Play Ball!

NatCast
Nationals vs. Arizona Diamondbacks, 7:05pm on April 14, RFK
Winds will be northeasterly from 10 to 15 mph, diminishing during the game. Temperatures will be about 65 when the gates open, but expect them to drop steadily after sunset at 7:44 from the game-time level of 58 down to the lower 50's by the 7th-inning stretch and into the 40's on the way home. Go Nats!

Currently

Today's weather map shows a weak low pressure area moving away from the North Carolina coast and high pressure dominating virtually the entire country east of the Rockies. The only precipitation showing on national radar in the eastern two-thirds of the U.S. is an area of lingering showers in the eastern Carolinas. Under brilliantly sunny skies, temperatures are rising from an official low of 42 through the 50's at mid-day toward highs in the mid 60's. Some of the outlying areas were down into the 30's last night with Frederick at 37, Dulles at 39, Culpeper at 33.

Under clear skies, temperatures should drop to near 40 tonight. Tomorrow should be slightly cooler with highs around 60.

Baseball and the atmosphere

Images (click to enlarge): Magnus force, from American Scientist

The May-June issue of American Scientist has an article on "Predicting a Baseball's Path". It explains how the spin of a baseball pitch interacts with the air through the "Magnus force" to affect the ball's motion. A ball moving through air has a turbulent wake behind it. The direction of spin affects the location of the "separation points" where the air flow becomes turbulent. In the case of topspin (movement of the top of the ball is in the direction of the pitch), the upper separation point is deflected upward, so the air in the wake has upward momentum. By the law of conservation of momentum, the ball must move downward. Conversely, a ball with backspin will move upward. By controlling the axis of rotation of the pitch, the pitcher can determine the direction of deflection of the ball.

Good afternoon, Charlottesville

Currently

Last night's rain showers were widely scattered and mainly confined to the south of the Washington metro area. The official rain bucket collected a minimal 0.01". As a weak low pressure area moves slowly off the Carolina coast, skies have cleared in the area. Temperatures were into the upper 50's by noon and lower 60's at 2pm. Here on the admittedly non-standard CapitalClimate Weather Patio, it's 65. In southern Virginia, where clouds and some light rain prevail, temperatures are only in the upper 40's.

Outlook

Under mainly clear skies, temperatures should be in the low 40's tonight, with highs tomorrow near 60.

NatCast
Nationals vs. Arizona Diamondbacks, 7:05pm on April 14, RFK
Outlook for the Nats' home opener: Light, mainly easterly breeze at game time; temperature 54, falling to about 50 by the 7th inning stretch. No rain!

Founding Father, Monticello Meteorologist

Today is the 262nd anniversary of the birth of Thomas Jefferson. The third President of the United States was a dedicated weather observer, recording the temperature at Monticello every day at dawn and at 4pm. He also recorded wind direction and speed and precipitation. The Washington and Jefferson Snowstorm of January 27-28, 1772, was so-named in recognition of the fact that it was recorded by both future presidents. Jefferson, who had just returned from his honeymoon, reported a snow depth of about 3 feet. According to David Ludlum's "Early American Winters", this was "the greatest snowstorm in the history of the middle and lower Potomac Valley." In 1776, Jefferson began to recruit volunteer weather observers around the state of Virginia. This was the forerunner of today's Cooperative Weather Program. The Thomas Jefferson award is the highest award for volunteer weather observation. No more than 5 of these awards are presented each year for "unusual and outstanding achievements." As President, Jefferson also created the Coast Survey (now the National Geodetic Survey), the country's first civilian scientific agency and the oldest component of what is now NOAA, the National Oceanic and Atmospheric Administration.

Current conditions in Charlottesville:
Clear skies, temperature 58.

Three-bagger

Currently

The Washington metro area enjoyed a three-base hit today, as the picture-perfect spring weather continued for a third day. Despite a northeasterly wind behind a cold front which moved through from the north overnight, a sunny sky pushed temperatures to near 70 or a bit above by mid afternoon. The only cool spots in the region were those with cold-water influences: Ocean City was at 50, and Annapolis was 59 at 3pm. The regional radar is clear. In fact, the only precipitation in the eastern half of the country is in the Gulf States ahead of the low pressure area which brought nearly 2 feet of snow to eastern Colorado and closed 200 miles of I-70 over the weekend.

