The Weather Page

July 4, 2009

The Weather Page

Jeff Brauner of Baltimore likes the name Hortense but hasn't heard of a Hurricane Hortense in a while. He wonders what became of the name. Alas, it was retired after flooding from a Hurricane Hortense in 1996 caused 39 deaths and $217 million in damage in the Caribbean. Puerto Rico saw 24 inches of rain; 20 inches fell in the Dominican Republic. Hortense was replaced by the name Hanna.

July 3, 2009

The Weather Page

Today the Earth is at aphelion, its farthest excursion from the sun this year. Astronomers calculate we are 94,206,500 miles from Old Sol. That's roughly 3.1 million miles farther than we are at "perihelion" - our closest approach, on Jan. 4. The extra distance doesn't cool us down much. The Northern Hemisphere's sunward tilt at this time of year is what really heats up the northern summer.

July 2, 2009

The Weather Page

In case you're keeping track, 2009 will be exactly half over today at 8 a.m. That assumes you're going by Universal Time. If you run your life on Eastern Daylight Time, as most of us around here do, the midpoint of the year comes at 1 p.m. Did you make any New Year's resolutions back on Jan. 1? If so, half the time available to make good on your promises has now slipped away.

June 28, 2009

The Weather Page

June ends this week, along with the second quarter and (for many) the fiscal year. It's been wet, but temperatures averaged out near normal. July is Baltimore's hottest month. Average highs peak at 88 on July 20; lows at 65. All but seven dates have record highs of 100 degrees or more. The oldest record still standing is the 2.28 inches of rain that fell July 28, 1871, the first year records were kept.

June 27, 2009

The Weather Page

Tonight's sunset will be the latest of the year in the Northern Hemisphere. For Baltimore, the last direct rays of sunlight will sink below a flat horizon at 8:37 p.m. EDT. At the beach, sunset occurs at 8:28 p.m. Total solar illumination has been diminishing since the solstice June 21, but the air and ocean are slow to respond. So average Maryland temperatures don't start cooling until after July 20.

June 26, 2009

The Weather Page

It's the lightning season again. Bolts from the sky kill more than 50 Americans each year, on average. Nine have died so far in 2009. Most are young males, and a third are struck at work. Ninety percent of those hit by lightning survive, but often with chronic pain, brain injury and thought-processing problems. Hear thunder? Go inside. Stay off (and unplug) hard-wired computers, phones or games.

June 21, 2009

The Weather Page

Ted Lingelbach in Parkville asks how a developing El Nino event in the Pacific will affect this hurricane season. El Nino conditions have already figured into forecasts of an average to slightly quieter-than-average Atlantic storm season. But El Ninos also tend to increase the chances for snowstorms of 8 inches or more in Baltimore. We could be in for some real snow, at last.

June 19, 2009

The Weather Page

After all this rain, Greg Koppenhoeffer of Ellicott City wondered whether Baltimore's reservoirs were full yet. He looked for numbers online but found none. The city hopes to post reservoir data on a new Web site sometime this summer. Call Public Works, and they'll say Loch Raven and Prettyboy are full. Liberty is rising at 98.9 percent. Combined, they're at 99.4 percent. Plenty.

June 18, 2009

The Weather Page

On Saturday I wrote here that the "equation of time" was zero on that date, so "solar time" and "clock time" were in agreement. I said our sundials should register 12 noon when our clocks did. Then Carl Yowell of Baltimore reminded me that our clocks are on daylight saving time. (Doh!) So, your sundial should have read high noon when your clock said 1 p.m. (noon, standard time)

June 14, 2009

The Weather Page

This morning's sunrise was the earliest of the year, at 5:39 a.m. EDT in Baltimore. But sunsets keep getting later, faster, for another week, so total daylight minutes will increase until the summer solstice June 21. We'll finally see the latest sunset June 27 at 8:37 p.m. EDT. The solar mileposts reverse with the earliest sunset Dec. 7; shortest day Dec. 21; latest sunrise Jan. 4.

June 13, 2009

The Weather Page

Today is the day to set your sundial. On this date the "equation of time" is zero. That means solar time and clock time are in agreement, and noon on your sundial should agree with noon on your watch. This is also true on Sept. 1, Dec. 25 and April 15. The rest of the year, your sundial might run as much as 16 minutes fast or 14 minutes slow. Blame Earth's tilt and elliptical orbit.

