Frigid February Fifteenth

Now

Variable clouds, windy, cold. The sun angle is almost halfway between the winter solstice low and the spring equinox, but that natural cycle was heavily outweighed today in the Washington metro area by some frigid Arctic air reinforced on strong northwesterly breezes. Highs barely reached the upper 20s: National 27°, Dulles and BWI 24° Combined with the chilly overnight lows, the month's double-digit deficit from average was extended further.

Although the record low of 5° at National is not in jeopardy tomorrow morning, the record of 11° last reached in 1987 at Dulles is the second highest daily minimum for February there and could be seriously threatened. The weekend will not be quite as cold, but still chilly.

Tonight and Tomorrow

Clear, very cold. Clear skies, low humidity, and diminishing winds should allow temperatures to plunge tonight to the mid teens in the city and upper single digits to near 10° in the coldest 'burbvilles. Tomorrow will be sunny and not quite as cold, highs 27-30°.

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

CapitalWeather.com chart based on Eq. 2.9 in Stull, Meteorology for Scientists and Engineers, photo © Kevin Ambrose

Cold Comfort: Could Have Been Worse

Now

Variable clouds, windy, cold. We now return to our regular programming. The "Praying Mantis Storm of 2007" (see image to the right of complex low pressure system at 7am this morning) could have done much worse damage to the Washington metro area if its massive quantities of sleet had been freezing rain. Nevertheless, over 100,000 customers lost power, particularly in Prince George's and Anne Arundel Counties.

After early highs in the mid 30s (National 35°, Dulles 34°, BWI 36°), , temperatures have dropped again this afternoon toward freezing, continuing the string of every day so far this month reaching 32° or below. (The 30-year average for February is 18.5 days, so we're well on our way to meeting the quota.) The monthly average through yesterday of 26.9°, if it continued to the end of the month, would tie this February with 1885 as the 4th coldest in Washington history.

Cold temperatures for the next several days mean that the ice will be with us for a while, and there is at least the possibility of some light snow from a clipper system this weekend.

Tonight and Tomorrow

SchoolCast
Clearing, windy, cold. Lows tonight under clearing skies will be in the upper teens to near 20° in the city and low to mid teens in 'burbville. Wind chills could be as low as zero. Tomorrow will be mostly sunny, windy, and cold, highs in the upper 20s to about 30°.

For the outlook through the weekend and beyond with Larson's Long-Range plus the latest Snow Lover's Crystal Ball, if any, tune in tomorrow for Josh's post.

Pictured: A snow blower needs assistance from some old-fashioned technology in western Fairfax Co. yesterday. In conditions like this, PM Update Central prefers the trusty ice chopper obtained a quarter century ago at Houst Hardware. By CapitalWeather.com photographer Kevin Ambrose.

Capitol Climate: The "F" Word (No, Not That One!)

In our last installment of the Capitol Hill Climate Follies, 4 scientists were testifying on the Hill about the recent IPCC climate change report. Last Friday's edition of the Chronicle of Higher Education provides a review of the session, including the purported role of dinosaur, shall we say, "flatulence".

Double Digit Departure Developing

Now

Clear, windy, cold. Winter continues its icy grip on the Washington metro area. With every day so far this February below average and today becoming the 4th consecutive day having a double digit departure from average, the month as a whole is now pushing into negative double digits. The next winter storm event is likely to take shape in the first half of next week, but the timing, track, and intensity are still subject to adjustment in the coming days.

Tonight and Tomorrow

Clear, cold. Lows tonight under clear skies will be in the mid to upper teens in the city and low teens to near 10° in 'burbland. Tomorrow will be much like today, but with a little less wind and highs about 30-32°.

For the outlook through the weekend and beyond, including the Snow Lover's Crystal Ball which has the scoop on next week's potential winter storm, scroll on down to Josh's post below.

