Ernestly Waiting for Rain

Now

Muggy. After missing by 1° on each of the weekend days, the official Washington temperature rose to 90° this afternoon for the 14th time this month, well over the 30-year average of 10.1 days of 90° or more in August. To the south, mid 90s were common in central and southern Virginia. Meanwhile, an area of showers and thunderstorms advancing toward D.C. and vicinity from the west threatens to end our dry spell as a mainly stationary front tries to work its way southward from the Mason-Dixon line.

Tonight and Tomorrow

More mugginess. There is a 30% chance of showers or thunderstorms through early evening and a 40% chance the rest of the night. Lows will be in the mid 70s in urban areas down to near 70° in the cooler 'burbs. Tomorrow will again be warm and humid with highs in the upper 80s to near 90° and a 40% chance of showers or thunderstorms.

Scroll down to Jason's post below for the outlook through the weekend.

Tropical Topics

The disruption to Tropical Storm Ernesto's circulation by the mountains of Haiti and then Cuba plus the inability to fly reconnaissance over Cuba have made it hard to pin down the storm's track, but it is now emerging back over warm waters north of eastern Cuba. The current forecast track brings it northward as a tropical storm along the southeastern coast of Florida Wednesday morning. The following track is quite uncertain. The 2pm forecast which had the storm moving back out to sea after brushing the Outer Banks has been replaced at 5pm with a more westerly path which brings the remnants of the storm as a depression up through central Virginia and a little to the west of the DC metro area late Friday. This could help bring some much-needed rain to the area. Stay tuned in the next several days as the situation becomes clearer.

Broadcast News

Spike Lee's documentary on Katrina, "When the Levees Broke" is being rebroadcast tomorrow night, the anniversary of Katrina, at 8pm.

Awfully Arid August

Now

Hot but dry. A bright August sun pushed the temperature to 91° by 3pm this afternoon. The humidity is only slightly higher than yesterday with dewpoints hovering near 60°. A strong thunderstorm developed along the coast near Ocean City, but otherwise regional radar is dry.

Tonight and Tomorrow

Mostly dry. A stationary front hanging around the Mason-Dixon line could help spark a few scattered thunderstorms this evening; otherwise, lows will be near 70 in the city to the mid 60s in the 'burbs under partly cloudy skies. Tomorrow will be sunny with highs near 90° and moderate humidity.

Scroll down to Josh's post below for the outlook through the weekend and Larson's Long-Range.

Tropical Topics

Debby continues to be an underachiever with maximum winds of 50 mph through today and little change expected in the near future. The forecast track keeps it away from land.

The tropical wave near the Windward Islands has developed a closed circulation according to this afternoon's reconnaissance report. It became TD 5 in the 5pm advisory with maximum winds of 35 mph and expectations of becoming a tropical storm in the next 24 hours.

Squandered Surplus

The large precipitation surplus which developed early this summer is being steadily eroded by the recent lack of rainfall. Although July as a whole was near average, most of that fell early in the month, and the accumulated deficit since July 1 is now over 1.5". No measurable rain has fallen at National Airport since the 0.17" on Aug. 10. At this rate, we are on track for a top-10 driest August.

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

A Quiznos Kind of Day

Now

Mm, mm, toasty! The official Washington temperature reached 90° at 2pm, but a mainly northerly breeze and dewpoints in the mid 50s have helped to keep it quite comfortable for August. The radar is totally dry in all directions for hundreds of miles, despite a weak front hovering near the Mason-Dixon line.

Tonight and Tomorrow

Warm, becoming more humid. Tonight should be fairly pleasant, but humidity is likely to creep upward by morning. Lows should be more of "the usual": near 70 city, mid 60s 'burbs. Tomorrow will be mostly sunny and a little more humid with a slight chance of PM showers or thunderstorms and highs in the upper 80s.

Scroll down to Dan's post below for the outlook through the weekend.

Tropical Topics

Debby gained a little strength in the eastern Atlantic with maximum winds of 50 mph this morning, but it is back down to 45 mph on the latest advisory. The expected track still keeps it well east of Bermuda.

An area of more potential threat is a tropical wave a couple of hundred miles east of the Windward Islands. It could develop into a tropical depression within 48 hours. A reconnaissance flight is tentatively scheduled for tomorrow to investigate.

Broadcast News

ABC News has announced that Sam Champion has been promoted from New York's WABC to be the weather anchor for "Good Morning America", beginning on Sept. 5. He will also be weather editor for ABC News and "will contribute feature reports on the environment and weather-related issues."

Photo from ABC News

August Anniversary Approaches

Now

Warm, a bit more humid. Temperatures in the upper 80s this afternoon are similar to those of yesterday here in the Washington metro area, but dewpoints have crept up from the upper 50s to the low and even mid 60s. Depending on your personal tolerance of humidity, you may need AC tonight even if you had it off last night. Regional radar is very dry, except for some scattered storms southwest of Richmond.

Tonight and Tomorrow

Similar to today. Lows tonight will be near 70 in the warmer urban areas to the mid 60s in the cooler 'burbs. Tomorrow will be a lot like today, but with slightly higher humidity, highs in the upper 80s.

Scroll down to Jason's post below for the outlook through the weekend.

Tropical Topics

Tropical Depression 4 was moving west-northwestward today at longitude 27.5W, away from the Cape Verde Islands. Its maximum sustained winds of 35 mph late this afternoon were only a little below tropical storm strength, which it is expected to reach "very soon." If it does become named, it will be called Debby.

The Weather Channel presented some statistics last night on storms which become named east of longitude 35W. Of those 34 storms in the last 20 years, only 4 reached landfall in the U.S., but several (perhaps all; I'm quoting from memory here) were major, including 2004's Ivan.

