Warm Washington Wednesday Cooler weekend ahead

Now

Sunny, warm, humid. It's another warm and somewhat humid afternoon in the Washington metro area. By mid afternoon, several regional locations had reported temperatures of 90° or more, although National had reached only 88°. Dewpoints are generally in the mid and upper 60s.

The month overall is now 1.6° above the long-term average, but the mean of 73°, which will undoubtedly be reduced by the weekend, is well below the 75° achieved just 2 years ago and significantly below the all-time warmest September of 77.1° in 1980 (pdf file).

A slowly approaching cold front provides this week's only (slim) hope for rainfall late tomorrow or early Friday.

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

Tonight and Tomorrow

Warm and humid, chance of showers. There is a slight chance of scattered showers or thunderstorms through this evening, especially over and to the west of the Blue Ridge. Lows tonight will be in the upper 60s to near 70° in the city to the mid 60s in the 'burbs. Tomorrow will feature variable cloudiness and highs in the mid to upper 80s with a 40% chance of showers or thunderstorms by evening.

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

Tropical Topics

Despite yesterday's indications of limited strengthening, Tropical Storm Karen was approaching hurricane strength in the eastern Atlantic this morning with peak winds of 70 mph. The predicted northwesterly track, however, continues to keep it away from land areas.

Tropical Depression 13 is near tropical storm strength and meandering slowly in the southern Gulf, expected to eventually make landfall in eastern Mexico. As of the 5pm advisory, it had still not strengthened and was nearly stationary.

There are several other areas of interest. A new low pressure area near Key West is being watched for possible development as it moves northeastward toward the Atlantic coast of Florida. A couple of tropical waves in the far eastern Atlantic also have the potential for development in the next couple of days.

Capitol Climate: National Security

The House Committee on Science and Technology's Subcommittee on Investigations and Oversight is holding a hearing tomorrow on "The National Security Implications of Climate Change". A former Army Chief of Staff and a former Director of Central Intelligence are scheduled to testify. The CNA Corporation (operator of the Center for Naval Analyses) recently issued a report on the subject based on the input of a blue-ribbon panel consisting of eleven retired 3+ star admirals and generals.

The subject is also the theme of an upcoming episode of The Weather Channel's Forecast Earth, previously postponed due to storm coverage.

September's Still Sultry

Now

Sunny, warm, more humidity. The calendar says fall, but it's still summery in the Washington metro area. By mid afternoon, at least half a dozen official reporting stations in the region had reached the 90° level, including Dulles at 91° (only 1° short of the record). Traditional hot spot Culpeper reached 95°. At 4pm, temperatures of 80°+ blanketed the entire East Coast and even extended into southern Canada. Humidity has also noticeably increased, although the dewpoints in the low 60s or less are not oppressive.

Temperature chart at 4pm today from Unisys

Tonight and Tomorrow

Mostly clear, very warm. Tonight will be mostly clear with lows only down to the upper 60s in the city and the low 60s in the 'burbs. Tomorrow will be sunny, a little warmer and more humid with highs 88-91°.

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

Tropical Topics

The PaBePo's Storm King has suggested that if Jerry was a storm "about nothing", then it should be followed by . . . Kramer! The National Hurricane Center has stuck to the script, however, and named the next storm Karen. As of the 5pm advisory, the new tropical storm had maximum winds holding steady at 40 mph. Although some intensification is expected, it is not likely to reach hurricane strength. The storm is quite far south in the eastern Atlantic, but its expected more northerly track could keep it away from all land areas.

An Air Force flight this afternoon was investigating the area of showers and thunderstorms in the southwestern Gulf of Mexico. Satellite images this morning indicated that this may be developing into a tropical depression.

In the ongoing search for the new Hurricane Center Director, the Miami Herald's Martin Merzer reports today that interim director Ed Rappaport has taken himself out of the running for the top spot.

Equinoctal Equanimity Summery conditions continue

Now

Sunny, warm, low humidity. Although the equinox is frequently a time of turmoil in the atmosphere, this autumnal one is passing very calmly (perhaps boringly) in the Mid Atlantic region following yesterday morning's beginning of astronomical fall. See Today in Weather History to the right for a much different scenario.

