"What is so Rare as a Day in June?"

Following this afternoon's instability and last night's thunder-stolen sleep, a picture-perfect June day is shaping up for the Washington DC metro area tomorrow. At post time, however, another storm cell moving southeastward from the upper Potomac Valley appears to be taking a path downstream to the District and vicinity similar to the one earlier this afternoon. Expect northwestern MoCo to be affected in the next hour or so.

Outlook: Tonight and Tomorrow

Some stray showers or thunderstorms are still possible through tonight as a cold front pushes southeastward from the Ohio Valley. Lows will be near 60 in the city to mid 50s in the cooler 'burbs. Tomorrow will be reminiscent of summer in New England with a few scattered clouds, northwesterly breezes, low humidity, and highs in the mid 70s.

For the rest of the weekend, check out Camden's post below.

Tropical Topics

Rev up the reconnaissance planes. The prospect that a low pressure area in the northwestern Caribbean could become the season's first Atlantic tropical depression in the next couple of days was enough to raise energy prices in this morning's commodity market trading.

Climate Corner

The final figures from last weekend showed that the climate change documentary "An Inconvenient Truth" was #9 at the box office nationwide, despite playing in only 77 theaters. It opens in more theaters this weekend.

Parts 2 and 3 of the PBS NewsHour's examination of the economic aspects of global warming Wednesday and Thursday night provided plenty of evidence that the inactivists are not only scientifically and morally bankrupt, but their economics are unsound as well.

Some Scarce Scattered Showers Seen

Tonight and Tomorrow

Skies will be mostly cloudy through this evening with a 30% chance of a shower or thunderstorm; a few storms could be locally intense. Lows will be in the low to mid 60s. Tomorrow will be partly to mostly sunny with highs near 81.

For the outlook through the weekend and into next week, scroll down to Josh's post below.

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As we've noted recently, real rain has been scarce around the Washington DC metro area lately, except for a few localized spots. Dulles did manage to pick up 0.15" overnight, but National eked out only 0.01".

A locally intense cell passing southeastward through Fairfax County last evening did produce some brief downpours and hail. CapitalWeather.com photographer Kevin Ambrose was able to capture this photo near the edge of that cell in Oakton. Here is his description:

Today I saw a weather occurrence that I never remember having seen before. We had a brief hail storm with lightning and gusty winds that occurred with full, unobscured sun light. As a result, there was a bright ground rainbow that followed me just in front of my car as I drove along the road. I pulled off the road and photographed the sight as a pedestrian took cover from the hailstones and rain.

Tropical Topics

The National Hurricane Center notes that upper-level conditions are unfavorable for the further development of a weak low pressure area in the northwestern Caribbean, but heavy rains are likely from the Yucatan through western Cuba in the next couple of days.

06/06/06: Devilishly Fine Weather

An unusually deep upper-level trough for this time of year is continuing to bring some clouds and relatively cool temperatures to the Mid Atlantic area. By mid afternoon, however, abundant sunshine had pushed temperatures well into the upper 70s in the Washington DC metro area; many locations were within spitting distance of the seasonal average at 79° by 3pm.

A very weak low pressure area off Cape Hatteras is producing clouds and some rain along the coast. On the Eastern Shore, Georgetown DE, Ocean City MD, and Wallops Island VA were all reporting light rain, and temperatures ranged as low as 64° at Ocean City. A stray shower or two is possible in the local area through tomorrow, but the bulk of the rain with this system is aimed at southern and eastern New England, where they don't need any more precipitation right now.

Chart above: Surface pressure (solid lines) and 500 mb height (color shading) map this morning from Unisys

Tonight and Tomorrow

Tonight will see variably cloudy skies with lows in the low 60s. There is a slight chance of a sprinkle through this evening. Tomorrow will be partly cloudy and a little more humid with a 40% chance of showers in the afternoon, but rain is more likely from about the Chesapeake Bay eastward. Highs will be in the mid to upper 70s, depending on how close the showers get to the east.

The forecast for the rest of the week and weekend continues here.

Call Me Anything But Late for Dinner

The USA Today Weather Guys have a link to a posting in The Morning News about weatherman names. Congratulations to Channel 9's Topper Shutt for making number 3 on the list.

