Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
1217 am EST Tuesday Dec 10 2013
a ridge of high pressure will build in from the southwest tonight. A
fast moving low pressure system will move east across the northern
Great Lakes region Tuesday with a reinforcing Arctic cold front.
High pressure will build east into the Ohio Valley on Thursday and
to the East Coast on Friday.
Near term /until 6 am this morning/...
no major changes to this forecast update. Light snow is spreading
northeast into the southern tier area from the southwest in
response to the upper level jet. Expecting light snow to continue
to spread into the area overnight. Light accumulations expected.
Short term /6 am this morning through Thursday night/...
some snow showers lingers in the snow belt as the winds will
become southwest and shift the bands into the lake. The snow/snow
showers over the southeast portion of the forecast area will be quickly
Another front will be moving through the region on Tuesday and the
winds aloft near the frontal boundary will be near 40 knots.
Added gusts up to 40 miles per hour in the afternoon. Some breaks in the
clouds will help bring down some of the wind.
Also debated about issuing a lake effect watch for the snow belt
for late Tuesday night into Thursday. With the 18z data still some
questions about the wind direction and the amount of moisture. The
GFS is the most pessimistic. The Canadian model is very dry. With
that will let the middle night shift take another look before issuing
or not issuing the lake effect watch.
the first half of Tuesday will generally be dry and
cool under the influence of high pressure. By Tuesday evening the
next trough arrives and lake effect snow will set up across northwest
PA/NE Ohio. Will hold off on a lake effect snow watch for this
package...with the heaviest snow not falling until outside the
third period. Lake effect will wind down by Thursday afternoon.
Most areas outside of the snowbelt will be dry. Wednesday night low
temperatures will drop into the single digits behind an Arctic
Long term /Friday through Monday/...
the models are a little more in agreement the second half of the
week with high pressure sliding east and the flow backing to
southwest by Friday. This will put an end to the lake effect threat.
Temperatures should bottom out on Thursday as some of the Arctic air
filters across the area. The trend upward will be relatively slow
as most of the country will be trying to modify from Arctic air and
of course the sun angle is at a minimum this time of year. Forecast
highs mostly in the teens Thursday and 20s on Friday.
Still no confidence on the scenario for Saturday. The models show a
decent short wave and corresponding surface low tracking from the
south central states and ending up along the middle Atlantic coast.
These systems often redevelop from the Ohio Valley to the East Coast
and we end up in the transition zone so not a lot of confidence on
the strength and track of the surface low yet. The forecast will go
for temperatures near freezing on Saturday and a chance of snow. We
may end up needing higher probability of precipitation and a mix of precipitation but will
wait to see the model trends this week. Colder again by Sunday into
Monday as the pattern remains cold.
Aviation /05z Tuesday through Saturday/...
a weak middle level system will spread some light snow or flurries east-northeast
across the southern half of the area from 07z through about 13z. Cak
may see 3 or 4 hours of IFR visibilities with the light snow...mfd and yng
will have a lessor threat while cle should only see a few flurries
Eri will keep an ongoing threat for scattered light shsn as lake effect
conditions set up with mean low level winds having just enough
onshore component for the snow bands to spread into the eri area. As
usual with lake effect shsn...expect to see highly variable
conditions as the on and off shsn occur.
An area of dryer low level dry air works east across the taf sites
and looks to be over tol...fdy through middle morning and over the eastern
sites early to middle afternoon. Any leftover MVFR at mfd...cak and yng
should lift to VFR as the dryer air moves in. However...at eri
conditions look good enough for lake effect shsn to continue to
pester the area through the day Tuesday and Tuesday evening or at least be on the
north side of the airspace.
West-southwest winds may gust around 20 knots near the Lakeshore tonight then
increase again later Tuesday morning into middle afternoon to be gusting 25
to 30 knots with the higher gusts at tol and fdy and along the
Outlook...non VFR conditions will linger at times through
Thursday...mainly over NE Ohio/northwest PA.
allowing Gale Warning to expire as planned at 7 PM. If wind forecast
needs to be increased a little more with new 00z data on the middle
shift then will likely need another gale for the east half of the
lake for later Tuesday into Tuesday night. Otherwise...Small Craft Advisory conditions will
tend to prevail into Thursday west part and into Thursday night East Part.
There will be a brief lull in winds and waves for the west part of
the lake later tonight into the beginning of Tuesday but consensus is to
just leave the Small Craft Advisory going since conditions ramp back up quickly later
The gradient will remain rather strong Wednesday into
Thursday...then relax as the surface high moves east across the Ohio
Valley. A storm system will affect the lower Great Lakes on the
weekend but not much confidence on the strength and track of the
Marine...Small Craft Advisory until 10 PM EST Thursday for lez145>149.
Small Craft Advisory until 10 am EST Thursday for lez142>144.