steady snow after midnight. Low 23F. Winds N at 15 to 25 mph. Chance of snow 70%. 1 to 2 inches of snow expected.

Are we that far off the track, or did they just not get around to updating our forecast?

Posted by: fed_chick | February 28, 2009 11:05 PM | Report abuse

That is what I fear. That we are off the track-- figures...

Posted by: celestun100 | February 28, 2009 11:08 PM | Report abuse

Snow picked up quite nicely here in Lake Ridge. Coming down at a pretty good clip and sticking to pretty much everything except the roads/sidewalks.. at least for now.

Posted by: ZmanVA | February 28, 2009 11:10 PM | Report abuse

Just came from my parents house in Lorton where there was a pretty good coating of sleet on vehicles and almost all grassy areas. Was actually quite impressed with it. Will be interesting tomorrow, but I won't believe it until I see it. Been burned FAR too many times by snow recently to have any faith in it.

Posted by: hobbes9 | February 28, 2009 11:12 PM | Report abuse

OK I just checked NWS and they had a big Montgomery County spot on the map. And it said 4-6 inches and then it disappeared!

Posted by: celestun100 | February 28, 2009 11:13 PM | Report abuse

Sleet here in Ashburn. Light coating on grass with moderate precip. falling.

Posted by: bodyiq | February 28, 2009 11:14 PM | Report abuse

Augusta Jim, Did the 0z NAM really shift east? When I look at the run to run comparisons, it seems that there is more precip on the west side, plus the mslp changes seem to indicate the storm is arriving at later time, but not necessary further east.

Posted by: mciaram1 | February 28, 2009 11:20 PM | Report abuse

Folks, I wouldn't worry -- at this point -- about the NWS' forecast for your exact location. They're based on grids that, as some of you have noticed, can get screwed up (due, essentially, to a programming error, or the like) and may say something erroneous or may say one thing for one place and then something very different for a place 2 miles away.

Anyways, it's impossible to forecast snowfall at a neighborhood by neighborhood, or even town to town, level. Just keep in mind that Capital Weather Gang's current forecast is for 3-6" with the possibility of 6"+, especially east of town.

Posted by: Josh-CapitalWeatherGang | February 28, 2009 11:21 PM | Report abuse

Josh:

If those are the current numbers for your forecast, when can we anticipate a change in your forecast?

Posted by: jpl1019 | February 28, 2009 11:27 PM | Report abuse

still just cold and rainy here in Richmond

Posted by: ksrgatorfn1 | February 28, 2009 11:29 PM | Report abuse

Folks-- I've been quiet b/c I've studying the new models and working on our next update. We will be upping snow amounts a little--most likely 4-8", w/ more to the east.

Posted by: Jason-CapitalWeatherGang | February 28, 2009 11:30 PM | Report abuse

@jpl1019,

Good question! Don't read too, too much into my wording. The answer is I'm not sure. In winter storms like this, the forecast is a consensus one, and I'm just one particular entity of the Capital Weather Gang. However, I don't think the forecast will change significantly from where it is right now. And my own personal gut feeling is that if we do tweak the forecast it's probably more likely the change would shift accumulation amounts upwards as opposed to the opposite.

Posted by: Josh-CapitalWeatherGang | February 28, 2009 11:31 PM | Report abuse

Jason, Ha! We wrote at the same time. Glad you're thinking what I'm thinking...

Posted by: Josh-CapitalWeatherGang | February 28, 2009 11:31 PM | Report abuse

Hey Jason and Josh - you guys should get to bed! If all holds true, you will be deluged with posts tomorrow as things heat up!!! My hubby is waiting for me with a DVD of "Action!" (if you haven't seen this - get it now!) and the promise of sweet slumber. Hope to awake to a "major" winter event.

Posted by: someonelikeyou | February 28, 2009 11:34 PM | Report abuse

josh:
thank you for that reality check. i've heard #'s up to 15" tossed around, and also heard "1/10ths of an inch". how do i know what to believe?

