Friday, October 21, 2005

Waiting, Watching Wilma

After some morning showers and thunderstorms, a northeast wind, heavy clouds, and a light drizzle are keeping temperatures in the Washington DC metro area in the distinctly non-Octoberish low 50s. (The long term average high for today is 66.) The precipitation is associated with a low pressure area moving slowly eastward through the Ohio Valley and a wave on the front extending eastward from the low to the southeastern Virginia coast. Rainfall amounts in the area have been quite light; the official amount so far is only 0.01", while heavier showers at Dulles produced only 0.12".

Tonight and Tomorrow

More rain is likely (90% chance) tonight with lows within 2 or 3 degrees of the current 52. Chances of rain will decrease to near 50% by late in the day tomorrow, but skies will remain cloudy with highs near 60.

Tropical Beat

Hurricane Wilma continues to pound the Cozumel/Cancun area of the Yucatan peninsula. Early this afternoon, the center of the storm was just 15 miles offshore from Cozumel; maximum winds were 140 mph. By late afternoon, the eye was crossing Cozumel, and the edge of the eyewall was on the coast of the peninsula. The track is still to the northwest at 5 mph, but a turn to the northeast is still expected over the weekend. Fortunately for southern Florida, an extended visit to the Yucatan will weaken the storm. Increasing wind shear over the Gulf of Mexico is another likely cause of weakening. If Wilma does make landfall in Florida as a Category 3 or higher, this would be the first time that 4 major hurricanes have made landfall in the U.S. in the same year.

Meanwhile, a tropical wave in the eastern Caribbean is showing signs on satellite imagery of developing a circulation. It could become Tropically Depressed in the next few days. If it turns into a named storm, it would be the record-setting 22nd storm of the season named "Alpha."

Capitol Climate: All-Star Cast!
Clear your calendar for next Tuesday early afternoon. The American Meteorological Society's Environmental Science Seminar Series is presenting a panel discussion on the subject, "Hurricanes: Are They Changing and Are We Adequately Prepared for the Future?"
  • Time: Tuesday, October 25, 2005, 12:00 - 2:00 p.m. (Followed by a Reception! Note to starving interns: This sounds like free food.)
  • Location: Dirksen Senate Office Building, Room G-50
The speakers have all published important papers in the last several months on trends in hurricane occurrence and intensity, some of which you may have read about right here on
  • Dr. Kevin Trenberth, Head of the Climate Analysis Section, National Center for Atmospheric Research (NCAR), Boulder, CO
  • Dr. Judith Curry, Professor and Chair of the School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA
  • Dr. Kerry Emanuel, Professor of Atmospheric Science, Massachusetts
    Institute of Technology, Cambridge, MA
The questions to be discussed are:
Are hurricanes, or certain categories of hurricanes, changing? Are these changes more likely tied to a globally-averaged climate warming or are they more likely to be manifestations of natural climate variability? Can large storms be unaffected by a globally-averaged climate warming that has resulted, in part, in an altered hydrologic cycle (i.e., more water vapor in the atmosphere)? Is it reasonable to presume that natural cycles and oscillations can go unaffected by a globally-averaged climate warming? Are there limits on a hurricane's intensity and, if so, what are they? Is there any scientific basis for concern over the plausibility of hurricanes in excess of a category 5 hurricane in the foreseeable future, in a climatically-altered world?
The public is cordially invited.

Katrina Post Mortem

Today's WaPo reports that a FEMA aide testified in hearings that FEMA Administrator Mike Brown's assistant was notified at 11am on Aug. 29 that the New Orleans levees had been breached. These warnings were ignored for 16 hours. If you were reading that day, you saw quotes from the Times-Picayune storm blog as early as 10:30 which indicated flooding was occurring.

