Tropical Development Possible, but DC Impact Likely Minimal

Now

Hot, humid. As temperatures climbed to the 90s in most parts of the metro area this afternoon, dewpoints were in the muggy low 70s at many locations. Dulles reached 92° by 3pm, and the humidity was producing a heat index as high as 96° the following hour. Although prolonged hot spells are relatively rare in September, at some point in the past National has observed temperatures in the 90s on every day of the month, and the all-time monthly high of 104° occurred on this date in 1881.

On this 12th consecutive rainless day, however, precipitation prospects from a possible developing tropical system are diminishing.

The area of storms lurking off the southeastern Atlantic coast has become more concentrated today, and a Hurricane Hunter flight investigated the situation this afternoon. As of 5pm, it had not found a closed circulation at the surface, but it was continuing to collect data. If a depression or tropical storm does develop, the most likely scenarios at this point are for it to move northwestward, weaken and dissipate over eastern North Carolina or for it to be swept out to sea ahead of a cold front moving eastward on Sunday.

Mediaorology

The scheduled topic for this weekend's Forecast Earth on The Weather Channel (5pm Saturday and Sunday) is "Paying For Climate Change", but the broadcast may be pre-empted for tropical coverage.

Sliding Toward September

In this post: Tonight and Tomorrow | Tropical Topics | Upcoming Meeting

Now

Sunny, moderately muggy. Following the warm streak for the first half of the month and the coolness last week, temperatures are sliding toward September very near seasonable averages for the highs and a little above average for the lows; overall the month is 2.2° above normal. By 5pm, readings were in the low and mid 80s throughout the region. Humidity is moderate, with dewpoints in the mid 60s.

Ahead of a cold front through central Pennsylvania and West Virginia, scattered showers and thunderstorms have broken out, mostly through northern West Virginia. Some storms could still develop east of the mountains through this evening, but the probability is only about 20%.

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

Tonight and Tomorrow

Partly cloudy, warm, seasonably humid, slight chance of showers. There is a 20% chance of showers or thunderstorms through this evening. Lows will be in the upper 60s to near 70°. Tomorrow will be sunny and warm with highs 84-87° and a slight chance of showers or thunderstorms in the afternoon.

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

Tropical Topics

The tropics remain relatively quiet, although the tropical wave now about 600 miles east of the Windward Islands still has the potential to become tropically depressed in the next couple of days.

A second wave about 250 miles west of the Cape Verde Islands has "minimal" shower activity, and any development is expected to be slow.

Upcoming Meeting

Now that Jason is retired as president of the local chapter of the American Meteorological Society (thanks for your outstanding service, Jason), there is not even the appearance of a conflict of interest in CapitalWeather.com promoting meetings of the DC-AMS. The first meeting of the new season on September 26 features Chris Mooney, author of "Storm World". The meeting is free and open to the public, but RSVP is required. Details will be posted soon on the DC-AMS website.

Not Bad for August

Now

Partly sunny, moderately muggy. Morning clouds and a slight easterly component to a mostly southerly wind have kept temperatures a degree or 2 cooler this afternoon in the metro area. Readings at mid afternoon were mainly in the low and mid 80s; while Dulles reached 85°, National has been hanging in at 83°. Culpeper was the warm spot in the region at 88°, while some 90s were observed in southern Virginia. Easterly winds kept Ocean City at 75°.

Humidity is seasonable, with dewpoints very near the long-term August average of 66°. The nearest precipitation on radar is in the form of very widely scattered showers in the mountains of far southwestern Virginia.

Tonight and Tomorrow

Partly cloudy, warm, seasonably humid. Lows tonight will be very similar to last night under hazy, variably cloudy skies: low 70s to near 70° in the urbosphere and some upper 60s in the sub-urbosphere. Depending on how early the clouds burn off tomorrow, high temperatures should be a couple of degrees warmer tomorrow, 85-90°.

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

Tropical Topics

The National Hurricane Center is tracking Depression 10-E in the Eastern Pacific, but the Atlantic is still relatively quiet. The disorganized area of storms off the Carolina coast still has the possibility for development as it drifts southward in the next couple of days. An Air Force flight is tentatively scheduled for tomorrow to investigate. The wave now about 900 miles east of the Windward Islands also remains disorganized, but conditions are expected to gradually become more favorable for development.

