Area Forecast Discussion
Issued by NWS Wilmington, OH-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KILN 221742
Area Forecast Discussion
National Weather Service Wilmington OH
142 PM EDT Wed Mar 22 2017
High pressure will settle south into the Great Lakes and Ohio
Valley today. The high will move east of the region tonight and
Thursday. A warm front is expected to push northeast through the
region Thursday night which may bring a few showers. After below
normal temperatures today and tonight, a warming trend is
expected into the upcoming weekend.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --Few to scattered stratocumulus in central Ohio will continue to
diminish through the afternoon. Cool temperatures with northeast
low level flow will persist.
-- End Changed Discussion --
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Models are in fairly decent agreement for the upcoming short
For tonight, the center of the sprawling high will move to a
position over the northern/central Appalachians by morning.
Winds will veer east overnight as this occurs. Although some mid
and high level clouds will begin spilling into the region from
the west, it will still be a very cold night, especially over
parts of central Ohio where clouds will be thin and winds the
lightest. A new freeze warning for locations along and south of
the Ohio River has been issued. There is some concern on the
thickness of mid and high level clouds across western parts of
this region. However, believe all locations even where cloud
cover develops, will likely fall below freezing. Lows will range
form the upper teens/lower 20s north to the mid and upper 20s
On Thursday, low level southerly flow will increase on the back
side of departing high. At the same time, a mid level ridge will
begin to poke northward into the mid/upper Mississippi River
Valley. WAA induced clouds will spread from west to east
through the day. In fact, a warm front will be organizing to our
west late in the day, which may bring a few showers to our
western zones by evening. A modifying airmass will boost
temperatures into the upper 40s far north to the mid/upper 50s
along and south of the Ohio River.
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
High pressure will be moving east of the ILN CWA on Thursday,
stalling and weakening over coastal North Carolina on Thursday
night. As this occurs, the 500mb pattern will be amplifying in the
vicinity of the Ohio Valley, even as relatively tranquil conditions
are expected at the start of the long term forecast period. Heights
will be rising as ridging builds into the Mississippi Valley, as a
complex low pressure system begins to take shape over the plains.
This system will eventually lead to unsettled conditions through the
To begin with on Friday morning, a north-to-south oriented warm
front is expected to move NE through the ILN CWA. This front will be
connected to the surface, allowing for an increase in southerly
flow, and non-diurnal temperatures through the overnight and into
Friday. However, the strongest push of theta-e advection will be at
and above 850mb, leading to a strong inversion. The warmer and more
moist conditions aloft will support elevated showers along the
front, particularly across the northern sections of the ILN CWA,
where forcing appears somewhat stronger. Both NAM and GFS solutions
present some weak elevated instability based at around 800mb, so
getting some convective showers or even thunderstorms may be
possible. For now, the forecast will be kept sans thunder, but it
might need to be added in later updates. Once this front has moved
through by early Friday afternoon, dry conditions are expected, with
the ILN CWA firmly in the warm sector. As a final note for Friday,
the continued warming and a tightening pressure gradient will allow
for somewhat of a mixed layer under the inversion -- along with
gusts of 20-25 knots (maybe even a little higher in the NW CWA).
After a dry period on Friday night and into early Saturday,
attention on Saturday afternoon and evening will turn to a
developing stacked low pressure center moving through Missouri.
Confidence continues to increase in the overall timing and placement
with this system, though recent model runs have allowed for a
slightly slower overall progression, leading to drier expectations
for much of Saturday. It is expected that there will be several
rounds of showers (and potentially thunderstorms) along with this
system, running primarily from Saturday evening through Sunday
afternoon. Though the overall motion of the low will be slow, the
juxtaposition of upper support, low level moisture transport, and
500mb vorticity advection will result in the possibility of multiple
time periods in which showers and possibly thunderstorms will be
able to develop. With 00Z GFS / 00Z ECMWF runs solidifying timing on
the Saturday evening time period for one such wave of activity, PoPs
have been increased to 70-80 percent, with generally 40-60 percent
chances Saturday afternoon and then again through much of the rest
of Sunday. Thunder has been included as a possibility on both days
as well. This system will have a respectable feed of theta-e and a
tight/compact 850mb-700mb low, so forcing and moisture should be
sufficient for widespread precipitation. The possibility for heavier
rainfall or strong storms is less certain, owing to differences in
model specifics and a pattern that is not necessarily a classic
setup for either threat. Nonetheless, there is at least a low-end
potential to watch and refine the forecast for in the next few days.
A narrow ridge behind the stacked low will provide a reasonable
chance for dry conditions for Monday, but the short wavelengths in
the busy 500mb pattern will mean that this dry period will not stick
around for long. In fact, there is now increasing confidence that
Monday night into Tuesday may time out for the next shortwave, and
PoPs have been increased for this time frame.
The warming trend on Friday is likely to bring temperatures into the
60s, and the slower progression of the incoming weather system will
allow even further gains for Saturday, reaching the upper 60s to
lower 70s. Near and behind the low on Sunday and Monday,
temperatures will cool slightly, but should still remain above
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --VFR conditions will prevail. The few to scattered stratocumulus
across the region will dissipate before 00Z. Otherwise will
only see some cirrus spreading into the region during the latter
part of the period. Northeast winds will diminish to less than
10 kt and then slowly veer tonight into Thursday.
OUTLOOK...MVFR ceilings and visibilities likely Saturday night
into Sunday along with a chance of thunderstorms.
-- End Changed Discussion --
OH...Freeze Warning from 11 PM this evening to 10 AM EDT Thursday
KY...Freeze Warning from 11 PM this evening to 10 AM EDT Thursday
IN...Freeze Warning from 11 PM this evening to 10 AM EDT Thursday