Climate Corner

Speaking of our VA neighbors at USA Today, the USA's largest daily newspaper has acquired a reputation as "McPaper" for its somewhat breezy approach to the news. I was very favorably impressed, however, with a CSPAN Washington Journal segment yesterday which featured last week's climate change coverage in USA Today. The paper's science writer, Dan Vergano, seemed to be well informed on the subject and did a good job of fending off the typical CSPAN "I'm pestering Sen. Lieberman's office 24/7 with my crackpot ideas" callers. Vergano received the American Geophysical Union David Perlman Award for Excellence in Science Journalism this year for his article in 2005 "The debate's over: Globe is warming".

Also on the subject of media coverage on climate change, the PBS NewsHour last night had a very interesting angle on the subject. While paid lobbyists for the oil industry (such as in the recent "article" in the Baltimore Sun) have been whining about the potential effects of climate policy on the free market, companies in several industries have been actually using the free market to promote both environmental improvement and their own bottom line. We're not talking about long-haired hippie bicycle shops here. Some of the largest insurance companies on the planet, for example, have gotten the message that a rational approach to a potential problem can help them two ways: by reducing catastrophic losses and also by selling more insurance. If the science is correct, some smart people are going to make a ton of money.

DC: Droughtiness Concerns

As Jason keenly observes below, the chances of rain in the next several days may be somewhat overrated. The kind of instability we have this week (cold air aloft) is much less likely to produce real rain than the kind we had late last week (warm air at the surface). On the other hand, between some occasionally menacing-looking clouds and a sprinkle or two, the northwesterly flow aloft is bringing us pleasantly cool temperatures and comfortable humidity for early summer.

The experimental National Weather Service map to the right shows that the precipitation Friday night was once again quite skimpy in the immediate area. In fact, large portions of Prince Georges and Anne Arundel counties and Northern Virginia received nothing. The heaviest amounts were northeast of Baltimore toward the Philadelphia area. Although we are not officially in the drought category yet, this spring and early summer are reminding me of the droughty conditions in the mid and late 60s.

Now

At mid afternoon, temperatures in the Washington DC metro area were consistently in the low 70s, several degrees cooler than yesterday at the same time, and dewpoints were in the low or mid 50s. I saw a few isolated drops on the windshield while navigating downtown Bethesda's mid day gridlock, but it was hardly cause for an umbrella.

Tonight and Tomorrow

Lows tonight under variably cloudy skies will be near 60 in the city to the mid 50s in the cooler 'burbs. There is a slight chance of widely scattered light showers through this evening. Tomorrow should be similar to today, but with a little higher chance (30%) of showers in the afternoon. Rain is more likely well toward the east of the DC region as a weak low pressure area tries to develop off the coast. Highs will be in the mid 70s.

For a rundown of how this plays out through the rest of the week, see Jason's post below.

Tropical Topics: It Coulda, Shoulda, Woulda Happen Tomorrow

The Weather Channel's It Already Happened "Katrina, the Lost Episode" was broadcast last night at 9 and will be shown again this Friday. Based on the pilot for the "It Could Happen Tomorrow" series, it was a retrospective look at the warnings for a New Orleans disaster in light of what actually occurred. Without putting a stopwatch to the TiVo replay, I would estimate that 10% or less of the show was from the original material. This is pure speculation, of course, but I suspect that most of the old show was cut because it was even too far over the top for the Katrina reality.

The WaPo reprints an AP profile of the TWC Hurricane Guy with the great name of Dr. Steve Lyons today. It's in your dead-tree Style section about 6 pages back from an oh-so-cute article about how a 69-year-old grandmother is having "Tons of Fun" with her 3½ ton urban assault vehicle on area roadways.

Breaking the Dry Spell?

The two essential ingredients for showers and thunderstorms are moisture and vertical motion. With dewpoints at the ground from 68° to 72°, there is plenty of moisture around. The vertical motion for yesterday's storms was provided mainly by heating: a threepeat in the form of a third consecutive day of 90°+ temperatures.

Today is a somewhat different story, since a persistent high overcast has limited temperatures, at least by mid afternoon, to the low 80s. (This overcast, which has nevertheless allowed a fair amount of strong June sun to penetrate, led to forecasts for today ranging from 76 on a certain cable channel to 80 from the local NWS. For a check on how PM Update did, scroll on down to here).

