Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
355 am EDT Thursday Aug 28 2014
high pressure will build into the Great Lakes and Ohio Valley
today...providing warm dry weather. A disturbance in the upper
atmosphere may trigger a few showers and thunderstorms Friday
afternoon in western locations. A cold front is forecast to bring
increasing chances for showers and thunderstorms through the
Near term /through today/...
cold front has dropped south of the iln area early this morning.
Surface high pressure centered over the northern Great Lakes is
poised to move to the eastern Great Lakes and Ohio Valley by this
evening. The high will be accompanied by subsidence and a drier
airmass that will keep the iln area free from precipitation today.
Temperatures are a bit tricky today. Cold advection on a northerly
flow will be offset by abundant sunshine. Opted for highs in the
80s...a bit above guidance as has been the trend in recent days.
Short term /tonight through Saturday/...
for Friday...a disturbance traveling along the western flank of
an upper ridge is prognosticated to enter Indiana. European model (ecmwf) has shown this
feature for the last several runs...while the latest GFS now is
in better agreement indicating a short wave trough providing
lift. This points to a low chance of thunderstorms Friday
afternoon. Factor working against widespread convection will be
high pressure and a persistently dry airmass to the east.
Therefore...locations west of Dayton will have the best chance for
convective development...with eastern sites expected to remain
Cold front will be moving toward the area from the west on
Saturday. Current indications are that a few showers and
thunderstorms may develop by Saturday evening across the western
half of the forecast area as convergence and moisture increase
ahead of the front.
Warm advection on a southerly flow in the presence of a strong
upper ridge will result in a very warm temperature regime. Highs
both Friday and Saturday will be close to 90. This compares to
normal highs in the lower to middle 80s.
Long term /Saturday night through Wednesday/...
for Saturday night into Sunday...a tandem of S/waves will move
east/northeast through the Great Lakes while a surface frontal
boundary lays out NE to SW over the Great Lakes as well.
Meanwhile...another shortwave is forecast to round northeast into the
Ohio Valley on the back side of middle level ridge. The combination
of these systems and some upper level dynamics/low level weak
forcing will bring a chance of showers and thunderstorms. Brought
probability of precipitation up to 50 percent. Clouds and precipitation will keep temperatures warm
Saturday night but cooler on Sunday with highs mainly in the lower
For Sunday night into Monday...middle level ridge moves off the
southeast U.S. Coast while a middle level trough digs east/southeast
toward the Great Lakes. Precipitation will wane Sunday night as energy exits
to the east. On Monday...we will see low chance probability of precipitation as
south/southwest moist flow continues over the region.
A better chance for showers/storms will arrive Monday night into
Tuesday as middle level trough moves across the Great Lakes...pushing a
cold front southeast through the Great Lakes and the Ohio Valley.
High pressure is then forecast to build south into the region
Tuesday night into Wednesday...bringing an end to the precipitation as well
Aviation /06z Thursday through Monday/...
middle/upper level ridge to build east into the region today with surface
high pressure working across Great Lakes. Expect some thinning middle
and hi level clouds this morning. In light winds flow and mainly
clear skies expect fog to begin to develop. Some drier air in light
NE low level flow will inhibit widespread dense fog fog from
forming. Have a mention of IFR at fog prone Kiln/kluk locations.
After fog Burns off quickly this morning...VFR conditions will
prevail through the day.
Light northeast winds less than 10 kts will become light east
Outlook...scattered thunderstorms possible on Saturday and Sunday.