Scientific Forecaster Discussion
fxus61 kcle 230020
Area forecast discussion
National Weather Service Cleveland Ohio
820 PM EDT Sat Jul 22 2017
broad area of low pressure will move through the central Great Lakes
through Sunday. A cold front will move south across the area late
Sunday ahead of a trough deepening aloft. High pressure will build
southeast out of Canada across the Great Lakes during the first
half of the week.
Near term /through Sunday night/...
a few showers continue east of cle to just east of eri to near
yng and also over Knox County. There is modest instability near
or below 1000 j/kg with warming aloft near 700 mb which may help
to keep the atmosphere capped. See little in the way of forcing
for convective initiation this evening so have reduced pops to
chance/slight chance across the region. Partial clearing has
progressed across the western and central counties and this
should continue to the east. Rather humid conditions prevail
with dewpoints ranging through the 70s. With high boundary
layer humidity and recent rain...patchy fog/stratus is likely
away from the lake tonight. Another warm night with readings in
the upper 60s to lower 70s.
Scattered showers and thunderstorms expected to re-develop on
Sunday with diurnal heating ahead of a trough dropping down from
the north. Best coverage is expected in NE Ohio/northwest PA where the
better moisture and low level convergence will be located during
the afternoon. The Storm Prediction Center does have the area
in a slight risk for severe thunderstorms, mainly during the
late afternoon and early evening. Coverage will likely be less
Short term /Monday through Tuesday night/...
a trough will be exiting the region off to the east on Monday.
There could still be a few lingering showers around Monday
morning, mainly across far northeast Ohio into northwest
Pennsylvania. These should move off to the east by the mid-
afternoon hours. High pressure will start to build in by Monday
night and will be the dominate feature through Wednesday with
Temperatures Monday and Tuesday will be a bit below normal as
northerly winds continue across the area. Look for temperatures to
rebound back to slightly above normal by Wednesday as winds veer
back to a southwesterly direction.
Long term /Wednesday through Saturday/...
low pressure will move east across the Great Lakes forcing a
cold front southeast across the area. The front will become
nearly stationary across the area while weak waves of low
pressure move east along the boundary. Limited moisture
associated with the cold front will slide southeast into the
local area with the front Wednesday night into Thursday. A
vigorous upper level positive vorticity maximum will slide
southeast in an upper level trough. This feature will help to
enhance further development of the low pressure system across
the Ohio River valley by Friday morning. The bulk of the
moisture should be southeast of the area and only limited threat
for showers expected going into the end of the week and first
part of the weekend. Warm air advection will take place ahead of
the cold front Wednesday night into Thursday. As the surface
low pressure slides east of the area Friday night, some weak
cold air advection will take place Friday night into Saturday.
Aviation /00z Sunday through Thursday/...
VFR conditions prevail across the region presently with only
isolated showers near yng and north of cle over Lake Erie.
Expect VFR conditions to give way to patchy fog after 07 UTC away
from Lake Erie with some potential of IFR cigs in fog
especially at yng. Patchy morning fog will lift by mid morning
to a sct-bkn cumulus deck near 3000-4000 ft. Scattered
convective development is possible mainly in the afternoon but
confidence is rather low on any specific location and time.
Outlook...non-VFR in early morning fog/mist may continue during
the first half of the week.
winds will generally be light and variable through tonight on Lake
Erie. Winds will turn to the northwest Sunday around 10 knots and
increase to around 15 knots Monday out of the north. Winds will then
slowly veer around from the north to the northeast by Tuesday,
remaining around 10 knots or so. Winds will veer back to the
southwest by Wednesday at less than 10 knots.