Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
633 am 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 this weekend.
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 Ohio Valley today. 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. Although convective available potential energy will be low...500 j/kg
M/l...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
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 Tuesday/...
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 /10z Wednesday through Sunday/...
some spotty SC will continue to affect the taf sites through the
first few hours of the taf period. We should then cumulus up through
late morning and into this afternoon as we begin to destabilize.
Short wave energy will drop down across our area later this
morning and through the afternoon. The combination of this and
some weak instability will lead to scattered showers and a few
thunderstorms. Expect best coverage to be at the northern taf
sites and will continue with a vcsh there from later this morning
through middle afternoon. Diurnal showers/cumulus should dissipate through
late afternoon/early evening...leaving mostly clear skies
overnight. With light winds...expect fog to be a little more
widespread than this morning...especially at kluk where some IFR
visibilities will be possible late tonight.
Outlook...thunderstorms possible Friday and Saturday.