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fxus61 kcle 102032 
afdcle

Area forecast discussion
National Weather Service Cleveland Ohio
332 PM EST Tue Dec 10 2019

Synopsis...
high pressure will briefly build northeast through the Ohio
Valley across the area tonight. A cold front will push southeast
through the Great Lakes into the area on Wednesday. High
pressure will quickly return to the area, building east across
the region Wednesday night, becoming centered over the East
Coast Thursday and Thursday night.

&&

Near term /through Wednesday night/...
a weakening surface trough over Lake Erie will attempt to push
southward into Northern Ohio and northwest PA late this afternoon
into this evening, while pressure rises continue northeastward
through the Ohio Valley into the southern Great Lakes. A modest
band of snow has formed ahead of this trough over the lake, and
is expected to push onshore over the next several hours, perhaps
dropping a quick 1-3 inches of snow. Confidence is low on the
exact evolution of this snow and lake effect/lake enhancement
through tonight across the snow belt. Hi-res guidance continues
to depict the surface trough pushing southeast across the snow
belt and weakening, with secondary shoreline convergence setting
up northeast of Cleveland, which seems to be playing out with
latest radar trends. The models depict one or two lake bands
becoming dominant and pushing onshore across the snow belt, with
several models favoring a band into northern Geauga/Lake and
another into Erie PA.

The current evolution on radar is a bit off from the model
depictions spatially and timing wise, but generally on the right
track. It seems the potential for heaviest snowfall will occur
over the next 4-5 hours, with lingering synoptic forcing
coinciding with good moisture from 900-750mb. However,
dendritic growth will be minimal with the best lift centered
much lower in the cloud layer, and some fairly dry air in the
lowest 3kft. Instability parameters are marginal as well, with
lake induced inversion heights peaking around 8-8.5 kft. After
00z, drier 925mb air will work south across the lake, which
could limit snowfall as well. Overall, kept the forecast fairly
similar to the previous, with accumulations centered a touch
farther north in the 2-4 inch range through tonight. Some higher
amounts up to 5 inches by tomorrow morning are possible in the
higher terrain of Erie PA. For now, with lower confidence in the
evolution of this snow, will not issue any headlines and will
monitor closely for the next several hours to see how the bands
are organizing.

Snow bands will diminish and push offshore around/after
midnight as boundary layer flow begins to back more southwest,
with continued drying of the cloud layer. By tomorrow morning,
the flow should keep any bands offshore into western New York through
at least midday. An upper vort Max and accompanying surface
front will quickly drop southeast through the Great Lakes
Wednesday morning. This now appears to be a relative glancing
blow for the local area, but enough of a cold punch to
reactivate lake effect into the local area, mainly northwest PA.
A brief shot of 850mb moisture will follow this wave passage,
with winds veering a bit more northwest Wednesday night. Dry air
looks to quickly work back across the region, so the snow
potential should be limited temporally. Currently forecasting an
additional 1-3 inches, with the highest amounts in eastern Erie
PA. Snow will quickly diminish after midnight as high pressure
build across the region.

&&

Short term /Thursday through Saturday night/...
the short term begins Thursday with models showing broad high
pressure centered over Pennsylvania. To our west, low pressure
will be in western Iowa. This low will move northeast to the
central Great Lakes and dissipate by Friday morning lifting a
warm front northeast through the region as the high moves off
the New England coast. Another low will move into the Dakotas.
This low will move into the western lakes Friday into Saturday
as another disturbance generates a coastal low in New England
from the mid Atlantic coast. Moisture will return north into the
region Friday with return flow out of the southeastern states
with rain chances into mainly eastern Ohio and nwrn PA by Friday
afternoon. Moisture deepens from the south Friday night into
Saturday. Will have pops increase to likely for the eastern half
of the area Friday night and Saturday. Precip may mix with a
little snow late on Saturday far west but precip should be
mostly rain. Highs Thursday in the mid 30s. Highs Friday and
Saturday in the 40s.

&&

Long term /Saturday through Tuesday/...
by Sunday, models show a dominant surface low over northern New
England tracking northeast into Canada. To our west, high pressure
will be moving east from Minnesota into Wisconsin. Between the two,
a cold front will be forced south through the area during the day
Sunday. Models begin to differ Sunday night with the European model (ecmwf)
continuing to bring cold air in the the region while the GFS begins
to warm advect. For now will side more with the European model (ecmwf) and continue
the threat of mainly lake induced precip nern Ohio and nwrn PA. The
European model (ecmwf) does eventually show this warm advection increasing into the
area Monday into Tuesday ahead of low pressure moving through the
mid Mississippi Valley into the lower Ohio Valley with moisture
increasing across the area out of the southeast. Will keep pops in
the chance category for now and go with mostly snow showers Monday
and a mix Tuesday.

&&

Aviation /18z Tuesday through Sunday/...
widespread MVFR ceilings blanket the region at the onset of the
period, ahead of a southeast moving surface trough. A band of
shsn expected along the trough, which will mainly impact Keri,
and perhaps kcle for a brief time. This could allow for a brief
reduction to IFR visibility, with more scattered shsn after 00z
through 06z at Keri. General improvement/scattering of ceilings
after 00z at most of the sites as high pressure tries to nose
northeast across the region. Another trough/front will approach
late in the period, with more MVFR reductions expected,
specifically at Keri, just beyond this period. Winds will
generally remain west to southwest through the period, with some
gusts in the 20-25 kt range early.

Outlook...non-VFR possible on Wednesday and Thursday with snow
showers and low ceilings, especially in the NE Ohio and northwest snow
belt. Non-VFR possible Friday night with rain/snow and Saturday
with all rain.

&&

Marine...
will extend the Small Craft Advisory across the western half of Lake
Erie through 4am Thursday. Winds this afternoon have remained near
the 20 knot range on the western basin and are not expected to
decrease significantly overnight before possibly rising a few knots
on Wednesday. Would have needed on for Wednesday anyway so will just
leave headline up. Also, for now, will continue with the gale watch
as is and allow later shifts to get another model run in. At this
time, current guidance touches gale force for a few hours from about
noon through 22z or so. For Wednesday night, winds will begin to
diminish as high pressure begins to build in from the west. The high
will cross the lake Wednesday evening causing winds to drop to under
10 knots by morning. The high will move to our east Thursday as low
pressure approaches the western lakes driving southerly flow at 10
to 15 knots. Southerly flow will increase to 10 to 20 knots Thursday
night into Friday as the pressure gradient tightens slightly. Winds
will remain fairly light through Saturday before increasing Saturday
night into Sunday from the west to 15 to 25 knots as deep low
pressure moves through New England and high pressure moves into the
western lakes.

&&

Cle watches/warnings/advisories...
Ohio...none.
PA...none.
Marine...Small Craft Advisory until 4 am EST Thursday for lez142>149.
Gale watch from Wednesday morning through Wednesday evening
for lez169.

&&

$$
Synopsis...greenawalt
near term...greenawalt

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