Tuesday, November 07, 2006
2006-07 Winter Outlook
Matt Ross @ 1:00 AM
Forecast First
Rain developing. Today will be cloudy with light to moderate rain developing in the late afternoon or early evening. Highs will be in the upper 50s and the chance of rain is 60%. We will see steady rain during the overnight hours with lows only dropping to around 50 degrees. Tomorrow, there is a 50-50 chance of lingering rain in the morning. Skies will remain cloudy with highs in the low 60s.
See Jason's forecast for the rest of the week and weekend.
CapitalWeather.com 2006-07 Winter Outlook: Executive Summary
Please refer to our outlook in its entirety here. This provides much more detail and explanation than what is below and will be archived on the features page ...
Winter is finally near, and the outlook is finally here. We'll start with the caveat. Long range seasonal forecasting is still in its infancy. Although great strides are being made, there is still a lot of uncertainty and therefore bust potential in these outlooks. We believe we can provide more value and accuracy than a mere coin flip, but the ideas presented should be viewed as general guidance and themes. The more specific we get, the more chance there is to err. This is especially true for snow amounts, as 1 or 2 storms or lack thereof can make or break snow totals. As always, we will grade the outlook both during and after the winter.
The following factors were considered in preparation of this outlook:
This winter will be colder and stormier than normal with above average snowfall. We will see both extended cold outbreaks and thaws, but as has been the case this fall, the cold will overwhelm the warmth and thus will be more commonplace and long lasting. The core of winter will be colder with respect to normal than the beginning and end, and I expect the January/February timeframe to also be the stormiest. The higher level of storminess also means we will see more mixed events then normal. I expect a number of events will not be all snow, but rather snow to rain, rain to snow, sleet, freezing rain, or a combination of all. Overall, I expect the coldest winter since 03-04 and possibly colder, and the snowiest since 2002-03, although not as snowy.
The temperatures predicted below will be measured against the official readings at National Airport (DCA), and snowfall measured against the airports as indicated.
Overall Temperatures for December through March: -1.25°F below normal
December: -1° to +1°, leaning very slightly above normal
January: -2° to -4°
February: Normal to -2°
March: Normal to -2°
Total Snowfall: 20-30% above normal
National Airport (DCA): 20" (versus average of 16")
BWI: 24" (versus average of 20")
Dulles (IAD): 27" (versus average of 22")
Arlington/Alexandria/DC: 19-25"
Fairfax Co.: 22-28"
Loudoun Co.: 26-33"
Mo Co: 23-29"
PG: 17-23"
What can go wrong
Rain developing. Today will be cloudy with light to moderate rain developing in the late afternoon or early evening. Highs will be in the upper 50s and the chance of rain is 60%. We will see steady rain during the overnight hours with lows only dropping to around 50 degrees. Tomorrow, there is a 50-50 chance of lingering rain in the morning. Skies will remain cloudy with highs in the low 60s.See Jason's forecast for the rest of the week and weekend.
CapitalWeather.com 2006-07 Winter Outlook: Executive Summary
Please refer to our outlook in its entirety here. This provides much more detail and explanation than what is below and will be archived on the features page ...
Winter is finally near, and the outlook is finally here. We'll start with the caveat. Long range seasonal forecasting is still in its infancy. Although great strides are being made, there is still a lot of uncertainty and therefore bust potential in these outlooks. We believe we can provide more value and accuracy than a mere coin flip, but the ideas presented should be viewed as general guidance and themes. The more specific we get, the more chance there is to err. This is especially true for snow amounts, as 1 or 2 storms or lack thereof can make or break snow totals. As always, we will grade the outlook both during and after the winter.
The following factors were considered in preparation of this outlook:
- Weak to moderate El Nino event
- Temperature/Precipitation Pattern
- Negative North Atlantic Oscillation (NAO) possibly becoming neutral
- Average to below-average hurricane season
- Other Indices Considered: Quasi-Biennial Oscillation (QBO), Pacific Decadal Oscillation (PDO), North Pacific Index (NP)
- Analog years
- Miscellaneous Factors
This winter will be colder and stormier than normal with above average snowfall. We will see both extended cold outbreaks and thaws, but as has been the case this fall, the cold will overwhelm the warmth and thus will be more commonplace and long lasting. The core of winter will be colder with respect to normal than the beginning and end, and I expect the January/February timeframe to also be the stormiest. The higher level of storminess also means we will see more mixed events then normal. I expect a number of events will not be all snow, but rather snow to rain, rain to snow, sleet, freezing rain, or a combination of all. Overall, I expect the coldest winter since 03-04 and possibly colder, and the snowiest since 2002-03, although not as snowy.
The temperatures predicted below will be measured against the official readings at National Airport (DCA), and snowfall measured against the airports as indicated.
Overall Temperatures for December through March: -1.25°F below normal
December: -1° to +1°, leaning very slightly above normal
January: -2° to -4°
February: Normal to -2°
March: Normal to -2°
Total Snowfall: 20-30% above normal
National Airport (DCA): 20" (versus average of 16")
BWI: 24" (versus average of 20")
Dulles (IAD): 27" (versus average of 22")
Arlington/Alexandria/DC: 19-25"
Fairfax Co.: 22-28"
Loudoun Co.: 26-33"
Mo Co: 23-29"
PG: 17-23"
What can go wrong
- El Nino becomes much stronger, or alternatively weakens much more quickly, than predicted. In both cases the result could be warmer conditions with less snow. Chance of either scenario: 10-15%
- The NAO is very positive for much of the winter. This would likely lead to warmer conditions and would also lead to many events being rain or snow to freezing rain/rain, thus less snow. Chance: 25%
- We never see a real pattern change/positive NAO emerge as we head through November, and December ends up much colder than forecast. Chance: 25%
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