"How Cold Is It?"

Now

A Freeze Watch is in effect for Friday night.

Clear, chilly. It's a bit early for the "How cold is it?" jokes, but you might want to at least start thinking about where you stored those flannel sheets over the summer. After some briefly heavy showers overnight (0.38" at National, 0.34" at Dulles), it's a brilliantly crisp fall afternoon in the Washington metro area. The daily high was officially 60° near 1am, but mid 50s are much more the order of the day this afternoon. It's also breezy; winds gusted as high as 30 mph earlier.

Although temperatures are substantially lower than yesterday, the drop in humidity is even more dramatic, with dewpoints generally in the 20s (an 18° report from the Culpeper robo-observer looks a bit out of whack). This will allow lows to plunge the next couple of nights, especially where winds are light.

Pictured: Temperature chart at 4pm today from Unisys shows a strong change over the Mid Atlantic area from earlier in the week.

Tonight and Tomorrow

Cold. Under clear skies and diminishing winds tonight, temperatures will drop to near 35° downtown and the upper 20s in the coolest 'burbs. Tomorrow will be sunny and cold for the season, highs in the upper 40s.

For the outlook through the weekend and Larson's Long Range, scroll down to Josh's post below.

Mediarology

Ted Turner and Richard Branson will be guests on The Weather Channel's "Climate Code" this Sunday at 5pm.

The dcrtv blog reported recently that WTTG Channel 5 morning weatherman Tony Perkins recently received an Alumni Achievement Award from American University. Perkins is a 1981 graduate of the School of Communication.

November's Nice Nascence

Now

Sunny, mild. An approaching cold front has become nearly stationary just to the north and west of the Washington metro area this afternoon. As a result, southerly breezes have nudged temperatures into the low 70s at most locations, providing a very pleasant late fall day for working off some of that leftover Halloween candy with leaf raking or lawn mowing. Highs were 71° at National, 72° at Dulles and BWI.

Meanwhile, a low pressure area getting organized in the Tennessee Valley will bring some rain to the area late tonight and early tomorrow, followed by some of the coldest temperatures of the season by the weekend.

Tonight and Tomorrow

Showers developing, becoming colder. Clouds will increase tonight, with showers likely by morning and lows in the upper 40s to near 50°. Rain will end by mid day tomorrow with clearing skies in the afternoon and highs only around 54°, turning colder at night.

For the Friday outlook and into the weekend, scroll down to Dan's post below.

More Winter Outlooks

Matt is busy working on the Capitalweather.com winter outlook to be published soon. Meanwhile, Weather America's Larry Cosgrove has issued a winter outlook through his newsletter. He's calling for temperatures to average from near normal in southeastern Virginia to below normal (-1° to -3°) in the immediate DC area. Precipitation is forecast to be much above normal (greater than 125%) with DC right on the borderline between above normal and much above normal (greater than 125%) snowfall potential. Larry is scheduled to be the guest of the WeatherTalkers this Sunday.

An important factor in the upcoming winter outlook is the progress of the developing El Niño. The latest El Niño area 5-day average sea surface temperatures show equatorial Pacific anomalies strengthening to approach a maximum of +2°C.

October Winds Down

Trick or Treat Outlook: Scroll down to Matt's post for the evening forecast.

Now

Sunny, mild. As October winds down to Halloween under some scattered high clouds, temperatures in the Washington metro area have reached the low to mid 70s by mid afternoon today. Some showers ahead of an approaching cold front are possible tonight, but they are most likely after the witching hour of midnight.

Tonight and Tomorrow

Warm, chance of showers late. Clouds will increase after midnight tonight with low temperatures in the low to mid 50s. The chance of showers by morning is around 20%. Skies will be variably cloudy tomorrow with a slight chance of showers and highs near 69°.

For the outlook through the rest of the week and into the weekend, scroll down to Jason's post below.

This October's average wind speed is about 10% below the long-term average of 8.8 mph, but the chart shows that there have been several more extreme events at roughly one week intervals, culminating with the 48 mph gust from the west-northwest on Saturday.

