Majority probable timing for any storms will be between 6 and 10 am arriving first along the Interstate 81 corridor and last in Southern Maryland.
Early Monday morning, the storm complex was just start organizing in Wisconsin. By the evening, area of severe storms expanded near the border of Indiana and Ohio.
A computer models all in all project complex for intensification over Ohio valley on From Monday evening to Tuesday morning before heading southeast across the Appalachians towards Pennsylvania, Maryland, Northern and Central Virginia and the county.
It is expected that the complex will develop along the northern periphery. of a heat dome producing record high temperatures in the central part of the United States. This zone is where it’s hot, unstable air meets cooler air and storms tend to erupt—sometimes referred to as the “ring of fire”.
There is outside chance that a storm complex known as a mesoscale convective system meets the criteria of derecho – extensive, fast-moving, a long-lived and strong arcuate squall. However, if a derecho forms, it is unlikely to be as strong as the infamous event about ten years ago on June 29, 2012
The Storm Forecasting Center of the National Weather Service posted region under level 2 out of 5 risk for heavy storm on Tuesday. Areas to the northwest are under a flat higher risk — up up to level 4 out of 5 – “in expectation of highly organized MCS/possible tree develops.
A thunder complex can create a streak of widespread wind damage spanning several states as it approaches the mid-Atlantic region early Tuesday.
The complex will follow the stalled front along the apex of in heat dome as it races from northwest to southeast. This front is shown in predicted surface weather card valid at 8 am on Tuesday. Solid maroon color over West Virginia points to probable location of severe weather the threat:
Will this complex last? in stressed and damaging state, east of Appalachian, very vague. Model predictions indicate that this is possible, as shown in the figure. in high resolution NAM model modeling below.
We define derecho as fast-moving difficult of thunderstorms which creates a destructive wind streak of at least 250 miles in length, with multiple continuous gusts of wind exceeding 58 mph, and occasionally higher (i.e. at 70-80 mph range).
But not all derechos are the same in that they seem to exist on a spectrum of intensity and size. If this complex is considered derecho, its intensity can be moderated by the morning time, when there is not enough sun to greatly destabilize the atmosphere.
Severe June 29, 2012, a derecho arrived here late in the evening, one up to two hours after sunset, in the afternoon, when the temperature reached 104 degrees – in Washington highest June temperature on record. This heat wave contributed to the highly unstable air mass is one of the most unstable ever measured in in region – what could survive for a little hours behind sunset.
Conversely, derecho of June 13, 2013 one of two that collided with the mid-Atlantic that day managed to cross the Appalachians in very early morning hours but ended up in pretty run down condition with minimal instances of destructive winds by the time he reached Washington.
In other words, time of crossing any storm complex of Appalachians and arrival on the east slopes seem to matter in terms of derecho outcome. The odds may be in favor of the less organized or the weaker system when storm complex tuesday arrives.
However, like some models keep simulating an angry thunder arc affecting DC area on On Tuesday morning, we must take this threat seriously. Even if the mountains bite out of the storm complex and the atmosphere are only slightly unstable, the vast and deep “cool pool” containing impetuous air can allow system keep yourself at an intense level for time to east of the mountains.
The CWG will monitor the updraft development trends, updated models and early evening weather balloon sightings and will post updates on situation at the top of this is story.