Thursday, October 20, 2005

Wilma Wending Westerly Way

A cold front which passed through the Washington DC metro area overnight is becoming stationary across southern Virginia. Temperatures which had been in the low 60s earlier have dropped to the upper 50s with some light showers. Radar in early afternoon showed an area of showers from near Morgantown, West Virginia eastward across far western Maryland, the eastern panhandle of West Virginia, and extreme northwestern Virginia. By mid afternoon, the bulk of the rain had moved quickly to north-central Maryland and the Baltimore area, but a few showers reached the western suburbs of Washington.

Tonight and Tomorrow

Tonight will be cloudy with a 50% chance of showers and lows in the low 50s. Tomorrow, cloudy skies and an east wind will keep high temperatures in the mid 50s with a 70% chance of rain.

Tropical Beat

Accuweather image via
Although it weakened somewhat yesterday from its most extreme intensity, Hurricane Wilma is still a Category 4 storm with maximum winds of 145 mph as of 2pm and back up to 150 at 5pm. It has been moving more westerly than originally expected, and so it is likely to make landfall on the northeastern Yucatan peninsula or remain just offshore tomorrow before turning toward the northeast and heading for southwestern Florida. The storm was centered 135 miles southeast of Cozumel in late afternoon, moving northwest at only 6 mph. Reports from Cozumel showed winds from the east-northeast at 35-40 kt this afternoon. (You can track real-time conditions at the Aviation Digital Data Service METAR web page. Enter station code MMCZ for Cozumel or MMUN for Cancun, although the latest from Cozumel states "FUSE POR WILMA".)

The track models are fairly consistent in turning Wilma toward the northeast and across Florida, but a few are hinting at a later threat to the New England coast, or even Cape Hatteras and Ocean City. The official "zone of uncertainty" extends as far west as the Chesapeake Bay and the lower Potomac. (There is probably a more descriptive term for the shape, but we'll leave that to Wonkette).

You Don't Need a Weatherman
Watch out, Topper, Bob, Sue, Joe, and company: A press release from Televirtual's UK Media Lab announces the world's first artificial TV personality. (That point might actually be debatable.) METman is "a virtual weather reporter/forecaster, whose entire performance is generated automatically from a few lines of text-based data issued as a meteorological summary, and accompanied by a weather map update." The METvoice speech engine is driven by XML-style mark up language to control lip-synch, moods, and gestures.

Wednesday, October 19, 2005

Wobbling Wilma Weakens

South to southwesterly breezes ahead of a cold front are pushing temperatures in the Washington DC metro area again into the upper 70s this afternoon. There is virtually no precipitation anywhere in the U.S. east of the Rockies.

Tonight and Tomorrow

Temperatures tonight will drop into the low 50s. Tomorrow will feature considerable clouds and cooler temperatures with highs around 64.

Tropical Beat

Hurricane Wilma intensified at an astonishing rate overnight, reaching the Atlantic Basin record low barometric pressure of 882 mb/26.05 inches this morning. (The previous record was 888 in '88 with Gilbert.) The storm weakened slightly during the day; the pressure rose to 900 mb at 2pm, and the maximum winds were "only" 165 mph, down from 175. At 5pm, max winds were 160 mph, and pressure was 892 mb. The path was wobbling (Can you say "trochoidal", boys and girls?) around an average direction of west-northwest at 7 mph.

Conditions will be somewhat less favorable once Wilma enters the Gulf of Mexico, but it is still likely to be quite strong if it approaches Florida as expected towards the weekend. All interests in the Florida Keys and peninsula need to keep an eye on developments. Some models are suggesting the hurricane will link up with a low pressure trough now moving eastward through the U.S. This could threaten parts of the East Coast, particularly southeastern New England. On the other hand, a close encounter with the Yucatan could throw a monkey wrench into the whole scenario.

Climate Mash
Just in time for Halloween is the Climate Mash, a fun video from the Clear the Air organization.

Broadcast News

The PBS NewsHour had a discussion about hurricane activity last night with Christopher Landsea, a meteorologist with the hurricane research division at NOAA, and Judith Curry, a climate scientist and chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.

