Wednesday, October 24, 2007

Hard Rain Gonna Fall, or a Hardly Raining Fall?


Cloudy, intermittent showers The nearly quarter inch of rain which fell overnight was enough to push the Washington September-October total to date beyond the record driest amount in 1930. (Even though we're still technically in the running, the 1930 3-month fall total of 1.83", just 18% of normal, will be tough to beat.) The rain was also sufficient to create significant traffic disruption in the morning rush hour. Although some heavier showers and thunderstorms brought about half an inch to Richmond earlier, these storms veered to the east as they moved northward, and much of the metro area has received only several hundredths of an inch during the day.

The clouds and rain are resulting from a frontal system and surface low pressure associated with an upper-level area of low pressure. The upper-level low has been cut off from the main west-to-east steering winds in the upper atmosphere, and is stalled over the Tennessee and lower Mississippi valleys. With the weather system nearly stationary or even moving slightly westward, conditions will be slow to clear out over the next couple of days.

Map of surface pressure (solid lines) and 500 mb height (color shading) this morning from Unisys

Tonight and Tomorrow

Mostly cloudy, cool, showers. Cloudy and damp conditions will continue overnight with showers likely. Lows will be generally in the mid 50s. Tomorrow will be cloudy and cool with a 70% chance of showers and highs 55-61°.

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

Climate Corner

Weather Channel senior meteorologist Buzz Bernard had an excellent post last week on the difference between climate science and climate policy. PM Update endorses his invitation to provide "some peer-reviewed scientific work that addresses 'other causes'" of global warming. (No, news reports of a retired professor's rants are not "peer-reviewed", no matter how prominently they were featured on the Drudge Report or squawk radio.)

Political Science

Speaking of policy (notice this is a separate section from the one above), a more careful review of the links in yesterday's Update indicates that the Warner-Lieberman climate bill hasn't been totally "endorsed" by anybody (except perhaps the WaPo in their Monday editorial). The Union of Concerned Scientists also regards the bill as a "good starting point for debate".

No comments:

Seasonal Outlook

Latest seasonal forecast: Click here.

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