Area Forecast Discussion
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FXUS61 KILN 281938
Area Forecast Discussion
National Weather Service Wilmington OH
338 PM EDT SAT MAY 28 2016
The Ohio Valley region remains in between low pressure in the
upper Mississippi Valley and high pressure off the mid-Atlantic
coast. This will support a chance of showers and thunderstorms at
times through Sunday. After a cold front moves through on Sunday
evening, drier conditions are expected for Monday and Tuesday,
with surface high pressure moving into the area. Chances for
precipitation will increase again later in the week.
.NEAR TERM /THROUGH TONIGHT/...
Both at the surface and aloft, low pressure is located over the
upper Mississippi Valley, and high pressure is centered just east
of the mid-Atlantic coast. With little-to-no impact from TD2
expected with regards to the overall pattern over the Ohio Valley,
nothing significant has changed for the ILN forecast area, in a
regime of weak forcing and very slightly confluent flow in the
With no significant capping today, showers and thunderstorms have
been able to develop, though the weak forcing and near-zero wind
shear have kept this activity very disorganized. Signals from
various high-res models (HRRR / NSSL-WRF / WRF-NMM) are all very
similar, focusing the period of scattered thunderstorms through
the peak of the diurnal cycle -- and allowing for much drier
conditions by evening. Without any other clear signals for storm
focus in either model or observational data sets, the current
forecast (30-50 percent chance of storms) will remain in place
through evening, before switching to dry conditions overnight.
The air mass has changed only slightly from yesterday (outside of
the storms), but is generally a little more moist. Based on
current dewpoints, and looking at last night`s low temperatures, a
min temp forecast in the middle to upper 60s appears reasonable.
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Sunday is expected to begin with generally dry conditions, with
very little overall adjustment to the weather pattern. That will
change later in the day, as the troughing over the upper midwest
moves northeast, and begins to flatten the east coast ridging into
more of a zonal pattern across the Ohio Valley by Monday. As this
process occurs, and as the axis of the trough (weak as it may be
this far south) moves through, a weak cold front will also move
ESE across MI/IN/OH. Neither the air mass change or wind shift
with this front will be particularly strong, so the amount of
forcing it will provide is definitely worth questioning.
Otherwise, ahead of the front, the pattern will remain weakly
forced -- probably similar to today (Saturday), with a chance for
disorganized storms (generally on the weaker end of the scale) to
develop as diurnal heating kicks in. Any chances for stronger
storms will probably be limited to areas closer to the front,
which based on timing would probably only really include the
northwestern section of the ILN forecast area. Shear is not going
to improve from current conditions -- 0-6km values of around 20
knots, and much less closer to the ground. Though instability will
not be lacking (MLCAPE forecast to be 1200-1800 J/kg on Sunday
afternoon), the forcing and shear are too weak to support a
significant severe threat, with too low of confidence to even
mention in the HWO at this point in the forecast process.
Max temps for Sunday were increased slightly ahead of the front,
especially in the southeastern CWA, where temperatures today are
pushing well into the mid 80s. Expected clouds and possible
convection will keep temperatures a little lower in the northwest.
The slightly drier air moving in behind the front on Sunday night
will allow for min temps in the lower 60s.
.LONG TERM /MONDAY THROUGH FRIDAY/...
In the wake of a weak cold front, high pressure will settle across
the region for the Monday/Tuesday time frame. Above normal readings
will continue with highs in the lower to mid 80s and lows in the
A mid level trough will be the main weather feature from mid to late
week as it slowly progresses from the northern/central Plains to the
Great Lakes. We should squeeze out one more dry day Wednesday, with
increasing chances for showers/storms late Wednesday night into
Thursday as associated surface cold front moves into the region
from the west. By Friday, the front will slip south of the Ohio
River, with drier conditions moving in behind. Temperatures will
cool some due to clouds/precipitation and then eventually some CAA
in the wake of the front.
For the upcoming weekend, models continue to forecast a long wave
trough developing over the western Great Lakes and extending
southward into the mid/lower Mississippi River Valley. There are
some indications that a weak impulse rotating through the eastern
part of this trough axis may bring a chance of showers and storms
across our eastern/southern zones on Saturday where mid to upper
level lift and deeper moisture will exist. The lower heights and
cooler 850 mb temperatures will result in temperatures going below
normal, with highs in the lower to mid 70s and lows in the 55 to
60 degree range.
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Scattered convection with isolated lightning strikes this
afternoon will continue but should have a bit less coverage than
earlier thinking. H5 ridge will see these storms work NNE through
the region and diminish as daytime heating wanes. A convergent
layer should help to keep some type of cloud cover overnight
which will break up Sunday morning. This will help inhibit storm
initiation until late tomorrow afternoon and push the threat for
any developing storms to be well east of the taf sites.
OUTLOOK...Showers and thunderstorms are possible Wednesday.