Tuesday, October 18, 2005

Weekend Wilma Worries?

Temperatures this afternoon are about 10 degrees warmer than yesterday in the Washington DC metro area, ranging from 77 to as high as 81 in the southern portions of the region. The only precipitation east of the Mississippi consists of some scattered showers in northern New York and New England.

Tonight and Tomorrow

Under clear skies, temperatures tonight will drop to the low 50s in the city and the mid to upper 40s outside the Beltway. Tomorrow will once again be sunny and dry with highs near 76.

Tropical Beat

Wilma became a hurricane this morning; at 5pm, maximum winds were 80 mph and the storm was moving west-northwest at about 8 mph from a position about 180 miles south of Grand Cayman Island in the Caribbean. Wilma is expected to intensify to major hurricane status (Category 3) as it moves more toward the northwest and into the Gulf of Mexico, eventually turning northeastward toward southern Florida. The storm's impact on our area is very uncertain at this point; that depends on whether it is (1) picked up by a trough in the westerlies and moves up the Atlantic Coast or is (2) pushed offshore to the south.

Climate Clues: A Hard Rain

Image from Meehl et al., Geophysical Research Letters, Vol. 32, L18719.

Today's WaPo has an article describing a study being published online in the Proceedings of the National Academy of Sciences. The study used a climate model to investigate the effects of a doubling of CO2 in the atmosphere by the end of the century. The model predicted that there would be a large increase in the number of extreme heat events and also an increase in the intensity of precipitation. An article in Scientific American online explains that this model increases accuracy from older models by doubling the horizontal resolution from a distance of 50 km between gridpoints to 25 km. By way of comparison, this is almost 16 times the resolution in each horizontal direction compared to what was used routinely in daily weather forecasting just a couple of decades ago.

This study is consistent with one recently reported by NCAR, the National Center for Atmospheric Research, and published in Geophysical Research Letters, which found that precipitation would become more intense with an increase in CO2. The biggest increases would be over land in the tropics. Other areas with large increases include northwestern and northeastern North America.

Monday, October 17, 2005

Warming Washington, Wandering Wilma

After yesterday's high of 68 and a low this morning of 53, temperatures this afternoon in the Washington DC metro area are well into the upper 60s under bright sunny skies. This is likely to be the 15th day so far this month with temperatures at or above normal. The first half of the month has averaged almost 5 degrees above the long-term normal. I turned on my heat for the first time last night, probably the latest I've ever done so as a homeowner.

Tonight and Tomorrow

With diminishing winds and clear skies tonight, lows should be in the low 50s inside the Beltway and in the 40s in the outlying areas. Tomorrow will again be sunny and dry with highs around 75.

Tropical Beat

At 5am this morning, TD 24 became Tropical Storm Wilma. This is only the second time in over 150 years that 21 storms of tropical storm strength or higher have occurred in a single season. Wilma is only 2 days short of beating by a month the development of the previous 21st storm on Nov. 15, 1933. Wilma has also already exceeded the strength of that 1933 storm, which only reached minimal tropical storm strength of 35 kt (40 mph). At 2pm, maximum sustained winds were 50 mph; strengthening to a hurricane is expected. The storm has drifted southward recently, but a more westerly and eventually northwesterly track is expected. There is huge uncertainty in the path at this point, however.

Media Matters

The Weather Channel has begun running ads for the Weather Man movie starring Nicolas Cage as a Chicago TV weatherman whose "personal life is in complete disarray." The movie opens next Friday.

Tony Perkins will appear exclusively on Fox 5 when he returns to Washington, not on other Fox outlets as well, according to the dcrtv blog.

Also from dcrtv is the news that Comcast in the Baltimore area will be carrying the Channel 11 (WBAL) digital weather channel "11 Insta-Weather Plus".

Seasonal Outlook

Latest seasonal forecast: Click here.

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