Area Forecast Discussion
Issued by NWS Wilmington, OH

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FXUS61 KILN 262027

Area Forecast Discussion
National Weather Service Wilmington OH
427 PM EDT Sun Mar 26 2017

Showers and thunderstorms will develop today into tonight as low
pressure moves to Lake Michigan. After a brief visit by high
pressure and drier air early Monday, another low will bring more
showers and thunderstorms Monday night and Tuesday. Dry weather can
be expected Wednesday under high pressure.


Upper level low pressure is currently in central Illinois with
the second band of precipitation getting ready to exit the CWA.
A third band of precipitation has now formed across the IND
forecast area and is expected to push east through central Ohio
later this afternoon into early evening. The latest run of the
GFS is showing slightly higher MU CAPE values for this afternoon
(some values slightly above 1000 J/kg). For the most part
forecast soundings show this CAPE to be weak and skinny.
Shortwave cooling and 800 - 500mb winds of 35 to 40kts will make
damaging winds and severe hail the primary severe threats for
this afternoon. Due to the above SPC has the area in a marginal


Monday an area of upper level low pressure will push east across
the central United States. This second system will be right on
the heals of the Sunday upper level low and will bring a quick
return for the chance of showers and thunderstorms. After the
brief break Monday morning the upper level low will move towards
Illinois with pockets of PVA crossing the ILN forecast area.
PWATs will also be on the rise towards 1.10" (NAM and GFS). The
best upper level lift from the RRQ will be further south towards
Kentucky but with a weak upper level jet streak moving overhead
think upper level support will be more than sufficient. MU CAPE
values on the NAM across the southern zones are nearing 1500
J/kg while are only around 500 J/kg on the GFS. On the GFS the
greatest 0-3km bulk shear is also further south across KY. The
NAM on the other hand is more north with the greatest shear and
instability. Thanks to the mentioned above SPC has most of the
area in a marginal risk.


Severe risk continues into Monday evening as an area of low
pressure moves across the region. Isolated damaging winds,
isolated large hail, and isolated tornadoes will be possible.
Have this highlighted in the HWO. Severe threat will diminish
later in the overnight hours as the area of low pressure moves
out of the region.

Additional showers and some thunderstorms will be possible
across primarily the southeastern half of the forecast area on
Tuesday closer to a frontal boundary. Dry conditions are then
expected for Wednesday and Wednesday night in between systems.

A warm front will lift northward on Thursday allowing for
showers and some thunderstorms. Shower and thunderstorm chances
will continue for Friday as a cold front moves through.
Precipitation will taper off Friday night into Saturday morning.

Another system will move into the area on Sunday. There are more
model differences with this system therefore limited
precipitation chances to the chance category.


Low pressure system is currently rotating over central Illinois
and slowly pushing northeast. Second band of precipitation is
currently moving through ILN/ DAY with restrictions down to IFR
visibilities/ MVFR ceilings possible. As this second round of
precipitation passes the TAF sites ceilings and visibilities
will recover to VFR. A third band of showers has formed in
central Indiana this afternoon and is forecasted to push east
through the TAF sites later this afternoon into evening hours.
As this band pushes east forecast soundings continue to show the
area destabilizing. As this occurs the amount of lightning
strikes will also increase. Due to this have added a tempo
group for thunder into all the TAF sites. Went ahead and used
current radar trends to help with timing of tempo groups. As the
line passes through the TAF sites some gusty winds and
restrictions in visbilities and ceilings will be possible.

As the line passes the TAF sites a brief recovery to VFR will
occur with a return of MVFR ceilings possible Monday morning.
The NAM is the most aggressive with the return of the MVFR
Monday morning while the GFS is more optimistic. The SREF
probabilities are more in between the two and have decided to
trend TAFs this direction.

During the day Monday any MVFR ceilings will quickly recover to
VFR with another upper level low moving east across the central
United States. By middle of Monday afternoon PVA and upper level
divergence will be overhead meaning a return of showers and
thunderstorms. For now have left mention out of TAFs as this
remains near the end of the period, but future TAF packages will
likely have to incorporate this.

OUTLOOK...MVFR ceilings and visibilities will be possible late
Monday into Tuesday morning.




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