Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
646 am EDT Sat Jul 26 2014
a series of upper level disturbances will rotate down across the
Great Lakes region through Sunday...resulting in occasional
showers and thunderstorms this weekend. A much cooler airmass
will settle into the area for the first part of the upcoming work
Near term /until 6 PM this evening/...
southwesterly low level flow will allow for an increasingly
warm...moist and unstable airmass to develop across the region
through this afternoon. By late afternoon...strong instability is
prognosticated just off to our west with moderate instabilities working
into our area as ml convective available potential energy push into the 1000-2000 j/kg range.
The warmer low/middle level temperatures may provide enough of a cap
to prevent much development through late afternoon...but will hang
to some lower chance probability of precipitation across the northwest as some weak short
wave energy will be dropping down from the northwest through late
afternoon. In a developing warm air advection pattern...expect highs today
ranging from the middle 80s north to upper 80s south.
Short term /6 PM this evening through Monday/...
better instabilities will continue to advect into the area heading
into this evening. A seasonably strong low level jet over the middle
Mississippi Valley should allow for an mesoscale convective system to develop off to our
west and then work east into our area through late evening into
the overnight hours. The NAM-WRF and nmm are in decent agreement
with this...pushing an mesoscale convective system across primarily southern portions of
our forecast area...but do differ by several hours in their timing with the
NAM-WRF being faster. Either way...it does appear like fairly high
probability of precipitation are in order for tonight and given the strong 0-3 km shear
vectors and good instability...a damaging wind threat will exist
tonight with these storms. Given the high precipitable water values...locally
heavy rain will also be possible...but the 0-3 km shear vectors
are oriented perpendicular to the mesoscale convective system movement which should allow
for more progressive storms...and hopefully limit any prolonged
Some uncertainty still exists to exactly how things will play out
heading into Sunday in the wake of the mesoscale convective system tonight...but both the
NAM and GFS continue to indicate strong instability developing
through Sunday afternoon across the area ahead of an approaching
cold front. With impressive shear profiles in place across the
region...severe storms appear likely...especially across our
southeast where the best instability should exist. Given the
degree of shear and instability...all severe weather threats will
be in play with damaging winds...large hail and isolated tornadoes
possible. Thunderstorms activity will taper off from the northwest
later Sunday afternoon into Sunday evening as the cold front moves
through. An unseasonably cool airmass will settle into the area
for Monday with highs only in the low to middle 70s. Scattered
instability showers and perhaps an isolated thunderstorm will be
possible Monday afternoon as the 500 mb trough axis swings across
Long term /Monday night through Friday/...
shower activity will taper off Monday evening. Cool northerly
flow will continue for Tuesday. Expect high temperatures on Tuesday
to be in the low to middle 70s. Temperatures will be slightly
warmer for Wednesday through Friday however still below normal for
this time of year. Weak disturbances will bring off and on chances
for showers and thunderstorms to portions of the area for
Wednesday through Friday.
Aviation /12z Saturday through Wednesday/...
broken to overcast middle level deck will continue across the region through
the morning. Showers and isolated thunderstorms may reach kcvg
later this morning and others may develop during the afternoon as
a weak disturbance passes across the area. Winds will increase out
of the southwest to around 10 knots this afternoon...gusting as high
as 20 knots as low level moisture increases across the region.
A second disturbance moving rapidly west to east across the region
late this evening is forecast to trigger the development of
organized thunderstorms. Latest model runs bring these organized
storms...with damaging winds possible...across the terminals
during the late evening tonight...into early morning hours
Sunday. Have forecasted tempo IFR for all the southern terminals
kcvg/kluk/Kiln...where current model runs show the best chances of
these storms being located tonight. However...cannot rule out the
northern terminals kday/kcmh/klck being affected.
Outlook...thunderstorms possible through Sunday.