June 12, 2009

The Weather Page

Frances Bowman in Perryville wants to know "how often weather reports are actually correct, and how meteorologists defend their batting average." The NWS runs lots of stats to rate its forecast offices. But if tomorrow's high is 74 instead of 75, is that wrong? Is a 5-degree error on a seven-day forecast bad? We predict eclipses with precision because there are few variables. Weather variables are countless.

June 11, 2009

The Weather Page

Jeff Brauner in Baltimore asks "what actually converges" in the intertropical convergence zone where Air France Flight 447 went down. He wonders if it's safe to fly there. Northeast trade winds above the equator and southeast trades south of the line converge in the ITCZ. They force warm, humid air skyward, forming equatorial thunderstorms. There's normally little risk to modern airliners.

June 7, 2009

The Weather Page

If skies clear tonight, watch the full moon rise over Baltimore at 8:54 p.m. (At the beach? Look for it rising over the ocean nine minutes earlier.) This is the third full moon after the vernal equinox, and the last before the solstice June 21. That makes it the Flower, Strawberry or Rose Moon. Speaking of flowers, has anyone else noticed the gush of red roses on gritty Eden Street, south of Fleet? Beautiful.

June 6, 2009

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Carl Yowell of Baltimore asks: "In today's Sun ... the forecast is 'Rain 80%, Forecast: occasional rain.' What exactly does that mean? Eighty percent of the state will get occasional rain? Or an 80 percent chance of the forecast being correct?" A perennial question. It means that 8 out of 10 times in the past, when conditions were identical, the forecast area had intermittent rain.

June 5, 2009

The Weather Page

Frances Bowman of Perryville asks: "What kind of education does a meteorologist need?" It's no cakewalk. The National Weather Service wants a bachelor's degree in meteorology or atmospheric science. Course work must include thermodynamics, analysis and prediction, remote sensing, physics and calculus. Then choose three: hydrology, statistics, chemistry, oceanography, climatology, aeronomy or computer science.

May 31, 2009

The Weather Page

A long-range space-weather forecast: After the quietest low in a century in the 11-year cycle of solar activity, NOAA scientists predict the next solar peak will top out in May 2013 at the lowest level since 1928. But even "weak" solar cycles can act up. A similar cycle in 1859 produced a solar storm that set fires in telegraph offices and sparked Northern Lights bright enough to read newspapers by.

May 29, 2009

The Weather Page

The 2009 Atlantic hurricane season begins Monday. The first named storms will be Ana, then Bill. Military forecasters during World War II were first to give female names routinely to tropical storms in the Atlantic and the Gulf. In 1953, the U.S. adopted the practice, alternating with male names beginning in 1979. The 21-name alphabetical lists omit Q, U, X, Y and Z, and they repeat every six years.

May 28, 2009

The Weather Page

With days to go, this is already one of the wettest Mays since record-keeping began here in 1871. The airport total through Tuesday was 7.1 inches, drowning the long-term average of 3.89 inches. The record is 8.71 inches, set in 1989. The second-wettest was just last year, when 7.77 inches fell at BWI. The third-wettest was 7.26 inches in 1894. This month's dunking has tied with May 1960 for fourth place.

May 24, 2009

The Weather Page

Attention, Space Cadets! Clouds might interfere, but if we get lucky, watch for a very bright International Space Station on Monday evening as it passes directly over Baltimore. Look for it to rise above the northwest horizon at 10:05 p.m. and pass right through the cup of the Big Dipper. It will climb nearly to the zenith (straight up) by 10:08, then vanish into the Earth's shadow a few seconds later.

May 22, 2009

The Weather Page

The 2009 Atlantic hurricane season begins in 10 days. Forecasts call for an average to slightly busier-than-average season. Colorado State forecasters Klotzbach and Gray concede in a May 13 paper that their December and April forecasts "have shown little forecast skill." May and August predictions do only a little better than those that merely extrapolate past averages. They say their revised models promise "increased skill in future years."

