Friday, September 01, 2006
Ernesto to Douse District and Surrounding Areas
Two to five inches of rain expected, strong winds
A. Camden Walker @ 11:00 AM
Tropical Depression Ernesto is likely to track close to the DC metro area today. Due to anticipated heavy rains, our area is under Flash Flood and Coastal Flood Watches. Strong winds are also possible and a Wind Advisory has been issued for noon to 10pm. Virginia and the District have issued a state of emergency. See further Washington Post coverage documenting the storm's landfall last night near Wilmington, NC.Today
Rain and wind. Rain has gradually increased in coverage and intensity from south to north across the region. Temperatures will hover in the upper-60s most of the day, under overcast skies.
Winds from the northeast have picked up along with the rain. They'll average 20-25mph through the daylight hours. Gusts could reach 45mph by late in the afternoon.
Both rain & wind will crescendo until 8pm, then decrease ever so slowly. After 2am tonight, rain will be less steady but will still fall in bursts.Tomorrow
End In Sight! After sunrise, winds will subside a bit, but it will remain breezy. Isolated rain showers could still be tropical (thus heavy) in nature and difficult to dodge. The overcast may break during the afternoon hours. Look for a high around 76 degrees, with slight humidity in the air. Road travel should be relatively safe & easy as steady rain ends sometime during the morning.The forecast for the rest of the holiday weekend continues below after Questions and Answers.
Questions and Answers
Who is most likely to see the heaviest rain? Friday's heaviest rain will stretch from southern Virginia through Washington, DC and areas just to the west. Overnight Friday and into Saturday, rain will slowly accumulate into the northern Blue Ridge mountains and central and western Pennsylvania.Pictured: Area Rainfall Potential, by CapitalWeather.com
What impacts can the area generally expect? Power outages cannot be ruled out, but should not be widespread. Winds could gust a few times above 40mph. Flooding risk is high if you live in a low lying area and had problems during our late-June deluge.
When it will start, and when it will it end? It will most likely start before dawn Friday in the southern suburbs, spreading into the northern suburbs around dawn, although there is some uncertainty with this timing due to the dry airmass overhead which may be tough to saturate. The rain should diminish overnight Friday into Saturday morning and will probably not be more than a 24 hour event, unless the storm unexpectedly slows.
What is the severe thunderstorm threat? If Ernesto was a stronger system, there'd be a higher concern of severe thunderstorms including the potential for isolated, small tornadoes, but that threat is mostly well southeast of us.
What are the uncertainties? How could the forecast go wrong? Ernesto could slow down due to strong high pressure to our north (giving us that chill in the air, currently). This same high pressure system, with its typical clockwise flow (easterly from the Bay) could push Ernesto onto a more westerly track. Alternatively, if the storm was not impeded by the high, it could take more of an easterly track.
Possible scenarios different from our current forecast:
- A SLOW TRACK JUST TO OUR WEST: The high slows but does not impede Ernesto's northward progress through the region. The Metro area sees more rain (5" or more) and more wind (gusts to 50mph within reach), with the rain lasting through a good part of Saturday.
- A TRACK FAR TO THE WEST: If the high pressure area suppresses the storm and/or steers it further westward, where an upper level trough could pick it up, we would see less rain and wind (1" or less, perhaps) as the storm heads up the mountains.
- A fast easterly track is also possible if the storm is not impeded by the high, and does not get "caught" by the trough to the west. In this scenario, the Metro Area might see only 1" or so of rain and winds would be reduced (but increased near the Bay/Beaches). We'd miss the brunt of the storm, and clear out faster.
- Doug Hill: General 3-6", more near the Bay.
- Sue Palka: 3-6", more East of DC, less west.
- Bob Ryan: 4-5" immediate area, 6"+ to the west, especially around the Blue Ridge; rain ends Saturday morning.
- Topper Shutt: Did not mention amounts, but thinks rain may linger until Sunday morning given High Pressure block; predicts slow movement of storm remnants.
Partial Sunshine. Near 80 with breaks in the clouds won't be horrible, all things considered. The end of your holiday weekend appears to be an improvement, as Ernesto tries to move out of the region and allow breezes to settle down. BBQs should stay greenlighted, especially if you head to the beach--sun should be brighter south & east of the Beltway!You are welcome to leave comments, questions, and storm reports. Please use the comments link at the bottom of the top post on this page.
CapitalWeather.com meteorologists Jason Samenow, Josh Larson, Steve Scolnik and Dan Stillman contributed to this post.
Comments are closed for this archived entry | Link | 
Email this post
Email this post
