Back to the Sixties

Now

Partly sunny, cool. Following yesterday's cold frontal passage, northerly breezes and some persistent clouds from a weak trough in the Ohio Valley have kept temperatures about 15° cooler this afternoon; most places are maxing out in the upper 60s.

Strengthening of the upper-level trough is likely to keep cooler temperatures and the possibility of showers in the area into at least part of the weekend.

Map of yesterday's rainfall from the NWS experimental precipitation analysis shows some amounts over half an inch (shades of green) mainly south of the District. Through much of Northern Virginia and the northern suburbs, however, amounts were below 0.25" (lighter shades of blue).

Tonight and Tomorrow

Mostly cloudy, cool, chance of showers. Low temperatures under mostly cloudy skies will be in the low to mid 50s tonight. Tomorrow will be mainly overcast with a 60% chance of showers, especially to the south and east of the metro area, and highs only 59-63°.

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

Climate Corner: Seeing the Forest or the Trees?

Thanks to an extensive cold spell in April, some people (including some professional meteorologists who should know better), have been implying that global warming is not a concern because "everything averages out." It's true that about 1200 daily low temperature records were set in the U.S. during the record cold outbreak of April 4-10. However, climate is not a subjective interpretation of extremes, and global climate is not determined only by what happens where most people (or even most meteorologists) live.

NOAA reported yesterday that, despite the extremes, April was near average for the U.S. overall. Globally, surface temperatures were the third warmest on record, and for the January-April period they were the warmest ever observed. Looking only at land locations, April temperatures were also the warmest on record. Nearly all of Europe averaged above average, with large portions of France, Switzerland, Germany, and Austria 9°F or more above average. Extensive warmth was also seen in Argentina and Brazil.

Showers, Storms, Some Severe?

Now

** Severe Thunderstorm Watch in effect until 8 PM **

Showers and possible thunderstorms. Clouds increased this afternoon as showers and thunderstorms approached ahead of a cold front through the upper Ohio Valley. The rainfall promises a chance of at least some relief to areas running at least 50% below average for precipitation in the last 30 days.

Temperatures reached the low 80s in most places before the clouds moved in, with a high of 83° at both National and Dulles by 2pm. With the onset of rain, temperatures quickly dropped to the low 70s at Dulles. Following the frontal passage, much cooler temperatures will prevail for the next couple of days.

NWS experimental precipitation analysis shows most of the DC region at less than 50% of normal precipitation (orange) for the 30 days through this morning. Some areas, particularly in Northern Virginia, are less than 25% of normal (red).

Tonight and Tomorrow

Showers and thunderstorms ending, cooler. The heaviest activity has now moved east of the District, but some showers and isolated thunderstorms could still persist through 7-8pm, followed by some clearing by morning. Lows will be in the low to mid 50s. Tomorrow will be mostly sunny with lower humidity and highs 68-72°

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

Tropical Topics

Eastern Pacific hurricane season officially began yesterday.

Science Daily reported yesterday on some new research from NASA's Goddard Space Flight Center in Greenbelt on the role of air flow in a hurricane's eye for storm intensification. The results, which appear in the June issue of the American Meteorological Society's Journal of the Atmospheric Sciences, indicate that interaction between the eye and the eyewall, previously considered insignificant, plays a crucial role in the operation of the hurricane's heat engine.

Hot, Then NotShowers and t'storms possible for tomorrow PM

Now

Sunny, breezy, warm. A southerly breeze gusting over 25 mph at times has helped push temperatures well into the 80s in the Washington metro area this afternoon, at least 10° warmer than yesterday. This brings the first half of the month to about 2.5° above average. By mid afternoon, the hot spots in the region were Leesburg and Winchester, both at 88°. Dewpoints are still quite comfortable, mainly in the upper 50s. Regional radar is clear in all directions.

An approaching cold front will bring a chance of showers or thunderstorms late tomorrow and much cooler temperatures for Thursday.