The Orlando Sentinel opines today about the selection of a new permanent Director of the National Hurricane Center: "Some of the whistles Mr. Proenza blew no doubt made it too uncomfortable for many to work for, near or above him. A department manager needs better people skills than that. But a department head also mustn't resist sounding alarms . . . "

Mediarology

South Florida's WFOR-TV has a video report on the NHC management situation.

The Weather Channel continues its coverage today of the second anniversary of Hurricane Katrina with live reports from Mike Bettes in New Orleans and Julie Martin in Mississippi.

DC: Decreasing Comfort

Now

Partly sunny, warm, more humid. Temperatures mostly in the mid 80s are a few degrees cooler this afternoon in the Washington metro area, but increased dewpoints have more than made up the difference with lower comfort levels. If you had your air conditioning off last night, you may want to reverse that decision tonight. Like yesterday, however, radar is completely clear except for a few tiny showers in the mountains.

Tonight and Tomorrow

Partly cloudy, moderately muggy. Lows tonight under partly to mostly cloudy skies will be near 70° downtown to the mid and upper 60s in the 'burbs. Tomorrow will be mostly sunny, a little warmer, and somewhat humid with highs 87-90°.

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

Tropical Topics

The tropical wave (more formally, an "easterly wave") noted yesterday in the eastern Atlantic is now about halfway between the Lesser Antilles and Africa. The Tropical Weather Outlook indicates that "environmental conditions are favorable for some development" as it continues moving westward.

The Miami Herald reports today that NOAA has partially reorganized the management of the National Hurricane Center following the recent ouster of Director Bill Proenza:

• Interim Director Ed Rappaport will remain in that position through the end of the hurricane season
• Bill Read, MIC (meteorologist-in-charge) of the NWS Houston-Galveston office will be interim Deputy Director
• Richard Knabb, a lead hurricane forecaster, will be team leader for all 10 hurricane forecasters

The Florida Sun-Sentinel reports that a formal nationwide search will be conducted for a permanent Director, and the Houston Chron reviews the changes from a Texas point of view.

Approaching August Averages

Now

Sunny, warm, less humid. Behind a weak cold front which has now moved off the Mid Atlantic coast, conditions are much more pleasant today than the weekend's sauna, which saw dewpoints at times above 75°. Temperatures this afternoon in the upper 80s (87° at 5pm at both National and Dulles) are near or a little above seasonable averages, and dewpoints are generally in the low 60s. Radar is clear in all directions for several hundred miles.

Tonight and Tomorrow

Partly cloudy, warm. Lows tonight under partly cloudy skies will range from the upper 60s downtown to the low 60s in the cooler 'burbs. A more easterly wind direction tomorrow creates some problems with the temperature forecast, but as of now the models are virtually unanimous in keeping skies mainly sunny, so highs should range from 83-88° with only a little more humidity. (Yes, I do hesitate to depart from Jason's always excellent forecast, but I also have some good company on this.)

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

Tropical Topics

The National Hurricane Center is watching a tropical wave in the eastern Atlantic, about 800 miles west of the Cape Verde Islands. It could possibly develop slowly during the next couple of days.

Mediarology

The PBS science series NOVA commemorates the second anniversary of Hurricane Katrina by rebroadcasting its excellent program, "Storm That Drowned a City". Check your local listings, but it's scheduled for 8pm tomorrow on WETA 26 and WMPT 22. The chart to the right, from pbs.org, shows the extent of the Katrina flooding by superimposing the blue-outlined area, from White Oak nearly to Tyson's Corner and southeast to Oxon Hill, on a map of the DC metro region.

As Jason noted yesterday, weather got almost as much attention as the play action at Saturday night's Redskins-Ravens game. Congratulations to WUSA-9's Howard Bernstein on his excellent coverage of the event. Tune in here at CapitalWeather.com on game days for the SkinsCast.

Saving Private August

Now

Cloudy, a little warmer, humid. Despite the "Partly sunny, High 85" on the front page of your dead-tree WaPo this morning, it's another cloudy and cool, but sticky, afternoon in the Washington metro area. (Wonder how that happened; those lazy drones at the National Weather Service and their freedom-hating lackeys at CapitalWeather.com said "upper 70s". Oh yeah, here it is in small print on the back page of the Metro section: "SOURCES: AccuWeather, Inc. . . ." I would have sworn I read somewhere (scroll down) that socialized meteorology was Bad for America.)

