Wednesday Night Update on Thursday Morning Snow (With Pencil Prediction)

A Winter Weather Advisory remains in effect for us tomorrow morning. From 4am in Upper MoCo and 6am in C/SW MoCo until 11am.

The National Weather Service has once again slightly increased its latest maps. About two thirds of MoCo is in the 2-3” range with a third in the 1-2” range. The “reasonable worst case scenario” map now shows up to 4 inches possible.

in the graphing below, by WUSA9, you see a wide range of model outputs for DC tomorrow morning. The 3” from the GFS brings even more to MoCo.

The HRRR, a model that is fairly accurate within short range, shows a very heavy squall line coming through the area around 6am. It has the snow clearing out around 10am.

Snow is likely to start between 5am-7am, which means there’s a chance no snow has fallen by the time MCPS usually makes it’s decision regarding potential inclement weather delays/closures (5am).

Snow will be moderate to heavy for an hour or two, which is why you’re seeing many outlets refer to this as a “burst” of snow. The heaviest would likely fall between 7am-9am, before wrapping up by about 10am.

This could be a situation where the school system has to close, but roads are generally fine by noon or so…just not safe to leave home at 9am (a time many would have to leave if there was a delay).

It won’t be an easy decision for MCPS!

Pencil Prediction: 3 Pencils