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.

Nice for August

Now

Comfortably warm: For the first time in about 2 weeks, Washington metro area afternoon temperatures are several degrees below average in the mid 80s after an official low of 68°. Although a few locations have crept past 60°, most dewpoints are in the very comfortable 50s. Regional radar is dry in all directions.

Tonight and Tomorrow

More humid, chance of showers: Humidity and clouds will be increasing overnight as the cold front which came through early yesterday tries to return from the southwest as a warm front. Lows will be in the low 70s in town, a few degrees cooler in the 'burbs. There is a chance of showers or thunderstorms tomorrow morning, especially to the south of the immediate area, but a better chance (40%) in the afternoon; highs will be in the low to mid 80s, depending on the amount of sunshine.

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

Tropical Topics

The National Hurricane Center is still watching a low pressure area which is now approaching the Lesser Antilles. A reconnaissance flight this afternoon found no closed circulation at the surface, but conditions look favorable for development of a tropical depression in the next day or so.

More Pleasant in Mount Pleasant

Now

Not as hot, less humid. Not just Mount Pleasant, but the entire Washington metro area is enjoying much more comfortable conditions this afternoon. Temperatures have run well up into the 80s and even to 90° in the southern fringes of the region, but dewpoints are 10° or more lower than 24 hours earlier after a cold front passed through around 5am. After a string of above-average temperatures extending back 2 weeks to July 26, the next several days will seem especially nice.

Tonight and Tomorrow

Dry and pleasant. Tonight will be mostly clear with comfortable humidity and low temperatures from the upper 60s in town to near 60 in the coolest 'burbs. (The last time the official low was below 70 was July 24.) Sunny skies and low humidity are on tap for tomorrow with highs in the mid 80s.
Scroll down to Jason's post below for the outlook through the rest of the week.

Precip Recap

The thunderstorms late yesterday afternoon and evening were quite skimpy in the immediate metro area. Most places inside the Beltway had less than 0.1" (light blue area); much of Montgomery County, for example, was bone dry. The 0.22" recorded at National was enough to keep the month of August so far just barely above average when combined with the amount which fell in the wee hours of yesterday morning. Following the very dry last 3 weeks of July, many lawns, at least in this part of MoCo, are looking quite brown.

24-hour precipitation through 8am today from NWS

Tropical Topics

The National Hurricane Center continues watching a low pressure area which is now about 800 miles east of the Windward Islands for possible development into a tropical depression.

NOAA today issued an updated hurricane outlook for the remainder of the season. The new outlook continues to predict an above-average (75% chance) hurricane season, but the numbers are slightly reduced from the earlier forecast: "12-15 named storms, with 7-9 becoming hurricanes, and 3-4 becoming major hurricanes."

The NOAA outlook follows by a few days the new Klotzbach-Gray prediction from Colorado State. This update also reduces estimates from earlier predictions with 15 named storms, 7 hurricanes, and 3 major storms.

Breaking the Spell of the Muggies

5:25 Update: The storm moving into Fairfax Co. has prompted a Special Marine Warning for the tidal Potomac.

Now

Muggy, chance of showers: Temperatures throughout the Washington DC region are in the low 90s and higher late this afternoon. The thunderstorms which awoke many residents early this morning have added to the mugginess; nearly all locations are reporting heat index values over 100. Relief is on the way, however, in the form of a cold front moving southeastward from the Great Lakes. Ahead of the front, radar is showing only a couple of extremely isolated thunderstorms from near Hagerstown to west of Charlottesville. One of them in southern Loudoun County is intensifying and moving slowly eastward into Fairfax County at post time.

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

Tonight and Tomorrow

Becoming cooler and less humid:There is still a 40% chance of thunderstorms through around midnight, but the timing of the frontal passage is looking unfavorable for any widespread activity. Lows should be mainly in the mid 70s. Tomorrow will be cooler and much less humid with highs about 88.

Scroll down to Jason's post below for the outlook through the rest of the week.

Tropical Topics

Tropical Storm Chris is now history, but the National Hurricane Center is watching a "well-defined" low pressure area about 1200 miles east of the southern Windward Islands for possible development into a tropical depression later today or tomorrow.

Today's WaPo has an article, "Research Team Seeking Clues to a Hurricane's Birth", about the NAMMA project, a joint study between NASA and NOAA's Hurricane Research Division, which is celebrating its 50th anniversary this year. The experiment is designed to help understand the process by which easterly waves, disturbances which move off the African continent, become tropical cyclones in the eastern Atlantic.

Wave Goodbye: Record Heat Peaking

5:45 Update: Other highs: Dulles 99° (tied record), BWI 100° (tied record), Baltimore downtown 102°.
Also setting new records were: Norfolk 102°, Richmond 102°, Salisbury 97°.

Now

Historically Hot: The analysts on CNBC often say, "It's just a number", referring to stock index values ending in multiple zeroes. Psychologically, however, it does have a certain ring to it: At 2:10 today, the official Washington temperature of 101° broke the record set in the historic heat wave of 1930. This morning's low of 81° was also the warmest low for the date, exceeding the 78° in 1995. Other stations joining in the centennial festivity this afternoon included: Ft. Belvoir, Fredericksburg, Leesburg, Winchester, Patuxent River, and BWI. Even at the beach, Ocean City clocked in at 99°. Click here to view the latest hourly heat index values from WUSA-TV9. The Excessive Heat Warning for the area continues until 9pm tonight.

Regional radar is again mainly dry, except for some scattered activity south of Charlottesville.

Tonight and Tomorrow

Not as hot: We have one more stifling night ahead as a cold front gradually approaches from the northwest. Lows will be in the low 80s in the warmest urban areas to the upper 70s in the 'burbs. Tomorrow's highs will be "just" in the low 90s with only a 30% chance of a thundershower.

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

Tropical Topics

Tropical Storm Chris exceeded expectations with 65 mph peak winds yesterday, but the latest advisory puts it down at minimum storm strength of 40 mph. The storm is now considered likely to become tropically depressed as it continues to track west-northwesterly through the northern Caribbean.