* High-wind warning from 11 p.m. Thursday to 6 a.m. Saturday *
Update at 10:45 p.m.
Damaging winds are moving closer to the Washington region, and are likely to begin from west to east over the next few hours. The National Weather Service has released a rather dire special statement on the “high-impact” wind threat that echoes much of what we say below. Here are two key excerpts:
“High winds will continue to progress eastward towards the major metropolitan areas of Baltimore and Washington overnight. By daybreak, winds across the region will be from the northwest sustained at 30-40 mph, with gusts 60-70 mph. Isolated wind gusts could reach 80 mph, particularly at higher elevations west of the Interstate 95 corridor.”
“Widespread power outages are expected. Travel will be difficult, especially for high profile vehicles. Pedestrians will face very hazardous conditions, and need to be aware of wind-borne projectiles. People should avoid being outside in forested areas and around trees and branches. If possible, remain in the lower levels of your homes during the windstorm, and avoid windows. If you use a portable generator, follow manufacturer’s instructions and do not use inside homes, garages, or apartments.”
A few quick tips:
* Charge your portable devices NOW
* Do not park your car under a tree
* If you have vulnerable trees near your house that you know could fall, sleep in the lowest level overnight in an interior room, away from windows.
* Please read the overview discussion below and do not venture out in the morning if conditions appear dangerous.
We will post updates starting between 5 and 6 a.m. Friday.
Original post from 9:46 p.m.
New data coming in this evening suggests the *possibility* of a severe burst of winds between about 5 a.m. and noon Friday. These gusts, if some model forecasts are correct, could reach 60 and 70-plus mph in parts of the region. Winds this strong would lead to significant tree damage, some structural damage, and thousands of power outages.
Importantly, they would present a dangerous situation for commuters, both pedestrians and motorists, as well as children on their way to school.
We urge pedestrians, motorists and parents to pay particular attention to conditions in the morning. Carefully review the forecast. This forecast could change and winds may not reach such worst-case forecasts, but we want everyone to be safe.
If winds become severe or are forecast to, do not venture out. Treat this event like you would a dangerous thunderstorm and remain sheltered, away from windows, until the worst of the winds subside some.
Winds in the higher terrain west of Washington are likely to see the strongest wind gusts, possibly exceeding 70 mph.
Already Thursday evening, locations to the west of Washington in West Virginia have reported 50- to 60-mph wind gusts, a sure sign hazardous winds are destined for our region. Charleston clocked a gust to 55 mph, Elkins 56 mph, and Petersburg 59 mph.
Damaging wind gusts could reach Washington’s far western suburbs as early as 11 p.m.
In its forecast discussion posted just before 8 p.m., the National Weather Service sounded the alarm, referring to a rare but menacing phenomenon known as a “sting jet” that could rake across the region:
Concern is increasing for the Friday morning hours between 6 a.m. and 12 noon for the strongest period of winds. A feature similar to a “sting jet” may cross the region during this time frame, increasing the threat for the 60-70 mph winds.
A sting jet describes a zone of particularly intense winds that sometimes forms on the southwest side of a developing storm. If such a feature evolves, winds similar to those observed during the 2012 June derecho could occur in parts of the region.
While sting jets are most commonly observed over the ocean, they can affect land areas and are occasionally witnessed over the British Isles. Their winds can exceed hurricane-force.
In its discussion of sting jets, the UK Met Office cautions “[s]ting jets are difficult to forecast because of their relatively small size, and the way each individual low-pressure system develops.” It is not a sure thing such a feature will develop over our region.
Whether or not we see this period of particularly intense wind gusts Friday morning, we are in for a long-duration pounding wind event.
“The fact that this is a long duration event and the ground will already be saturated means that widespread tree damage is expected along with power outages,” the Weather Service says. “This is going to be one of the most powerful wind storms in recent years. Through this evening … it is a good time to secure lightweight objects outside, and check flashlights and batteries as well as other items needed in a power outage.”