Area Forecast Discussion
Issued by NWS Cleveland, OH

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000
FXUS61 KCLE 030206
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
906 PM EST Fri Dec 2 2016

.SYNOPSIS...
Low pressure across the eastern Great Lakes will shift to the east
coast tonight allowing high pressure to begin building in from the
southwest. The high will move over the local area Saturday night
and move to the east coast on Sunday. A weak warm front will lift
north across the area Sunday night with another high briefly
building in on Monday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The rain and snow showers have dissipated across the area as of 9
PM. Have cut back on PoPs over the next few hours as well as
precipitation amounts across northwest PA. We should see a band of
precipitation (snow inland and a rain/snow mix along the lake shore)
develop late tonight across northwest PA as there will be a brief
window with a Lake Huron connection. However, the combination of
some warm-air advection, a lowering inversion height, and some
directional shear will prevent any significant snowfall from
occurring. The higher elevations of northwest PA could see an inch
or two by morning, but wouldn`t really expect anything more than
that.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
The lake effect will continue through Saturday night but will
really begin to taper the precip off from west to east on
Saturday as the inversion lowers. By 00z Sunday the snow showers
should be confined mainly to NW PA. After daybreak Saturday accums
will be localized with no more than another inch or two any given
location. The surface ridge will move through early Sunday and we
should be able to squeak out a dry morning. A warm front will
lift across the area later in the day and bring with another
period of precip. Temps and low level thicknesses may remain cold
enough for most of the precip to start as snow or mixed precip.
The precip could stay mostly snow in the north but the models warm
the southern half of the area enough for a change to rain.
Fortunately QPF amounts will be less than a tenth of an inch with
the precip generally lasting for a period of 6 to 9 hours most
areas. Another high will scoot east across the area on Monday
keeping the area dry. Big model differences begin to take shape at
the every end of the short term period. Lot`s of uncertainty about
precip early Tuesday and will let later shifts take a look at
that. Have used a blend of guidance for temps.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Potentially big changes coming up in the extended periods.  Another
deep digging upper level trough will rotate south into the western
United States and then push east across the rest of the country.
This feature has the potential to bring some of the coldest air of
the season to the forecast area by the middle to latter part of next
week.  The big caution is the timing of the arrival of the cold air
mass.  The European model suggests a deep diving panhandle hook low
pressure system will move east across the Ohio Valley allowing the
arctic air to plunge southeast into the area Thursday night.
Whereas, the GFS model suggests surface low pressure will develop
and then strengthen over the delta region of the Gulf of Mexico by
Tuesday afternoon and track northeast across the Ohio Valley.  This
track will allow the arctic air to arrive Wednesday night.  The
thinking is to come up with a solution some where in the middle of
the two models until a better agreement in timing is achieved.

Temperatures at 850 MB are expected to drop to between -16 C and -18
C by Thursday evening.  This will set-up extreme instability over
the lake.  Not only that, wrap around moisture will slide south
across the area from the surface trough Thursday night.  The
combination of the arctic air and available moisture in concert with
the lake moisture, there is the possibility for another significant
lake effect snow event in the northeast snowbelt if all of these
ingredients come together. A big caution is if the air mass remains
as cold as the models suggest and does not modify considerably with
time over the lakes. And, this all depends on where the winds setup
for lake effect bands to develop. There has been some consistency in
the models over the last few days that the event can occur.

For the entire area, the question remains as to how cold it will get
during the peak of the cold air mass.  Highs may not get out of the
20s by Friday and overnight lows in the teens Friday and Saturday
mornings.

&&

.AVIATION /00Z Saturday THROUGH Wednesday/...
Marginal lake effect conditions will continue thru saturday but any
rain or snow showers should mostly just affect eri, especially
after 06z tonight. Mix of vfr and mvfr cigs should lower some
late tonight into sat morning but should still stay mostly mvfr
except may higher end ifr at yng. A little improvement in cigs by
late sat afternoon.

OUTLOOK...Mostly mvfr cigs much of the time thru wed with areas of
rain and snow.

&&

.MARINE...
Small craft advisory will remain in effect through tomorrow
morning for all but the west end of the lake. Winds will remain
between 15 and 25 knots on the lake through the night and this
will keep the waves up as well. Winds finally start to diminish
Saturday and continue through Sunday as high pressure builds
across the area. Generally light flow is expected across the lake
Monday and then begins to increase out of the southeast by Tuesday
well in advance of the next storm system. As low pressure moves
northeast across the area, winds diminish again on Wednesday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 10 AM EST Saturday for LEZ145>149.

&&

$$
SYNOPSIS...Kubina
NEAR TERM...Kubina/Mottice
SHORT TERM...Kubina
LONG TERM...Lombardy
AVIATION...Adams
MARINE...Adams/Lombardy


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