Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
112 PM EDT Thursday Aug 21 2014
a warm front over the Midwest will slowly move northeast to near
Lake Erie this weekend. The front will likely stall and remain in
the area into early next week.
Near term /until 6 PM this evening/...
strong warm advection over the Midwest is being blocked by the
upper low over the eastern Great Lakes...at least for the time
being. The westerly flow aloft will enable the showers and
thunderstorms over Indiana and western Ohio to slide east into the
forecast area this afternoon as that cluster of storms has
essentially become a middle level convective vortex. The best chance
for widespread showers/storms would seem to be from around
Findlay to Mansfield to Canton and points southeast. The heaviest
may slide just south of the forecast area.
There is already enough cape and low level moisture that
convection will pop US elsewhere but probably in a more random
fashion from outflow boundaries or other convergence sources.
There may be enough debris clouds to suppress the activity for a
while. There will likely be a Lake Shadow up the east Lakeshore
that may protect Ashtabula and Erie from any new convection for a
while but no guarantees. Not much shear aloft but not as warm
aloft as one might guess...the freezing level is generally between
13-14k. Cannot rule out a few energetic thunderstorms but as has
been the case the rain is more of a threat. If we get any training
then there could be localized flood problems.
The humid air mass and increasing clouds should help to keep
temperatures from rising too much. Expect highs from upper 70s to the lower
80s...maybe a few middle 80s where there is the most sunshine. Lowered
forecast hourly and maximum temperatures across the southwest counties where
it will stay cloudiest with the most showers.
Short term /6 PM this evening through Sunday night/...
the front will remain stalled over or near the area through Sun night
to continue to provide a focus for convection. As waves of
convection occur the threat for flooding will remain higher than
normal. Next round of heavy rain may hold off until late tonight
into Friday with a complex that develops over WI/northern Illinois and moves east-southeast
into the County Warning Area then end of tonight and Friday. Some of these storms in
the west could be severe tonight and Friday.
Sat into Sat night somewhat drier air is shown moving over the area
so this time period may be the best shot at seeing the least amount
of convection. Sat and sun have the best potential to be very warm
days...especially in the SW if enough sunshine can occur. Highs
these days in the SW may be near 90 degrees.
Long term /Monday through Wednesday/...
the upper level ridge will continue to increase its influence on the
area into at least Tuesday. Afternoon heating and any localized
convergence may be able to cause a few afternoon/evening
thunderstorms. By Wednesday the ridge should be breaking down and
start to get nudged eastward as a trough digs into the northern
plains. This may mean increasing thunderstorm chances for Wednesday.
The region will continue to see the longest stretch of warm and
humid air of the season. Highs will remain above average with middle
and upper 80s common. Slightly cooler near the Lakeshore.
Aviation /18z Thursday through Tuesday/...
a warm front that is located from central Illinois into southwest
Ohio will become the main concern for our weather the next day or
The atmosphere remains moist with some instability near the
warm front. Showers and thunderstorms will clip the southern half
of our County Warning Area. We can still expect scattered
thunderstorms this afternoon and evening mainly from kcle eastward
across kcak into the kyng area.
There appears to be a chance of an area of thunderstorms with
heavy downpours will possibly occur after midnight into Friday
morning as a mesoscale convective system (mcs) develops and moves
into Northwest Ohio. Other locations further east could be in the path
after 12z on Friday.
Outlook...non VFR possible in showers/thunderstorms this afternoon
through Friday night.
a warm front will be located over Ohio into the weekend. This
occurring as high pressure slowly builds in the middle levels of the
atmosphere into the weekend. This should mean fairly light winds
through the period with winds attempting to become onshore each
afternoon. A land breeze is anticipated each night. Waves will be 2
feet or less away from the thunderstorms. The best chances for
thunderstorms will be tonight into the first half of Friday.