May 21, 2009

The Weather Page

Did you scuffle out early this morning to grab your paper? If it's still mostly dark out, go back and look toward the east, close to the horizon. Find the slim crescent moon, just three days short of "new." The bright "star" below and to the right of the moon is the planet Venus. Just below the moon is the much fainter Mars. Twice as high, in the southeast, stands gleaming Jupiter.

May 17, 2009

The Weather Page

Last week Baltimore passed beyond the reach of a freeze. Probably. Temperatures in May have sunk to 32 degrees only once since record-keeping began here in 1871. That was on May 11, 1966. That is also the date of our latest trace of snow - in 1951. Barring freak weather, or nuclear winter, we should be safe until fall. The earliest freeze on record here occurred Oct. 4, 1974.

May 15, 2009

The Weather Page

Lou Borowicz of Baltimore dialed the weather line April 26 and heard that the downtown temperature was 101. A friend in Hamilton had 99.7, but the next day's Baltimore Sun reported just 91. "Can you explain these differences?" Lou asks. Sure: location. We reported BWI's high. The Science Center reached 93. Here on Calvert Street, it was 95. The phone company's rooftop thermometer often records the highest temperature of all.

May 14, 2009

The Weather Page

Terry Shepard lives just west of Baltimore's Inner Harbor, where he has "a tiny mystery." Each day, for more than a week, he emptied "an inch or more" of rain water from his recycling bins. "Yet every day the paper would report much smaller amounts." Why? Probably because our "24-hour" rain data are actually midnight-to-5 p.m. totals. Thanks to your note, I've asked for new wording.

May 10, 2009

The Weather Page

Attention, Space Cadets! If the skies clear in time tonight, we'll get a fine view of the International Space Station and its crew of three as they zip from Alabama to Maine. Look for a bright, star-like object above the western horizon at 9:56 p.m. It will climb to more than halfway up the northwest sky by 9:59, to just below the Big Dipper, then race off toward the northeast, disappearing at 10:01 p.m.

May 8, 2009

The Weather Page

All this rain has ended the drought for farmers, and water tables are rising again. But we are not quite back to normal. The USGS says more than 60 percent of Maryland's monitoring wells remain below seasonal norms. If the rain keeps up, hydrologist Wendy McPherson expects groundwater will keep rising: "Perhaps most of the water levels will be normal by the end of the month."

May 3, 2009

The Weather Page

Keith Young in Baltimore notes that Maryland had the nation's highest temperatures for two days last week - 96 degrees in Frederick (Sunday) and Cumberland (Monday). "How many times has Maryland been host to the country's high or low temperature?" he asks. Our data supplier doesn't track it but agrees it's extremely rare: "The heat wave was fairly historic for Virginia and Maryland."

April 26, 2009

The Weather Page

Perry Hall'sEd Stawinski writes: "I say winter is when the sun is closer to where we live, to provide more warmth, and is further away in summer, so we don't fry. True or false?" Charming, but false. The sun is closest to Earth during our northern winter, but that's also summer south of the equator. Earth's axis is tilted. When your hemisphere tilts away from the sun, solar heating is diminished. That's your winter.

April 25, 2009

The Weather Page

April 2009 is shaping up as the wettest April since 1983, when 6.55 inches fell at BWI. This month, the airport has recorded more than 5.7 inches, almost double the 3-inch average. Only three Aprils since 1940 have seen more than 6 inches of rain (1952, 1973, 1983). In the 69 years of records before that, 11 Aprils got that wet. Why has the frequency of very wet Aprils declined?

April 24, 2009

The Weather Page

The hurricane season forecasts continue to roll in. This time, it's Phil Klotzbach and William Gray at Colorado State, dialingback their December guesstimate. They now expect only an "average" season, with 12 named storms, including six hurricanes, two "major." Chances for a East Coast landfall are put at 32 percent. Gray credits an expected neutral or weak El Nino and cooler Atlantic waters.

April 23, 2009

The Weather Page

Attention, Space Cadets! Planning an early start Friday? Catch the International Space Station before dawn as it races toward Maine atop clear skies. Our giant money pit will fly into sunlight at 4:51 a.m., appearing like a bright, moving star well above the northwest horizon. At 4:52 it will pass the handle of the Big Dipper. Wave as it slips away to the northeast, disappearing at 4:55 a.m.

