Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Cleveland Ohio
123 am EDT Thursday Oct 2 2014
a ridge across the area will shift east tonight. Low pressure
will move northeast across the western Great Lakes and take a
strong cold front across the local area Friday afternoon and
evening. A trough will move across the lower Great Lakes Saturday
and high pressure will begin to build into the Ohio Valley on
Near term /until 6 am this morning/...
the fog is developing early as expected...although getting thicker
a bit faster. We are beginning to get concerned about a decent
sized area of dense fog overnight if the southeast winds take much
longer to develop. Unfortunately it looks as if it will be closer
to sunrise before the south to southeast winds will increase
enough to make a difference. So with that said we have increased
the coverage of dense fog. Will continue to monitor trends and
issue a dense fog advisory if needed.
The clouds will continue to decrease and then more low clouds and
patchy dense fog will form overnight. The question is where. The
air mass is moist east of Mansfield...however...downslope winds
will help keep the clouds and fog from becoming too widespread.
While over Northwest Ohio an increase in the boundary layer winds
will help keep the fog from becoming too dense. Mentioned patchy
dense fog in the favored valley area. Lows are tough depending on
the cloud cover...used a blend of guidance.
Short term /6 am this morning through Saturday night/...
dry Thursday with some clouds and then slowly increasing clouds
Thursday night. The models continue to slow down the timing of the
front. Will try to keep most of the area dry Thursday night and then
gradually increasing the probability of precipitation for Friday as the front moves through.
At this time going with a frontal passage at tol at 19z/3pm...00z 7 PM at cle
and 03z/11 PM at eri.
On Friday will increase the probability of precipitation from west to east as the day GOES
on. In some ways still some question how widespread the thunder
will be. The showers will be widespread...however...the thunder
may be more scattered. At this time continued with a chance of
thunder. The shear will be moderate...so will have to watch for a
threat of strong to severe thunderstorms. The heavier rainfall
should be more isolated...some locations could accumulate up to an
inch and a half of rain...most will be around three quarters of an
inch. Since the ground is relatively dry not excepting much in the
way of flooding issues.
Plenty of wrap around moisture behind the front to keep showers
likely in the north Friday night into Saturday with chance probability of precipitation
over the southern half of the forecast area.
Depending on the cloud cover for Friday that will affect the highs
but did go with warmer values in the east because it will remain
drier longer. Depending on the cloud cover for Saturday night some
locations may have to worry about frost if the clouds
decrease...mainly inland of the lake.
Long term /Sunday through Wednesday/...
the models differ on the timing of a trough moving through the area
around Sun night/Monday then whether the larger upper trough will
persist over the area Tuesday through Wednesday. Enough moisture and upper
support looks to be in place for scattered rain showers and cool temperatures sun with
the surface trough leading to additional rain showers Sun night through Monday.
Much more uncertainty enters the picture for Tuesday and Wednesday. Will stay
with low chance probability of precipitation for mainly the NE on Tuesday then back to slight chance
for Wednesday. Temperatures even more uncertain by Wednesday due to model differences
of 10 degree c at 850 mb.
Aviation /06z Thursday through Monday/...
a few patches of low clouds and some reduced visibilities across
the area should start to improve as southeast to south flow
develops across the region. Expecting a swath of middle level clouds
to move into the region later today and then lift northeast of the
region and return back to mainly high cirrus clouds as a dry slot
tries to form this evening. This is in advance of precipitation
headed our way after 06z in the west. Winds will be on the
increase mainly after 06z as well from the south.
Outlook...non VFR Friday in showers and thunderstorms. Non VFR
likely Saturday NE Ohio/northwest PA...perhaps lingering into Sunday
with the high moving off the East Coast and a strong cold front
approaching...NE to east winds of about 5 to 15 knots will veer to
south then start increasing Thursday night into Friday so eventually a Small Craft Advisory
will be needed. The passage of the cold front later Friday will turn
the winds to west-southwest and speeds up to 30 knots look reasonable late Friday
night into Sat. Winds should decrease a little later Sat but may
stay strong enough to keep Small Craft Advisory waves going through sun. A trough moving
through the lakes around Monday will likely lead to some backing of the
winds later sun/Sun night into Monday.