Wednesday, August 16, 2006

AAA-Rated: Awesome August Afternoon


Warm, but not humid. It's a few degrees on the high side of the Official 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.

Tuesday, August 15, 2006

Dry Run Continues


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.

Monday, August 14, 2006

Want Stickiness With Those Fries?


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.

Seasonal Outlook

Latest seasonal forecast: Click here.

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