This is from near Balto
https://forecast.weather.gov/product.php?site=LWX&issuedby=LWX&product=AFD&format=CI&version=1&glossary=1&highlight=off
.NEAR TERM /THROUGH TONIGHT/...
Snow is overspreading the entire region at this time and all the way
back through the Ohio Valley. It took a bit to moisten up the
column, but most areas starting to report snow now, and it is
already beginning to cover area roadways. Low pressure is off the
Carolina coast and tracking northeast this morning.
The upper level shortwave responsible for this is located over the
midwest at this time, but is quickly moving in our direction. It is
expected to dive south and east through the day today, with the core
of shortwave energy pushing through southern VA. This will put
northern VA into central MD in prime position underneath the left
exit region of a potent 150+ kt jet streak in the upper levels.
Overnight guidance continued an upward trend as far as QPF is
concerned, so came up about a half a tenth to a tenth of an inch in
that department, given very strong forcing.
Given the strong dynamics aloft, an inverted trough axis will likely
develop well to the NW of the offshore surface low. With the cold
airmass and a deepening DGZ to around 150 mb, snowfall in some areas
may very well overperform beneath wherever this trough axis sets up.
The overnight guidance was very persistent in the placement of this
trough axis from northern VA up into central NJ. This is why an
uptick in QPF was noted before. Thus, have decided to upgrade those
areas to Winter Storm Warnings for this event. It will likely be
very borderline given how progressive the system is, but under the
band of heaviest snowfall, some could see rates near an inch per
hour at times.
Lingering low-level moisture, increasing MUCAPE in the BL
(stretching up into a lowering DGZ), and lift via continued PVA
ahead of a trailing wave, could cause at least scattered snow shower
activity to linger through late Friday afternoon or evening.
Overnight hi-res guidance was again persistent in developing some
northwest flow streamers as far south and east as the I-95 corridor
and I-66 corridor. Worth watching, as some of these bands could
produce some locally heavy snowfall in spots. Generally though,
expect another coating to an inch from lingering snow showers this
afternoon/evening.
