Area Forecast Discussion
Issued by NWS Wilmington, OH-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KILN 180212
Area Forecast Discussion
National Weather Service Wilmington OH
1012 PM EDT Mon Oct 17 2016
With surface high pressure over the southeastern states, warm
conditions will continue over the Ohio Valley tonight and
tomorrow. A cold front will move into the region on Tuesday night,
stalling over the area through the middle of the week. As low
pressure moves along this front, occasional chances for rain will
occur. Cooler conditions are expected for the end of the week.
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --Another mostly clear and warm night across the region. Expect a
few patches of cirrus to work through, but in general skies should
be mostly clear.
Winds will hold up overnight which will also help keep
temperatures well above normal. Lows will only fall into the mid
60s, with some of the extreme eastern counties seeing lows in the
-- End Changed Discussion --
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Warm temperatures will be the main story for Tuesday, but an
approaching (and stalling) cold front will complicate the weather
through the middle of the week.
The warmest 850mb air will be moving over the ILN CWA during the
peak of the diurnal cycle on Tuesday -- around 16C at ILN. While
continued warm advection through the boundary layer should lead to
another well-mixed (and slightly gusty) day, there will also be
increasing clouds from the northwest, well in advance of the
approaching cold front. Raw model and SREF plume output still
appears too low based on observed conditions Monday and the
expected continued warming going into Tuesday. However, with
clouds moving in and only a slight change in 925mb-850mb temps,
it was important to not jump too high for max temps on Tuesday. In
particular, ECMWF guidance has been running too warm, and
represents the high end of the envelope -- unlikely to verify.
Thus, combined with mixing expectations from GFS/NAM soundings,
the max temp forecast for Tuesday ranges from around 2F-4F higher
than Monday in the southeastern CWA (mid to upper 80s) to values
close to Monday in the northwestern CWA (lower 80s). This will
again bring Columbus into contention for a record high
temperature, with a lesser (but not impossible) chance for
Cincinnati or Dayton.
The approaching cold front will become more and more detached from
its parent low as Tuesday night approaches, eventually pivoting
into a WSW-to-ENE orientation, and stalling near the northern
border of the ILN forecast area. Initially, convergence along this
front will be somewhat limited, with weak forcing on Tuesday night
/ early Wednesday aided by a more favorable positioning with
regards to the 500mb jet. However, the majority of model solutions
do not support widespread precipitation development, and PoPs have
been limited to 20-30 percent.
The front will remain in place on Wednesday, moving very little,
but forcing a re-orientation of the temperature fields.
Temperatures are likely to remain well above normal, though 80s
will be limited to the southeastern CWA, with the front (and its
associated clouds and low-end rain chances) limiting temperatures
to the middle to upper 70s through the main metro areas of the ILN
It will not be until Wednesday evening that chances for
precipitation begin a more significant upward trend, with a 500mb
trough finally focusing some stronger forcing in the vicinity of
the surface front. As this occurs, NAM/GFS projections both
indicate the development of a surface low along the front, which
will be moving northeast into the region at around the same time.
PoPs increase significantly between 00Z and 12Z on Thursday,
especially in the northwestern CWA, along and just behind the
surface front. Instability is marginal, but enough to include a
slight chance of thunder for a few hours Wednesday evening.
.LONG TERM /THURSDAY THROUGH MONDAY/...
An upper level trough will pivot east across the Mid and Upper Ohio
Valley Thursday into Thursday night with an associated cold front
sagging slowly southeast across our area. Broad southwesterly flow
ahead of this feature will allow for good moisture advection up into
our region through the day on Thursday. The combination of this,
some mid level energy rotating around the base of the trough and low
level convergence associated with the front, will lead to widespread
precipitation during the day on Thursday, slowly shifting east
through Thursday night. There are some timing issues with the trough
and front as well as with some possible low pressure waves riding up
along the front on Thursday. The 12Z ECMWF is the fastest with the
12Z NAM the slowest and have generally trended toward the 12Z GFS
which is somewhat in between. This timing will help determine the
amount of instability that is able to be pulled up into our area
during the day but it does look like there will be enough to
support at least a chance of some embedded thunderstorms through
The upper level trough will begin to shift east of the area on
Friday but both the ECMWF and CMC are indicating some secondary
short wave energy dropping down the back side of the trough heading
into Saturday. This would help keep a broader trough back across our
region into the weekend. Will therefore hang on to some lower end
pops for Saturday, primarily across northeastern portions of our
forecast area. Mid and upper level ridging will then try to build in
from the southwest through the first part of next week, keeping our
region in a general northwest flow pattern. This will allow for some
weak energy to drop down across the area Sunday into Monday, but
timing and placement is uncertain so will maintain a dry forecast
A colder airmass will settle into the region behind the front for
late in the week. This will lead to below normal temperatures Friday
and Saturday with highs mainly in the 50s. We should then see a
gradual moderation to highs back into the 60s through the first
part of next week.
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
High pressure ridging at the sfc and aloft will provide one more
night of mostly clear skies. However, the tight pressure gradient
will keep winds up tonight. Gusts around 20kt will be possible.
In addition, models swing a H9 jet of 45-50kts from the mid MS
valley into the Lower Great Lakes tonight. With this feature
moving through, there will be a chance of some LLWS, so kept the
previous mention of LLWS at the TAFS from 06Z-14Z.
Between 12-18Z the heart of the H9 jet pulls away, but there
should still be enough wind aloft that when daytime mixing kicks
in that gusts on Tuesday will reach into the lower 20 kts. Also
during the morning, models bring a surge of H8 moisture in the
region, so brought in VFR broken cigs around 14-15Z.
By late afternoon, winds will be tapering down as the h9 and h8
winds continue to decrease. Cigs however will be dropping with the
approach of a cdfnt. With convergence and lift ahead of the front,
scattered pcpn will begin to develop. so added a VCSH to the DAY
TAF aft 21Z.
For the extended CVG TAF, MVFR cigs will be possible and the rain
will continue to develop.
OUTLOOK...MVFR Ceilings and visibilities possible Wednesday into
10/17 record highs ----- 86 in 1950 --- 83 in 1968 --- 86 in 1910
10/18 record warm lows - 67 in 1905 --- 65 in 2007 --- 65 in 1947
10/18 record highs ----- 86 in 1938 --- 83 in 1938 --- 86 in 1908