Flood Watch Through Saturday Morning

Now

5:30 Update: Totals through 5:00: National 3.38", Dulles 2.23", BWI 2.03". The amount at National is more than the average total for the entire month of October.

Rain, moderate to heavy at times. The flood watch for West Virginia and western portions of Virginia was cancelled at mid afternoon, but the watch remains in effect for DC and adjacent Maryland and Virginia through Saturday morning. Additional rainfall of 1-3" is possible with some urban flooding or flash flooding from thunderstorms.

Although not as heavy as Wednesday evening, the rainfall rate has picked up today following the drizzle and light rain on Thursday. Storm totals through early this afternoon included: National 2.61", Dulles 2.1", and BWI 1.75". Radar shows a steady stream of showers extending as far back as the Carolinas. This is all moving generally northward, although the heaviest showers were concentrated east of I-95, headed toward the eastern areas of Virginia and Maryland which received lighter amounts through yesterday. The whole area of rain will be shifting very gradually eastward, and precipitation should be tapering off in the immediate metro area by about 8am Saturday.

Temperatures tonight should remain near steady, around 60° to the lower 60s.

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

Who You Gonna Call? Drought Denters!

Now

Light rain, drizzle, cool. The rain of as much as 2"+ at National may not have busted the drought, but it certainly put a large dent in it. After last night's more drenching showers, today's activity has been more of the light drizzle/heavy mist variety. At mid afternoon, most precipitation heavy enough to show up on radar was south of a line from Charlottesville to Richmond, but there's a better chance for more significant rain tomorrow.

As high pressure to the north has enhanced northerly flow into the area, temperatures are much cooler than we've been used to this month; the high so far is the midnight temperature of only 57°, giving a chance for the first below-average day in over a month.

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

Tonight and Tomorrow

Showers or rain likely, cool. Conditions will remain cloudy and damp overnight with a 90% chance of showers and lows in the low to mid 50s. Rain is likely tomorrow with highs 58-62°.

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

Volunteer Opportunity

The Union of Concerned Scientists is looking for volunteers to help with PowerShift 2007, the first national youth summit on global warming, to be held November 2-5 at the University of Maryland.

Political Science: Who You Gonna Call? Ghost Writers!

Today's WaPo reports that those cunning linguists in the White House Office of Science and Technology Policy have apparently stopped tinkering with the wording of government climate change reports---they simply deleted over 6 complete pages from the testimony of CDC Director Dr. Julie Gerberding on climate change and public health. In addition to the Senate investigation cited in the article, the House Committee on Science and Technology is also looking into the matter. Chairman Miller of the Oversight Subcommittee said, "My advice to any administration witness is if you're convicted of contempt of Congress, obstruction of justice or perjury, [White House Science Advisor] Dr. Marburger will not serve your sentence for you."

Hard Rain Gonna Fall, or a Hardly Raining Fall?

Now

Cloudy, intermittent showers The nearly quarter inch of rain which fell overnight was enough to push the Washington September-October total to date beyond the record driest amount in 1930. (Even though we're still technically in the running, the 1930 3-month fall total of 1.83", just 18% of normal, will be tough to beat.) The rain was also sufficient to create significant traffic disruption in the morning rush hour. Although some heavier showers and thunderstorms brought about half an inch to Richmond earlier, these storms veered to the east as they moved northward, and much of the metro area has received only several hundredths of an inch during the day.

The clouds and rain are resulting from a frontal system and surface low pressure associated with an upper-level area of low pressure. The upper-level low has been cut off from the main west-to-east steering winds in the upper atmosphere, and is stalled over the Tennessee and lower Mississippi valleys. With the weather system nearly stationary or even moving slightly westward, conditions will be slow to clear out over the next couple of days.

Map of surface pressure (solid lines) and 500 mb height (color shading) this morning from Unisys

Tonight and Tomorrow

Mostly cloudy, cool, showers. Cloudy and damp conditions will continue overnight with showers likely. Lows will be generally in the mid 50s. Tomorrow will be cloudy and cool with a 70% chance of showers and highs 55-61°.

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

Climate Corner

Weather Channel senior meteorologist Buzz Bernard had an excellent post last week on the difference between climate science and climate policy. PM Update endorses his invitation to provide "some peer-reviewed scientific work that addresses 'other causes'" of global warming. (No, news reports of a retired professor's rants are not "peer-reviewed", no matter how prominently they were featured on the Drudge Report or squawk radio.)

