The remnants of “Beta” is on the way and may cause flash flooding, especially across portions of Southwest and South Central Virginia late Thursday into Friday. However, some models are “iffy” in regards to how far north moisture will get as the system continues to weaken.
The European model has always been the “more bullish” of the models, showing anywhere from 1 to locally 3 inches of rain across portions of Southwest Virginia. It originally had heavy rain further north across Central Virginia, but has trended southward in the past few model runs.
While the GFS (American) model has kept much of the rain along the North Carolina / Virginia Border, it has come more into agreement with the European model, spreading rain into Central Virginia. It also shows the potential for heavy rainfall across the Southern Blue Ridge.
The North American Model (NAM) Model has slowly been pushing the heaviest rain across the Southern Blue Ridge and into South Central Virginia. It does not have much (if any) rain near the Interstate 95 corridor.
Thursday Evening / Early Friday Morning: Scattered showers will develop across Southwest Virginia and the Southern Blue Ridge as early as Friday afternoon, but will become steady as we move ahead into Thursday night. We expect the rain to be heavy at times Thursday morning across the same areas with the potential for flooding.
Friday Afternoon / Evening: This will be a “slow mover,” and the latest model guidance does not show much movement in the rain all day Friday, continuing across Southwest Virginia, slowly moving into South Central Virginia. This is why we are concerned about flash flooding across these locations.
We are currently forecasting less than one-half inch of rain just south of Interstate 66 in Northern Virginia, southward into the Charlottesville and I-64 area. The best chance for the heaviest rain will be just south and southwest of Richmond, especially Southside Virginia, extending into the Southern Blue Ridge where 1 to locally 3 or more inches of rain will be possible. This will be the area to watch late Thursday Night through Friday for flash flooding.
We will review model data Friday morning and make any adjustments necessary to the rainfall forecast.