Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
542 am EDT Tuesday Sep 30 2014
a low over Ontario Canada will move across Buffalo this morning
and take a cold front across Northern Ohio/northwest PA. High pressure
north of the lakes will spread south to Lake Erie Tuesday night
then shift off to the east Thursday. Low pressure will move
northeast across the western Great Lakes and take a strong cold
front across the local area on Friday.
Near term /until 6 PM this evening/...
narrow band of showers has arrived at Toledo early this morning.
This band of showers is associated with the arrival the first cold
front to the region in over a week. Water vapor img clearly shows
upper low moving across northern lower Michigan with forecast models
taking it to NE Ohio and slowly filling it as it shifts eastward
tonight. Surface cold front will work its way across the area
during the morning hours...and will be east of the area by early
afternoon. Southern extent of at least scattered showers should be
from fdy to Montana Vernon with the better chances north of that.
Mentioned a chance of thunder...a rumble or two possible across
the west and then also east closer to midday. Lightning strikes
have been very limited early this morning across Michigan/Northwest Ohio and
Ontario. In the wake of the showers skies will remain cloudy with
a solid deck of low clouds. With the front through most of the
area by early afternoon...temperatures will struggle in Toledo
reaching only the lower 60s. Further east with a little Morning
Sun temperatures could reach the upper 60s.
Short term /6 PM this evening through Friday night/...
lingered some low precipitation chances into tonight with upper low
overhead and a weak surface reflection of a trough. Moisture
rather shallow. Upper energy pulls out for the overnight. Believe
entire area will be blanketed by clouds through much if not all
of the night with moisture trapped under the inversion. Core of
colder air aloft stays to our west. Therefore have lows tonight
that are slightly warmer than guidance.
Cant really say that high pressure builds into the area for
Wednesday. Still lingered a silent 20 percent chance of a shower
out east with some weak cyclonic flow and some lingering moisture.
Upper ridge remains to the west across mi/ind. Went on the cool
side of guidance or lower especially across the East.
Ridge moves overhead Wednesday night and by Thursday temperatures
moderate with a southerly flow. Met guidance still showing
temperatures a handful of degrees cooler than the mav guidance.
Cant see how we can be lower 70s across the entire area.
Upper trough moving out of the Central Plains becomes negatively
tilted as a low closes off across Ontario Canada. This will take a
strong cold front across the region on Friday. Timing is a little
slower than previous forecast but not by much. By 12z Friday
showers will likely have reached western Ohio. The bulk of the
precipitation will occur during the daylight hours on Friday. With
good moisture advection and upper dynamics still feel good about
precipitation chances of 70 percent. As long as timing sticks than this
can be raised higher. Added the chance for thunder with optimal
daytime timing we may be able to get slightly unstable.
Temperatures will be hampered by the rain Friday. Will go with
upper 60s. As it looks right now...it should be rain free after
the front for Friday night. 800 mb temperatures fall to or below 0c by
Saturday morning. Lower/Middle 40s across the area for lows.
Long term /Saturday through Monday/...
the trough aloft will be over the Great Lakes Friday night into
Saturday. Both the GFS and European model (ecmwf) now develop a closed low over the
Great Lakes. The European model (ecmwf) remains a bit slower on the eastward
progress. The boundary flow in the European model (ecmwf) is somewhat more southwest.
850 mb temperatures are prognosticated to drop to about -2c. Cannot rule out a few
showers anywhere Saturday with the trough aloft but the best chance
of course will be from the Lake Erie contribution. Will continue
with a "chance" of showers in the snowbelt but eventually we will
have to try and pin down the best location and time and use "likely"
in the snowbelt. Highs only in the 50s Saturday.
The upper low is prognosticated to pull out quickly on Sunday. All of the
models show some ridging early Sunday but another fast moving short
wave also shows up on all of the models. Not sure how quickly we
will see new showers develop. It will also remain cold enough aloft
for lake effect showers although they will likely try to shift
toward Buffalo at some point. Will keep a chance of showers in the
snow belt and a slight chance elsewhere Sunday. Probably a somewhat
better chance of showers Sunday night into Monday. Continued cool
with highs probably not much better then the lower 60s Sunday and
Aviation /06z Tuesday through Saturday/...
the forward progress of the showers with the cold front will
likely slow this morning as a weak wave begins to develop on the
front. There is currently a fair amount of IFR ceilings following
the front...but as the system slows the lower ceilings and
visibilities will take until late morning or afternoon to reach
kcak and kyng. Ceilings will probably improve to MVFR this
afternoon across Northwest Ohio but stratus and IFR ceilings will likely
linger or redevelop across NE Ohio/northwest PA Tuesday evening.
Outlook...non VFR through Wednesday morning and again on Friday.
Non VFR likely Saturday across NE Ohio/northwest PA.
a weak cold front will Cross Lake Erie this morning. Winds will
shift to northwest and then north on the west half of the lake. The
wind shift will occur somewhat slower on the east half of the lake
as a weak wave of low pressure develops on the front. The wind may
be somewhat variable on the east half of the lake for much of the
day. Eventually the wind will veer to a more northeast direction
tonight and then veer to southeast and south by Thursday ahead of
the next cold front.
The next cold front will be stronger and mariners can expect a more
typical autumn cold frontal passage on Lake Erie where the wind
picks up from the southwest and west rather quickly Friday after the
passage of the cold front. Winds and waves will quickly exceed Small
Craft Advisory criteria Friday and could approach gale force Friday
into Saturday. Winds will diminish slightly by Sunday and back more
from the southwest but will likely continue to exceed Small Craft