Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
153 am EDT Monday Jul 14 2014
the first of two cold fronts will slowly cross our area tonight.
Showers and thunderstorms will be likely along and ahead of this
front. The second cold front will cross the area Monday evening.
Additional showers and thunderstorms will be possible with the
second frontal passage...with an unseasonably cool airmass
expected to enter the region behind this front.
Near term /until 6 am this morning/...
convection developed along and ahead of first of two cold fronts
during the afternoon. Moderate instability and bulk shear around 30 kts helped
fuel and organize these storms across southern/central Ohio and northern Kentucky.
Some of these storms produced severe weather with damaging winds
being the main threat. Instability has diminished but ml cape values
around 1500 j/kg still exist across northern Kentucky and far southern Ohio. Expect
the focus for convection to continue to shift southward into
the region of more favorable instability. The severe threat is expected
to diminish as instability diminishes. Isolated wind gusts will still
be possible with heavy rain and flooding still a potential across
the far south.
Convective enabling models have been showing a little northward push
to the convection toward sunrise over SW Ohio. Have showed this
potential in the grids with a slight northward surge of probability of precipitation late
tonight. Temperatures will be mild tonight with lows ranging from
the middle/upper 60s far north to the lower 70s far south.
Short term /6 am this morning through 6 PM Tuesday/...
on Monday...convection may be ongoing during the morning along
the washed out first frontal boundary across our southern zones.
Meanwhile...a second cold front will approach northwestern Ohio
and northern Indiana as a deep upper trough moves east across the
Great Lakes. This second cold front will have additional showers
and thunderstorms develop along and ahead of it during the
afternoon. Although 0-6 km shear will be a moderate 40-45 knots...M/l
convective available potential energy between the two cold fronts are not expected to rise much
above 500 j/kg. Therefore...current thinking is that updrafts may
not be strong enough to incorporate the full potential of this
shear...although a few strong storms cannot be ruled out during
Temperatures will rise into the lower 80s across most locations
ahead of this second cold front on Monday. Behind the
front Monday evening into early Tuesday morning...temperatures will
rapidly drop through the 70s and into the 60s. By daybreak Tuesday
morning...temperatures will have dropped into the middle 50s across the
northwestern zones and middle 60s across the southeastern zones.
Long term /Tuesday night through Sunday/...
an unseasonably cool surface high pressure system will build into
the area through middle week. In a developing cold air advection pattern...850 mb
temperatures will drop off through the day...ranging from around 7
degrees celsius northwest to around 10 degrees southeast by late
afternoon...with the core of the coldest air then settling across
the area by 12z Wednesday morning. As a result...expect highs on
Tuesday ranging from near 70 across our northwest to the middle 70s
in our southeast. Highs on Wednesday will be in the low to middle 70s
across the entire area. Lows both Tuesday and Wednesday night
should drop into the low to middle 50s. These temperatures will be 10
to 15 degrees below normal for this time of year.
The surface high will shift off to the east through the end of the
week. As we get into some return flow on the back side of the
high...temperatures will slowly modify heading into the
weekend...but still remain a few degrees below seasonal normals.
The 12z GFS and European model (ecmwf) differ somewhat in their timing/strength and
placement of short wave energy moving out of the lower Mississippi
Valley Friday into Saturday...with the European model (ecmwf) faster and further
north than the GFS. Based on these difference...will go ahead and
introduce some lower end probability of precipitation primarily across our southeast for
Friday into Saturday.
Aviation /06z Monday through Friday/...
there are several potential concerns to aviation during the next
First...it appears that low-level moisture will be sufficient to
produce low clouds and reduced visibilities through the next 6
hours. While MVFR conditions are being specifically forecast for
this set of tafs...very low stratus (lifr) is also developing in
east-central Ohio. This may move into the Columbus taf sites...and
the forecasts will be amended if this appears more likely.
Further south...convection developing over Illinois and Indiana
will continue to move toward the Cincinnati taf sites over the
next several hours. Precipitation appears certain to occur...with
a chance of thunder at the taf sites as well.
After a break during the typical minimum in the diurnal
cycle...additional showers and thunderstorms are expected to
develop by late afternoon and into the evening. This will be ahead
of a cold front moving southeast into the region. The front will
pass through late on Monday night...switching winds to the northwest.
Outlook...no significant weather is expected.