Political Science and Mediarology: Stern Warning

Today's WaPo has an article on Page A18 which reports on a British Government study directed by Sir Nicholas Stern analyzing the potential economic damage from global warming. The impact is estimated to range from 5 to 20 percent. An accompanying article notes that, despite a wider political spectrum than in the U.S., there is a strong consensus for climate change action in Britain, with the 3 major parties each accusing the others of not being active enough on the issue. By contrast, the WaPo yesterday editorialized ("Changing Climate on Climate") on the continued inaction of the current administration on climate change.

According to the NYT, residents of the Bangor, Maine, area are unlikely to see this news on TV. The general manager of the ABC and Fox stations WVII and WFVX (both under the same ownership) is quoted as issuing a stern warning prohibiting the stations, which recently began broadcasting previously taped versions of the 11:00 news, from covering global warming. When "Bar Harbor is underwater, then we can do global warming stories," he said.

Halloween Treat: Unscary Weather

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Sunny, mild. Today's sunny, mild weather has been a preview of the kind of warm Halloween the Washington metro area has experienced for most of the current century. In the 5 years starting with 2001, Halloween highs have been: 64°, 47°, 70°, 79°, and 71°. This afternoon's temperatures at National were hindered slightly (high of 68°) by the infamous southerly river breeze, but Dulles reached 70° at 3:34, and several locations in the southern fringe of the region were in the 70s.

Pictured: Temperature map at 4pm shows large pre-Halloween area of 60s and 70s (shades of orange) in the eastern U.S., from Unisys.

Tonight and Tomorrow

Dry and mild. With clear skies and light winds, lows tonight will be in the upper 40s downtown ranging to near 40° in the cooler 'burbs. Tomorrow will be sunny and seasonably warm with highs near 74°. Little ghosties and goblins should expect temperatures in the low 60s and light winds at Trick or Treat time; chance of rain is less than 5%.

For the outlook through the rest of the week and into the weekend, scroll down to Jason's post below.

Winter Outlooks

In the annual triumph of hope over experience (September/October temperatures explain only 9% of the variance of Washington winter temperatures), winter outlooks have been rolling out. Dave Tolleris (DT) of WxRisk.com gave his yesterday on WeatherTalk Radio. He's calling for temperatures within +/-1° of average and snowfall near to a little above average. He also disclosed that he is moving from the snow-challenged Richmond area to Leesburg. Welcome to the local blogging area, DT!

Several other winter outlooks are posted on the WeatherTalk web site. Stay tuned here for the CapitalWeather.com winter outlook coming out soon.

Cold Rain, Then Cold Wind Cold Theory in the Cold

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Showers, cold. Despite a breeze with a south of east component, heavy clouds and light showers are keeping temperatures from reaching 50° in most of the Washington metro area this afternoon. Precipitation amounts through 5pm have been only 0.1" at National and 0.05" (all of which fell in the last hour) at Dulles.

Rainfall should be heavier overnight, however, as a developing low pressure area in the mid Mississippi and lower Ohio valleys gets cranked up on its way to the eastern Great Lakes by tomorrow. Following the passage of this very deep low, strong winds should bring another shot of cold air in for the rest of the weekend. The National Weather Service has issued a High Wind Watch for Saturday evening through Sunday morning for the potential of sustained winds at least 40 mph or gusts at least 58 mph throughout the local blogging area.

Pictured: One model's prediction of a very strong (980 mb) low centered over southern Canada Saturday evening. The closely-spaced isobars indicate strong winds over the Mid Atlantic area; from NCEP/NWS

Tonight and Tomorrow

Rain, then windy and colder. Rain will become heavier tonight, with temperatures steady in the upper 40s to near 50°. The rain will end as showers by mid day tomorrow. Southerly winds ahead of a strong cold front could push temperatures into the low 60s around the middle of the day, but strong northwesterly winds following the frontal passage will bring falling temperatures through the rest of the afternoon and into tomorrow night.

For the outlook through the rest of the weekend, scroll down to Camden's post below.

