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Posted at 10:45 AM ET, 04/ 9/2009

Grading Our 2008-09 Winter Outlook

By Matt Ross

* Showery Tomorrow: Full Forecast | Will Misleads on Climate *


An early-March snowstorm made cross-country skiing possible on the Mall. But the 5-8" of snow wasn't enough prevent the D.C. area from finishing winter with well below-average snowfall. By CWG photographer Kevin Ambrose.

Even as April is off to a rather cool start, the official winter season becomes a more distant memory with each passing day. As such, it's time to soberly grade our 2008-09 Winter Outlook released in late November. The winter left a lot to be desired for snow lovers. Looking back, the accuracy of our forecast left quite a bit to be desired, too.

Keep reading for a full recap and grading of our 2008-09 Winter Outlook...

OUR PREDICTED TEMPERATURES

December: -2°F to -4°F (below normal), Actual: +0.8°F
January: Normal to +2°F, Actual: -3.3°F
February: +2°F to +4°F, Actual: +1.7°F
Overall: Normal to +1°F, Actual: -0.3°F

December was a pretty bad miss for us, especially considering we released the outlook only two weeks before the month started. There was a strong signal for a cold December, but Mother Nature does what she wants. Any hopes of a cold December were dashed with a very warm week after Christmas including a high temperature of 70 on the 28th. This allowed the month to finish slightly above normal. December Grade: D+

January was also a solid miss and was our first below-normal January since 2004. You might recall the cold, windy conditions that ushered in the new year, and that cold never really relented for the entire month. The coldest anomalies fell during the middle of the month, when we failed to reach the 40-degree mark for nine consecutive days. It was D.C.'s seventh coldest January in the last 30 years. January Grade: D

In February we finally got it almost right. Despite some cool/cold days sprinkled throughout the month, many of the warmer-than-normal days were really warm and thus in the end the warmth won. Just as January had a cold spell in the middle of the month, February had a warm spell in early to mid-month, capped by a 72-degree day on the 11th. Five out of our last six Februarys have finished above normal. February Grade: B

Overall, temperatures for the three-month period finished just slightly below normal for our first below-normal winter since 2003-04. We actually almost got the seasonal forecast right, even if our path there was quite shaky. Overall Temperature Grade: C+

OUR PREDICTED SNOWFALL

Slightly below normal, but around the median...

*National Airport (DCA): 12-14" (avg: 15.2"; median: 12.1"), Actual: 7.5"
*Dulles Airport (IAD): 18-20" (avg: 21.5"; median: 17.6"), Actual: 8.0"
*BWI Airport (BWI): 16-18" (avg: 19.2"; median: 15.5"), Actual: 9.1"
*Fairfax/Loudoun/Montgomery counties: 16-22" (avg: ~20-26"), Actual: 8-10"
*D.C./Arlington/Alexandria/P.G. County: 12-18" (avg: ~15-20"), Actual: 9-12"

This was another disappointing winter for snow lovers. While we saw several dusting to 1" events, the majority of our snow fell in two separate systems. A general 2" snowfall occurred on Jan. 27 and a larger 5"-8" snowfall occurred with the strong storm of March 1-2. While we did predict below-normal snowfall, our numbers were not nearly low enough.

Snowfall Grade: C+

OVERALL WINTER OUTLOOK

It was another lackluster winter for the D.C. area. We mentioned in our winter outlook the possibility of a weak La Nina developing and indeed we observed unofficial weak La Nina conditions for much of winter. Extended stretches of cold air were able to penetrate the region, but as was the case with 2007-08's stronger La Nina, the storm track was often west of us through the Ohio Valley, and we just couldn't get much precipitation into the area.

Overall Winter Outlook Grade: C+

LOOKING FORWARD TO NEXT WINTER

There are some very early and very speculative indications of an El Nino event for next winter which gives some hope for snow lovers. While far from a slam dunk in terms of producing snow, weak to moderate El Nino events are often associated with a split flow regime with two predominant storm tracks. The more southerly storm track through the lower plains and into the deep south is frequently a snow producer for us. That track was almost completely missing the past two winters.

I'll leave you with our latest winter snowfall norms through the 2008-09 winter. For snow lovers, reality bites...

30-year running averages (winters 1979-80 through 2008-09):

DCA: 14.2" (median: 11.7")
BWI: 18.0" (median: 15.3")
IAD: 20.4" (median: 17.4")

10-year running averages (winters 1999-2000 through 2008-09):

DCA: 12.7" (median: 11.0")
BWI: 18.0" (median: 14.5")
IAD: 16.7" (median: 14.3")

By Matt Ross  | April 9, 2009; 10:45 AM ET
Categories:  Local Climate, Recaps  
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Comments

Tornadoes for Kansas and Missouri today. http://www.kansasvortex.com/

Posted by: eheadwest | April 9, 2009 11:01 AM | Report abuse

Two cool days in a row may feel like a cool start to April, but the other 6 have been at or above average, and the month to date is +1.0°. Expected mid 60s today won't put any dent in that.

Happy No Snow Day! tomorrow

Posted by: CapitalClimate | April 9, 2009 11:20 AM | Report abuse

This winter definitely FLUNKED in my book!!!

To "pass" you need DOUBLE_DIGIT snow accumulations and AT LEAST ONE Federal shutdown. I don't think we've seen a Federal shutdown since 2006!

There was plenty of cold weather, so I'm frankly MYSTIFIED at those "above-normal" temperature averages.

In terms of cold winds, we flunked again! "March" began aoa Valentine's Day, and is still "continuing" well into April!

The two high points came Dec. 31 at 10:30 AM with our only thundersnow and Mar. 1 with the only "big" snowstorm of the season. Yet there was NO accumulation AT ALL from the thundersnow. Normally one would expect two to four quick inches of snow with a thundersnow squall here. And, of course the big snow did not result in a Federal shutdown.

2008/09 Grade: F.

Posted by: Bombo47jea | April 9, 2009 11:35 AM | Report abuse

I called for the temps to be basically ave for the winter +1 to -1. It finished -.3 so I'll give myself an A. I had 14-18" of snow for Dec-Feb & only 2" fell during that time, grade F. Look for next winter, at this point, to have above temps, 1.5 to 3 above, & below snow.
Shad run is infull force on the Rappahanock River.

Posted by: VaTechBob | April 9, 2009 2:38 PM | Report abuse

BTW, I think you mean 197*9*-1980, not 1970-80 in the 30 year snowfall averages.

Posted by: ah___ | April 9, 2009 5:38 PM | Report abuse

ah -- thanks for catching the typo. now fixed.

Posted by: Dan-CapitalWeatherGang | April 10, 2009 1:13 PM | Report abuse

Dan,

I think you were a bit generous with your overall temp grade. Given the D, D+ and B, I would probably end up with a C- not a C+, particularly considering the actual temp was slightly colder than normal and you had predicted 1 degree warmer than normal, different directions.

That being said, Feb is probably an A- as the actual was almost on top of the low end of your range. Anything in the range is an A in my books. But for Dec and Jan, I would probably give worse grades (D and D-) as both were meaningfully directionally wrong.

Posted by: RMVA | April 13, 2009 9:28 AM | Report abuse

The comments to this entry are closed.

 
 
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