Thursday, September 27, 2007

Washington Wonders: Will We or Won't We?
Showers possible, then continued dry


Sunny, warm, humid. With only 3 days so far this month with measurable rain (average for September is 7.2) and none in the past 12 days, the Washington metro area is wondering if we'll get anything significant out of a frontal system that's barely moving out of the Ohio Valley. (In the 18 hours ending early this afternoon, it moved only across the state of Ohio.) By mid afternoon, a line of thunderstorms had fired up across far western Maryland and eastern West Virginia, prompting a Severe Thunderstorm Warning for Allegany County until 4:45. East of the mountains, however, activity has been minimal at best in the dry tongue extending across the central Mid Atlantic region.

Temperatures this afternoon are running a couple of degrees less warm at regional observing stations with fewer 90s than in the last couple of days, but humidity is still noticeable with dewpoints mainly in the mid and upper 60s.

Infrared satellite image at 3:30 this afternoon from Unisys

Tonight and Tomorrow

Warm and humid, chance of showers. Warm and humid conditions will continue with a 30% chance of showers or thunderstorms through this evening and overnight lows from the upper 60s downtown to the mid 60s in the 'burbs. Tomorrow will be mostly cloudy in the morning and a little cooler, with decreasing clouds and lower humidity in the afternoon. Highs will be 78-83°.

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

Tropical Topics

Tropical Storm Karen is a little weaker today with maximum winds of 60 miles per hour as of 5pm, and further slow weakening is likely as it continues on a west-northwesterly track which should keep it from threatening land.

TD 13 was promoted to Tropical Storm Lorenzo early this afternoon in the southern Gulf of Mexico. Its maximum winds are now around 70 mph, and it is expected to hit the Mexican coast as a hurricane.

Capitol Climate

Today's WaPo has several items of interest in the climate policy area:
  • "Kaine, O'Malley Urge U.S. Action on Global Warming": Both local governors testified yesterday at a Senate Environment and Public Works Committee hearing on the effects of climate change on the Chesapeake Bay. The Dog Bites Man Award goes to this article for the statement, "One contrary note in the hearing came from Sen. James M. Inhofe (R-Okla.), who has said he thinks climate change is a hoax."
  • "The Climate Change Peril That Insurers See": An op-ed piece co-authored by state insurance officials from Montana and Florida discusses the economic implications of global warming on the insurance industry in widely differing venues.
  • "White House Taking Unearned Credit for Emissions Cuts": The administration is playing games with data and semantics on the subject of mandatory vs. voluntary emission controls.

Wednesday, September 26, 2007

Warm Washington Wednesday
Cooler weekend ahead


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. 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.

Tuesday, September 25, 2007

September's Still Sultry


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.

Monday, September 24, 2007

Equinoctal Equanimity
Summery conditions continue


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. 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.

Seasonal Outlook

Latest seasonal forecast: Click here.

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