Grading Our 2008-09 Winter Outlook
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")
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