Outlook

The cooler air which is now moving in over us will be reinforced by the strong "meridional flow" pattern which we are in. As the pattern continues through the week, we can expect cool and damp conditions, as described by Jason below. Expect lows tonight in the low to mid 40's and highs tomorrow in the mid to upper 50's with increasing cloudiness.

Blog log: Vote early and often!

The WeatherBug Storm Chase 2005 blog has narrowed down the field to 3 contestants to go storm chasing with them. Read about the 3 candidates, and then cast a vote for your favorite.

Broadcast news

The radio Weather Talk guys Justin Berk and Tony Pann have launched a web site in connection with their show. The first show was yesterday afternoon. If you listened, tell us your impressions of the show in the comments section (link below). I suspect that for at least some parts of the DC area, reception for the Baltimore station will be weak at best. In west-central Montgomery County, I could tune it in only on the upstairs clock radio at maximum volume.

NatCast
Nationals vs. Arizona Diamondbacks, 7:05pm on April 14, RFK
See Jason's post below for a preview of the conditions for the Nats' home opener Thursday night, and watch this space for updates during the week. The blogger gods willing, we'll have a last-minute update Thursday afternoon, so you'll know what to wear and whether to bring your brolly. (Hopefully, umbrellas won't be banned if they're necessary.) One thing we can be confident of at least: With a 7:05 starting time, you won't need sunscreen.

How warm is it?

Currently

If you're still sitting in the office looking out the window, it's not because we didn't warn you. Forecasts of highs near 80 turned out to be a wee bit conservative, as temperatures rose 30 degrees by mid afternoon from an early morning low of 52. Temperatures in the Washington DC metro area were all above 80 at 3pm, except for Quantico, which stubbornly reported 69. Either the south wind at 16 mph was producing a mean river effect, or the site may need a calibration. A southeast breeze off the Bay was chilling Annapolis to 59. The warm spot was Leesburg VA at 88. Roughly due east of there in Montgomery County, I'm seeing a temperature of 88 as well. With the storm windows and doors still in place, that's about a 20 degree excess above the indoor temperature. Shortly before 4 pm, both Leesburg and Frederick MD reached the magic 32 Celsius (90 Fahrenheit). Let us know in the comments how warm it is where you are. (And ignore the comment count; it's being a little flaky.) Last year, the temperature was above 70 only once in the first half of April, reaching 80 for the first time on the 17th.

Outlook

A storm system now slowly working its way through the Gulf States will bring an increasing threat of showers by late tomorrow through the middle of the day Friday. After lows tonight about 60, highs tomorrow should be in the low 70's. Further cooling is on tap for Friday, with highs in the low 60's.

Mass Market Media Meteorologist Moves

The American Meteorological Society announced on Monday that Jack Williams will be joining the AMS staff as the public outreach coordinator. Williams has been the weather editor of USA Today for over 20 years since it first began publication. He has received the AMS Louis J. Battan Author's Award twice: for the "USA Today Weather Book" in 1994 and with co-author Dr. Bob Sheets in 2004 for "Hurricane Watch: Forecasting the Deadliest Storms on Earth". His first task at the AMS will be to develop a new book on weather and climate aimed at promoting scientific literacy. The Weather Grill gang sends best wishes to Jack on his new assignment; don't forget to bring your snow shovel to Boston.

Back to our regularly scheduled season

Currently
Temperatures this afternoon are mostly 15-20 degrees warmer than yesterday at this time. For a while yesterday, Washington was rivaling central Maine in temperature. (At 8am, for example, Washington National at 44 was 2 degrees colder than Lewiston, Maine. At 1pm, DC was just 2 degrees warmer than Lewiston.) Yesterday's high of 53 was not reached until 10pm. Despite brisk breezes as the low-pressure area which caused all the weekend commotion spins down just north of New England, today's late-afternoon temperatures are generally in the mid 60's. There are even a few reports of upper 60's under brilliantly sunny skies.

Look for a warming trend through mid-week, with the next chance of rain Thursday or Friday. Mid or even upper 70's are not out of the question for Wednesday, so make those "I forgot to come back to work after lunch" plans NOW. See Jason's post below for the details.