Broadcast News

The second part (acts III and IV) of Spike Lee's documentary on Katrina, "When the Levees Broke" is on HBO at 9 tonight. If you missed the first half last night, the entire 4 hours will be rebroadcast next Tuesday, the anniversary of Katrina, at 8pm. The program was previewed in yesterday's WaPo.

The Discovery Channel is presenting "Surviving Katrina" on Sunday at 9pm.

This is also Katrina Week on The Weather Channel, with various Storm Stories and other documentary features.

Photo of director Spike Lee from AP, via washingtonpost.com

AAA-Rated: Awesome August Afternoon

Now

Warm, but not humid. It's a few degrees on the high side of the Official CapitalWeather.com Nice Day Stamp, but any long-time Washington resident will confirm that today's weather is nearly the finest that August can offer. (For a reminder of how nasty the month can be, take a glance several hundred pixels to the right for "Today in Weather History.") As early as 1pm, the official temperature at National was pushing into the upper 80s after a morning low of 70°, but even by late this afternoon temperatures are mainly in the upper 80s throughout the region. Dewpoints are generally in the very comfortable low 50s.

Tonight and Tomorrow

Warm, gradually increasing humidity. Lows tonight will be in the upper 60s in town, as low as 60° in the coolest 'burbs, with comfortable humidity. Tomorrow will be sunny with highs in the upper 80s and gradually increasing humidity.

Scroll down to Dan's post below for the outlook through the weekend.

Tropical Topics

Two low pressure areas in the southwestern Atlantic have merged and moved northward toward the Carolinas. Some isolated strong thunderstorms were reported with this system early this afternoon. Upper-level winds are expected to become unfavorable by tomorrow, but some development is still possible. A reconnaissance flight was investigating the area this afternoon.

Broadcast News

Steve Villanueva, earlier reported to be the new Channel 4 meteorologist, is listed as a member of both the American Meteorological Society (AMS) and National Weather Association (NWA) in his WWOR official bio. He is evidently the recipient of an NWA Weathercaster Seal of Approval issued in November 2000. (Clay Anderson is not.) Steve (great name for a meteorologist!) is also reported to be an experienced Cannoli Eating Contest host.

Dry Run Continues

Now

Gradual clearing: Despite juicy dewpoints, a weak front passing through the Washington metro area at an unfavorable time (around noon) with little upper-air support wasn't enough to generate any serious precipitation. Dulles briefly reported light rain but only a trace of accumulation. Regional radar shows thunderstorms limited to a band from just south of Charlottesville to the Northern Neck of Virginia.

Tonight and Tomorrow

Warm, less humid: The main effect of the frontal passage will be a clearing trend into this evening and lower humidities. Lows tonight will range from the low 70s in the city to the mid 60s in the cooler 'burbs. Tomorrow will be sunny and less humid with highs in the upper 80s.

Scroll down to Jason's post below for the outlook through the weekend.

Dry August

Despite the near-normal conditions in July, rainfall in the first half of August has been quite low in the area. The experimental precipitation analysis from NWS shows that very few places inside or near the Beltway have received even as much as 0.5" (green-shaded areas) in the last 2 weeks. Much of northern MoCo has less than 0.1" (light blue), and there is a small strip near the Howard County line with no rain at all.

Tropical Topics

The two areas of recent interest remain in the tropical Atlantic. The low pressure area just north of the Bahamas has appeared better developed, but the reconnaissance flight has been put off until tomorrow. The low pressure area off the coast of Africa which was looking strong yesterday has weakened, and development is no longer expected.

Want Stickiness With Those Fries?

Now

Seasonably warm and humid: If the weekend weather had you thinking that August itself had gone on vacation along with most of the rest of Washington, this afternoon should bring you back to what passes for reality in Spin City. Upper 80s are prevalent in the immediate Beltway vicinity, and the Usual Suspects toward the south, such as Stafford, Culpeper, and Fredericksburg, are all at or above 90°. Those pesky dewpoints are into the sticky upper 60s to 70°. Regional radar is dry except for some extremely isolated showers along the Blue Ridge.

Tonight and Tomorrow

AC weather: The MOS (Model Output Statistics) are predicting MOS (More of Same) through tomorrow, except for a better chance of PM thunderstorms, as a not-so-cold front approaches from the west. Lows tonight: low to mid 70s, highs tomorrow: upper 80s. Chance of afternoon or evening thunderstorms: 50%.

Scroll down to Jason's post below for the outlook through next weekend.

Tropical Topics

There are two areas of interest in the tropical Atlantic. A low pressure area just north of the Bahamas shows some signs of developing a circulation, and a reconnaissance flight is tentatively scheduled for tomorrow to investigate. A strong low pressure area off the coast of Africa has already had wind gusts of up to 50 mph in squalls today. A tropical depression could develop out of this as it approaches the Cape Verde Islands tomorrow.

Climate Corner: Greenland Ice vs. Antarctic Snow

While PM Update was on break, Friday's WaPo had an article, "Greenland's Melting Ice Sheet May Speed Rise in Sea Level" about two issues related to the question of sea-level change. On the subject of Greenland's ice sheet, a new study has found that the recent rate of melting, although based on a short period of observation, is 3 times higher than the rate of the previous 5 years. The other subject is much more significant to sea-level change, since global warming critics frequently claim that everything balances out because more snow in Antarctica compensates for Greenland melting. In fact, a study published in the latest AAAS Science magazine finds that

There has been no statistically significant change in snowfall since the 1950s, indicating that Antarctic precipitation is not mitigating global sea level rise as expected, despite recent winter warming of the overlying atmosphere.

An animation of Antarctic snowfall trends is available online.