Capitol Climate

U.S. contributors to the recent IPCC climate change report, Drs. Susan Solomon (NOAA), Kevin Trenberth (NCAR), Richard Alley (Penn State), and Gerald Meehl (NCAR), were busy on Capitol Hill today, testifying this morning to the House Science and Technology Committee and this afternoon to Senate Environment and Public Works. Copies of the prepared testimony and webcasts are available through the respective committee web sites, and at least the House hearing was covered on CSPAN, so it should be available in reruns during the next several days.

The portion of the House hearing Q&A which I saw indicates that many politicians on both sides of the aisle are increasingly understanding the science and are willing to discuss it from a non-ideological point of view. From the context of the conversation, it appears that several committee members have scientific backgrounds, although the specifics were not clear. Obviously, there are significant differences regarding the policy implications, but most of the discussion, with the notable exception of the final rebuttal, was refreshingly free of the anti-scientific propaganda still echoing around various web noise sites and squawk radio, as well as, sadly, the editorial page of the Wall Street Journal, which is inexplicably attached to what is otherwise a world-class newspaper.

Snow? You Call This Snow?

Now

Clear, cold. Well, that was as exciting as the real thing: 1-2" of very fluffy powder (egged on by 463 exuberant comments from CapitalWeather.com visitors) from a fast-moving "clipper system" across the Washington metro region last night has been followed by sunny, breezy, and cold conditions this afternoon and a rapidly disappearing "snow pack". Highs have been generally in the upper 20s: 29° at National, 28° at Dulles, 27° at BWI, for another double-digit negative departure from average. Josh will undoubtedly have more to say on this later, but the cold temperatures are likely to continue well into next week, with some early indications of a more substantial (perhaps even "superstantial") winter event early in the week. (NWS, going out on a bit of a limb at the 6-day range, is calling for 50% chance on Tuesday in their latest update.)

Tonight and Tomorrow

Clear, cold. Winds will diminish tonight with clear skies and lows near 15° in the city and 10° in 'burbsylvania. Tomorrow will be sunny, windy, and cold, with highs near freezing.

For the outlook through the rest of the week and the Snow Lover's Crystal Ball, scroll on down to Dan's post below.

Snow Daze

Closing decisions by area school systems are an easy target, and hindsight is always 20/20, but as a long-time taxpayer of the great state of Maryland and Montgomery County in particular, PM Update is seriously wondering if someone can explain what happened today. (Yes, teachers, we feel your pain. The young Update ran off to sea rather than spend more than 1 semester trying to indoctrinate some of the parents of today's little darlings in the intricacies of non-base-10 number systems.)

Card-carrying members as we are of the reality-based community, we took the PM Update mobile unit out to gather some real-time data on the situation. Traveling the bone-dry pavements of North Bethesda and Kensington, we were surprised to observe some conditions that some of you more sheltered city-dwellers might not easily apprehend. At the major intersections, there was considerable danger of skidding . . . from the massive quantities of sand on the roadway. Another hazard which might not be intuitively obvious to the non-professional was the sand trucks themselves hurtling across the double yellow line as they raced back to the garage at the end of their grueling 3 or 4 hour shifts. Finally, not to be overlooked is the subtle snow-day menace posed by the SUVs full of high school students careening down Rockville Pike to meet their friends to hang out at White Flint Mall.

It's not as if the scope of this "storm" was incorrectly forecast, either here or by any other outlet I observed. In comments to the previous post, I noted that the water equivalent of this powder ranged up to a high of 0.07" at Dulles. Assuming that the snow depth was a full 2" (probably rounded up; I had to really stretch to find as much as 7/8" even on the north side at Update Central in MoCo), that means almost 97% of the stuff was air, which is exactly what most of it turned into by lunch time, especially on those 50% of all ground surfaces which face south. If there was any question at all about conditions, and it's extremely hard to believe there was one, why wouldn't a 2-hour delay have been sufficient?