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

Tonight and Tomorrow

Mainly clear, warm, then chance of showers and t'storms. Under mostly clear skies, lows tonight will be in the summery 60s: mid and upper in the city and lower in the 'burbs. Tomorrow morning will be mostly sunny, but clouds will increase in the afternoon, and there is a 50% chance of showers and possible thunderstorms by late afternoon or evening. The Storm Prediction Center has indicated a slight risk of severe weather. Highs will be 78-82°.

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

Climate Clues

NASA announced today that large areas of Antarctica, roughly the size of California, were observed to melt in January 2005. Melting was observed in multiple regions as far as 560 miles inland, within 310 miles of the South Pole, and at elevations above 6600 feet. Konrad Steffen, director of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder, one of the leaders of the team of scientists, said

"Antarctica has shown little to no warming in the recent past with the exception of the Antarctic Peninsula, but now large regions are showing the first signs of the impacts of warming as interpreted by this satellite analysis. Increases in snowmelt, such as this in 2005, definitely could have an impact on larger scale melting of Antarctica's ice sheets if they were severe or sustained over time."

Law of Unintended Consequences

The rural electric coal subsidy story we linked to yesterday gets a more complete treatment on the bunny trail.

Maybe May, Maybe Not

Now

Mostly sunny. The May temperature rollercoaster continues. After chilly lows of 49° at National and 40° at Dulles, temperatures have rebounded nicely to more nearly average May levels this afternoon, despite some high clouds drifting in from the northwest. Mid afternoon readings are mostly in the low 70s. Radar is generally dry; a small area of showers across the eastern WV panhandle has apparently dissipated. Westerly flow will bring in warmer air tomorrow from the Midwest, where readings were well into the 80s today, with upper 80s reaching as far north as central Minnesota.

Temperature chart at 4pm today from Unisys

Tonight and Tomorrow

Partly cloudy, becoming much warmer. Under partly cloudy skies, lows tonight will be in the mid to upper 50s in urban areas and lower 50s to near 50° in the cooler 'burbs. Tomorrow will be sunny and warmer with highs in the low to mid 80s.

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

Law of Unintended Consequences

The lead A1 article, "Federal Loans for Coal Plants Clash With Carbon Cuts", in today's WaPo describes how a Depression-era subsidy intended to bring electricity to rural areas is now subsidizing coal plants at the expense of CO₂-reducing energy alternatives. By providing the additional energy needed for new ethanol production, these coal plants are even undermining the effectiveness of biofuels in reducing CO₂ emissions.

Balancing the Budget

Now

Summery. After a mainly cool beginning to the month (6 days at or below average), May is rebalancing the temperature budget with another summery day in the Washington metro area. Temperatures have reached the low 80s in most places with dewpoints in the low to mid 60s.

Showers on radar are quite sparse south of the Mason-Dixon line, but a line of strong thunderstorms north and west of Harrisburg prompted a severe thunderstorm warning for portions of central PA. Warm temperatures and moderate humidity should persist through tomorrow before some cooler air arrives for the weekend.

Tonight and Tomorrow

Partly cloudy, warm, slight chance of showers. There is a slight chance of showers through this evening, but skies will be partly cloudy the rest of the night with lows in the low to mid 60s. Tomorrow will be partly to mostly sunny with highs 80-83° and a 25% chance of afternoon or evening showers and thunderstorms.

For the outlook through the weekend and beyond, scroll on down to Josh's post below.

Tropical Topics

A reconnaissance flight this morning indicated that Andrea's maximum sustained winds had decreased to 35 mph, and the storm was downgraded to a subtropical depression. Movement is a slow southward drift. There was little change in the 5:00 advisory.

Capitol Climate: Budget Battle

An op-ed piece in today's WaPo, "The Planet NASA Needs to Explore", discusses the scientific impacts of shifting budget priorities at NASA. Among the endangered satellite species is QuikSCAT, which National Hurricane Center Director Bill Proenza mentioned specifically at last month's DC-AMS meeting as an essential tool in improving the accuracy of hurricane intensity forecasts. Two of the authors of the op-ed are directors of the country's leading oceanographic institutions, Scripps and Woods Hole.

