Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
104 PM EST Sat Mar 8 2014
a weak cold front will drop down across the region through this
evening...resulting in a chance of showers. High pressure will build
back into the area for Sunday.
Near term /until 6 PM this evening/...
a weak cold front has started to work into northwest portions of the forecast area
and will continue to work through the region today. Precipitation
will generally be confined to northern portions of the forecast area along
and north of Interstate 70 through the late afternoon hours.
Chances for light precipitation then begin to work southward
across the forecast area by the evening hours.
Temperatures will be warm enough that precipitation across the
north through the afternoon hours will generally be in the form of
rain. As colder air works into the region this evening expect the
light rain to change over to light snow across the north.
Short term /6 PM this evening through Monday/...
as the front pushes south...better but still relatively weak
forcing will shift into southern portions of our forecast area through this
evening. This will allow for precipitation to taper off in the north with
a chance of some light showers across the south through this
evening. Precipitation may mix with some snow as low level cold air
filters into the south through this evening.
Surface high pressure will build into the area for Sunday before
being suppressed off to the south through the day on Monday. In
northwest flow aloft...the GFS continues to hint at perhaps some
light showers brushing across far northern portions of our forecast area but
chance appears low enough to leave mention out of the forecast.
Meanwhile...developing west to southwest low level flow will lead to
increasing warm air advection through Monday. Near to slightly below normal
temperatures on Sunday will bounce back into the 50s across much
of the area on Monday with even some lower 60s possible across the
Long term /Monday night through Friday/...
the weather pattern through the extended forecast period will be
characterized by generally-west-northwest flow aloft...with the bulk of the
northern stream remaining just north of the Ohio Valley through
Tuesday. At the surface...there will be alternating brief periods of
high and low pressure...with the low tracks mainly focused north of
the region until mid-week. The greatest forecast complication will
be on Wednesday...as surface low pressure passes through the
Tennessee and southern Ohio Valley regions.
Early in the week...all signs point to a continued warming
trend...with sprawling surface high pressure over the southern
states. This will reach far enough north to influence the Ohio
Valley on Tuesday...with a sharp frontal temperature gradient
expected to be pushed to the northern border of the iln County Warning Area
(potentially out of the County Warning Area entirely). Temperatures in the lower 60s
appear possible for the southern County Warning Area...with skies impacted mainly
by high clouds spilling in from the north.
Precipitation now appears fairly certain for the iln County Warning Area at some
point in the Tuesday night through Thursday time frame...with the
12z model runs today focusing primarily on Wednesday.
However...this timing has not been overly consistent during the
past few run-to-run cycles. The greatest concern in terms of
forecast confidence is the challenge of determining how the
various shortwaves will interact with each other as they move into
the eastern half of the country. The relatively-active northern
stream is sure to send a shortwave through the region...but
whether or not it fully interacts with another shortwave moving
east-northeast out of Texas is what will help determine the eventual strength
and placement of the surface low development. This will not only
have an impact on precipitation amounts...but also the weather
types and temperatures...with the transition from rain to snow
expected to cross through the region. Given the timing
concerns...temperatures were run as diurnal...but the eventual
evolution of the system may require this to be changed.
One thing that does appear fairly certain is that a surface front
will pass south through the area on Tuesday night through Wednesday
morning...bringing a return to cooler condition heading into the
second half of the week. Broad surface high pressure will spread
across the southeastern states through the end of the
week...extending far enough into the Ohio Valley to keep conditions
dry through Friday.
Aviation /18z Saturday through Thursday/...
a weak cold front will work through the taf sites this afternoon
into this evening. VFR ceilings to start will become MVFR this
evening. MVFR ceilings will remain across the taf sites through the
overnight hours. Cloud cover will begin to dissipate Sunday morning.
Some haze is still occurring at kday and expect this to continue
through the afternoon hours. Otherwise VFR visibilities will start out
the taf period. Some light precipitation will work into the taf
sites this evening with a greater likelihood of the light
precipitation at kday...kcmh...and klck. Have a time period of
MVFR visibilities with a rain snow mix this evening across these
locations. Limited precipitation mention to vcsh at
kcvg...kluk...and Kiln. Precipitation will taper off tonight.
Outlook...MVFR ceilings and visibilities possible Tuesday night into