Pictured: Class, this is what real snow looks like, observed last weekend by CapitalWeather.com's Matt and Ian, along with a group of DC-area snow-starved lake-effect storm chasers at Pulaski, NY. Some of the "chase team" appeared with Mike Seidel on the Weather Channel Monday night. Some video by Randy Legette of Easternuswx.com is on YouTube.

How Cold Is It?Chance of Snow Tomorrow Night

Now

Windy, very cold. "[I]t's so cold outside, the politicians have their hands in their own pockets." (Va. Rep. Tom Davis at last week's House Government Oversight Committee hearing on climate science censorship.) After an official low of 14°, the Washington area's latest Arctic blast limited temperatures to near 20° in many places this afternoon, although the southern fringes of the region saw readings as high as the mid and upper 20s. Winds gusting as high as 30 mph at times made the temperatures even more uncomfortable and dewpoints in the negative teens added to the drying effect.

Temperature chart at 4pm today from Unisys

Tonight and Tomorrow

Very cold. Winds will diminish tonight. Along with clear skies and very low dewpoints, lows will drop to near 10° in town to the low single digits in the 'burbs. Tomorrow will be mostly sunny and not quite as cold, but with increasing clouds late in the day and highs in the upper 20s.

Tomorrow Night

Chance of Snow. A weak "clipper" system sliding in from the northwest could bring some light snow or flurries to the area before moving off the coast. With the extreme dryness of the current airmass and the weakness of the system, any accumulations are likely to be minimal. There's about a 50-50 chance we'll see more than half an inch in the metro area, but most likely under 2 inches.

For the outlook through the rest of the week and the Snow Lover's Crystal Ball, scroll on down to Jason's post below.

Cold Comfort

The proof of the pudding will be tonight, but some of the more breathless media claims of "coldest in a decade" may have been a bit premature. Today's low of 14° is the lowest since February 19 last year. If we reach single digits tonight, as seems likely, it will be the first time since . . . well, actually since 8° 3 years ago on Jan. 10. If tomorrow's high is at least 25°, the low would have to be 4° or below to equal that 2004 day's average.

Looked at another way, there's a long way to go in the next 3 weeks or so in order to "cancel out" the above-average record so far this winter. To balance the +30° departure from average on Jan. 6 this year, tomorrow would have to see a low of -1° and a high of 15°. Overall, the rest of February would have to average 12.8° below normal for the winter to be average. In order to do this, high temperatures would have to average no warmer than about the mid 30s for the next 23 days.

Climate Corner

After sleeping on it over the weekend, the WaPo has an editorial today on the latest IPCC global warming report.

In the blogosphere, Stu Ostro of the Weather Channel "fired" back Friday against the anti-scientific global warming skeptics. The links include several useful references to the scientifc literature. In another post early this afternoon, he responds to an earlier comment by clarifying and confirming what we've been saying here all along, that Dr. Heidi Cullen's so-called demand for "decertification" of AMS Seal of Approval holders was completely invented by the ideological noise machine and amplified by certain parties for their own purposes. Thank you, Weather Channel, for standing up for the science against ideological ignorance.

Dr. Cullen has a joint blog entry with 2 other climate scientists today, "There is More Heat. Let There be Light", discussing the IPCC report.

Another Arctic Attack Approaching

Now

Mixed precipitation showers, cold. Some leftover moisture and energy from yesterday's non-event was being swept over the Washington metro area today ahead of a cold front moving eastward from the Ohio Valley. Showers of mixed precipitation type were falling through temperatures mainly in the mid and upper 30s. The next Arctic attack, now massing on the Canadian border, will sweep into the area over the weekend, setting the stage for what promises to be the most frigid week of the season so far.

Tonight and Tomorrow

Showers/flurries ending, clearing, breezy, cold. Scattered showers and snow flurries will end this evening, with cloudiness decreasing by morning. Lows will be in the mid 20s in the city, near 20° in the 'burblands. Tomorrow will be partly cloudy, windy, and cold, highs near 34°.