April 19, 2009

The Weather Page

Jeff Brauner writes from Baltimore: "What is an 'occluded front'? Is that sort of an old-fashioned term that modern meteorologists don't use much anymore?" Occluded fronts occur when cold fronts sweep counterclockwise around a low-pressure center and overtake slower warm fronts on the other side, lifting the warmer air. Meteorologists do use it. Maybe they skip it in forecasts to avoid explaining it.

April 18, 2009

The Weather Page

Hank Walter in Phoenix asks why the temperature in Salisbury is often 10 degrees lower than the surrounding areas: "In the mornings, the temperature there is usually as cold as it is in York, Pa." I've heard that before. Best guess: Salisbury, at the center of the Delmarva Peninsula, cools more at night because it's farther than nearby towns from the moderating influences of the bay and ocean.

April 17, 2009

The Weather Page

Our April 1 switch to a new weather data vendor for this page has introduced some subtle changes. Several alert readers noticed that the new outfit - Weather Underground - uses a formula that yields precipitation probabilities in increments of 1 percentage point instead of more familiar 10 percent increments. We use them when the WJZ forecasters' predictions are unavailable.

April 16, 2009

The Weather Page

Joanne Nathans writes from Baltimore: "In recent issues of The Sun, the normal precipitation for April is amazingly small. For example, on April 6 it was 0.53 [inch]. Is this correct?" It was. We switched to a new data vendor on April 1, and for the first week they gave us the 30-year average rainfall for the month to date - not the full month. They've since returned to using the BWI average for the full month.

April 5, 2009

The Weather Page

WeatherBug is the latest weather service to venture predictions for the 2009 Atlantic hurricane season. Citing a warm Atlantic but a waning La Niña, they're expecting less activity than last year but more than average. The Bug sees 11 to 13 named storms, of which six to eight become hurricanes, and three to four reach Category 3 (111 mph or more). Next up: Colorado State's experts this month, the feds in May.

April 4, 2009

The Weather Page

Joan Fitzpatrick writes from Fallston: "I am wondering where I can find daily local pollen counts. I notice they are not being published in the weather section anymore." The Johns Hopkins University produces a daily forecast for Weather.com. There's another from Pollen.com that offers desktop widgets and gadgets. These sources don't always agree, so Google "Baltimore pollen count" and take your pick.

April 3, 2009

The Weather Page

Emily Johnston in Westminster asks: "What's the latest freeze date - may be different from frost date - for the Balt. area? Latest snow date? I can remember snow in April, with the jonquils happily blooming, but I don't remember when." The latest 32-degree reading at BWI was May 11, 1966. The latest snow, a trace, fell on the same day in 1951. Most recent measurable April snow was 0.2 inch on April 7, 2007.

April 2, 2009

The Weather Page

Jeff Brauner, in Baltimore, asks if there's a difference between cumulo-stratus clouds and strato-cumulus: "Also, are there really nimbo-stratus clouds? Sounds like an oxymoron." Cloud names are bewildering, but I find only stratocumulus in my references – broad, low clouds with brighter, puffy heaps. Nimbo means rain, so nimbostratus clouds are simply low, featureless clouds that rain.

March 29, 2009

The Weather Page

Today is the 67th anniversary of the "Palm Sunday Storm" in 1942, which remains the heaviest March snowfall on record for Baltimore. The "surprise" storm began as rain but changed to snow and dumped 22 inches here, doubling the March record and stopping the city in its tracks. The "freak" snow was declared good for the war effort, boosting water supplies and sparing gas, oil and tires.

March 28, 2009

The Weather Page

Most of the U.S. entered daylight-saving time March 8, but Europeans are just getting around to it tonight. At 1 a.m. Sunday Universal Time (9 p.m. today our time), European Union countries turn their clocks ahead one hour, switching from Standard Time to Summer Time. That will restore the time spread between Baltimore and London to five hours, after three weeks at just four hours.

March 22, 2009

The Weather Page

Maisie Fischel, a first-grader at Roland Park Elementary School, was asked in class whether snow in July in Baltimore was "impossible" or "less likely." She said "impossible," and was marked wrong. Her mom, Christine, asks, "Has it ever snowed in July in Baltimore?" May and October, yes. July? Not since records began in 1883. But "ever" is a long time. A big volcanic blast might just do it. Google "Tambora 1815."

