Area Forecast Discussion
Issued by NWS Wilmington, OH

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KILN 162011
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
311 PM EST Sat Feb 16 2019

.SYNOPSIS...
A low pressure system will move across the Ohio Valley on
Sunday, bringing a mixed bag of precipitation to the region.
High pressure and drier conditions will build into the area for
Monday and Tuesday. However, a chance for precipitation will
return on Wednesday as a low pressure system moves into the
Tennessee Valley.

&&

.NEAR TERM /THROUGH TONIGHT/...
Clouds have been slowly but steadily decreasing along the
southern edge of the stratocumulus field this afternoon. As the
low level flow continues to become more southerly and low level
WAA develops, these clouds should continue to erode away
through late afternoon into early evening. We will then get into
a period of mainly clear skies as we head into tonight before
mid clouds begin to spread back in from the southwest later
tonight. With the models trending slightly slower with the
approaching low pressure system, it looks like any precipitation
should hold off through the overnight hours. Lows tonight will
range from the mid 20s across the north to around 30 in the
south.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Mid level short wave energy will move out of the mid Mississippi
Valley across the Great Lakes region Sunday into Sunday night.
As it does, a weak low pressure system will lift northeast
across the Ohio Valley through the day on Sunday. Ahead of the
low, precipitation will overspread our area through the morning
hours and continue into the afternoon before tapering off from
the southwest Sunday evening. The models continue to hint at
somewhat of a split in the precipitation field with one area of
precipitation affecting more of our southeast and another affect
more of our northwest.

Thermal profiles support pcpn starting off as mainly snow if
the precipitation starts off early enough Sunday morning.
However, a strengthening low level jet moving up across the
Tennessee Valley during the day on Sunday will help pull warmer
air aloft into our area. In northeasterly surface flow ahead of
the low though, temperatures will likely take a while to rise.
As a result, the precipitation will mix with sleet and then
change over to freezing rain as we progress through the day. As
temperatures eventually warm above freezing, the precipitation
will become all rain across at least our south.

There remains quite a bit of uncertainty between the models as
to how long this period of mixed pcpn/freezing rain will last.
The NAM remains the most gung-ho, allowing for a several hour
period of freezing rain and thus ice accumulation. This is
backed up by a few of the SREF members that are suggesting
upwards of a tenth of an inch of ice accumulation across parts
of our area. Meanwhile, the GFS and ECMWF are much more
brief with their freezing rain period and thus not nearly as
aggressive with the ice accumulation.

Would think the best chance for more significant ice
accumulation would be for areas north of I-70 where the surface
temps should remain below freezing through most, if not all
afternoon. This is also the area that will likely change over
to mixed pcpn the latest though too, adding to some of the ice
accumulation uncertainty. At this point, think the best
approach is to allow for a few hundredths of an inch of ice
accumulation across our northwest with lesser amounts elsewhere
across our area. Snow amounts of an inch or less will also be
possible across mainly our northwest. Toyed with an advisory for
northwest portions of our area, but given some of the continued
uncertainty and in collaboration with surrounding offices, will
hold off for now and continue with a mention in the HWO.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
There will be a low chance of snow in northern locations Monday in
leftover moisture on a cyclonic northerly flow behind low pressure.
High pressure forming under a zonal flow aloft will provide dry
weather on Tuesday. Low pressure developing ahead of a major
perturbation in the upper flow will bring precipitation Tuesday
night and Wednesday. Though heaviest precip is forecast to remain
south along the path of deepest moisture transport, a band of
isentropic lift could result in accumulating snow, followed by rain
that may cause more high water issues over moist soils, and on
streams exhibiting well above normal flow.

Colder temperatures and residual moisture behind the system may
combine to produce some light snow Thursday as precip diminishes.
High pressure centered over the Great Lakes should result in mainly
dry weather Friday, before the next area of low pressure brings the
likelihood for rain on Saturday.

Temperatures will start below normal, with highs mainly in the 30s
Monday and Tuesday. A transition to more springlike readings should
be observed by the end of the period, with highs possibly reaching
the 50s most locations by Saturday.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
MVFR stratocumulus is hanging in across our north. It has been
trying to slowly erode from the south but so far has not made
much progress. Will therefore go ahead and continue with MVFR
cigs at the northern TAF sites over the next few hours. We
should begin to see an improvement as we head through late
afternoon and the low level flow begins to become a bit more
southerly.

We should then get into a period of mainly clear skies heading
into tonight before mid level clouds begin to move back in from
the southwest ahead of the next low pressure system. This low
pressure system will lift northeast across the Tennessee Valley
through the day on Sunday. Ahead of this, precipitation will
spread into our area from the southwest through Sunday morning
as cigs fall into MVFR. The precipitation may start off as a
brief period of snow before transitioning over to freezing rain
and/or rain from the south through mid to late morning.

OUTLOOK...MVFR conditions expected into Monday. MVFR conditions
are possible again Wednesday into Thursday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...JGL
NEAR TERM...JGL
SHORT TERM...JGL
LONG TERM...Coniglio
AVIATION...JGL



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.