Although the wind still has an easterly component, it's been more out of the south than recently, and some thinning of the low overcast has allowed temperatures to reach the mid and upper 70s by mid afternoon. At 3:00, you'd have had to go as far south as Richmond to see a temperature of 80°. Dewpoints are even more muggy than yesterday, in the sticky upper 60s to 70°. If you opened your windows, you're probably going to need air conditioning to get the humidity down. Radar is showing an impressive area of storms and an associated warning box northeast of Pittsburgh, but it's dry east of the mountains.

As we've been promising and Jason explains in his post below, more August-like temperatures are on the way and should be here for the weekend.

Tonight and Tomorrow

Decreasing clouds, humid, warmer. Without much of an incentive (maybe they should be privatized) to leave town just yet, the clouds will persist tonight, and the high dewpoints should contribute to mist and fog in some places with lows in the upper 60s to near 70°. Although the clouds will last into the morning, indications are good that some sun in the afternoon tomorrow will allow temperatures to finally get back to the mid and upper 80s, perhaps even 90° for a high.

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

Tropical Topics

Dean was declared dead, and the last advisory was issued at 11pm last night. No new development is expected in the Atlantic for the next couple of days.

Political Science

Bob King, who covers hurricanes for the Palm Beach Post in his Eye on the Storm blog, does an excellent job of deconstructing the Faux News war on the National Hurricane Center in his post yesterday. He includes a link to some unofficial, but absolutely devastating, data on the issue of AccuWeather vs. Hurricane Center accuracy on Katrina (and Rita, as well). In 5 cases (6 for the feds), the AccuWeather 5-day position error for Katrina was more than double that of the Hurricane Center.

The Dog Nose Days of August

Now

Cloudy, very cool, humid. Like a dog's nose, the metro area's weather remains cool and damp. The record low maximum of 69° for today was threatened with breakage only through early afternoon, but the more optimistic temperature predictions by most forecasters were clearly busted. Some sun penetrated the continuing low clouds, but even by mid afternoon temperatures were struggling to pass 70° at most locations in the region. Despite the high humidity, however, radar has been clear in all directions.

A gradual decrease in cloudiness should lead to a warming trend, but there is wide disagreement among models on the pace of that warming.

Tonight and Tomorrow

Decreasing clouds, humid, gradual warming. Skies will be mostly cloudy overnight with lows in the mid to upper 60s. Clouds will decrease gradually tomorrow, and the actual amount of sun will strongly determine the degree of warming; model predictions range all the way from 77° to 89°, about as wide a range as you're likely to see around here. Humidity will remain high, but there is only a 20% chance of showers throughout the period.

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

Tropical Topics

Hurricane Dean made a second landfall on the Mexican Gulf coast about 40 miles south of Tuxpan around 12:50 Eastern time today. The storm had strengthened back to a Category 2 (max winds 100 mph). It was already weakening over land this afternoon; by the 5pm advisory it was down to tropical storm strength. It is expected to quickly dissipate as a heavy rain storm over the mountains of central Mexico.

Elsewhere in the tropics, no development is expected in the Atlantic Basin for the next 48 hours.

The Phillyweather blog had some interesting comments yesterday about media coverage of the hurricane. Also in the blogosphere, The Weather Channel has some typically insightful comments by Dr. Greg Forbes on the persistence of Erin's remnants and by Stu Ostro on Dean's minimum pressure.

Local Event

Next Monday, the 27th, the Center for American Progress is presenting a panel discussion, "Forecast: Storm Warnings". This forum "will discuss the impact of global warming on hurricane severity and frequency. In addition, there will be a discussion of necessary federal, state, and local policies that would increase the resilience of hurricane prone communities. The forum will feature, Mayor Richard Crotty (R) of Orange County, Florida, hurricane scientist Dr. Peter J. Webster, John B. Copenhaver of DRI International, and Jane Bullock, former chief of staff of Federal Emergency Management Agency director James Lee Witt."

The event is free and open to the public, but RSVP is required.