Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 160532

Area Forecast Discussion
National Weather Service Cleveland OH
1231 AM EST Sat Dec 16 2017

A warm front will develop near Lake Erie Saturday then lift north of
the lake Sunday through Monday. A cold front will push east across
the region Tuesday.


Warm advection snow developing in lower MI and will spread ESE into
the snowbelt the rest of the night to offset the lake effect snow
showers tapering down some.

An area of drier mid-level air will also move overhead. While this
is ongoing aloft, favorable low level conditions remain with flow
down the long fetch of the lake. Deeper moisture can be seen on
satellite imagery upstream moving into the midwest. This moisture
will overspread the lake for the second half of the night with lake
effect snow intensifying.

Interesting set-up for a lake effect event with the airmass
starting to warm late tonight. What the event lacks in lake
induced instability will likely be made up for by the synoptic
forcing and moisture. The backing low level flow is expected to
intensify low level convergence with the potential for a
dominant band producing high snowfall rates of 2- 3" per hour
late tonight into Saturday morning. Still some uncertainty as to
where this band will set up but the NAMDNG, ARW, and NMM all
place over an inch of QPF across primarily inland Erie County
PA. Expecting the favored upslope areas in the north half of the
County to see the highest accumulations of 7-9 inches through
midday Saturday. We will need to monitor the placement of the
heavier lake effect bands overnight and can not rule out needing
to upgrade an adjacent area to a warning, either the lakeshore
areas of Ashtabula/Erie Counties if the heavier band sets up
there, or across inland Crawford PA if the band pushes farther

Areas outside of the snowbelt will see flurries to a light
accumulation possible prior to dawn. Lows will only drop off a
couple degrees tonight into the lower to mid 20s. A gradual warming
trend will continue on Saturday with highs in the lower to mid 30s.


Overall upper level pattern trends toward becoming more zonal
across the continental United States and result in fast moving
shots of moisture toward the area along with an upper level
positive vorticity maximum being ejected northeast out of the
desert southwest.

A low pressure system will move northeast toward the area at a
fairly fast clip. A stationary front extending northeast from the
low will move little across the forecast area Saturday night through
Sunday night. The front eventually lifts northeast of the area
Monday as a warm front as the low moves northeast of the area.
Periodic shots of moisture will move northeast along the boundary
and bring with it a chance of precipitation Monday into Tuesday.

As the stationary front becomes a warm front and lifts north of the
area, we will start to see some warmer air move into the local
forecast area by Tuesday.  Highs by Tuesday will push into the 40s.
Overnight lows will be back into the upper 30s across the area
Monday night in the warmer air.


The long term begins Tuesday night with low pressure over
Quebec and a cold northwest low across the region. High pressure
will be building into the area from the southwest however with
the flow across the lake would expect lake snow in the snowbelt.
Better details as time nears however will have likely pops for
Ashtabula and northwest PA, slight chance or less elsewhere for
Tuesday night. Wednesday will shave Ashtabula out of the likely
pops as warm advection and drier air move in. For nwrn PA expect
best chance will be in the morning. Again, dry elsewhere.
Wednesday night and Thursday look dry as low pressure develops
in the Central Plains. Thursday night will bring chance to
likely pops back as the low and associated cold front move
through the area. Ahead of the system however 850mb temps above
zero so expect some precip as rain. Friday looks drier behind
the system however cold air again across the lake will bring
lake effect back to the snowbelt.


.AVIATION /06Z Saturday THROUGH Wednesday/...
Expecting mostly VFR to prevail thru 06z Sat night except in the
core snowbelt where a band of warm advection snow will produce a mix
of mostly MVFR/IFR conditions in periods of snow. Skies will become
partly cloudy from southwest to northeast thru 18z. Cigs and VSBY`s
at ERI will improve late today into this evening as the snow tapers
off but may not improve above MVFR until late tonight.

W to SW surface winds will gradually diminish overnight and will
actually become light and variable by this evening. Winds will be
slower to drop off at ERI and expect some gustiness most of the

OUTLOOK...Non-VFR possible Sunday night into Monday. Non-VFR also
possible in northeast Ohio and northwest Pennsylvania on Tuesday.


Cold front will push east across the area this afternoon and allow
winds to increase from the west behind it.  We are already seeing
winds at 15 to 25 knots on the lake at this time with a further
increase around 25 knots after frontal passage tonight.  Winds are
expected to decrease fairly quickly during the afternoon Saturday.
Small craft advisory will remain in effect overnight but is expected
to be dropped during the afternoon Saturday as waves also subside.
Lake is expected to be relatively quiet through Monday but will
become disturbed again Monday night as winds increase out of the
southwest. A small craft advisory will likely be needed again
Tuesday into Wednesday as a high pressure ridge tries to build down
toward the lake increasing the gradient across the area.


OH...Winter Weather Advisory until 4 PM EST Saturday for OHZ014-089.
PA...Winter Weather Advisory until 4 PM EST Saturday for PAZ003.
     Lake Effect Snow Warning until 4 PM EST Saturday for PAZ001-
MARINE...Small Craft Advisory until 4 PM EST Saturday for LEZ145>149.
     Small Craft Advisory until 10 AM EST Saturday for LEZ142>144.


NEAR TERM...KEC/Kubina/Adams
SHORT TERM...Lombardy
MARINE...Lombardy is the U.S. government's official web portal to all federal, state and local government web resources and services.