Vertical motion is being helped today by a nearly stationary front draped across Pennsylvania. Therefore, more widespread storm activity is possible late this afternoon and through tonight. The NWS has issued a flash flood watch for Washington DC and the immediate area. By mid afternoon, radar was showing storms widely scattered from near Hagerstown to southwest of Richmond. These were generally moving northeast.

Tonight and Tomorrow

Showers and thunderstorms are likely late this afternoon through tonight. Some locally heavy downpours could produce flash flooding. Lows will be in the mid to upper 60s. Some showers may linger through early afternoon tomorrow, especially in the eastern portion of the region, with gradual clearing later in the day and highs in the mid 70s.

Yesterday's Rain

The map from the NWS of total precipitation centered roughly on DC shows that yesterday's rainfall was quite disappointing in much of the metro area. Except for a very small portion of far western MoCo where amounts were as high as possibly 2.5", most of the area saw 0.1" or less, and large portions of the District and adjacent Virginia were completely dry. Official DC reports were a trace at National and a whopping 0.02" at Dulles. BWI, which benefited from stronger storms in the Baltimore area, had 0.24". Amounts were also higher over the Bay and large portions of the Maryland Eastern Shore.

Climate Corner

The climate change documentary, "An Inconvenient Truth", which opens today in several area theaters, is reviewed in today's WaPo Style.

Muggy; Thunderstorms Possible

A ridge of high pressure is weakening over the Mid Atlantic area, but the setting is still at "steamy" on the muggo-meter in the Washington metro area. Dulles had reached 90° by 2pm, but National was still no higher than 89° at 4pm. Dewpoints around the region were mostly in the upper 60s, with some at 70° or above.

In a pattern similar to yesterday's, showers and thunderstorms, some of them heavy, have broken out in the mountains to the west. In spite of very weak steering currents aloft, these do have some eastward motion. At post time, they had begun crossing I-81 in Virginia. The heaviest storms were mainly west of Winchester.

Some of these storms may make it as far as at least the western suburbs by this evening. Isolated storms could also break out at any time. At 4:16, the National Weather Service issued a Special Marine Warning for a small, but strong, thunderstorm moving slowly eastward over Baltimore harbor.

Tonight and Tomorrow

Tonight will be warm and humid with a 40% chance of thunderstorms through this evening, especially to the west of the District. Some storms may be severe, and locally heavy downpours are possible. Lows will be from the upper 60s to low 70s. Tomorrow will be mostly cloudy with showers or thunderstorms likely and highs in the low 80s.

DC AC

Move directly to summer. Do not pass "Go." Do not collect $200. It's air-conditioning season in the Nation's Capital region today as temperatures have soared into the 90s by early afternoon. Unlike the beautifully dry conditions over the holiday weekend, humidity is also high.

Several locations in the region with dewpoints in the 70s were reporting heat indices over 100 as early as 2pm. By 4pm, Dulles had reached 95° and National and BWI had hit 94°. The robo-observer at Frederick checked in with 97°. The highly non-standard exposure here at Afternoon Blog Central in Montgomery County briefly touched triple digits.

Temperature chart at 4pm today from Unisys

A more easterly flow should knock temperatures back into the upper 80s tomorrow, but humidity will remain sticky. For tonight, keep the AC cranked high as you enjoy the waning hours of cheap electrons before the Pepco rates ratchet up 39% in Montgomery and Prince Georges Counties at midnight tomorrow night; BGE rates will go up 72%.

Tonight and Tomorrow

Tonight's lows should be near 70 in the city to the mid and upper 60s in the 'burbs. Tomorrow will be partly cloudy and continued humid, but with highs only in the upper 80s.

Political Science: Irony is Not Dead

Joel Achenbach's cover article "The Tempest" in Sunday's WaPo Mag is a lengthy (7500 word) exploration of the skeptic mindset in the realm of climate change. It focuses mainly on Colorado State hurricane researcher, general curmudgeon, and DC native William Gray. Achenbach, whose expertise seems to be more in the area of political science than physical science, gives a fascinating view of the power of faith. In spite of the mounting evidence, Gray is seemingly unable to see the cruel irony in vehemently rejecting climate models as a hoax because models can't predict the details of the weather next month, while at the same time his own reputation rests on the statistical modeling of the number and intensity of hurricanes in a season, even though his models can't predict the details of any individual storm.

A transcript of this morning's interactive discussion with the author is available online.