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Area forecast discussion 
National Weather Service Cleveland Ohio
1241 PM EST Sat Dec 3 2016

Synopsis...
high pressure will begin to build east across the Great Lakes
region today. The high will move east over the weekend and off the
New England coast by Sunday night. A warm front will lift
northeast through the region Sunday night with high pressure
building back into the region on Monday.

&&

Near term /through tonight/...
update...no significant changes for the afternoon.

Continued to trim pops in NE Ohio through the morning hours, with
little activity noted on radar/obs. Hi-res guidance suggests an
area of colder 850mb temps pushing across the lake this morning,
which could increase lake effect activity in NE Ohio, so kept
slight chance/chance pops with little/no accumulation expected.
Kept likely pops in northwest PA, with some radar returns being picked up
in Erie County. Overall diminishing pop trends continue through
the afternoon.

Original discussion...
lake effect has been predominantly east of Erie this early this
morning, as shown by low level trajectories with Lake Huron
contribution. Trajectories from secondary/westward Huron band
would favor an uptick in precip across Erie/NE Crawford over the
next several hours. Maintained Cat/likely pops in this area over
the next few hours, with lesser chances along the Northwest Ohio
snowbelt. This activity is expected to taper off through the day
as flow backs westerly. Expecting mainly an inch or less in the
higher elevation in northwest PA through the day. Otherwise, quiet
weather elsewhere, with cloudy conditions and seasonable
temperatures near 40 as high pressure begins to build across the
region.

&&

Short term /Sunday through Monday Night/...
Lake effect will continue to diminish Saturday night as high
pressure builds east across the region. Attention turns to shortwave
ejecting from the plains towards the Great Lakes Sunday. This wave
will tap into some return flow and overspread some light precip
across the forecast area Sunday afternoon and evening. Expecting
fairly light amounts with best forcing north of the area, however a
rain/snow mix at the onset cannot be ruled out, with predominantly
rain Sunday afternoon. Thermal profiles suggest a changeover to
mainly snow for much of the area, especially higher elevations,
Sunday evening and overnight, where a few tenths up to an inch of
snow accumulation in higher elevations is possible.

After another brief shot of high pressure and dry conditions Monday,
potent southern stream shortwave will eject through the Ohio Valley
Tuesday. Some difference remain between the models with respect to
precip onset timing, however confident enough in the Tuesday
time frame to raise pops a bit to likely most locations and
categorical south. This event should mainly be rain, however a
brief mix cannot be ruled out in higher elevations. This system
will begin to exit the region Tuesday night. Overall, temperatures
will remain near or slight above normal through Tuesday night.

&&

Long term /Tuesday through Friday/...
models still advertise the coldest air of the season arriving
during the extended. Some differences remain in timing and details
but very cold air with 850mb temperatures of -16 to -18c will
result in lake effect snow for the end of next week. The 00z
GFS/Gem show the colder air arriving on Wednesday night with cold
advection continuing right through the day on Thursday. Meanwhile
the 00z European model (ecmwf) is slower with the upper level trough and shows a
wave of low pressure moving north through the Ohio Valley on
Thursday in advance of the cold push. Not a lot of confidence in
which solution will verify but think it is entirely possible for
the whole system to slow as the trough deepens to our west. Did go
with a blended approach for now with respect to temperatures, with
highs gradually cooling from Wednesday through Friday. Models in
good agreement that there will be a prolonged period of westerly
flow across Lake Erie behind the front which will be a favorable
set-up for lake effect snow. Flow down the long fetch of the lake
does support the potential for significant accumulations for a
portion of the primary snow belt.

&&

Aviation /18z Saturday through Thursday/...
overcast conditions on the threshold of VFR to MVFR will be
persistent. As high pressure shifts east of the local
area...sites will begin to develop some breaks in the
overcast...starting with fdy and working northeast. Low confidence
in exact timing and eri may sit at MVFR through 18z sun. As low
clouds break up...they will be replaced by an advancing cirrus
canopy. Lake effect showers will continue nearby eri through
approx 05z. The west- northwest flow will go light/variable this
evening and then gain a southeast direction for Sunday.

Outlook...frequent non-VFR conditions...Sunday evening through
Monday evening...Tuesday afternoon through Thursday.

&&

Marine...
as of 9 am, winds on the east end of the Ohio waters of the lake
have diminished to 15 to 20 knots with this trend continuing into
the afternoon. Therefore the Small Craft Advisory for this portion
of the lake has been allowed to expire at 10am. Winds the Small
Craft Advisory remains in effect until 4 PM for the Pennsylvania
waters where waves are expected to be a little slower to subside.

High pressure will expand over Lake Erie tonight with winds dropping
below 10 knots late. Generally good marine conditions expected to
continue through Monday as a weak trough lifts north across the
lake. East to southeast winds will increase to 15 to 20 knots ahead
of a fast moving low that will track north from the Gulf Coast to
the eastern Great Lakes. A strong cold front will follow during the
mid-week period with strong westerly winds to end the week.

&&

Cle watches/warnings/advisories...
Ohio...none.
PA...none.
Marine...Small Craft Advisory until 4 PM EST this afternoon for lez149.

&&

$$
Synopsis...greenawalt
near term...greenawalt/tk
short term...greenawalt
long term...kec
aviation...oudeman
marine...kec/oudeman

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