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

Climate Corner

The release of the first volume of the IPCC Fourth Assessment Report this morning was widely covered in the world press. Among at least 1000 others, articles appeared online in the WaPo, NYT, ChiSunTimes, BoGlo, USAT, and Miami Herald. The package of articles at the UK Guardian was especially comprehensive. A pdf file (about 2.3MB) of the report and the webcast of the announcement are available online. RealClimate.org has started a thread for discussion of the report.

Bob Ryan had a short, but effective, interview on the subject last night with Ralph Cicerone, who is President of the National Academy of Sciences here in Washington. Imagine that: a broadcast meteorologist actually consulting a real climate scientist, an "atmospheric scientist whose research in atmospheric chemistry and climate change has involved him in shaping science and environmental policy", instead of promoting radical right radio rhetoric. One of Dr. Cicerone's comments should be listened to carefully by Bob's more paranoid broadcast brethren: There will still be jobs for operational forecasters, even with global warming!

The belief tanks, of course, have geared up for attack mode in response. If you want to keep score at home, the droll Prof. Rabett has devised a version of Global Climate Denialist Bingo. Get 4 hits in a row and win a prize! In addition to his political role, Benjamin Franklin was one of the founders of American scientific meteorology, so it's only fitting that the denialists are putting their money where their mouths are and offering 100 Benjies for attacking the IPCC.

Snowstorm Suppressed South

Now

Cloudy, cold. "Do your homework, boys and girls." (Bob Ryan, 11pm last night) Fortunately or frustratingly, depending on your position on the Washington snow spectrum, light snow slid off to the east today south of a line from just south of Charlottesville to near Ocean City. The precipitation was associated with an Atlantic coastal front northeast of a weak low pressure area having trouble getting organized along the Gulf coast. This low is expected to develop more off the Carolina coast tonight, taking the main body of precipitation away with it south and east of the Beltway.

Little, if any, frozen accumulation is likely. The CapitalWeather.com team will continue to monitor the situation and post a mid-evening update if conditions warrant.

Surface weather map at 1pm today from HPC/NCEP/NWS shows . . . not a lot going on in the Mid Atlantic area

Tonight and Tomorrow

Mostly cloudy, cold, some light precipitation, mostly to the south and east. Skies will remain mostly cloudy overnight with some light snow or mixed precipitation developing after midnight, mainly to the south and east of the immediate metro area. Lows will be in the low 30s. Clouds will linger through most of tomorrow as the next Arctic attack approaches, with a chance of some showers or snow flurries in the afternoon or evening. Highs will be near 40°, but turning colder late in the day.

Analysis

A trace of precipitation was recorded today from very widely scattered snow flurries in the metro area. Perhaps the site visitor who criticized Bob Ryan's long and distinguished career yesterday would like to reconsider those remarks. Bob's 11pm forecast of flurries or a dusting at most was definitely more accurate than the one on a certain HDTV news broadcast.

"Sometimes a cigar is just a cigar." (S. Freud) The reason the models have had a hard time getting a handle on this system is simply that there hasn't been much to get a handle on. The much-maligned NAM model has been hinting at a southern suppression of the precipitation since at least yesterday at this time, however. This afternoon's models continue in that direction.

Capital Climate

"This generation has altered the composition of the atmosphere on a global scale through . . . a steady increase in carbon dioxide from the burning of fossil fuels." (Al Gore? Heidi Cullen? Union of Concerned Scientists? No, President Lyndon Johnson in 1965.) Naomi Oreskes, professor of science history at UCSD and author of an important survey of scientific consensus on global warming, has an op ed piece, "The Long Consensus On Climate Change" in today's WaPo tracing the more than century-long history of scientific concern with greenhouse gases' effects on climate.

Set your clock radio: The release of the IPCC Working Group I report will be webcast tomorrow from Paris at 3:30am Washington time.