March 21, 2009

The Weather Page

How far can Baltimore's temperature swing in five days? BWI went from 8 degrees on March 4 this year to 76 degrees on the 8th - a 68-degree leap. Steve Zubrick, science officer at the National Weather Service's Sterling, Va., office, says that ties the widest such leap on record here, set March 8-12, 1990, when the temperature rose from 18 to 86 degrees. The largest five-day drop was 62 degrees, from 87 to 25 degrees, Oct. 20-24, 1969.

March 20, 2009

The Weather Page

The northern spring begins at 6:45 a.m. today as the sun crosses the celestial equator into the northern hemisphere. Many still think the equinox occurs March 21, but the last time that happened in our time zone was in 1979. The next will be in 2103, says Geoff Chester of the U.S. Naval Observatory. Spring arrives on the 20th until 2020, when a March 19 equinox becomes possible.

March 19, 2009

The Weather Page

Kurt Kroncke in Federal Hill has been reading about orbital collisions: "Will all the space junk orbiting planet Earth eventually form a ring around our planet?" It already has. Communications satellites and others, working and defunct, already form a ring 22,236 miles above the equator, orbiting once a day. Track them in real time at a way-cool NASA site. Google: "3D JTrack"

March 15, 2009

The Weather Page

Space Cadets! Shuttle Discovery remains on the pad, but the International Space Station flies on. Tonight's pass will be clouded out, so try again on Tuesday. Look for a bright, star-like object rising in the southwest at 7:39 p.m. It will fly close to the bright star Aldebaran in Taurus, then pass the zenith - straight up - at 7:42 p.m. The ISS will disappear into the Earth's shadow at 7:46.

March 14, 2009

The Weather Page

Caroline Baker, in Baltimore, says "tiny black ants have shown up in my bathtub and kitchen sink ... Are they ... looking for water because the ground is so dry?" Nope. UM entomologist Mike Raupp says they're "odorous house ants," foraging for the sweet aphids hatching now. "If they find a nice supply of goodies in the kitchen, they will set up a trail and drive you nuts." Follow the trail to a food spill.

March 13, 2009

The Weather Page

Any shelter in a storm. After a March snowstorm in Baltimore 49 years ago, gale winds drifted waist-high snow across Dulaney Valley Road north of Loch Raven Reservoir, stranding 40 motorists. They took refuge at the Cloverland farm north of Peerce's Plantation. The Sun reported: "The unexpected guests were able to keep warm in the barn with the 100-head herd of milk cows." And no one went thirsty.

March 12, 2009

The Weather Page

To which saint was the 1667 Brick Chapel at St. Mary's City dedicated? Christians then often oriented churches with the sunrise. Archaeologists noticed that the chapel's ruined foundation was aligned with a spot on the eastern horizon where the sun rises Feb. 2. That's Groundhog Day, but also the date of the Feast of the Purification of the Virgin Mary, supporting the historians' obvious best guess.

March 8, 2009

The Weather Page

The start of daylight-saving time today means darker mornings. Sunrise today jumps from 6:28 a.m. in Baltimore to 7:28, making the morning as dim as it was on Jan. 4. We won't recapture that lost morning light until April 15. Happily, sunset occurs after 7 p.m. now, and will advance daily, reaching its latest at 8:37 p.m. on June 27.

March 7, 2009

The Weather Page

Most of the nation returns to daylight-saving time at 2 a.m. tonight, spinning the dial ahead to 3 a.m. Officially, there will be no 2 o'clock hour. Hawaii, most of Arizona and Indiana skip the switch, as do Puerto Rico and the U.S. Virgin Islands. The rest of us spend 65 percent of our year on DST, and "noon" comes an hour before the middle of our day.

March 6, 2009

The Weather Page

Space cadets! Up early with the dog? Watch the International Space Station as it flies 220 miles over Baltimore early Saturday. It will rise in the northwest at 5:36 a.m., as bright as Venus, pass the Big Dipper and soar directly overhead at 5:39 a.m. From there, it slides off to the southeast, disappearing at 5:42 a.m. Please pick up after your pet.

