Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
912 am EST Wednesday Dec 4 2013
low pressure over Oklahoma will move northeast to the upper Great
Lakes Wednesday night pulling a cold front across the region early
Thursday. A wave of low pressure will move along the front Friday
across West Virginia. High pressure over the northern plains will
move east across the area Saturday night. A low will move north
from the Gulf Coast across the area early Monday.
Near term /until 6 PM this evening/...
based on the latest Sat and radar pictures and short term model output
the ongoing forecast looks on track so little changes needed.
The southerly flow will have even a bigger influence today as low
pressure across Oklahoma moves northeast to Wisconsin pushes a warm
front north of the area. The range of temperatures expected today
will be from 50/lower 50s where there still is snow pack in northwest PA to
near 60 for Findlay and Marion. Biggest question will be how much
precipitation we might get with that warm front lifting north.
Really hit or miss and have worded the forecast as isolated or
scattered at best for this afternoon/early evening. The better focus
is across southern Michigan. No changes for this early morning update.
Short term /6 PM this evening through Saturday night/...
temperatures will remain mild tonight ahead of the approaching
cold front. Concerned about the coverage of showers for tonight
still with a lot of middle level dry air. With that have remained in
the chance category and worded it as scattered.
Cold front reaches the I-75 corridor by Thursday morning. Much
better moisture spreads northward for Thursday and this is when
precipitation chances will get into the likely category. With the fronts
passage locations will begin the downward slide in temperatures.
Precipitation nearly exits the area late Thursday afternoon/early
evening...but a wave develops along the front and overrunning
precipitation is expected to expand back north across the area. Still
uncertainty as to the westward extent of the better precipitation
Thursday night. At the same time Thursday night temperatures will
be falling enough to make a change over to snow. A second wave
moves across Friday...but this time just a bit further to the
southeast than the first. So in the end some light snowfall
accumulations are possible...especially from Huron to Findlay and
points to the east. The best chance for an advisory level snow...4
or 5 inches would be from Marion to Youngstown and points
southeast. But this is just a first guess as this system has a
lot of uncertainties with the details. Snow on its way out Friday
Strong high pressure across the Dakotas nudges into the Ohio
Valley quickly by Saturday. Limited...if any...in the way of lake
effect late Friday night/Saturday am.
Temperatures continue their fall into Saturday. By this point highs
will struggle in the middle and upper 20s. Teens expected Saturday
night...but clouds will be increasing in advance of the next
system coming up from the south.
Long term /Sunday through Tuesday/...
high pressure will move into Quebec by Sunday afternoon. This
occurs as low pressure takes shape over the Tennessee River
valley...moving quickly northward into Ohio by Sunday night.
There will be plenty of moisture flowing over the cold air that
remains at the surface. There is much uncertainty about the type
of precipitation that will occur Sunday night into Monday morning.
At this point there appears to be enough low level cold air to
warrant a mention of a wintry mix. Many locations will start as
snow Sunday evening before the possibility of sleet and freezing
rain arrive for the overnight hours. We may even be dealing with a
change over to all rain for a few hours across the east. Still
plenty of time for the models to arrive at a definitive solution
over the next few days but keep in mind that travel could be a bit
more difficult Sunday night into Monday.
A cold front will sweep across the area early on Monday with
temperatures holding in the 30s. Colder air will arrive for Tuesday
into Wednesday. An upper level trough will also be moving across the
region at this time and should enhance the lake effect snow chances.
Winds look to be southwest to west for this event so the heavier
snow may just clip northwest PA to start before shifting down the Lakeshore
into NE Ohio and northwest PA for Monday night into Tuesday.
Aviation /12z Wednesday through Sunday/...
southeasterly winds will gradually become south and increase through
the day. MVFR ceilings will gradually fill in across the region
through the afternoon. However the eastern portion of the area
will attempt to keep low end VFR ceilings. We will then wait to
see how many showers will develop during the late afternoon. Not
confident enough at this time to go with more than a vicinity
shower. The better chances of showers and low end MVFR conditions
will arrive from southwest to northeast ahead of the cold front.
The front should reach Northwest Ohio around 12z. There may be some IFR
ceilings near and in the wake of the cold front.
Outlook...periods of non VFR Thursday into Friday then lingering
across NE Ohio and northwest PA into Saturday.
a warm front will Cross Lake Erie today allowing winds to slowly
shift around to the southeast and south. We will then wait for low
pressure to develop over the Midwest and deepen as it tracks towards
James Bay on Thursday. A cold front will move across Lake Erie on
Thursday with increased westerly winds in its wake. This may persist
just long enough to need small craft advisories for a few hours
Thursday evening through Friday morning. The front will stall near
the Ohio River valley on Friday as high pressure builds across the
region from the plains. This high will remain in control into early
Sunday. We will then monitor the movement of low pressure that will
move across Ohio Sunday night.