Friday, September 14, 2007

Damp Friday Yields to Nicer Weekend


Cloudy, muggy, light showers. Precipitation sandwiched between a strong cold front through the Great Lakes and Ohio Valley and a weak warm front through the Carolinas spread rapidly northeastward this afternoon, but the heaviest amounts were over and to the west of the mountains. By mid afternoon, each of the 3 major airports had reported a trace of rain; Frederick had 0.01".

Temperatures in the metro area are generally in the mid to upper 70s, but dewpoints are in the muggy mid 60s. Behind the cold front, temperatures in the upper Midwest were in the upper 40s shortly after lunch time.

More showers are likely overnight before cooler and much drier air arrives for the weekend.

Tonight and Tomorrow

Showers, then clearing and cool. There is a 40% chance of measurable rain through early evening (more likely to the north and west) and a 60% chance of showers overnight. Lows will be in the mid 60s downtown and in the low 60s to near 60° in the 'burbs. Cloudy skies should clear from west to east tomorrow morning along with decreasing humidity and gusty northwesterly breezes. Highs will be 72-76°.

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

Humberto's History, Ingrid Increases Intensity

After setting the record for fastest intensification from first advisory to hurricane, Humberto quickly became history yesterday, although its moisture brought some drought relief to extremely parched areas of the Southeast. Stu Ostro of The Weather Channel has an excellent retrospective (with pictures) in a series of blog posts.

Ingrid, about 750 miles east of the Lesser Antilles, is a little stronger today at 45 mph, but it is still expected to be weakened by wind shear to a depression without reaching hurricane strength.

Climate Corner: Tropical Topics

This month's American Meteorological Society (AMS) Environmental Science Seminar Series presentation is "Hurricanes and Global Warming: Where are we now?". The seminar is scheduled for next Friday, the 21st, from noon to 2:00 in the Dirksen Building. The public is invited; reservations are not necessary, but registering on the web will allow you to bypass the registration table.

This is also the topic of the DC AMS presentation by Chris Mooney the following Wednesday, the 26th.

Jeff Masters discusses the topic "Humberto and Felix--a sign of climate change?" in his blog post today.

Some new material on the topic of a possible hurricane/climate change connection was published in last week's (September 4) issue of the American Geophysical Union's EOS Transactions (subscription required). The papers "Misuse of Landfall as a Proxy for Atlantic Tropical Cyclone Activity" (Holland) and "Atlantic Tropical Cyclones Revisited" (Mann, Emanuel, Holland, and Webster) both provide new statistical evidence to support the notion that increasing intensity of Atlantic tropical cyclone activity is real and not an artifact of improved observational technology.

For more background on the subject, see MIT Prof. Kerry Emanuel's 2007 AMS Haurwitz Memorial Lecture. It's available for viewing online in both Windoze Media and Quicktime format.


The subject of "Hurricanes & Climate Change" will also be covered on this weekend's "Forecast Earth" on The Weather Channel (5pm Saturday and Sunday):
Will we see more hurricanes in a warmer world? The latest research contains new clues about global warming's influence on the number of hurricanes. We go to the leading climate experts for answers.

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