Sunday, January 11, 2009

Inauguration Weather Forecast Update:
Cold Week Coming Up, Some Moderation Possible

With Inauguration Day 9 days away, it's still too early for a specific daily forecast, but a pattern is emerging for a cold pre-Inaugural week. Some moderation is possible by January 20, but the exact timing is not yet definite.

Today's extended range forecasts continue to show below-average temperatures for the Washington, DC region in both the 6-10 and 8-14 day periods. For Jan. 17-21, temperatures are forecast to be below average along the entire East Coast with a 40%+ probability. Likewise, Jan. 19-25 is also projected colder than average, with the chances for the Mid Atlantic area closer to 50% than 40%.

Precipitation probabilities continue to favor below-average amounts: 33-40% for Jan. 17-21 and 50%+ for Jan. 19-25.

Looking at the day-to-day pattern evolution (read the caveats!), a series of Arctic airmass outbreaks across the eastern U.S. is forecast through the upcoming pre-Inauguration week and into next weekend. As of now, however, there is at least the suggestion of some moderation by the day of the event.

Today's temperatures (final):
High 40
Low 28
Departure from average: -1
Month to date: +0.8

Today 0.10"
Month to date 2.02"
Departure from average +0.87"
Days with measurable accumulation: 4 out of 11

Click here for all Inauguration Weather posts.

Images, top to bottom (click to enlarge):
6-10 day temperature,
8-14 day temperature,
8-14 day precipitation forecasts from Climate Prediction Center/National Weather Service/NOAA;
GFS model output map for sea level pressure, 1000-500 mb thickness, and precipitation, 7 am, January 20, 2009, from NCEP/NWS/NOAA ;
CapitalClimate chart of January 2009 observed and forecast daily temperatures from NWS data, background image © Kevin Ambrose

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Seasonal Outlook

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Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.