FXUS61 KILN 261042
Area Forecast Discussion
National Weather Service Wilmington OH
642 AM EDT Mon Jun 26 2017
An upper level trough swinging through the Great Lakes will
bring a chance of showers and thunderstorms this evening and
tonight. High pressure will provide dry weather at midweek with
increasing precipitation chances toward the end of the week as
temperatures warm to near normal.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
High pressure centered across the Mississippi valley is
providing a mostly clear morning. Nocturnal AC that had been
affecting the region has been decreasing.
H5 will dig down into the Great Lakes today. However models have
delayed the development of showers and thunderstorms from this
afternoon to tonight. So just expect diurnal cloud development
Temperatures will still be 5-10 degrees below normal, with highs
in the lower to mid 70s.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Out ahead of the s/w, a 30-35kt low level jet will combine with
500-1000 J/kg of lingering CAPE cape this evening to support
showers and thunderstorms dropping e from Indiana. Expect the
convection to be scattered in nature as it works across the
region. Lows tonight will be in the lower to mid 50s.
Precipitation could be lingering in the southeast early Tuesday,
but will move e into the Appalachians by mid morning. Tuesday
afternoon will be dry with highs again in the lower to mid 70s.
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Dry high pressure is expected to remain in control of the
weather Tuesday night through early Thursday, influencing
conditions through the middle part of the week. With a turning
of winds to the south on Wednesday, a more appreciable warmup
will begin, with temperatures returning to the 80s.
As a more progressive pattern begins to set up for Thursday and
beyond, model differences become more pronounced, leading to lower
confidence -- especially in precipitation timing near the end of the
week and into the weekend. There is agreement that a frontal zone
will set up east-to-west across the southern Great Lakes beginning
early Thursday, with the ILN CWA in the warm sector within solid
deep-layer southwesterly flow. As convection develops at the north
end of this warm sector, and along the frontal area, there will
eventually be some propagation downstream which should impact the
ILN CWA -- likely beginning on Thursday afternoon, and then again as
additional waves of precipitation occur going into Friday. How much
of the CWA remains capped is a question, as is the exact position of
the front. However, model runs have trended a little southward with
precipitation chances, increasing the probability for storms in the
ILN CWA on Thursday and Friday (especially in the northern half of
the CWA). PoPs have been increased slightly through this time
period, but with little change to temperatures, as there is
confidence in continued southwesterly flow through the period. In
addition, with ample instability and at least somewhat favorable
deep-layer shear, some strong to severe storms could be possible on
Thursday and Friday.
Differences in the evolution of an upstream trough going into the
weekend will preclude more than very low confidence in the forecast
Saturday into Sunday.
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A dry airmass will see high based cu develop and become more
broken as the day wears on. This is in response to a mid level
shortwave pushing through the Ohio Valley early in the day,
followed by a deeper low pressure center crossing just north of
the area later in the day. Skies should clear later in the
overnight hours as subsidence behind the upper shortwave
combines with a building surface high pressure system to the
Models are showing some showers over the region from the forcing
of this system, but a lack of moisture in the lower levels has
me keep the forecast dry today at all TAF sites. Previous
discussion mentioned thunder and the region is in general
thunder for today, but initial thoughts are that any showers
that would develop would be lacking in lower level moisture and
not be deep in nature - at least not deep enough for a charge
separation necessary for thunder. Any showers that do present
themselves later today will be VFR.
WNW winds will increase to around 10 to 12kts during the day on
Monday, with a few gusts to 20kts possible.
OUTLOOK...Showers and thunderstorms are possible Thursday and
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