Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
149 PM EDT Wednesday Jul 30 2014
a persistent trough will remain across the region through the end
of the week. This will provide near to below normal temperatures
across the area until the start of next week. Expect chances for
mainly daytime shower and thunderstorm activity today...Friday...and
Near term /through tonight/...
a deep upper low is centered just north of the Great Lakes with a
trough extending south of the low across most of the eastern
Continental U.S.. an embedded shortwave is expected to round the trough and
pass across the region this afternoon into early this evening.
The enhanced forcing from this disturbance is expected to produce
an increased coverage of diurnal heating driven shower and
thunderstorm activity across our area this afternoon and evening.
Per latest hrrr...it appears the greatest coverage will occur
along and southeast of the I-71 corridor this afternoon.
Thus...have raised probability of precipitation to likely in these locations...especially
central Ohio. Although convective available potential energy will be relatively low...500-700 j/kg
of 1 km mixed layer cape...with temperatures aloft remaining cool
in the vicinity of the trough...it will not take a very robust
updraft to produce small hail this afternoon. Mostly cloudy skies
developing during the day are expected to keep temperatures from
rising out of the 70s.
Short term /Thursday through Friday/...
the shortwave will exit our region to our east while a deep upper
low spins in place north of the Great Lakes tonight. Any remaining
showers and thunderstorms this evening will quickly dissipate with
the loss of daytime heating and forcing. Another cool night is
expected with skies becoming partly cloudy. Expecting lows in the
middle to upper 50s tonight.
On Thursday... our area will be centered between the exiting
shortwave from today...and another shortwave approaching from the
west. Models are hinting at isolated shower and thunderstorm
activity. However...with there also being indications of weak middle
level ridging between the two shortwaves...am thinking that
Thursday will remain dry. With more sunshine expected
Thursday...and slightly higher 500-1000 hpa heights moving over the
Ohio Valley...temperatures will likely rise to the lower 80s
across most of our zones by the afternoon.
After a partly cloudy night with lows in the upper 50s Thursday
night...Friday will see a rebound of temperatures to near normal.
This will be due to weak return flow developing around high
pressure across New England. This return flow will also bring a
slight uptick in low level moisture across our area. This increase
in moisture...along with the approach of additional shortwave
energy from the west will result in a chance for afternoon showers
and thunderstorms for Friday.
Long term /Friday night through Wednesday/...
an upper level trough will be in place across the area from Friday
through the weekend. Multiple disturbances will bring chances for
showers and thunderstorms off and on through the weekend. The
greatest chance for precipitation will be during the day on
Saturday. Below normal high temperatures can be expected through
the weekend with this trough in place. This feature will begin to
move east of the area on Monday allowing for day conditions. A weak
disturbance will move across northern portions of the forecast area on Tuesday
allowing for a chance of thunderstorms across the north.
Aviation /18z Wednesday through Monday/...
a large scale upper level trough will remain from eastern Canada
..the Great Lakes and New England region...And then into the Ohio
Valley through the taf period. An embedded disturbance rotating
southeast through this trough will combine with daytime heating to
produce numerous showers and thunderstorms this afternoon...mainly
from the central Ohio tafs of kcmh/klck to Kiln. This disturbance
will move east of the area by early this evening. Subsidence in
the wake of this feature and loss of heating will allow precipitation to
shift east and also wane.
For the overnight hours into Thursday...a stronger embedded
disturbance will rotate east/southeast across the Great Lakes.
This should stay north of our forecast area and thus have little
effect except maybe a few middle clouds. Winds will become light to
calm overnight and with some clearing we should see some MVFR to
locally IFR mist at some of the taf sites. Kluk may see more river
fog and have allowed for visibilities to drop below Airport minimums.
On Thursday...area will be in a lull in terms of embedded
disturbance activity so some diurnal cumulus is expected to form
after mist/fog Burns off during the first part of the morning.
Outlook...thunderstorms possible Friday through Sunday.