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Posted at 8:55 AM ET, 03/ 8/2011

Forecast: Decent day before next storm

By Matt Rogers

Flood Watch Wed. night to Thurs. night

updated at 8:55 a.m., originally posted at 5:00 a.m.

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


Today is an improvement with warmer weather and still some sun around.
Get the 'Digit' on Twitter


Today: Partly to mostly sunny skies. 49-54. | Tonight: Partly cloudy. 26-34. | Tomorrow: Cloudy, late p.m. showers. 45-49. | A Look Ahead | Get Express Forecast by E-mail


Our weather pattern is currently on fast-forward as storm systems aim for the area every three to four days. This faster timing is typical of a variable springtime pattern. After Sunday's soaking, we're looking at another drenching Thursday with clouds rapidly building back in tomorrow. Fortunately, this weekend falls in between storms with mainly dry weather.

Snow Potential Index: 0 → - Snow may mix with rain before ending late Thursday and early Friday, but no accumulation expected.

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

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 (Tuesday): Today could qualify for the best day of the week due to partly sunny skies, warmer temperatures, and lighter breezes compared to yesterday. This is the calm before the (next) storm. Highs from around 50 into the low 50s with light breezes from the east and northeast mainly. Confidence: High

Tonight: Partly cloudy skies, mostly calm winds, and low temperatures range from the middle 20s out near Dulles and in the far northwest 'burbs to maybe only the middle 30s in the city. Confidence: Medium-High

Keep reading for the forecast through the weekend...

Tomorrow (Wednesday): Here comes the next storm event. Look for a dense overcast for most of the day with highs struggling to push up through only the 40s. The timing of precipitation is speeding up a bit, so showers could arrive in the area by late afternoon into the evening rush hour (40% chance). Confidence: Medium

Tomorrow Night: Cloudy with rain that starts on the light-to-moderate side before shifting toward the moderate-to-heavier side probably toward dawn. Lows in the 40s. Confidence: Medium


Thursday is our gully-washer day and with the soils already saturated by recent heavy rains, the recently issued Flood Watch seems reasonable. Precipitation totals combined with Wednesday night could reach 1.5-2.5". Cloudy skies, moderate to heavy rain at times, and somewhat warmer temperatures are favored with highs in the mid-to-upper 50s. Rain most likely continues into the Thursday evening commute before tapering off overnight (perhaps another .5" due to evening rains) and yes, possibly mixing with snow again. No accumulation is expected as temperatures only drop to the mid-to-upper 30s. Confidence: Low-Medium

Friday Some morning clouds along with a few scattered early rain/snow showers (30% chance), but otherwise, skies should clear toward midday and afternoon. Gusty winds from the west start the drying process and our high temperatures move up into the upper 40s and low 50s. Partly cloudy skies Friday night with lows in the low-to-mid 30s. Confidence: Low-Medium

This weekend looks considerably better than the last one with partly to mostly sunny skies, close to seasonal or slightly colder temperatures, and mainly dry weather. Highs should be mainly in the 50s with lows in the 30s. Confidence: Low-Medium

By Matt Rogers  | March 8, 2011; 8:55 AM ET
Categories:  Forecasts  
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With all this rain having come, does this area still have a water deficit? If it does, how much and will this latest storm fill it in?

Posted by: Byzantium1453 | March 8, 2011 6:30 AM | Report abuse

Hi Byzantium1453, Washington National is reporting a .86" deficit since January 1, while Dulles reports only a .18" shortfall. This storm should push us over the top into surplus for the calendar year.

Posted by: MattRogers1 | March 8, 2011 6:52 AM | Report abuse

forget about thurday/friday - my morning snow hunt bagged a snow storm on the 15th! better check it out now because it will probably be gone by the next model run. nonetheless it's there now.

GFS is showing precip and freezing 850mb and ground temps 162 to 174 hours out. here are the ground temps in 6-hour intervals:


for a total 12-hr precip of 5" for my house, with the unusual profile of LESS to the north and west:

if you watch the loop, you can see the problem might be a late change-over to stupid rain. we'll see.

now, i'm not expecting or predicting this, but, i'm just sayin'....

Posted by: walter-in-fallschurch | March 8, 2011 7:34 AM | Report abuse

Walter, you are correct that it will probably go away. The 6z GFS is the worst-performing operational model in the American model suite.

Posted by: MattRogers1 | March 8, 2011 8:12 AM | Report abuse

i know the 0 and 12 are better than the 6 and 18, but i didn't know the 6 was worse than the 18. oh well... maybe i should do my hunting on the 0 or the 12. it's a shame because the 6 is the latest one available when i wake up. would you say the 0 would be better to use, even though it's 6 hours older?

i remember as a kid, before i new of or paid attention to weather reports, EVERY winter morning i would wake up and go to the window hoping to see snow. well, this snow-hunting business is my "adult" equivalent of that....

Posted by: walter-in-fallschurch | March 8, 2011 8:32 AM | Report abuse

Yeah, the 0z is the best of the four. The 6z just doesn't have as good of initialization data to kick off the model.

Posted by: MattRogers1 | March 8, 2011 8:37 AM | Report abuse

So I suppose this year it will be "March showers bring April flowers"...? :)

Bring on the rain, and spring! (with apologies to Walter...)

Posted by: MKoehl | March 8, 2011 9:23 AM | Report abuse

CWG, so whan are you all going to drop the snow potential thing? Yeah, I know, there have been historic snow falls in Mar and April around here, however, you know each day that passes with no snow or cold means the chances are just about zero.