March 5, 2009

The Weather Page

This week's snow left 5.8 inches at BWI, the most since February 2006. The storm brought the total snowfall for Baltimore this season to 9.1 inches, exactly half the 30-year average. Only three winters since 2000 have produced less. There's still time for more. Every March date has seen snow at least once since snow tallies began in 1883.

March 1, 2009

The Weather Page

Don Gansauer watched from Canton as a mushroom cloud rose over theBrandon Shores power plant. "What is the meteorological explanation of mushroom clouds?" Heat (nuclear fireball, or cooling-tower steam) rises into still, colder air. As the column climbs, it cools to surrounding temperatures, slows and piles up into a "mushroom" cap.

February 27, 2009

The Weather Page

Warm enough? Scientists at the NASA Goddard Institute for Space Studies in New York say that 2008 was the coolest year globally since 2000. But the same analysis concluded that, while cool for the new century, 2008 was still the ninth-warmest year for the planet since records began in 1880. The 10 warmest years have occurred between 1997 and 2008.

February 26, 2009

The Weather Page

Linda Tanton writes from Baltimore: "Has Baltimore become more windy over the past 3-4 years? Seems so to me." The NWS doesn't compile annual wind data, but we have seen more wind advisories and warnings this year. A month-to-month check finds February 2009 has been the windiest month at BWI since April 2007, averaging 8.2 mph. A 40-mph gust Feb. 12 was the third-strongest since January 2007.

February 22, 2009

The Weather Page

Joe Kokosinski was up just after sunrise in Ferndale on Tuesday: "I was amazed to see a veritable blizzard of 'stuff' in the air that was backlit by the sun ... Is the pollen already starting to fly, or is it the price I pay for living in Central Maryland?" Dr. Ray Hoff, at UMBC, checked the weather data for that day. His best guess: At 19 degrees and a high dewpoint, "it is possible he was seeing ice fog or ice crystals."

February 21, 2009

The Weather Page

That brilliant "star" blazing in the southwestern sky on clear evenings this month is actually the planet Venus. It is currently at its very brightest, rated by astronomers at a magnitude of minus-4.6. Venus is highly reflective, but it is only partially illuminated by the sun. Through a telescope, it looks like a bright smile, or the crescent moon. During March, it will fade quickly and slip deeper into the dusk.

February 20, 2009

The Weather Page

Pat Koehler in Baltimore asks: "What causes the axial tilt of planet Earth?" Earth spins on an axis tilted 23.4 degrees from the plane of its orbit around the sun. That tilt produces our annual seasons. The initial spin and tilt were the result of impacts as the Earth formed. The drag of solar and lunar gravity have since slowed the spin and altered the tilt some. Tilts vary. Mercury's is 2 degrees; Uranus' is 98.

February 19, 2009

The Weather Page

Linda Di Lembo of Puyallup, Wash., was in Ocean City as a kid when "the ocean froze. ... I remember actually walking on the ocean. ... My friends just don't believe me." I do. It was mid-February 1979, the second-coldest on record. Mayor Harry Kelley Jr. told The Sun that the ice slabs "froze the surf. ... I actually saw people walking on the ocean." Sea ice wrecked a pier and piled 15 feet high on the beach.

February 15, 2009

The Weather Page

Space cadets! Do you have to work on Presidents Day? Me too. As long as we're up, let's step outside for a look at the International Space Station. If skies are clear, watch it rise like a star in the southwest tomorrow at 6:22 a.m. Climbing past the waning moon, it will be high in the southeast by 6:25 a.m. Itslipsbetween Vega and Altair before vanishing in the northeast at 6:28. Then it's off to work we go.

February 14, 2009

The Weather Page

The data wizards at the National Weather Service are at it again. They've found the biggest day-to-day drop in high temperatures on record for Baltimore: from a high of 78 degrees on March 18, 1934, to a high of 36 degrees the next day - a 42-degree difference. The largest one-day gain is 40 degrees: from a high of 34 degrees on Dec. 27, 1946, to a high of 74 the next day. That's still the record high for a Dec. 28.

February 13, 2009

The Weather Page

It's Friday the 13th, and whenever that happens in February (in a non-leap year), March delivers another. Worse still (for the triskaidekaphobes among us), this year brings a third Friday the 13th in November. Such triple threats occur in 14 or 15 years per century. The last was in 1998; the next is in 2015. Friday falls on the 13th more than any other day. Just our luck.