A special report in this month's Physics Today analyzes the 2008 science budget across the entire government. Although proposed R&D spending for NSF, DOE, and NIST is increased, EPA is cut by 3.1% and NOAA by 9.5%. The NOAA research cut is within an overall decrease for the agency of 2.7%, but the National Weather Service would go up by 6.5%. NOAA's education programs (scholarships and outreach programs) would be cut in half.

Moderate May Mugginess

Now

Sunny, warm, moderately humid. Increasing humidity produced some low clouds over the Washington area this morning, but winds more southerly than easterly have helped skies clear this afternoon as temperatures have reached at least into the upper 70s. By 4pm, many locations, including Dulles, were 80-82°. Dewpoints in the summery low 60s are reflected in relative humidity ranging over 60%. Radar is clear over the entire Mid Atlantic region.

Pleasantly warm conditions are likely to continue for the next couple of days.

Surface weather/satellite image map at 2pm today from HPC/NCEP/NWS shows subtropical storm Andrea, the first of the season, lurking off the Southeast coast.

Tonight and Tomorrow

Partly cloudy, warm. Skies will be partly to mostly cloudy tonight with lows in the low 60s in the city to the upper 50s in the cooler 'burbs. Some clouds in the morning tomorrow will give way to mostly sunny conditions in the afternoon with highs 77-82°. There is a 20% chance of showers or thunderstorms in the afternoon or evening.

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

Tropical Topics

The tropical disturbance off the Georgia/South Carolina coast noted yesterday became the first named storm of the tropical season (which begins officially in the Atlantic on June 1) this morning. A tropical storm watch is in effect from portions of the Georgia coast southward to Flagler Beach, FL. As of the lastest advisory, subtropical storm Andrea was still poorly organized. Top winds were near 45 mph with higher gusts. Movement was erratic, but generally slowly to the west. The heaviest rains are expected to remain offshore for the next 24 hours. The next advisory will be issued at 5pm.

The Weather Channel's Stu Ostro has a very nice illustrated discussion of the history of this storm and subtropical storms in general in his blog post this morning.

A subtropical storm (unnamed) formed in the Atlantic as early as Jan. 18 in 1978. Other early-season storms were observed on: 2/2/1952, 3/6/1908, 4/18/2003, 4/21/1992, 5/5/1932, and 5/6/1981. In addition, there have been 17 others in May, including 2 in 1887 and a second one in 1908.

Exceptional

Now

Clear, warm. It's another exceptionally nice spring afternoon in the Washington metro area. Temperatures have warmed into the mid 70s throughout the region. Humidities are somewhat higher than in the last couple of days but still quite comfortable. Clouds are likely to increase tomorrow, and there is a slight chance of showers.

Tonight and Tomorrow

Some clouds developing, warm. Tonight should be mostly clear and seasonably mild, with lows from near 60° downtown to the mid and upper 50s in the 'burbs. As a more easterly flow prevails tomorrow, some clouds should develop, and there is a 20% chance of showers. Highs will be in the low to mid 70s.

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

Tropical Topics

The National Hurricane Center issued a Special Tropical Disturbance Statement this morning for the non-tropical storm which has been hanging around about 230 miles off the Georgia/South Carolina coast. Satellite wind measurements showed 35-40 kt. winds off the coast, and strong winds and heavy surf were affecting the coast from Georgia through the Carolinas. "No significant strengthening" is expected, but an Air Force reconnaissance flight will be available if necessary tomorrow morning to investigate.

A posting at the WunderBlog indicates that the 31 days through today with no tropical storms anywhere in the world is the longest such streak since worldwide satellite surveillance became available in the 1980's.

Also on the tropical front, a paper in last week's (May 1) American Geophysical Union Transactions by Christopher Landsea takes some exception to the notion of a relationship between tropical cyclone activity and global warming. Landsea provides statistics which indicate that increases in the number of tropical storms in recent decades are due to improved observational technology (satellites and aircraft). This could be interpreted as contradicting the work of MIT's Kerry Emanuel and others which has supported a link with global warming. A significant aspect of Emanuel's work, however, involves the intensity of tropical cyclones, which does not appear to be considered in Landsea's analysis.

Enhanced satellite infrared image over the Southeast this afternoon from Unisys