Despite some skepticism about the incredibly huge amounts of rain being forecast by the models for this weekend's storm, some really amazing results did occur. The Weather Channel reported that West Shokan, in New York's Catskills region, received 5.68" of rain. In Pennsylvania, the Poconos received 5" at Tobyhanna and 4.87" at Mt. Pocono. There has been widespread flooding along the Delaware and Susquehanna Rivers and other areas of the Northeast. In some locations, the Delaware River crested over 10 feet above flood stage.

Hurricane outlook
With less than 60 days to go until the official start of the season, hurricane researcher Dr. William Gray has issued an updated outlook for this year's storm activity. The outlook calls for above-average tropical storm activity and above-average probability of U.S. landfall by major hurricanes. The forecast includes 13 named storms, of which 7 are expected to be hurricanes. These figures are compared to 1950-2000 averages of 9.6 and 5.9, respectively. The probability of at least one major (category 3 or higher) storm landfall on the East Coast is given as 53%, compared to the average for the last century of 31%. These figures are increased from the level of activity predicted in the early December forecast.

Blog watch
Somehow we missed this in all the fun on Friday, but the realclimate blog had a post on the change of seasons expressing doubt on the beginning of spring. Realclimate is "a commentary site on climate science by working climate scientists for the interested public and journalists."

A Miss, but a Win for the Models

Currently
The recent trend of cold, but dry, weather continues in the Washington DC area as the models correctly predicted that precipitation would stay south of the region. The sun gradually strengthened this morning through a high overcast which was caused by a weak low pressure area bringing mostly rain to the southeastern states. In far southwestern Virginia, precipitation was in the form of snow. At mid-morning, radar showed precipitation advancing as far as just north of Richmond and just south of Charlottesville, but none of it was reported reaching the ground. These areas were becoming more scattered by noon. A few stations in West Virginia had light snow. Light rain reached as far north as the Norfolk area in southeastern Virginia.

Temperatures should warm up to near 50 this afternoon in most locations. It's now 49 here in Montgomery County.Tonight should see temperatures below freezing for the 12th time so far this month, with lows about 30. Tomorrow will be sunny with temperatures a few degrees warmer, into the low 50's, nearly seasonable for this time of year.

March so far
March is normally one of the wettest months in Washington, with an average of 10.1 days, or 33%, having measurable precipitation. For the first half of this month, we have seen only 2 such days. Last year on the 16th, we were beginning a 6-day stretch of rain and drizzle. As for the temperature, there has been only one day so far which averaged above normal. The overall average of 5.3 degrees below the long-term normal, if it continues, would make this the coldest March in over 20 years, just 0.1 degree warmer than in 1984.

In the news
The industrial grade 80,000-ton ice sculpture near Fairbanks we mentioned last week has collapsed from above-normal temperatures, according to a report in the Anchorage Daily News.

On a somewhat larger scale, there were reports this week that the snow cap of Mt. Kilimanjaro has melted for the first time in 11,000 years.

It's mid-March; do you know where your spring is?

Currently
It's a few degrees warmer today than at the same time yesterday, although the winds are actually stronger, gusting as high as 29 mph around the area at 1pm. Temperatures ranged from 45 to 48, heading for a high around 50 under sunny skies.

Outlook
Clouds will increase by tomorrow morning as a low-pressure area getting organized in the western Gulf of Mexico this morning heads eastward. Yesterday, we told you that precipitation from this storm was likely to remain south of us, and that trend has been confirmed by model runs since then. Both major U.S. models this morning are again keeping the precipitation to the south, although some measurable precipitation does make it as far north as central Virginia. This means we can't totally rule out some light rain or snow in the southern part of the area; the most likely time would be tomorrow morning or early afternoon. After that, the most likely time for precipitation in the area is Saturday or Saturday night; amounts will probably be light.

Through the looking glass
I have rarely looked at Southern Hemisphere weather maps, so I find them a bit disorienting; they're a mirror image of what we're used to. Severe tropical cyclone Ingrid, after bouncing around the northern Australian coast, was making its third landfall this morning (early hours of Wednesday Australian time) as a category 4 storm with wind gusts up to 260 km/hr. It had previously strengthened to a category 5 over the Gulf of Timor. ABC News (Australian Broadcasting Corp.) was reporting that winds of over 280 km/hr were hitting the remote resort of Faraway Bay. The storm had moved north of Darwin, which was nearly destroyed by Cyclone Tracy on Christmas Day, 1974.