Scientific Forecaster Discussion
fxus61 kcle 201042
Area forecast discussion
National Weather Service Cleveland Ohio
642 am EDT Fri Sep 20 2019
a warm front will lift northeast across the area tonight. A cold
front will move slowly east toward the local area by Sunday
night. Low pressure will develop along the front late Sunday
night and move east Monday. The trailing cold front will move
east of the area Monday afternoon. High pressure will build east
across the middle Mississippi Valley region into the Ohio Valley
by Tuesday night.
Near term /through Saturday/...
an upper level ridge is expected to remain nearly stationary
through the day today as a potent little shortwave trough and
associated positive vorticity maximum moves east across Lake
Erie today. Latest radar shows thunderstorm activity beginning
to develop here at sunrise just south of the forecast area. More
convection continues to move east from Illinois and will slowly
may progress east by this afternoon. A limited area of moisture
is expected to move into the western portions of the forecast
area today. Dewpoints will rise into the 60s over the western
half the area as well. There should be enough instability and
upper level support to produce some isolated showers or
thunderstorms this afternoon. Will introduce a slight chance for
showers and thunderstorms over the west today. Otherwise, in
the east half of the area expecting fair weather to continue
through the day. A lake breeze will likely develop along the
Lakeshore and this should keep any convection that develops
south of the lake. Warm air advection will take place today and
boost temperatures in the middle 80s west to upper 70s to lower
80s in the east. Best surge of warmer air will arrive later
tonight with the warm front.
Slight amplification of the upper level ridge will take place
tonight in response to the digging upper level trough over the
plains states. The upper level shortwave progged to move east
across the local area this afternoon and evening will shift east
by Saturday morning. This will reduce any leftover evening
threat for showers and thunderstorms in the west and expect
activity to diminish overnight. Otherwise, should see fair
weather continuing tonight. Lows overnight will remain well into
the 60s in the west and around 60 east as warm air advection
strengthens behind the warm front.
The upper level ridge will move east of the area Saturday and
keep the warm air advection streaming northeast into the local
area. This will allow temperatures to climb into the middle to
upper 80s most areas and possibly even flirt with the 90 degree
mark in the west. Some lingering effects of the exiting
shortwave trough could cause a few showers and thunderstorms
over the eastern half of the area and once again away from the
lake during the afternoon hours. Will keep a slight chance for
Saturday afternoon. Cold front does not arrive until late
Sunday night into Monday.
Short term /Saturday night through Monday night/...
temperatures will be running well above normal on Sunday as a slow
moving cold front remains to our west. Will go with a breezy, dry,
and warm forecast through much of Sunday. With guidance running so
cool as of late and the front/much convective coverage looking
likely to wait until after mid afternoon have bumped temperatures up
several degrees which is closer to ecmwf's warmer temperatures. We
may get close to marginal fire weather concerns. Shower chances
increase for Sunday night and early Monday. Will continue the
mention of thunder. Front passes by early Monday and highs Monday
will be much closer to mid September normals. A lingering trough
across the eastern Great Lakes may continue the shower chances a bit
longer into Monday.
Long term /Tuesday through Thursday/...
high pressure builds east to the Ohio Valley for Tuesday. The flow
aloft is more zonal and will keep the seasonable temperatures around
for a few days. Closer to Thursday some return flow and a front
across the Central Lakes may yield showers for Thursday. For now
will leave a low chance until details can be worked out.
Temperatures Wednesday/Thursday will warm into the mid/upper 70s.
Aviation /12z Friday through Tuesday/...
an upper level disturbance is expected to move east across the
area today and tonight over the top of the upper level ridge.
This feature along with some increasing moisture could produce a
stray shower or thunderstorm over the western portions of the
forecast area mainly away from the lake. Can't rule out even a
very isolated cell over the east this afternoon. VFR conditions
will prevail through the period with the exception of some lower
ceilings developing in the east by the end of the period. Winds
should be fairly light through the period.
Outlook...non-VFR possible in patchy fog Saturday morning and
in showers/thunderstorms Sunday through Monday.
quiet on the lake Friday/Saturday with light gradient winds and high
pressure across the mid-Atlantic extending to the eastern lakes.
Will get an onshore component this afternoon and across only the far
east end Saturday. By Sunday a breezy system and a cold front will
be nearing. Southwest winds will increase to 15 to 20 knots with the
choppiest water further offshore. Most of the wind precedes the cold
front Sunday night and by Monday winds westerly winds will be
subsiding. There will be period that a Small Craft Advisory will be
needed. A trough lingers Monday across the eastern lakes and by
Tuesday high pressure will be working across the Ohio Valley. This
will bring winds back around to the southwest mid week as the high