Scientific Forecaster Discussion
fxus61 kcle 161116
Area forecast discussion
National Weather Service Cleveland Ohio
616 am EST Sat Dec 16 2017
a warm front near Lake Erie today will lift north of the lake Sunday
and Monday. A cold front will move east across the area Tuesday.
Near term /through Sunday/...
the band of warm advection snow over the NE half of the County Warning Area will
start to weaken by late morning then take most of the rest of the
day to dissipate. Some lake enhancement will occur to increase snow
amounts for Erie co PA and surrounding counties. Current guess is
for about 3 to 6 more inches in Erie co with amounts tapering down
across the rest of the snowbelt and little or no accumulation for
areas bordering the snowbelt.
Will keep headlines for snow warning and advisories going until late
Weak high pressure over the area tonight into early Sunday should
keep things quiet for a while. A weak upper trough will race east-northeast
into the cwa Sunday. Temps at the surface and aloft should warm just
enough for mostly rain to be the threat as light precip tries to
spread NE across the cwa from noon thru the rest of the day.
Highs today will be warmer due to the warm advection with highs
generally from around 30 in the far NE to near 40 in the far SW.
Lows tonight should be in the 20s then highs on Sunday will be a few
degrees warmer for the NE half of the area, with mid to upper 30s
being more common.
Short term /Sunday night through Tuesday night/...
the short term forecast begins on Sunday night with a weak low
pressure system just off to the northwest with a front draped over
the area. This front will move off to the northeast on Monday as a
warm front and will allow for temperatures to be well above normal
for a couple days. Several pieces of energy with this low pressure
system and the influx of additional moisture from the south will
allow for rain chances for much of the short term period... although
the best chances will be Sunday night with the warm front.
The other best chance for precipitation will be with the cold front
that will move across the area during the latter half of Tuesday.
Rain will change over to snow as temperatures drop back down below
freezing. The winds will shift around to the west and allow for lake-
effect conditions in the snow belt region, however, at this point,
there may be some residual warm air aloft with 850mb temps around 0c
that may prevent the lake-effect machine from getting too out of
hand on Tuesday night.
Long term /Wednesday through Friday/...
the long term begins on Wednesday with a cold front to east and
westerly winds allowing for a lake-effect setup over the snow belt
region. High pressure building to the south on Wednesday will allow
for winds to shift around to the southwest and then to the south by
Wednesday night to shut off the lake-effect machine and have a dry
forecast for much of Thursday. Meanwhile, a low pressure system
develops off to the west waiting to move in for Friday and Saturday.
The southerly winds on Thursday will usher in some warmer air and
allow for temperatures to go back into the 40s. The initial
precipitation type with the low pressure system on Friday will be
rain with the warmer air will remaining in place. Cold air wrapping
behind the system will allow for rain to chance over to snow on
Friday night into Saturday, as temperatures go back below freezing.
Westerly flow over Lake Erie will allow for lake-effect to set up
over the snow belt for Saturday.
Aviation /12z 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 20z. Cigs and vsby's
at eri will improve late today into this evening as the snow tapers
off but may not improve above MVFR tonight.
Probably will see some fog develop later tonight for all but the
snowbelt where more clouds will try and hang around and keep the fog
from trying to form.
West to SW surface winds will gradually diminish through early
afternoon and will actually become light and variable by this
Outlook...non-VFR possible Sunday night into Monday. Non-VFR also
possible in northeast Ohio and northwest Pennsylvania on Tuesday.
westerly flow that has set up over Lake Erie will continue for the
first half of today with winds 10 to 20 knots eventually decreasing
to 10 knots or less later this afternoon. High pressure off to the
north will allow winds to shift around to the north and then
northeast for overnight period and light and variable winds will be
expected for Sunday. Low pressure moving northwest of the area on
Monday will allow for the flow to switch around to the southwest and
increase to 10 to 20 knots. As the low moves off to the northeast
and a cold front approaches the area winds will increase to 25 knots
and winds will shift slightly to the west, allowing for likely Small
Craft Advisory conditions for Tuesday into Wednesday. High pressure
building to the south on Thursday will ease the winds over the lake
and shift winds around to the south for the end of the week.
Ohio...Winter Weather Advisory until 4 PM EST this afternoon for
PA...Winter Weather Advisory until 4 PM EST this afternoon for
Lake effect snow warning until 4 PM EST this afternoon for
Marine...Small Craft Advisory until 4 PM EST this afternoon for
Small Craft Advisory until 10 am EST this morning for