Area Forecast Discussion
Issued by NWS Wilmington, OH-- Remove Highlighting --
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FXUS61 KILN 261830
Area Forecast Discussion
National Weather Service Wilmington OH
230 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.
.NEAR TERM /THROUGH TONIGHT/...
Upper level low pressure is currently moving into western
Illinois this morning with the first band of precipitation
getting ready to exit the CWA. The second wave of precipitation
has already formed near KCVG and is in association with another
band of PV rotating around the upper level low. This afternoon
forecast soundings will continue to slowly destabilize as low
level cooling commences due to the approaching low along with
weak surface heating. ML CAPE values on both the NAM and GFS are
between 200 and 400 J/kg with MU CAPE values of 500 to 1000
J/kg. Forecast soundings show this CAPE being weak and skinny
with 500 to 800mb winds between 35 to 40kts. This second round
of precipitation is then forecasted to intensify this afternoon
across our far eastern zones. High res models then have a third
round of showers and thunderstorms forming across central
Indiana this afternoon and pushing east across the area late
afternoon into evening. There will be a potential for isolated
hail and gusty winds in any stronger storms due to the
instability mentioned above. Lapse rates in the hail growth zone
do become less favorable during the afternoon into evening
which would tend to limit the large hail potential. Given enough
instability, moisture, lift, and flow SPC has us in a marginal
Low pressure centered over Illinois will travel to Southern Lake
Michigan by this evening. Moisture transport from the Gulf of
Mexico ahead of this slow moving, vertically stacked system is
evident on satellite. Radar shows that showers have developed
and are affecting western counties. This band of showers will
push across the area through today, so kept categorical pops
that have been in the forecast for a few days.
Instability will increase with diurnal heating. Models continue
to depict marginal instability, with CAPE values reaching about
500 J/KG, enough to produce thunderstorms this afternoon.
Potent mid level wind flow will aid in organization of
thunderstorms, and some thunderstorms cells could approach
severe limits, especially in eastern counties where better
forcing and instability may be more in phase.
High temperatures in the mid and upper 60s will be about 10
degrees above normal.
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
Thunderstorms are forecast to linger this evening, mainly over
eastern locations. Showers will be diminishing in strength and
coverage later tonight as the low pressure system moves farther
northeast into an upper ridge and weakens.
For early Monday, a ridge of high pressure will provide a brief
respite from precip chances. Showers and thunderstorms may
return by Monday evening ahead of the next area of low pressure
that will be moving toward the area from the west.
Above normal temperature trend will continue, with highs in the
mid 60s north to low 70s south.
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Weakening upper level shortwave and associated surface low to track
through the Ohio Valley Monday night. This feature will provide
widespread showers and thunderstorms. As this progressive system
shifts east pcpn will come to an end Tuesday. Temperatures will
remain above normal, with Tuesday`s highs ranging from near 60
northwest to the upper 60s southeast.
Surface high pressure to build across the Great Lakes at mid week.
This will provide dry weather Wednesday into Thursday. Temperatures
will be closer to normal, with highs on Wednesday ranging from the
mid 50s northwest to the mid 60s southeast.
Model solutions diverge on handling late week weather system. GFS
continues to be outlier and takes the southern plains upper low into
the Ohio Valley and therefore is quicker with return pcpn.
The more consistent ECMWF and Canadian solutions have the closed low
lifting northeast into the upper MS VLY Friday. Will continue to
trend the forecast toward the ECMWF/Canadian.
Will bring chance pops into the west Thursday and increase these
pops to likely Thursday night into Friday, as moisture and
instability increase across the region. Will mention chance pops for
thunder Friday afternoon into Friday evening. Temperatures to
continue a little above normal with highs from the mid/upper 50s
north to lower/mid 60s south for Thursday and Friday.
As this system exits the region pcpn will end Saturday. High
pressure to offer dry weather through the remainder of next
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --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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