Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 170932

Area Forecast Discussion
National Weather Service Cleveland OH
432 AM EST Thu Jan 17 2019

Low pressure over the southern Plains will reach the Central Great
Lakes tonight, then continue northeast across Quebec on Friday.
Surface high pressure will build back into the area behind this
system on Friday. A stronger low pressure system will track
from the southern Plains through the Tennessee Valley to the
East Coast by Sunday bringing significant precipitation followed
by an arctic airmass to the region.


Light precipitation is expected today and tonight ahead of a
stronger storm system that will impact the region over the weekend.
We are starting off dry this morning with precipitation noted
upstream across Central Illinois on the north side of an inverted
surface trough. A broad surface low is over the southern Plains this
morning and will track to near Toledo by 00Z, then continue across
the eastern Great Lakes overnight. Warm advection precipitation will
develop over the area starting late this morning in Northwest Ohio,
reaching the I-77 corridor by mid to late afternoon, and NW
Pennsylvania this evening. Shallow lift develops in western areas
this morning and can not entirely rule out seeing a little freezing
drizzle before the deeper moisture and lift arrives shortly
after. A few locations have reported freezing drizzle back
towards Indianapolis and that will be something to monitor this
morning. Would like to see an expansion of the freezing drizzle
before adding to the forecast, especially given the brief
window but will be something to keep an eye on after the morning
commute. Most of the area expected to see around an inch of
snow. Backed off on the accumulations a little across the south
where a warm nose of air is expected to be pulled north this
evening and may cause snow to mix with or change over to rain.
Raised temperatures into the lower 30s this evening with both
the NAM/RAP bringing the 0C isotherm at 925 mb up to the
lakeshore. We may also get into a situation where the deeper
moisture departs first leaving insufficient ice nuclei for snow
before precipitation tapers off. Expect surface temperatures to
be above freezing while the precipitation is ongoing so did not
include any freezing rain tonight but will be close.

Will carry a low chance of rain or snow showers in the snowbelt into
Friday although expecting to dry out rather quickly. Little
temperature rise, maybe 2-3 degrees with cold advection expected on


Low pressure will move toward the region from the Southern
Plains/Western Gulf of Mexico region Friday night with increased
warm advection. There will be some dry air in place ahead of it
which should slow the onset of the snow. However by Saturday morning
light snow should be occurring at most locations. This storm system
still has NOT moved onto the West Coast of the US yet so still
plenty of room for error. ECMWF typically handles southwestern US
storm systems best and have leaned heavily on it. There is still
concern that this storm system could still end up being a bit
further south. We will continue to monitor this potential. So for
now we will go with our best estimate and say that 6+ inches of snow
will be possible near and east of a line from Upper Sandusky to
Lorain. The heaviest snow may be near a Mount Gilead to Youngstown
line but we will have to see if any warm air can sneak into these
areas and end up producing lighter amounts. So we will say it again
STORM SYSTEM. Any wobble will have significant impacts up or down
with snow amounts.

Saturday will see highs in the 20s but gusty northeast winds will
make it feel like it is in the teens. Colder air begins to spill
into the region Saturday night into Sunday. Lows Saturday night
should be in the teens to as low as 10 degrees across NW Ohio.
Sunday will not warm much with highs in the teens.


In the wake of the storm system on Sunday the coldest air of the
season will begin to flow into the region. So some lake effect snow
will develop by Sunday afternoon and continue into at least Monday
morning. It will be a northerly flow which will likely favor a
multiple band setup. Drier arctic air will be over the region and
will have impacts on the amount of snow that can occur. It is a
given that there will be more snow during the period Sunday night
into Monday but confidence in a significant lake effect event are
low. the reasons against something significant are inversion heights
below 5000 feet and fairly short residence time of air parcels over
the lake to gather moisture due to the stronger winds. The snow that
does accumulate during this time period will be light and fluffy
compared to what occurs Saturday afternoon into Sunday morning.

High pressure will return to the region on Monday and should end the
lake effect snow showers by Monday evening across NE OH/NW PA. This
area of high pressure should control the weather into Tuesday
morning. Tuesday afternoon into Wednesday look to be the timing for
the next storm system.

Sunday night will be the coldest night with most any locations that
clears out dropping below zero. Elsewhere it will still drop to the
single digits. Still cold on Monday with highs in the single digits
and teens. Warmer air arrives by Tuesday into Wednesday. Highs by
Wednesday afternoon should be in the 30s area wide.


.AVIATION /06Z Thursday THROUGH Monday/...
MVFR stratus remains at ERI with VFR elsewhere to start the TAF
period. Ceilings will lower to MVFR from south to north into
Thursday ahead of a low pressure system moving out of the
Plains. IFR eventually expected as snow spreads in from the
south and west ahead of the low Thursday afternoon and moves
east across the area through 06Z. Tried to time the onset of
snow and delayed eastern terminals by another hour or two. As
the low moves into Northwest Ohio Thursday evening, warmer air
is pulled into the southern terminals and may cause snow to mix
with rain. A transition to drizzle is even possible as the
deeper moisture departs to the east.

East to northeast winds tonight will veer around to the
southeast at 10 knots or less Thursday morning and eventually
southwest behind the low Thursday night.

OUTLOOK...Non-VFR late Thursday night into Friday and again on
Saturday and Sunday. Saturday into Sunday could potentially
feature moderate to heavy snowfall. Non-VFR possible in the
snowbelt Monday.


High pressure over southern Quebec well drift eastward today. Weak
low pressure will move across Lake Erie Thursday night with a cold
front crossing the lake. A second surge of cool air will follow on
Friday. Saturday deep low pressure will move northeastward near or
just to the south of the Ohio River Valley reaching the Middle
Atlantic Coast by Sunday morning. This will be the time period when
northeast winds will be the strongest. Small craft advisories are a
definite but will need to monitor for a low end gale. The gale
potential all hinges on the exact path of the low Saturday into
Saturday night. High pressure will build across the lake on




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