Scientific Forecaster Discussion
fxus61 Kiln 182345
Area forecast discussion
National Weather Service Wilmington Ohio
645 PM EST Sat Nov 18 2017
showers and thunderstorms will continue into early evening as a
strong cold front pushes through the region. Precipitation will
then taper off overnight as a much cooler airmass settles into
the region for Sunday into Monday.
Near term /through Sunday/...
the surface low is moving into far Northwest Ohio attm with the
attendent cold front extending southwest from it across central
Indiana and into far southeast Illinois. The front is forecast
to sweep east across our area through early evening, as it does,
the convective line along and ahead of the front will continue
to overspread our area through late afternoon. These storms are
being enhanced by a narrow band of marginal ml CAPES (generally
less than 500 j/kg) advecting up into southern Indiana. The
models continue to show this weakening as it progresses east
into our area through early evening which may help limit the
severe threat across our area. A period of heavy rain will also
be likely with the storms. Overall, they should be progressive
enough to limit widespread flooding concerns. However, the line
does appear to be laying out a bit more west to east across our
north. This is also in the area that received the heavier rain
this morning, so will go ahead and continue with the Flood Watch
and also expand it about a tier of counties to the south.
A deformation axis back to the west across Illinois will pivot
east across our area later this evening and into the early
morning hours. This will lead to some lingering showers into
tonight but they should taper off from the west later tonight
as drier air works in from the west. Gradient winds out ahead of
the front continue to be impressive with occasional winds gusts
in excess of 40 knots occurring across our southern areas.
The low level thermal fields off the NAM and GFS are both
keeping pcpn mainly rain through the night over all but
possibly our northwest. The Cobb method is trying to show a mix
developing up across our northwest later this evening possibly
working east through the overnight hours and this may be more
representative given the good cold air advection developing in the low levels.
Will therefore go ahead and at least allow for a rain snow mix
for a brief period before tapering off the pops overnight.
Short term /Sunday night/...
we will remain in weak cyclonic flow and low level cold air advection through
much of the day on Sunday as a secondary mid level short wave
pivots across the region. There will be a fetch off of Lake
Michigan but moisture will generally be limited to below 850 mb.
This could lead to a few snow showers through early afternoon,
especially across northern portions of our area. In the caa,
expect highs on Sunday only in the mid to possibly upper 30s.
Surface high pressure will build in from the southwest Sunday
night allowing the low level flow to begin to back. This should
allow for clearing skies Sunday night with lows dropping down
into the mid 20s.
Long term /Monday through Saturday/...
surface high pressure will push off the the east through the
day on Monday. As we start to get into some return flow,
temperatures will begin to moderate with highs rising into the
mid to upper 40s. Short wave energy rotating across the upper
Great Lakes will help push a cold front southeast across our
area Tuesday into Tuesday night. Moisture is limited with this
so will maintain a dry forecast at this point. Highs on Tuesday
will be in the upper 40s to lower 50s.
We will remain in a northwest flow pattern through the end of
the week. There are some timing and placement differences
between the models with weak energy dropping down toward the
area through Friday. However, the airmass will remain relatively
dry with the next chance of pcpn not until some stronger energy
drops down from the northwest heading into Saturday.
Aviation /00z Sunday through Thursday/...
deep surface low pressure over Lake Erie to continue lifting
quickly northeast through the eastern Great Lakes overnight.
Showers and perhaps an embedded thunderstorm with strong
southward trailing cold front moving through the taf sites
early this evening. IFR cigs and vsbys possible in some of the
heavier downpours early this evening.
This pcpn will push east across the taf sites as the front
sweeps east. As the front comes through, wind gusts up to
37 kts will be possible with winds veering to the northwest.
Mid level deformation zone over Indiana with additional showers
will offer a chance of lingering pcpn into the overnight hours.
Will continue MVFR cigs overnight into Sunday with improvement
expected Sunday afternoon.
Outlook...no significant weather expected.
Ohio...Wind Advisory until 4 am EST Sunday for ohz026-034-035-042>046-
Flood Watch until midnight EST tonight for ohz026-034-035-
Kentucky...Wind Advisory until 4 am EST Sunday for kyz089>100.
In...Wind Advisory until 4 am EST Sunday for inz050-058-059-066-
Flood Watch until midnight EST tonight for inz050.