Today's noon sun angle of 50.4° was well below the peak of 74.5° in June, but the crystal clear skies and the subsiding air from a strong ridge of high pressure have helped push regional temperatures into the 80s by mid afternoon. A southerly breeze was keeping Quantico the lone exception at 78°. Dewpoints have crept up slightly, but are still very comfortable in the upper 40s and low 50s.

CapitalWeather.com chart based on Eq. 2.9 in Stull, "Meteorology for Scientists and Engineers", photo © Kevin Ambrose

Tonight and Tomorrow

Clear, mild to very warm. Lows tonight under clear skies and calm winds will range from 59-62° in urban areas to the low and mid 50s in the cooler 'burbs. Tomorrow will again be sunny and very warm with highs 86-90° and a little more humidity.

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

Tropical Topics

Jerry, the 10th named storm of the season, developed from a subtropical system in the middle of the Atlantic over the weekend and reached tropical storm strength before being downgraded to a depression today. It was never any threat to land, and it is expected to be absorbed quickly by a strong non-tropical system.

The National Hurricane Center is also watching several other areas for possible development:

• a tropical wave approaching the Lesser Antilles
• a large low pressure area in the eastern Atlantic
• an area of strong showers and thunderstorms in the southwestern Gulf of Mexico

Each of these has the potential to become a tropical cyclone in the next couple of days.

Job Listing

Polish up your resume. Bob King's "Eye on the Storm" blog in the online PaBePo has the NOAA job announcement for the new Director of the National Hurricane Center, pay range $111,676 to $168,000. Deadline for applications is Oct. 24.

Crowds of Clouds Create Capital Cooling

Now

Partly sunny, mild. A nearly stationary front extending northeastward off the Atlantic coast from a weak low pressure area in the eastern Gulf of Mexico has helped some cloudiness encroach westward into the National Capital region this afternoon. This has held temperatures down somewhat from earlier forecast levels. Mid afternoon readings were generally in the mid 70s, and humidity was a little higher with dewpoints near or a little over 60°. Precipitation on radar is confined to the southeastern corner of Virginia and eastern North Carolina. The main short-term forecast problem revolves around how persistent these clouds are likely to be.

Infrared satellite image at 3:40 this afternoon from Unisys

Tonight and Tomorrow

Considerable cloudiness, mild. Lows tonight under mostly cloudy skies will be generally in the low 60s, ranging to the upper 50s where fewer clouds persist, mainly to the west. Highs tomorrow under variable clouds will be 75-80°, but into the low 80s if more sun emerges.

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

Tropical Topics

A reconnaissance flight this afternoon investigating the area of storminess near Florida (Jerry wannabe) found a weak circulation in the eastern Gulf of Mexico about 115 miles west-southwest of St. Petersburg. Thunderstorms, as shown on the Tampa radar, remain rather scattered and disorganized, but the system has the potential to become a subtropical or tropical cyclone in the next couple of days.

Presentation: Hurricanes and Global Warming

The DC chapter of the American Meteorological Society has posted an announcement of the presentation next week by Chris Mooney on "Storm World, Hurricanes, Politics, and the Battle over Global Warming". RSVP is required by Monday.

For background on the topic (besides Mooney's excellent book), see Monday's posting by Kevin Trenberth on the nature.com Climate Feedback blog. Trenberth wrote a feature article, "Warmer Oceans, Stronger Hurricanes" in the July Scientific American. The SciAm article was critiqued by wunderground.com's Jeff Masters in his blog.

Still Seeking September's Seasonable Showers in Spectacular Sunshine

Now

Sunny, warmer. It's a perfect day to sneak out early and mow the lawn with your pollution-reducing cordless electric mower, if you have any grass still alive to mow. A northeasterly wind and a slight increase in humidity (dewpoints up to the mid 50s) produced some morning low clouds which held temperatures down until bright blue skies once again appeared. By mid afternoon, temperatures were well into the upper 70s in most locations, and the traditional hot spot of Culpeper was 81°.

The down side, of course, is that much-needed rain is still not in the forecast. National is now below 25% of average precipitation month-to-date and just barely over 75% for the entire year.

