Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
652 PM EST Thursday Dec 12 2013
high pressure south of the region will move off to the east on
Friday. An approaching low pressure system will spread snow across
the area Friday night. Precipitation may mix with rain as the low
tracks just south of the area Saturday.
Near term /until 6 am Friday morning/...
light southerly winds will continue through the night with high
pressure remaining centered across the Tennessee Valley. Sheared
out short wave dropping down in northwest flow will bring some
occasional middle to high clouds. Overall do not expect to get
anywhere near as cold as this morning. Forecast lows closer to
colder GFS MOS temperatures.
Short term /6 am Friday morning through Saturday night/...
high pressure gets nudged off to the east on Friday. As a
substantial short wave moves out of the Southern Plains Friday
evening...low pressure will begin to organize in the middle south
with an inverted trough extending northeast into the lower Great
Lakes. Precipitation will develop across the forecast area Friday
evening. Most of this will be snow...but there could be a
snow/rain mix near and south of the Ohio River. Precipitation does
not look particularly heavy but 1-3 inches seems possible Friday
Somewhat greater precipitation is expected Saturday as the
surface low tracks near or just south of the southern boundary of
the forecast area. However as the low gets closer it will be able
to draw warmer air in the region. So the snow/rain mix will likely
lift north especially in the afternoon with far southern counties
having a good chance of changing to all rain. Warmer temperatures
and solar radiation filtering through the clouds may hold back a
bit on additional accumulation on Saturday...but there will be
more...particularly in the morning. Guidance has had a reasonably
consistent signal that this will be an advisory event where
precipitation is primarily snow. So have issued for all but the
far southern counties.
Precipitation will taper off late Saturday afternoon into Saturday
evening as the low weakens in the Lee of the Appalachians and
energy transfers to the coast. Could be a few lingering
flurries/snow showers...but overall little additional activity for
the latter part of the night.
Leaned towards cooler guidance for highs. Lows Friday night will
likely be early with steady or slow rising readings later in the
night. Some discrepancy on how fast colder air comes in behind the
low Saturday night. So just used a blend for that time frame.
Long term /Sunday through Thursday/...
snow will be just east of the area at the beginning of the long term
time period. Winds off of the lake are not very favorable for lake
effect snow on Sunday and therefore have decided to go with a dry
forecast. Cold airmass will be in place on Sunday and therefore
temperatures will struggle to rise. Only expect a degree or two
rise in temperature on Sunday from Saturday night low temperatures.
A couple of weak disturbances will move through the area Monday into
Tuesday. Moisture is limited with these disturbances and therefore
decided to go with only a slight chance of snow showers across the
forecast area Monday night into Tuesday morning.
High pressure will be present near the area Wednesday and Thursday
allowing for dry conditions across the region. Southerly flow will
pick up across the area for Thursday allowing temperatures to warm
into the middle 30s to the lower 40s.
Aviation /00z Friday through Tuesday/...
taf sites will stay VFR through 24 hours as high pressure
centered to the south moves east. Clouds will increase and lower
on Friday in advance of the next snow producing system due to
arrive Friday night. Went with MVFR in snow at cvg starting 02z
Saturday. Winds will be southwest to south around 10 knots.
Outlook...IFR and MVFR conditions expected late Friday night into
Ohio...Winter Weather Advisory from 9 PM Friday to 7 PM EST Saturday
Kentucky...Winter Weather Advisory from 9 PM Friday to 7 PM EST Saturday
In...Winter Weather Advisory from 9 PM Friday to 7 PM EST Saturday