Posted by: walter-in-fallschurch | February 28, 2009 11:35 PM | Report abuse

Location: east of Front Royal, VA.

Storm #1 Update:
I measured the snow on the back deck at 9/16". Light precip continuing. It is difficult to see, but now appears to be in the form of sleet and what feels like freezing drizzle. Current temp: 24.4F

Storm #2: Sounds like DC will beat the mountains in terms of snow.

I'm going to bed in a few minutes and will post an update in the morning if new snow piles up.

Posted by: spgass1 | February 28, 2009 11:46 PM | Report abuse

Walter, that brings up an interesting point. Why do forecasters measure snow in inches and tenths? It seems to be a weird blend of the English and metric system. If we're going to use inches, why not use 16ths like what is printed on rulers?

Posted by: spgass1 | March 1, 2009 12:01 AM | Report abuse

Current temp. in Burke: 32.7 and sleeting/snowing pretty hard.

Posted by: Yellowboy | March 1, 2009 12:10 AM | Report abuse

Same here in Logan DC - still sleeting and some snow covering grassy areas.
spgass1: I haven't heard of 1/10"s being used for snow measurements? That seems unnecessary to be that precise. maybe 0.25 "quarter inches" is about as reasonable as it can get I think...

Posted by: Camden-CapitalWeatherGang | March 1, 2009 12:27 AM | Report abuse

I am very worried (now living here in downtown DC) about how sharp the precip cutoff is going to be on the west side of the second storm, at least as it passes by. Am, however, encouraged by the amount of hangback in the 00Z models. Bottom line is that there's going to be enough to make it pretty but I know that if something can go wrong in a DC snowstorm, it will...and that gradient is very scary.

Put me down for 3 in the western burbs and 9-12 southeast of town. Guess that puts the city in 3-6. In reality, I'm picking the weenie middle between nothing and something big. The experienced forecaster in me would nonetheless buy a hedge fund that rewarded slim and none at this point, while still forecasting 3-6.

Pat Michaels
Cato/UVa

Posted by: pmichaels1 | March 1, 2009 12:29 AM | Report abuse

Bring on the snow Daddy-O! Then spring time can begin. I will be driving down from NYC - my sister got engaged today and the family surprised her. Good times. A good snow would top off a fabulous weekend!

Posted by: mjwies11 | March 1, 2009 12:30 AM | Report abuse

spgass1: that's funny! because i work work with people (civil engineers) who deal in 1/10ths (and 1/100ths) of a foot!

both systems have merit. metric is cool because of all the zeros, but the imperial is nicely divisible in halves and quarters etc...

Posted by: walter-in-fallschurch | March 1, 2009 12:34 AM | Report abuse

When will we have a final update from the CWG crew before bed time? Also, any thoughts on if this thing shifts further west? How much of a jog would it take to get bullseye snow from DC to Loudoun?

12:30am Leesburg Update:

Sleet and Light Snow.

Posted by: stinkerflat1 | March 1, 2009 12:34 AM | Report abuse

camden:
i swear i saw it (1/10ths of an inch) on the NWS forecast from earlier today at the link at the upper left of the page. i see they've "come on board" with their #s now!

Posted by: walter-in-fallschurch | March 1, 2009 12:39 AM | Report abuse

@cvilleMan

For a storm to stall you need something to stop it...usually it's what we refer to as high latitude blocking. It's absent for this storm...so this storm will not stall...but it will still be a big impact event I think.

Posted by: Jason-CapitalWeatherGang | March 1, 2009 12:40 AM | Report abuse

@PeterBethesda

I would be shocked if NWS does NOT issue a winter storm warning in the next 6 hours.

Posted by: Jason-CapitalWeatherGang | March 1, 2009 12:41 AM | Report abuse

actually, maybe they were talking about sleet accumulations...?