February 12, 2009

The Weather Page

Ever wonder how far apart one day's high and low temperatures can be in Baltimore? Me neither. But NWS data wizards searched the books and found a record 48-degree spread on April 1, 1978, from 40 degrees to 88. The narrowest temperature range on one calendar date? Zero! On March 24, 1884 it was 52 degrees, all day. Six dates varied by only one degree, most recently on Jan. 27, 2009: high 28; low 27.

February 8, 2009

The Weather Page

The second full moon since the winter solstice rises over Baltimore tomorrow at 5:59 p.m. Our ancestors knew it as the Wolf Moon, the Snow Moon or the Hunger Moon. It's easy, and chilling, to imagine why. This one rises nine hours after a "penumbral eclipse," a slight darkening of the moon as it passes through the edge of the shadow Earth casts into space. It will be visible from Asia and the Pacific.

February 7, 2009

The Weather Page

Don Gansauer wrote from Canton on Tuesday after watching the sun shining into a snow shower. "To form a rainbow, sunshine must be shining through a rainstorm," he said. "If the conditions were perfect, could one see a snowbow?" Sorry. Rainbows appear when sunlight is reflected off the rear surface of liquid raindrops and refracted, or split into colors. Solid snowflakes can't perform the same trick.

February 6, 2009

The Weather Page

Marylanders may get a naked-eye look at a comet this month. Comet Lulin was discovered in 2007 by astronomers in China and Taiwan, and it has rounded the sun, headed our way. It's now low in the southeast before dawn, too dim to see without a telescope. But by Feb. 24 it should be faintly visible to the naked eye (and easy to see with binoculars) near Saturn, high in the southeast before midnight.

February 5, 2009

The Weather Page

Rick Angelini in Bel Air thinks big hurricanes and major snowstorms that once tracked up the Atlantic coast seem scarcer now. He asks: "What causes this type of long-term weather pattern?" Changes in Atlantic and Pacific ocean temperatures shift atmospheric patterns around. So persistent high pressure over the East Coast help fend off hurricanes. Snowstorms slip by too far east or west.

February 1, 2009

The Weather Page

Wes Orem in Catonsville asked for "the temperatures and number of days in January 1977 that were below freezing, which caused the Chesapeake Bay to freeze." Icebreakers moved the shipping, but that month is still the coldest January on record for Baltimore. Eighteen days failed to reach 32 degrees. Twenty-four days had lows below 20. Five nights reached single digits, and Jan. 17 sank to minus-2. Brrrr!

January 31, 2009

The Weather Page

February arrives at midnight. Beware the middle weeks. Five of Baltimore's biggest snowstorms struck between the 11th and the 18th. The snowiest February was in 2003, with 40.5 inches at BWI. But days lengthen, and average daily highs climb from 42 to 48 degrees. Lows rise from 24 to 29. We reached 83 degrees on Feb. 25, 1930, but sank to minus 7 twice - in 1899 and 1934.

January 30, 2009

The Weather Page

If skies clear tonight, look for a slender crescent moon alongside brilliant Venus, high in the southwestern sky after sunset. Look closely for the faint outline of the "dark" portion of the moon's disk, the part that is not bathed in direct sunlight. It's dimly illuminated by "Earthshine" - sunlight bounced off the Earth onto the moon's surface. Leonardo da Vinci was the first to explain the phenomenon.

January 29, 2009

The Weather Page

So a guy named Obama moves his family from Chicago to D.C., and they make a discovery: We close schools when snow falls. "As my children pointed out, in Chicago, school is never canceled," Obama says, incredulous. "Are folks here wimps?" he is asked. "I'm saying, when it comes to the weather, folks in Washington don't seem to be able to handle things." Just wait. Can these transplants take a Chesapeake summer?

January 25, 2009

The Weather Page

This week Baltimore's average daily highs and lows tick upward noticeably for the first time since the high hit bottom (41 degrees) on Jan. 5, and the low sank to 23 on Jan. 11. On Tuesday, the average low rises to 24 degrees, and the high bumps to 42 on Friday. The coldest days occur after the shortest (Dec. 21) because it takes several weeks before the increasing solar input exceeds heat being lost to space.

