From RAH:
Forecast confidence decreases by the weekend but is looking
increasingly interesting for potential wintry precipitation. First
of all, recent model runs have trended significantly lower with
temperatures this weekend, in large part due to a stronger and
farther south surface high over SE Canada or the Northeast US, which
would act as a supply of cold air to the region. This high looks to
remain in place as it will be blocked by the aforementioned coastal
low that will be over far eastern Canada by then. Thus went a bit
below NBM for temps and decreased forecast highs to 40s on Saturday
and Sunday, with even upper-30s possible in the north, and lows
Saturday night in the mid-20s to lower-30s. Meanwhile, the 12z runs
of both the
ECMWF and
GFS have come into better agreement on a
northern-stream wave diving SE from the Midwest on Saturday to off
the coast of South Carolina by early Sunday. Thus have chance
POPs
from Saturday into early Sunday, with the best chance of
precipitation on Saturday night.
If this more southerly track
occurs, temperatures look cold enough both aloft and at the surface
that frozen precipitation is possible, and introduced rain or snow
to the wx grids during this period. However, models have not shown
run-to-run consistency with this system yet so confidence remains
low. A return to dry weather but continued below-
normal temperatures
are expected on Monday.