Tuesday, November 15, 2005
Wintertime is Coming, Windows are Filled With Frost
Matt Ross @ 1:00 AM
Forecast
As a warm front moves over the area from the south early today, expect some occasional showers, mostly in the southern and western portions of the region. High temperatures will be very warm in the low 70s under partly to mostly cloudy skies. Conditions will change rapidly late on Wednesday as a strong cold front moves through. As a result we should see below normal temperatures settle in for the short term period through the weekend.
Pictured above right: Our 1st snowfall of the season last January in front of Farragut North Metro. Could our 1st snow this season be close at hand?
Gamma?
Tropical Depression 27 continues to move westward through the Caribbean toward the Central American Coast. Strengthening is very likely and Gamma should be born today, if not already. Accuweather's Joe Bastardi is predicting that Gamma will rapidly strengthen to a Category 2 or 3 later in the week as it approaches the Western Caribbean. At this time it appears that any threat to the US will be tangential and indirect, but as always it is worth monitoring as this record tropical season rolls on.
November Climatology Notes
As mentioned before, we have yet to hit the freezing mark this year, only getting below 40 degrees twice so far. We have seen quite a bit of variability the past several years in terms of the 1st freeze. In the incredibly warm and snowless winter of 2001-02, we didn't have our first freeze until December 22nd. While two years later in 2003, we broke the 32 degree barrier on October 10th. Yet the following November was one of the warmest ever. The 1st freeze of the historic 2002-03 winter was a more normal November 27th, and last year we hit the freezing mark on December 4th. I think getting our first freeze is one of those stats that is misleading. While a very meaningful weather benchmark, as a statistical one it is rather insignificant. As such it is important to look at the totality of the occurrent weather as opposed to artificial achievements. That said, we have a reasonable if not great chance to hit the freezing mark at National Airport(DCA) over the next week or so.
I have seen the phrase uttered, "The weather in November, the winter will remember". Well, I have to disagree. Every time I look at correlations between November weather and that of the following winter, I am less and less impressed. Recently, I looked at Decembers in which DCA achieved 6 or more inches of snow. This has happened 13 times in the 64 year period of record at DCA. Of these 13 years, 7 had above normal November average temperatures, 1 was normal and 5 were below normal. So even though it is a small sample, there is still no evident correlation. An good anecdotal example is November 2003. As mentioned above it was very warm -- over 4 degrees above average. A few days before Thanksgiving, afternoon temps reached the mid 70s. Exactly 2 weeks later on December 5th, a major snowstorm hit the East Coast, dropping several inches in town and up to 10" in the western suburbs. This serves as a reminder that patterns can change very quickly this time of year. We will see a precursor of that on Wednesday with the cold front and some further evidence over the next few weeks.
While there is still half the month left, it is looking pretty probable that November will finish above average. While I do think we will see some negative departures the 2nd half of the month, it will likely not be enough to cut into the sizeable warm surplus we have built up over these past 2 weeks. If in fact November finishes above normal, that will make 9 of the 11 months above normal so far this year including six in a row starting with June, thus our entire summer and fall. Yet the 2 months that finished below normal, March and May, both finished well below normal. A lot of people are alluding to a cold December. It will be interesting to see if December follows the amazing persistence that has occurred since June, or if it will be a notable exception like March and May. Perhaps it will simply finish at right around normal for the month as we suggested in the CapitalWeather.com winter outlook. We shall see real soon.
As a warm front moves over the area from the south early today, expect some occasional showers, mostly in the southern and western portions of the region. High temperatures will be very warm in the low 70s under partly to mostly cloudy skies. Conditions will change rapidly late on Wednesday as a strong cold front moves through. As a result we should see below normal temperatures settle in for the short term period through the weekend.Pictured above right: Our 1st snowfall of the season last January in front of Farragut North Metro. Could our 1st snow this season be close at hand?
Gamma?
Tropical Depression 27 continues to move westward through the Caribbean toward the Central American Coast. Strengthening is very likely and Gamma should be born today, if not already. Accuweather's Joe Bastardi is predicting that Gamma will rapidly strengthen to a Category 2 or 3 later in the week as it approaches the Western Caribbean. At this time it appears that any threat to the US will be tangential and indirect, but as always it is worth monitoring as this record tropical season rolls on.
November Climatology Notes
As mentioned before, we have yet to hit the freezing mark this year, only getting below 40 degrees twice so far. We have seen quite a bit of variability the past several years in terms of the 1st freeze. In the incredibly warm and snowless winter of 2001-02, we didn't have our first freeze until December 22nd. While two years later in 2003, we broke the 32 degree barrier on October 10th. Yet the following November was one of the warmest ever. The 1st freeze of the historic 2002-03 winter was a more normal November 27th, and last year we hit the freezing mark on December 4th. I think getting our first freeze is one of those stats that is misleading. While a very meaningful weather benchmark, as a statistical one it is rather insignificant. As such it is important to look at the totality of the occurrent weather as opposed to artificial achievements. That said, we have a reasonable if not great chance to hit the freezing mark at National Airport(DCA) over the next week or so.
I have seen the phrase uttered, "The weather in November, the winter will remember". Well, I have to disagree. Every time I look at correlations between November weather and that of the following winter, I am less and less impressed. Recently, I looked at Decembers in which DCA achieved 6 or more inches of snow. This has happened 13 times in the 64 year period of record at DCA. Of these 13 years, 7 had above normal November average temperatures, 1 was normal and 5 were below normal. So even though it is a small sample, there is still no evident correlation. An good anecdotal example is November 2003. As mentioned above it was very warm -- over 4 degrees above average. A few days before Thanksgiving, afternoon temps reached the mid 70s. Exactly 2 weeks later on December 5th, a major snowstorm hit the East Coast, dropping several inches in town and up to 10" in the western suburbs. This serves as a reminder that patterns can change very quickly this time of year. We will see a precursor of that on Wednesday with the cold front and some further evidence over the next few weeks.
While there is still half the month left, it is looking pretty probable that November will finish above average. While I do think we will see some negative departures the 2nd half of the month, it will likely not be enough to cut into the sizeable warm surplus we have built up over these past 2 weeks. If in fact November finishes above normal, that will make 9 of the 11 months above normal so far this year including six in a row starting with June, thus our entire summer and fall. Yet the 2 months that finished below normal, March and May, both finished well below normal. A lot of people are alluding to a cold December. It will be interesting to see if December follows the amazing persistence that has occurred since June, or if it will be a notable exception like March and May. Perhaps it will simply finish at right around normal for the month as we suggested in the CapitalWeather.com winter outlook. We shall see real soon.
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