Posted by: VikingRider | March 8, 2011 9:43 AM | Report abuse

I've seen stats showing the various runs are almost statistically the same in error. Any model solution a week out has been pretty bad this season. It will be interesting to see if anyone can start with some frozen precip late tomorrow. The NAM in particular is holding CAD in nicely as the precip arrives -- showing some wintry stuff to our west not too far at least.

Posted by: Ian-CapitalWeatherGang | March 8, 2011 9:54 AM | Report abuse

It's possible Ian might have been bribed to talk up the "wintry stuff" tomorrow.

Posted by: FIREDRAGON47 | March 8, 2011 10:07 AM | Report abuse

Yesterday and today morning were still pretty cold (maybe it's just the wind). About when will mornings be not warm, but at least not bitterly cold, with minimums at around 40?

Posted by: superseiyan | March 8, 2011 10:21 AM | Report abuse

The SPI for the next storm is zero but "Snow may mix with rain before ending..." The SPI for the last storm was zero nada zilch nil bumpkin pumpkin. Based on the above, one might think that we could see some snow N&W on Thursday night, but the forecast looks like we have less of chance this time than we did last time.

Posted by: eric654 | March 8, 2011 10:42 AM | Report abuse

as spring shifts earlier due to global warming, your "march showers bring april flowers" may become the expression.... ;-)

actually, that "april showers" expression implies a lot of rain happens in april, but, at least around here, april is our second DRIEST month:

looking at those stats, maybe the expression should be "may showers bring june mosquitoes"....

matt, ian,
thanks for the replies. it's so cool to get expert feedback from all you guys. i'm sure any model is pretty bad a week out... to matt's point, i did notice that the 6z clearly shows snow on the 15th whereas the 0 and 18 and 12 show a sunny day.... so it's the "outlier" at the moment...

nonetheless, i choose ian's answer (keeping matt's warning in the back of my head, though) since it lets me imagine snow's coming - at least until the next run pours cold water in my face...

didn't sunday's "SPIgate" affair show you it's too early to put the SPI away for the season?

Posted by: walter-in-fallschurch | March 8, 2011 10:46 AM | Report abuse

Question: do you guys foresee a rainy spring like we had in 2009? I believe that was the end of a moderate La NiƱa year, and similar to this past winter, December-January (2008-2009) were cold, February warmer, and snow/precip were pretty deficient all winter.
Subsequently, it was cold and rainy during much of the spring (particularly that awful two-week stretch in May 2009 when it poured nonstop for two weeks). Any thoughts?

Posted by: meteorolinguist | March 8, 2011 11:28 AM | Report abuse

YEAH! MORE RAIN!! I am doing my Happy Dance!!!

Remember, we also need to make up for last year's sizable rainfall deficit (4.60" at National Airport). Moreover, last year's dreadful, awful, withering heat as well as this winter's dry and windy conditions have combined to exacerbate our drought conditions.

Let's hope for a very rainy spring to replenish the water tables and soil moisture--particularly critical if this summer's heat is anything like last year's.

Bring it on!!!

Posted by: TominMichiganParkDC | March 8, 2011 11:40 AM | Report abuse

walter, that's true though if you check the 12z GFS you'll see the storm there again -- with pretty nice blocking as well. It's sometimes a "hot" debate on the weather forums, but from what I've gathered the differences in error between 0z/12z and 6z/18z runs is much less than it once was and in general they are about the same. My look at past Ninas did indicate a spike of 1"+ snow days near mid-March... not saying that means there are better odds than usual (which are pretty low of late), but I've been hesitant to "close down" the season at the typical time.

Posted by: Ian-CapitalWeatherGang | March 8, 2011 11:46 AM | Report abuse

I'm really hoping we don't get a repeat of that phenomenal monsoon event of Sept. 30, 2010. I remember the forecast was calling for "up to 3" of rain, 4" in isolated areas," and here along the Chesapeake Bay we received upwards of 10-11" in a short period of time. While this front doesn't have the benefit of being able to tap into a tropical cyclone, the models are nevertheless showing a freight train of moisture streaming straight out of the GOM for this one.

Posted by: marklandterrapins | March 8, 2011 12:53 PM | Report abuse

Back to our usual rainy weather patterns I see. Sure was nice last summer to get a break from this monsoon-like area...

Posted by: j0nx | March 8, 2011 1:13 PM | Report abuse

And if the post is saying 2" of rain then it will be more like 4-5" which is about the norm for their predictions on my end.

Posted by: j0nx | March 8, 2011 1:15 PM | Report abuse

12z GFS definitely still showing potential for snow next Tuesday.

Posted by: formerwxman1 | March 8, 2011 1:25 PM | Report abuse

thanks. i see that at least precip is still there on the new run (so maybe the 6z was onto something), but isn't it now showing up as being (juuust barely) too warm at ground level?

how/where do i see this "blocking" to which you refer? (is it that 1038 "H" directly to the north surrounded by the -30 degree contour? or does it appear on some other image?) and, is this "blocking" something that leads you to think the model might be overdoing the warmth? or is the blocking what's even giving this any chance in heck of being anywhere near cold enough?

(btw, the idea of heated debates among mets about the virtues of the various models runs tickles me...)

Posted by: walter-in-fallschurch | March 8, 2011 1:57 PM | Report abuse

Walter, yeah it's close on the surface temps but those are pretty useless in this range. The blocking is the high pressure seen over Greenland. Often our better snowstorms come with that type of look. If you look at the 500 pattern it's pretty good for snow around here too on the GFS with the main vort going southeast of us. But there is not much backing up the GFS right now, and knowing how hard it is to get a good snow in prime snow months here it's hard to get too excited yet.

Posted by: Ian-CapitalWeatherGang | March 8, 2011 2:15 PM | Report abuse

*dance, dance, dance*

Posted by: manassasmissy | March 8, 2011 2:57 PM | Report abuse

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