Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
416 PM EDT Friday Jul 31 2015
a weak cold front will approach the area tonight and dissipate
but not before providing a slight chance of a shower or
thunderstorm. Surface high pressure will build across the Ohio
Valley Saturday into Sunday...allowing for dry weather conditions
and near normal temperatures. Chances for showers and storms will
gradually increase from Sunday afternoon into the new week.
Near term /until 6 am Saturday morning/...
northwest flow aloft with short wave dropping southeast through the Great Lakes
tonight. Associated weak front to push into Northwest Ohio early and then
drop southeast across iln/S forecast area and further weaken and lose its identity
this evening. Latest visible satellite imagery shows area of less cumulus
over SW Ohio in between surface trough to the east and front pushing
across northern Indiana. Low end moderate instability has lead to scattered
convective development along and just ahead of the front. These
storms to push into west central Ohio and weaken this evening.
Have low probability of precipitation...mainly across the north this evening before
convection diminishes with the loss of daytime heating.
Temperatures will be close to normal with lows from near 60 NE to
the Lower/Middle 60s SW.
Short term /6 am Saturday morning through Sunday night/...
in northwest flow pattern surface high pressure to build across
the Ohio Valley Saturday. Expect a good deal of sunshine in
relatively dry airmass. Temperatures will be at or slightly below
normal with highs from the lower 80s north to the middle 80s south.
A return southerly flow will develop on Sunday on the back side of
retreating surface high pressure. An increase in moisture will lead to
marginal instability ahead of an approaching front. Will continue very
low probability of precipitation across the northwest late in the day Sunday. Highs on Sunday to
be close to normal...ranging from lower 80s north to the upper 80s
The weak surface front will push southeast and further weaken and lose its
identity Sunday night. Will continue low probability of precipitation into the evening and
then allow chances to diminish. Lows Sunday night look to be in
the middle and upper 60s.
Long term /Monday through Friday/...
multiple waves of precipitation are expected through the long term
period. With some disagreement with timing and strength of these
features have gone closer to the European model (ecmwf) for the long term period.
A frontal boundary will move across the area on Monday. This
feature will remain near the area into Tuesday. A better chance of
precipitation will be on Wednesday as an area of low pressure
approaches the region. This feature will begin to move out
Wednesday night into Thursday morning. After this time have dry
conditions for the remainder of the forecast. The GFS tries to
bring another round of precipitation into the region Thursday night
into Friday however went with the drier European model (ecmwf) solution at this time.
Monday is expected to be the warmest day of the long term period.
With cloud cover associated with the low and then cooler air moving
into after the passage of this system...expect temperatures only in
the 70s to low 80s for Wednesday through Friday.
Aviation /20z Friday through Wednesday/...
a ridge of high pressure situated just south of the area continues
to provide VFR conditions this afternoon. Cumulus field is increasing
in response to daytime heating and more instability than
yesterday. Winds are also picking up a bit and will gust to 20
knots through early evening. A weak cold front currently over
Northwest Indiana has already triggered a few storms there early
this afternoon. Expect convection to be somewhat suppressed across
our area due to limited moisture and a layer of warmer air aloft
per area forecast soundings. However...isolated showers and
storms will be possible late this afternoon into this evening as
the front pushes southeast. Northern terminals will see the best
chance for any convection but have only mentioned vcsh in the tafs
at this time due to low areal coverage and predictability.
Skies will mostly clear out overnight with winds becoming light.
With a similar setup to last night...have gone with a period of
IFR br at kluk before sunrise. The high will drift across
Kentucky on Saturday providing VFR conditions for the remainder of
the taf period.
Outlook...MVFR ceilings and visibilities possible late Sunday and Sunday
night in scattered storms.