Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
349 PM EDT Thursday Aug 21 2014
a warm front over the Midwest will drift northward on Friday...
then stall over the weekend. Warm and humid weather will continue
into next week.
Near term /until 6 am Friday morning/...
very warm and humid air continues to pump northward in the ridge
over the middle of the country. The warm front remains over the
Midwest. Other thunderstorms have developed across northeast Ohio
and northwest Pennsylvania where it is slightly colder aloft and the
lapse rates are steeper. This activity should diminish overnight
while the activity to the west should expand as the low level jet
remains moderately strong over the Midwest.
Some of these showers and storms will spread across Northwest Ohio
overnight. No Flood Watch planned at this time given the fact that
the stronger storms and the threat for back building and training
may remain just to the west of the forecast area for now. This
threat may get near the I-75 corridor of Northwest Ohio by Friday
morning and will have to monitor.
Started with the lows from last night and added a degree or two in
most areas given the increasing dew points so the low temperature
forecast will be a little above guidance.
Short term /6 am Friday morning through Sunday night/...
Friday should start with warm advection showers and storms across
Northwest Ohio. These showers and storms will spread east...probably
a little farther east than today as the overall pattern flattens out
and the warm front nudges northeast and the Theta-E axis pushes
across Northwest Ohio. Will have to continue to monitor for the need
for a Flood Watch. It will ultimately depend on the amount of
redevelopment and training that occurs. The majority of the
activity should remain across Ohio...probably not quite reaching
extreme northeast Ohio and northwest Pennsylvania although will
obviously allow for a chance there as well. Highs generally within a
few degrees of 80 and humid although could be warmer where it
remains rain free.
The blocking pattern aloft is prognosticated to weaken and move east by
Friday night and Saturday. This will allow for the ridge to build
across the Great Lakes. The surface low that has enhanced the low
level jet across the upper Midwest will also lift out. The
building ridge will result in the surface high spreading out
across the eastern Great Lakes and more subsidence. By Friday
evening this should result in a less favorable pattern for the
warm advection thunderstorms that have been affecting the Midwest
the last couple of days. With any Luck...the widespread showers
and storms will be back well to the west of the area by the
weekend. Cannot rule out scattered thunderstorms through the
weekend but each day will generally be partly cloudy warm and
humid. Highs in the 80s.
Long term /Monday through Thursday/...
the upper level ridge will begin to give way by Wednesday and
Thursday. Look for a generally dry Tuesday due to the upper ridge
..but another weather disturbance approaches from the west and will
bring a chance of precipitation Wednesday and Thursday.
Our forecast area will continue to see the longest stretch of warm
and humid air of the season. Highs will remain above average with
highs in the 80s.
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 from central Illinois to southwest Ohio will gradually
meander northward into central and Northern Ohio over the next 24
hours or so. The movement of this front along with available
moisture should be enough to spread scattered showers and
thunderstorms over the lake...and this will extend well into the
Waves will be 2 feet or less away from the thunderstorms. The best
chances for thunderstorms will be this afternoon through tonight and
long term...British Columbia