Climate Corner

The RealClimate blog today revisits the issue of global cooling claims made in the 70s. Newsweek has just done a re-evaluation of their 1975 article titled, "A cooling world." They conclude in the cold light of today that huge improvements in data collection and modeling technology have made "any forecasts from 1975 as inoperative as the predictions being made around the same time about the inevitable triumph of communism." The real lesson here is: Don't get your science from the SCMSM (so-called mainstream media).

Chilly Still on the Menu

A strong ridge of high pressure extending from northern Hudson Bay across eastern North America to Cuba continued pumping cold air into the Mid Atlantic region on Wednesday. A northwesterly breeze again gusting over 30 mph at times kept temperatures well below seasonal averages in the Washington metro area. High temperatures were 55° at National and Dulles, 54° at BWI.

Despite diminishing winds, temperatures will remain well below average today as a low pressure area becoming organized in the central Rockies and incorporating leftover moisture from what was eastern Pacific Huricane Paul brings the threat of rain late Friday into part of the weekend.

Surface weather map at 11pm last night from HPC/NCEP/NWS

Today and Tonight

Continued cold, less windy. Under mostly sunny skies, today's highs will be in the mid 50s. Overnight, clouds will increase toward morning with lows near 40° in the city, low to mid 30s in the cooler 'burbs.

For the outlook through the weekend, scroll down to Dan's post below.

Fun with Numbers

Larson's Long-Range is off today, but we can take the opportunity to look at the connection, if any, between fall and winter temperatures. With both September and October running cooler than average, the question arises whether or not this indicates anything about the upcoming winter. As Matt has already noted, the relationship is quite complex.

The chart shows the September and October (SO) average temperature on the x-axis, and the following December, January, and February (DJF) average on the y-axis. The data points include the 135 years of Washington observations through last year. The solid regression line represents the best fit to the data, with the equation of the line shown in the upper left. The upward slope of the line shows that there is a positive relationship, but the correlation is very weak. The value 0.09 for R² means that only 9% of the variability in winter average temperatures is explained by the September-October average. Note that out of the 5 coolest SO averages, there was one year with the coolest DJF average, but there was also one with the second warmest DJF. (For more on regression analysis, see the discussion of the December-January relationship posted last year.)

For more Washington DC data, see:
Washington DC Weather Records

CapitalWeather.com chart from NWS data, photo © Kevin Ambrose

A Winter's Day

Correction: The reference to the daily high below (which did hold at 51°) should have said that it was within one degree of the record low maximum for the date. The fact checkers at PM Update have been suitably admonished to stay off the fried Coke.

Now

Cold, windy. It's "a winter's day in a deep and dark . . ." October? Returning from a weekend visit to the pig races and fried everything (including Coke) at the N.C. State Fair, PM Update finds that someone left the freezer door open.

Assisted by a northwesterly wind gusting over 30 mph, temperatures in the Nation's Capital region are struggling to reach the low 50s this afternoon, and the wind makes it feel much colder. The high hourly reading at National of 51° at 2pm, if it holds for the day (It's been back to 50° through 5pm), would be the average high for Dec. 2-4, and it misses the record low minimum for the date in 77 years of records by only 1°. The last time the daily high was below 55° was March 26.

CapitalWeather.com chart from NWS data, photo © Kevin Ambrose

Tonight and Tomorrow

Continued cold, breezy. Winds should die down somewhat tonight, but not enough to push lows below the mid to upper 30s in most places. Tomorrow will be partly cloudy and breezy, but not as windy as today, with highs around 54°.

For the outlook through the rest of the week, scroll down to Jason's post below.

Climate Corner: "Would You Like Information with Your Data and Fries?"

If you've ever done any searching in an unfamiliar subject area in the virtual haystack known as the web, you know it's often very hard to separate the golden from the garbage. RealClimate.org, the climate site run by climate scientists, announced today that they are participating in a new service by Google Co-op which allows searches to be performed using only sites which have been selected to meet some level of quality. So, if you'd rather get your climate change information from scientists instead of paid political propagandists, fiction writers, the oil industry, or Homer Simpson, try out their new search facility.