January 23, 2009

The Weather Page

Fred Weiss reads the newspaper in Baltimore and wonders: "The Sunpapers shows only 0.2 inches of snow for January on their Weather Page. Is that correct? Is that based on snow at BWI?" Yes. The Jan. 19 storm that dropped 2 to 3 inches north and west of the city, and sent motorists skidding, left only a dusting at BWI. But that's the station of record. So officially we've had just 0.8 inch so far this winter. Pitiful.

January 22, 2009

The Weather Page

Bob Hausler writes from Catonsville: "What month has the most snowfall for the state of Maryland?" During the 30-year stretch from 1971 through 2000, January saw the most snow at BWI, averaging 7.0 inches, followed by February (6.4 inches) and December (1.7 inches). The snowiest month on record for BWI was 40.5 inches, in February 2003. The average seasonal total is 18.2 inches. We're overdue.

January 18, 2009

The Weather Page

Attention Space Cadets! If clouds thin or break before the big game tonight, watch the International Space Station fly over your house. Look for a bright, star-like object rising above the southwestern horizon at 6:18 p.m., passing just right of brilliant Venus. Soaring up the Appalachian chain, the ISS will pass 224 miles over Baltimore at 6:21 p.m., then vanish from view over Cape Cod at 6:22.

January 17, 2009

The Weather Page

Mid-January and only 0.6 inches of snow. Bob Brown in Cockeysvillewonders: "When was the last time there was no snow through the middle of January? Is there a year when no snow was recorded?" Only a trace had fallen at BWI by Feb. 1, 1973. That season saw just 1.2 inches. It also happened in 1913-1914, but 23 inches fell after Feb. 1. Skimpiest snow season? Seven-tenths of an inch, in 1949-1950.

January 16, 2009

The Weather Page

Ice happens in any season. Steve Zubrick, science officer at NWS Sterling, was asked about the largest Maryland hailstones ever recorded. He found a science journal report on a storm in Annapolis on June 22, 1915, that dropped 12 stones averaging 3 to 3.5 inches in diameter. Two 4.5-inch stoneswere reported - in Baltimore on June 18, 1970, and in La Plata, linked to the F4 tornado on April 28, 2002.

January 15, 2009

The Weather Page

It's cold, but we've seen worse. One of the worst Maryland ice storms in recent memory ended 10 years ago today. A half- to three-quarters of an inch accumulated; 40-mph winds helped drag down trees and wires. Emergencies were declared. A half-million customers lost power, some for a week. Eight hundred pedestrians were hurt in icy falls. Thirty Montgomery County school buses skidded off the roads.

January 11, 2009

The Weather Page

Feeling better? We're now a week past the year's latest sunrise, and Old Sol is already climbing above the eastern horizon about a minute earlier than he did on the 4th. We'll gain 12 minutes more morning sunshine by month's end, and we'll add 22 minutes in the evening. So get out there. Enjoy the increasing daylight. Rejigger your circadian rhythms. Expose your skin and try to manufacture some vitamin D.

January 10, 2009

The Weather Page

Tonight's full moon rises over Baltimore at 5:55 p.m., though clouds may spoil the view. The first full moon after the winter solstice was once known as the Moon After Yule, or the Old Moon. It seems larger than usual because it is just 17 hours past perigee (and closest approach to Earth in 2009). Watch for high tides. We'll have 13 full moons this year, with two in December - on the 2nd and 31st.

January 9, 2009

The Weather Page

Holly Curtis writes from Salisbury: "I am a transplanted Pennsylvanian longing for some snow here. ... What do you think about our chances of getting any fairly decent snowfall this winter?" Not much. Conditions in the North Pacific and a resurgent La Nina suggest another mild winter. And when the rain/snow line reaches Maryland, Salisbury's usually on the rainy side.

January 8, 2009

The Weather Page

Joe Bollinger writes from Glen Burnie: "Can you recap the temperatures for 2008 ... specifically the departures from normal?" Sure. It was another warm year. Temperatures at BWI averaged 55.7 degrees, 1.1 degrees above the 30-year norm. Nine months were warmer than average. Only May, August and November were cooler. May was coolest – 2.4 degrees below average. June was warmest, 3.5 degrees above.