Friday, March 31, 2006

Going Out Like a Lamb

Strong southerly flow ahead of a strong low pressure area over the western Great Lakes brought balmy temperatures to the entire East Coast this afternoon. Readings in the 60s and even the 70s reached well into northern New England. Here in the Washington DC metro area, the month is ending on an up note with widespread upper 70s.

Showers out ahead of the cold front extending southward from the low were just reaching the outskirts of Pittsburgh and the northern West Virginia panhandle around 4pm. By 5pm, a first wave of showers had ended at Pittsburgh with less than 0.10" of rainfall; Morgantown WV reported a trace. A few of these showers may make it over the mountains into the metro area overnight, but the focus of upper-level energy will remain near or to the north of the Great Lakes.

Tonight and Tomorrow

Clouds will increase this evening with a 40% chance of showers in the late evening or early morning and lows near 56. Tomorrow will see a chance of showers in the morning and decreasing clouds in the afternoon, highs near 70.

"Parched March"

Today's WaPo has an article "After a Parched March, Water Worries Percolate" discussing the developing drought situation in the area. One item not mentioned is that a scan of the records indicates that if the current total holds through midnight, this month would join only 3 other months in 135 years of Washington records with less than 0.10" of precipitation. The others were April 1985 (0.03"), October 2000 (0.02") and October 1963 (trace).

Thursday, March 30, 2006

Today's Weather Brought to You by the Letter D

It's Definitely, Delightfully spring in the Washington DC metro area this afternoon, but the Drought continues into a 6th week. Southerly flow from a large high pressure area sliding off the Atlantic coast brought spring conditions as far north as southern Canada. In Farmington, Maine, a sure sign of the season is the return of the Hot Dog man to the side of routes 2 and 4.

By mid afternoon, temperatures in the metro area were in the upper 60s to lower 70s. A storm system organizing in the Northern Plains will move northeastward to the Great Lakes tomorrow, but the bulk of the precipitation with it is likely to remain to the northwest and south of the DC region. If you missed Josh's earlier comment, check out the "Dome of Dryness" over the area through Sunday being predicted by one of this morning's models. A similar pattern, although not quite so extreme, is shown by the latest run this afternoon.

Temperature chart at 3pm today from Unisys

Tonight and Tomorrow

Skies will remain clear to partly cloudy through tomorrow afternoon with lows in the upper 40s and highs in the mid 70s. Clouds will increase later in the day tomorrow with only a slight chance of showers before midnight to close out the probable record-breaking month.

Glen or Glenda?

The tropical season continues in full swing Down Under. Tropical Cyclone Glenda is forecast to weaken from a category 2 to 1 as it continues inland along the sparsely-populated northwest coast of Australia. It made landfall as a Category 4.

The Colorado State University Tropical Meteorology Project 2006 season update is scheduled to be released on Tuesday.

Tuesday, March 28, 2006

Who'll Start the Rain?

The drought continues in the Washington DC metro area this afternoon. Scattered showers, a few with moderate rain, were mostly confined to the mountains of West Virginia at mid afternoon. A few very widely scattered showers had made their way along and east of I-81, but they were all south of I-66. They were heading to the northeast, but the easternmost ones seemed to be drying out as they got nearer to I-95. Charlottesville reported light rain at 3pm which lasted less than 20 minutes, and the amount was a trace. Sunshine through a broken high overcast was enough to push temperatures into the low 60s at most metro area locations.

The showers, which are associated with a weakening low pressure area pushing eastward from the Ohio Valley, may still manage to reach the metro area this evening, but accumulation amounts are likely to be meager at best.

Regional radar image shortly after 4pm today from

Tonight and Tomorrow

For tonight, mostly cloudy skies early will give way to gradual clearing by morning with lows around 42. There is a 30% chance of measurable rain. Tomorrow will see more sunshine than today and highs around 62.

Drought Marches On

Unless a downpour parks itself directly over the official rain bucket tonight, we are well on our way to breaking the record for driest March by a margin of over ½". This raises the interesting question of the connection between temperature and precipitation in March. Is a dry March warm because it has more sunshine, or is it dry because there is more cold, dry northwesterly flow?

The chart to the right shows a plot of the average monthly temperature vs. total precipitation for the Washington DC period of record starting in 1871. There is a lot of scatter in the data, so the relationship is fairly weak, but the regression line shows that, on average, March tends to be drier with increasing temperature. In fact, the second-driest March so far (0.64" in 1945) was also tied for the warmest at 55.5°. The driest, 0.57" in 1910, was also fairly warm with an average of 51.2°. What's unusual about this month is that the average temperature has been so, well, average. The monthly mean so far of 46.5 is less than a degree below the long-term average.

CapitalClimate chart from NWS data, photo © Kevin Ambrose

Monday, March 27, 2006

Marching Into Spring

On Sunday, Jason declared winter over, and I can now confirm that it's official. I've seen my first dandelions of the year, and fortunately they're in my NEIGHBOR's yard. (Thank you, Greenturf!) Under brilliantly blue skies, temperatures this afternoon in the Washington DC metro area are pushing close to the average high for late March. Most reporting locations were sunny and in the upper 50s by mid afternoon.

As the nearly complete lack of precipitation approaches the end of its 5th week (0.25" fell on Feb. 22), there is a chance of showers late tomorrow from a storm system moving eastward out of the Missouri Valley. The chances look better from the next system on Saturday, however.

Tonight and Tomorrow

Lows tonight under mostly clear skies will be near 40 in the city, down to the mid 30s in the colder 'burbs. Tomorrow will be mostly cloudy with highs in the upper 50s and a 40% chance of showers in the late afternoon or evening.

Media Climate

Confirming Dan's assertion that the media are starting to "get it" about the story of climate change, this week's Time Magazine has a cover package of articles on global warming. The main article refers to the Science Magazine glacial melting paper we cited here last Thursday. I still haven't seen any reference to it, however, in the Local Paper of Record of the Capital of the Free World. Whassup, WaPo? You had plenty of space for an A-section full-page color ad from Chevron-Texaco today.

Time online also has a link to an ABC News special report on the subject.

Seasonal Outlook

Latest seasonal forecast: Click here.

Latest 3-month temperature outlook from Climate Prediction Center/NWS/NOAA.