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

Tonight and Tomorrow

Partly cloudy and comfortable. Under partly cloudy skies, lows tonight will range from the low 60s in town to the mid and upper 50s in the 'burbs. Patchy fog is possible in low-lying areas. Some morning clouds tomorrow should give way to abundant sunshine, slightly warmer temperatures, and a little more humidity with highs 78-82°.

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

Tropical Topics

The area of storminess over northern Florida and the adjacent Atlantic continues to show some strength as it drifts westward toward possible further development as a subtropical or tropical cyclone in the next couple of days.

Otherwise, the remnants of Ingrid are still dead.

Weather Biz: CNBC Meets the Weather Channel

Phil Flynn of Alaron Trading and recently-appointed Chief Strategy Officer Paul Walsh of Storm Exchange discussed "Fall Weather Risk" on CNBC's Squawk on the Street this morning. During the segment, the assertion was made that 30% of the economy is subject to weather-related risk.

The Storm Exchange calculates a "sweater index", which is the cumulative total of daily low temperature deviations below 60°. Warm weather in September is considered bad for retail sales because: (1) People have better things to do than shop at the mall, (2) Demand for winter clothes is low. Other indices provided by the Exchange include: the Thanksgiving travel rain delay index and the Labor Day BBQ index.

Continued Clear and Comfortable

Now

Sunny, not quite as cool. This afternoon's weather map shows a large high pressure ridge extending from eastern Canada across most of the eastern half of the U.S. and into the northern Gulf of Mexico. Despite a light northeasterly breeze, the strong September sun (today's noon sun angle was 52°) has raised metro area temperatures generally into the low 70s, with a few higher readings. Culpeper was the warm spot in the region at 4pm with 79°; the major local airports were both 73° but BWI was a couple of degrees cooler. Humidity is also in the very comfortable range; dewpoints are in the upper 40s to low 50s. The nearest showers on the national radar map are over northern Florida.

Surface weather map at 1pm today from IntelliWeather

Tonight and Tomorrow

Clear and comfortable. Under mainly clear skies, lows tonight will be a little warmer than last night, ranging from the upper 50s downtown to the upper 40s in the 'burbs. Tomorrow will be much like today, but with highs 75-79°.

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

Tropical Topics

The main area of interest in the tropical Atlantic is a wave associated with some showers and thunderstorms off the Florida coast and over the Bahamas. The National Hurricane Center sees the "potential for subtropical or tropical cyclone formation over the next couple of days" as this system rotates westward around the large high pressure ridge across Florida and into the eastern Gulf of Mexico.

School Daze: $$$$$

Attention students (and anyone paying tuition for students): As another school year begins, the American Meteorological Society has posted a reminder of its various undergraduate and graduate scholarships in the atmospheric sciences. Most deadlines are February 8.

DC: Definitely Crispy

Now

Clear, cool. After crisp morning lows as cool as the mid 40s in some places (50° at National and only 1° off the BWI record at 45°), temperatures have rebounded to the low 70s in most places under clear September skies. While dewpoints are not as arid as yesterday's upper 30s, they are still in the mid 40s.

Meanwhile, the continuing dryness has prompted Stafford County to impose water restrictions beginning today; the county has 139 days of water supply left in its 2 reservoirs, so crispy lawns may need to stay that way. A warming trend through the week should bring a return to readings near seasonable averages, but little or no rain is in sight.

Tonight and Tomorrow

Clear and cool. Clear skies and light winds will lead to lows tonight in the mid 50s downtown to the mid and upper 40s in many of the 'burbs. Tomorrow will again be sunny; highs will be a little warmer, 73-76°.

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

Tropical Topics

What had been Tropical Storm Ingrid was disintegrating as a depression last night, and advisories were discontinued at 5am.

A new tropical wave is located about 1000 miles east of the Lesser Antilles, but any development is expected to be slow. (That didn't stop it from being blamed for an increase in natural gas prices in commodity trading this morning, however.)

Climate Corner

Today's WaPo science 3/4 page (A7 for the dead-tree fans) is devoted entirely to the issue of the effect of climate change on species habitat ("Climate Change Brings Risk of More Extinctions"). Unfortunately, like many mainstream media reports, it confuses the issue by conflating the effects of bad wetlands conservation policies with the direct effects of sea level rise in the Chesapeake Bay.