Posted by: walter-in-fallschurch | March 1, 2009 12:42 AM | Report abuse

@pmichaels

Looking at the oz runs, I'm pretty bullish about this one...but I'd still diversify my porfolio with some assets in your hedge fund :)

Posted by: Jason-CapitalWeatherGang | March 1, 2009 12:43 AM | Report abuse

While I no longer reside in the metro area, I remember these types of events well, and all the headaches that go with them :)

A quick glance at the old fashioned raw GFS data(00z) is quite interesting. For one, there will be a band of 10"+ snow with this event. The "headache" is caused by the elongation of the developing 850-500 mb troughs.

"Duck-in-a-barrel" events often feature a broader phased U-L trough into a slow moving cutoff (i.e. 1996), or a prolonged period of low level deformation over a fairly large area (i.e., 2003).

This type of event, on the other hand, will not show its hand until sometime later today. While the 00Z GFS 850 mb low track is ideal for all or most of the DC area, a 50-100 mile shift one way or the other will change the outcome.

The good news in all of this is the fact that prep day is Sunday, so even a 50 mile shift in the brief but potent deformation zone should be able to be handled by road crews, etc, without a commute to deal with.

Should be interesting to watch. In like a Lion, indeed!

Posted by: wxdancer | March 1, 2009 12:45 AM | Report abuse

Jason-CapitalWeatherGang: I predict sometime after the ECM comes out. I'm PRAYING for a slight shift west.

Posted by: clintonportis17 | March 1, 2009 12:53 AM | Report abuse

Snowing ever so lightly here now. Temp has dropped to 29. Am thinking, despite radar, acc is about done here ....

Posted by: weathergrrl | March 1, 2009 12:58 AM | Report abuse

@pat michaels
are you THE pat michaels?

Posted by: walter-in-fallschurch | March 1, 2009 12:58 AM | Report abuse

Camden, perhaps the tenths aren't used much in forecasting but are used for measurement for some reason.

I checked outside again and it's snowing moderately again: 7/8" accumulation thus far; current temp 23.9F

P.S. I know I said I was going to bed earlier, but ended up staying up watching a stupid episode of Saturday Night Live for some reason.

Posted by: spgass1 | March 1, 2009 1:02 AM | Report abuse

Hey, after reading all the posts, where is ou Weatherdude?????

Posted by: weathergrrl | March 1, 2009 1:06 AM | Report abuse

My prediction, just for fun:

DCA: 11
IAD: 13
BWI: 14
RIC: 5

some extras:

Charlottesville: 10
Roanoke: 8
Philly: 9
NYC: 12
Boston: 8
Atlanta: 3

Posted by: jfva | March 1, 2009 1:07 AM | Report abuse

Cato plus UVa plus weather report = THE Pat Michaels

I bet the farmette and my mulish dog, too.

Posted by: CollegequaParkian | March 1, 2009 1:13 AM | Report abuse

This is ridiculous...I am so pumped about a major winter event and all the dynamics that I can't get to sleep. I am pushing 40 years of age and I am still like a kid excited about the SNOW!

Posted by: stinkerflat1 | March 1, 2009 1:14 AM | Report abuse

Weather Channel at 1:15am Headlines:

Heavy Snow to Hit the Megalopolises!

Posted by: stinkerflat1 | March 1, 2009 1:16 AM | Report abuse

@walter

Yes--That was THE Pat Michaels. I was lucky to have Pat as a professor at UVA for weather forecasting and applied climatology.

@everyone...

We have a new post up with accumulation map, timeline, FAQs, etc

Posted by: Jason-CapitalWeatherGang | March 1, 2009 1:17 AM | Report abuse

i notice (joyously) the absence of RAINMAN

Posted by: walter-in-fallschurch | March 1, 2009 1:20 AM | Report abuse

Pat Michaels,
For once, we can agree on something. No matter what happens with this puppy, somebody will be upset.

Posted by: CapitalClimate | March 1, 2009 12:03 PM | Report abuse

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