Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
405 am EDT Friday Sep 4 2015
a weak upper disturbance will linger across the Great Lakes region
into the first part of the weekend before dissipating. This will
continue the chance of showers and thunderstorms. An upper level
ridge is then expected to build across the region Sunday...and
remain across the area into Monday. Temperatures will remain very
warm for early September.
Near term /until 6 PM this evening/...
an upper level closed low will slowly rotate westward across the
western Great Lakes today. At the surface...a weak boundary will
remain near our northwest County warning forecast area. The airmass has not changed since
yesterday...with precipitable waters averaging around 1.5 inches. High
resolution models indicate that our northwest County warning forecast area will have a higher
chance for showers and thunderstorms during the peak heating of
the day due to its proximity to the boundary and upper low. Mean
cloud bearing flow will be northwest to north...so some of this
activity could drift southward toward evening before dissipating
by midnight. Have ranged probability of precipitation from 40 percent northwest to 20
percent along and south of the Ohio River. It will remain very
warm and humid with highs similar to yesterdays readings which
peaked into the upper 80s and lower 90s. Given slow motion of
storms...some locally heavy rain will be possible again along with
some gusty winds in the more robust storms.
Short term /6 PM this evening through Sunday night/...
convective activity is expected to wane this evening...leaving
mostly clear to partly cloudy skies overnight.
On Saturday...upper level low will shear and eventually lose its
identity by Saturday evening as middle level ridging tries to build
into our area from the west and east. We should see one more day
for a threat of a shower/storm during peak heating...but coverage
should be less than today. By Saturday night...skies will become
For the period Sunday into Sunday night...models indicate that middle
level ridging will build and extend from the Southern Plains
northeast through our region then into New England. Increasing
subsidence along with a little bit drier air from the east should
keep the forecast dry.
Temperatures will remain very warm over the weekend with highs in
the upper 80s to near 90 and lows generally in the middle and upper
Long term /Monday through Thursday/...
southerly flow will allow for temperatures to climb into the middle 80s
to near 90 degrees across the forecast area Monday through Tuesday. Sunday
through Tuesday will primarily be dry however a few storms will be
possible across northwest portions of the forecast area Tuesday afternoon into
Tuesday night as the next system approaches.
On Wednesday a frontal boundary will move into the area bringing
better chances of precipitation to the region. There are some
differences with the models on how quickly this feature moves out
and whether or not a secondary area of low pressure moves along the
front and lingers precipitation across the region.
The European model (ecmwf) favors the slower solution with the secondary area of low
pressure. Decided to linger the precipitation longer than the GFS
however not as long as the European model (ecmwf). Temperatures will be cooler on
Wednesday with precipitation around the region and on Thursday
after the passage of the front.
Aviation /08z Friday through Tuesday/...
aside from some thunderstorms passing just north of the Columbus
taf sites during the next few hours...dry conditions are expected
for the first part of the forecast period. With light winds and
plenty of moisture...MVFR fog will be likely at all taf
sites...with some temporary IFR conditions possible at times.
The weather pattern has changed very little over the past few
days...so another round of isolated storms will be expected on
Friday afternoon. A thunderstorms in the vicinity has been included in the tafs for all
locations...with low confidence in exact timing and placement of
the convective development. Where storms develop...MVFR to IFR
conditions will be possible...along with brief gusty winds.
Outlook...no significant weather expected.