Information is from the NWS Wilmington, OH Office


ILN Area Forecast Discussion/SKEW-T

FXUS61 KILN 211938
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
338 PM EDT Sat Sep 21 2019

.SYNOPSIS...
Southerly flow over the Ohio Valley will persist through the
weekend, offering increased moisture and continued warm
temperatures. A few showers are expected through this afternoon,
then the chance for showers and thunderstorms will increase
Sunday night ahead of a cold front that will cross the region
early Monday. The threat for storms will decrease Monday, as
surface high pressure begins to build into the region.

&&

.NEAR TERM /THROUGH TONIGHT/...
Initial area of showers that moved across central Ohio earlier
today has dissipated, but scattered pop up showers/isolated
thunderstorms have developed across the Miami Valley and west-
central Ohio. This activity is on the fringe/periphery of a mid-
level ridge that is building into the Ohio Valley and
within/near a local area of higher instability. A few of these
showers may work into portions of central Ohio later this
afternoon, but given the influence of the ridge, am not
expecting any development much further south into the CWA. Those
areas that receive convection will have moderate to briefly
heavy downpours and the potential for lightning strikes, but
strong/severe storms with wind/hail are not expected.

Any convection along with cumulus will dissipate by sunset this
evening, leaving mainly mid-high clouds overnight. Lows will be
in the lower to mid 60s.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Mid level ridge starts to move away on Sunday as a trough swings
east in the Upper Midwest/Upper Mississippi Valley. Sunday will
be another very warm day with temperatures in the mid 80s.
Gradient tightens up a bit as well, with midday and afternoon
wind gusts possibly 25 to 30 mph. Sunday should be dry, then as
a cold front approaches from the northwest Sunday night, clouds
will increase during the evening and showers and perhaps a few
thunderstorms are expected to move into western portion of the
CWA, generally after midnight. Convection will spread through
much of the CWA through sunrise Monday.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Model consensus remains in good agreement showing a fairly quick
progression of the much-anticipated cold front southeast through the
ILN FA Monday morning, yielding progressively drier conditions from
late morning onward from northwest to southeast. Even with this
said, do expect a gradual weakening trend of one or more initially
cohesive bands of showers and isolated thunder as the activity
pushes further to the south/east -- owing to a gradual loss of
focused forcing. This will result in mainly dry and clearing
conditions by mid/late afternoon -- even in the east. And with the
arrival of the aforementioned drier air will come seasonably cool
overnight lows Monday night and Tuesday night with highs generally
in the mid to upper 70s both days.

The cold front will allow for cooler and drier air to infiltrate the
Ohio Valley from Monday afternoon through at least midweek -- with
near normal to slightly above normal temperatures during the first
part of next week. This will occur coincident with surface high
pressure briefly building into the region followed by a secondary
weak frontal passage Wednesday night into early Thursday morning.
While certainly this FROPA could deliver another round of scattered
showers to the area -- as of right now, it does appear that the
forcing and moisture availability will be rather meager. This would
tend to suggest for the front to progress through the area with just
some chance PoPs at best before drier conditions once again return
by Thursday afternoon.

Beyond Thursday, longer range guidance remains in remarkable
agreement showing potent quasi-zonal mid/upper level flow
transitioning to anomalously expansive and strong ridging initially
across the southeastern U.S. late in the workweek before
overspreading pretty much all of the Tennessee/Ohio Valleys by next
weekend. While there are some natural discrepancies that exist in
longer range solutions -- specifically as they relate to exact
positioning and timing of ridge development -- there remains above
normal confidence in another period of very warm temperatures
setting up by the end of the long term period. The persistence of
several deterministic and ensemble solutions showing this highly-
amplified pattern lends itself to high confidence in above to even
much-above temperatures to close out the month next weekend into the
following week. In fact, EPS mean H5 heights approaching 2 standard
deviations are being advertised across the Tennessee Valley about 7
days from now, with H8 temps 8C+ above normal. This type of pattern
-- should it evolve in such a manner -- would suggest the potential
for record or near record temperatures to close out the month.
Of course, the specifics of the pattern which will ultimately
dictate the sensible weather locally will still be coming into
better focus in the coming days. So certainly this pattern and
the eventual evolution will be watched closely in the coming
week.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A stray shower could still affect KCMH/KLCK through mid-
afternoon, otherwise with a mid level ridge bumping up into the
Ohio Valley, expect dry conditions with prevailing VFR
conditions. Exception late tonight would be KLUK where MVFR/IFR
visibilities may occur for a time in fog. On Sunday, as
south-southwest flow tightens a bit, expect midday/afternoon
wind gusts to increase to 20-25 knots.

OUTLOOK...Thunderstorms possible on Sunday night into Monday.

&&

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

&&

$$
SYNOPSIS...BPP
NEAR TERM...BPP
SHORT TERM...BPP
LONG TERM...KC
AVIATION...BPP


Skew-T

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