LWX posted watches for Garrett/Allegany in MD and Mineral County in WV. Up to 0.3” ice and 1” of snow/sleet.
Good write-up too by LWX explaining the set-up and possibilities:
Complex (but somewhat typical for this area) storm system will
affect the area Thursday into Friday. A lead shortwave will be
responsible for an initial round of precipitation Thursday,
then a stronger shortwave will force an area of low pressure to
develop along the stalled front to our south, before tracking to
our west and north Thursday night and possibly redeveloping
offshore Friday. Meanwhile, a strong Arctic high will be located
over Canada feeding cold/dry air southward which will become
dammed east of the Appalachians. The atmosphere may be cold
enough (or at least wet bulb low enough) for precipitation to
start as some snow or sleet for parts of the area. However, the
air aloft will warm with time, eventually leading to a rain or
freezing rain scenario. Surface temperatures are always tricky
during CAD, but probabilities support the greatest chance of any
icing generally north and west of I-95...but particularly
within a couple counties of the PA border where the greatest QPF
is expected Thursday night to Friday morning. In some of these
areas, especially in the Cumberland MD area, the wedge may not
break until the trailing cold front arrives later Friday
morning.
Some of the factors that will have an effect on this system:
1. There will be an interesting play between air temperatures
and precipitation with the initial round Thursday due to wet
bulb processes, which may ultimately determine the
strength/breadth of the CAD.
2. There will be very dry air at the surface, so precipitation
could have a hard time progressing northward Thursday.
3. While not a common solution in models, there is some
potential for a more prolonged period of sleet near the PA
border which could reduce freezing rain accumulations.
4. For much of the area, temperatures will be marginal for the
event, and the preceding days have been very warm. Any areas
where freezing rain is light or brief may not have as much of an
impact as it would otherwise.
5. Uncertainties about if and how much temperatures drop
Thursday evening and rise thereafter, as well as QPF during the
second wave, which will largely be focused north of the area.
In the end, issued a Winter Storm Watch due to the potential of
more than a quarter inch of ice for Allegany, Garrett
(especially eastern), and Mineral Counties. This is based on a
combination of NBM probabilities, QPF forecasts, and CAD
climatology. Interesting enough, if western Garrett stays warm
and sees mostly rain, we may have to monitor localized minor
hydro issues. It`s also possible places like Catoctin Mountain
could near a quarter inch of ice, but confidence/areal coverage
is expected to be much lower in these areas. We will evaluate
the need for advisories/warnings later today.