Political Science

Speaking of policy (notice this is a separate section from the one above), a more careful review of the links in yesterday's Update indicates that the Warner-Lieberman climate bill hasn't been totally "endorsed" by anybody (except perhaps the WaPo in their Monday editorial). The Union of Concerned Scientists also regards the bill as a "good starting point for debate".

Here Comes the Sun? Not YetShower chances shift to tonight and tomorrow

Now

Cloudy, very warm, humid. Brisk southerly breezes have pushed temperatures to 80 or above for the 15th time this month, despite persistent overcast skies. By 4pm, National was 81°, although Dulles was only 79°. Dewpoints are in the noticeably humid range of the low 60s. In the much-sought precipitation department, radar shows only the most isolated activity east of the mountains. Fortunately, some areas of the Southeast which need the precipitation even more than we do have been getting some pretty good rainfall amounts.

The surface weather map at 4:09 this afternoon from The Weather Channel shows precipitation bypassing the Mid Atlantic region to the north and west.

Tonight and Tomorrow

Mostly cloudy, warm, chance of showers. Tonight will be mostly cloudy and humid with a 40% chance of showers, mainly after 8 p.m., and lows in the mid to upper 60s. Mostly cloudy skies will continue through tomorrow with a 40% chance of showers and highs 68-74°.

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

Climate Corner

A tip of the rabbit ears to the Professor for a pointer to a new paper appearing this week in the Proceedings of the National Academy of Sciences. The to-be-published results have some bad news on the efficiency of CO₂ removal from the atmosphere:

This study finds that the recent swift increase in atmospheric CO₂ is due to faster economic growth coupled with a halt in carbon intensity reductions, in addition to natural sinks removing a smaller proportion of emissions from the air. Efficiency of natural sinks to remove emissions from human activities has been declining for 50 years.

Mediarology

The PBS NOVA science series is reviewing solar energy tonight in an episode entitled, Saved by the Sun (originally broadcast on April 24). Showtime is 8pm on WETA 26 and WMPT 22.

Political Science

The Hill Heat blog has a review of the Warner-Lieberman climate legislation and a comparison with competing proposals. The bill known as the America's Climate Security Act has been endorsed by the National Environmental Trust as well as the utility company PG&E.

Lake Wobegon Autumn Continues Warm streak at day 32

Now

Sunny, very warm. Washington's Lake Wobegon string of consecutive days with average temperatures at or above normal reached day 32 as readings once again broke 80° early this afternoon. With only 9 days left in the month, this October is now averaging 9.7° above average. By comparison, the warmest October in history (1984) was 5.5° above average. Humidities have also crept up a bit with dewpoints mostly in the low to mid 50s.

After a good chance for the proverbially much-needed rain tomorrow, more seasonable temperatures will return for midweek.

Tonight and Tomorrow

Increasing clouds, warm, chance of showers. With clouds increasing overnight, lows will have a hard time breaking below the summery low 60s in the city and the upper 50s in the 'burbs. Tomorrow will be mostly cloudy with a 70% chance of showers and possible thunderstorms, especially in the afternoon or evening; highs will be 73-77° with summery humidity.

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

Climate Corner

Today's weekly science three-quarter page in the WaPo (A10 for the dead-tree fans) has a review of recent news on polar icecap melting, "At the Poles, Melting Occurring at Alarming Rate". Although the article doesn't mention the specific amount, NASA has reported that this year's minimum Arctic sea ice extent on September 14, shown in the image (Siberia is to the lower left, Alaska and Canada are to the right), was 25% less than the previous record low in 2005. The author of the WaPo article was online this morning for a chat on the topic.

Mediarology

Today's Kojo Nnamdi Show on WAMU-FM featured a discussion on "Scientists vs. Politicians in Public Policy", and the Diane Rehm Show had a review of the current drought situation with an engineering professor from UMD, a climatologist from the National Drought Mitigation Center, and a meteorologist from the National Climatic Data Center. Podcasts are available online.

Political Science

An editorial, "Climate Change on Capitol Hill", in today's WaPo favors the passage of the climate change bill (America's Climate Security Act) introduced on Thursday by Sen. Warner (R) of Virginia and Sen. Lieberman (R-lite) of Connecticut. The Environmental Defense blog has a more comprehensive analysis of the bill.