Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
647 am EDT Sat Aug 29 2015
a weak warm front will lift north across the area today while an
upper level disturbance pushes east across the region over the
weekend. This will result in an increasing chance of showers and
thunderstorms and seasonable temperatures over the weekend.
Near term /until 6 PM this evening/...
a weak warm front will lift north this morning allowing a warm and
more moist air mass to overspread the region. Convective available potential energy over 1000 j/kg
will develop over the forecast area. With the approach of an 500 mb short wave swinging
through the Great Lakes...there will be enough instability and lift to
carry a slight chance of a shower or thunderstorm across the
Temperatures will return to normal values today as highs will
generally be in the middle 80s.
Short term /6 PM this evening through Monday/...
the 500 mb short wave is forecast to weaken tonight as it swings north of the forecast area.
Moisture being pulled into the region on the backside of high
pressure will linger across the region tonight into Monday.
Lingering weak convergence will keep a chance of convection for
the rest of the period...but the chances will be decreasing late
Sunday night into Monday.
Highs on Sunday and Monday will be a little cooler...in the low
to middle 80s. Lows will be in the middle 60s.
Long term /Monday night through Friday/...
with a weak flow pattern aloft...models continue to exhibit erratic
run to run behavior and significant spread in their handling of
synoptic features through the extended period...especially as the
remnants of Erika come into play. To account for model
discrepancies...have used a blend of solutions and relied on
A middle level shortwave will lift from the Gulf of Mexico into the Middle
Atlantic States. Under the influence of this feature the 28.00z
European model (ecmwf) run featured an upper level shortwave morphing into a slow
moving cutoff low over the Great Lakes region through early
Wednesday. The 28.12z European model (ecmwf) run is a completely different story
and much more in agreement with the GFS...showing the Ohio Valley
and Great Lakes region under an amplified middle/upper level ridge on
The middle/upper ridge will flatten out a bit Tuesday through Thursday
which is when model solutions diverge significantly under the
influence of weak flow aloft to around 400mb. Forecast details start
to become murky as a result. Synoptic forcing will be lacking but
given the unseasonable warmth and moisture /high temperatures 5+ degrees
above normal and precipitable waters 1 to 2 Standard deviations above normal/ have
gone with slight chance diurnal probability of precipitation each day. Highs will generally
be in the middle to upper 80s with lows in the middle to upper 60s.
Aviation /12z Saturday through Wednesday/...
showers are expected to become more prevalent over the region in
the 18-0z time frame this afternoon but should remain VFR. They
should primarily affect northern taf sites but there is not any
particular feature that the models are picking up to definitively
say when or where they may or may not occur. Kept VFR showers at
kcvg/kluk towards 6z. The VFR showers at kday and Kiln in the
late day with vicinity after 0z. Similar at kcmh/klck with vc
starting at 22z. South-southwest wind will turn southeast and decrease to <5kt after
about 0z as the gradient relaxes.
Outlook...thunderstorms possible Sunday.