Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
424 PM EST Friday Nov 28 2014
high pressure will slide off to the east tonight. Southerly flow
on the back side of the high will bring a warming trend through
the weekend. A cold front will move through the region Sunday
night with high pressure building in behind the front.
Near term /until 6 am Saturday morning/...
some flurries/snow showers will pass just north of Columbus late
this afternoon. Otherwise middle and high level clouds will continue
to slide across the region through much of the overnight. Surface
high pressure centered over southeastern Ohio this afternoon will
continue off to the east. Southerly flow will persist through the
night. So temperatures will make an initial drop this evening...
more so in the eastern counties where winds are lighter...and then
likely steady out or perhaps even rise a degree or two.
Short term /6 am Saturday morning through Sunday night/...
low level jet over the Ohio Valley will strengthen Saturday into
Saturday night. The jet weakens some on Sunday but the axis
remains across the forecast area. This will bring good warm and
moist advection into the region along with weak low level lift.
Models have been very consistent in bringing a substantial
increase of low level moisture over the area by Saturday afternoon
which will result in quite a bit of cloud cover. In addition...
some light precipitation will likely start to develop late in the
day. It is not clear whether this will be light rain or drizzle.
Precipitation will increase in coverage Saturday night and
continue into Sunday with perhaps a slight shift northward. Chance
of measurable rainfall will increase with time. It is recognized
that this could be a trace event for many places. So have limited
probability of precipitation to the chance category.
A cold front will approach the northwestern counties late Sunday
and the increased lift with the boundary will bump up the chance
of measurable rain further by late in the day. The front will push
through most if not all of the forecast area Sunday night. A more
coherent band of rain should accompany the boundary so probability of precipitation remain
highest for Sunday night.
Forecast highs for Saturday have stayed close to the MOS
consensus. There will be little if any fall in readings Saturday
evening...then temperatures will rise through the rest of the
night. It should be quite mild on Sunday. But a sharp cool down
will occur Sunday night behind the front with temperatures quite a
bit cooler by daybreak Monday.
Long term /Monday through Friday/...
cold air will continue to filter in during the day on Monday. Due
to this expect temperatures to drop through the day. Precipitation
will gradually taper off from northwest to southeast through the day and into the
evening hours on Monday. Skies will begin to clear from northwest to southeast
and therefore expect the coldest temperatures across northwest portions of
the forecast area Monday night. Have temperatures dropping down into the teens
across northwest portions of the area to the middle 20s across southeast portions
of the region.
Dry conditions will continue for the daytime hours on Tuesday
however a weak frontal boundary will move through Tuesday night into
Wednesday allowing for a return of precipitation chances to the
area. A mix of rain and snow is expected with this system. With
cool airmass in place on Wednesday do not expect a large rise in
Models continue to diverge for the later parts of the extended
forecast for Wednesday night through Friday. As with the last
couple of days continued to closely follow the European model (ecmwf) solution. This
solution has precipitation exiting the area by the evening hours on
Wednesday. High pressure and dry conditions then build into the
area through Thursday. The next system will approach the area
Thursday night into Friday and bring a return of precipitation to
the region. Temperatures are expected to be warm enough with the
Thursday night into Friday system that precipitation will be in the
form of rain.
Aviation /21z Friday through Wednesday/...
there are still a few MVFR ceilings lingering across the area but for
the most part we are dealing with a middle level cloud deck this
afternoon. A fair amount of returns are showing up on radar...but
much of this does not appear to be reaching the ground. That being
said...it will be tough to rule out a few flurries as we progress
through the rest of the day but do not expect much of an impact if
any on aviation. Expect some partial clearing overnight as middle
level moisture shifts off to the east. Increasing southwesterly low
level flow will allow for abundant low level moisture to advect up
into the area through the day on Saturday. This will lead to
increasing clouds and a lowering of the cloud deck with some MVFR
ceilings possible through late morning and into the afternoon hours.
Toward the latter part of the kcvg taf...low levels will continue
to saturate with some IFR ceilings and lower visibilities likely developing.
Outlook...IFR ceilings and visibilities will be possible Saturday night
through Sunday night.