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fxus61 Kiln 301050 
afdiln

Area forecast discussion
National Weather Service Wilmington Ohio
650 am EDT Thu Mar 30 2017

Synopsis...
a few showers or thunderstorms will be possible today in the
warm airmass ahead of a strong low pressure system. Showers and
thunderstorms will become more numerous tonight, as the low and
its associated cold front move through the Ohio Valley. A few of
the storms late this afternoon and this evening may be severe.
The low will move slowly off to the east on Friday, when linger
precipitation is expected. High pressure will offer dry weather
and cooler temperatures for this weekend.

&&

Near term /until 6 PM this evening/...
upper level low over the Central Plains to slide NE into the mid
MS Vly today and across the Great Lakes tonight. Flow backs
and moisture increases across the area. This is a complex
weather system with several chances for showers and
thunderstorms.

Looking at expected details, axis of favorable low level
convergence associated with 40 kt llj pivots north ahead of
advancing surface warm front this morning. This forcing along
with marginal elevated instability may lead to a few showers or
thunderstorms early, especially across the northwest counties.
These initial early morning storms are expected to be below
severe limits.

Uncertainty exists regarding potential for severe today. One
factor is the amount of instability that develops in the warm
sector ahead of the pre-frontal trof. Best instability looks to
stay to our SW during the day where genesis region for storms is
expected. An axis of instability will work into the southwest
late in the afternoon, with blyr CAPES lkly between 1000 and
1300 j/kg. There appears to be a window with the potential for
severe weather this afternoon into evening, with a pre-frontal
surface trof pushing into the area. Second stronger 50-55 kt low
level jet will provide good axis of lift during late
aftn/evening hours, which coincides with this instability.

Bulk shear in 0-km layer suggests organized storms will be
possible and low level shear is favorable but local heights are
initially high. However model solns suggest the LCLs drop toward
evening.

Besides the question of the amount of instability, there is a
question regarding phasing of parameters (shear/instability) and
then how far east the storms get as they weaken with diminishing
instability.

Also, flow backs with the increase in moisture resulting in
pw/S increasing to around 1.3 inches by late this afternoon
into this evening, which is 200 to 225 percent of normal.
Although storms will be moving, the potential for localized
heavy rain and flooding will also exist.

Will mention the severe potential and flood potential in severe weather potential statement
product. The main threats are damaging winds and large hail and
local flooding but isolated tornadoes can not be ruled out. Very
warm temperatures to continue today with highs from the mid 60s
far north to the upper 70s far south.

&&

Short term /6 PM this evening through 6 PM Friday/...
upper level low to pivot into the Ohio Valley tonight into
Friday. Ongoing storms, some with potential for severe weather
and localized flooding this evening to push east and weaken
overnight. Surface cold front to sweep east thru iln/S fa toward
sunrise Friday. Lows tonight to range from the upper 40s NW to
the mid 50s southeast.

With the upper low pivoting through Ohio Friday, a good chance
for showers will continue through the day. Cloud cover, low
level caa and pcpn will keep temperature cooler, closer to
normal readings. Expect highs on Friday to range from the upper
50s northwest to the lower 60s southeast.

&&

Long term /Friday night through Wednesday/...
upper air pattern will feature a broad ridge for much of the period,
interrupted by a couple of vigorous low pressure systems.

Showers will be exiting east Friday night behind departing low
pressure. High pressure building at the surface and aloft will
provide dry conditions Saturday and Sunday. Low pressure will return
with showers and possibly thunderstorms on Monday, with showers
diminishing Tuesday behind the system. Another area of low pressure
arriving quickly on a westerly flow aloft will keep the chance of
showers in the forecast on Wednesday, with thunderstorms also
possible Thursday.

Temperatures will start a bit below normal Saturday under cold
advection on a northerly flow, with highs reaching the 50s. Readings
are then expected to rise above normal Sunday through Wednesday due
to insolation and warm advection, with highs generally in the 60s.
Highs may then retreat to around 60 next Thursday under clouds and
modest cold advection.

&&

Aviation /12z Thursday through Monday/...
upper level low over the Central Plains to slide east into the
mid MS Vly today and across the Great Lakes tonight into Friday.
Mid level flow has backed with mid level clouds developing
across the Ohio Valley.In warm air advection pattern a few rain showers and
weakening thunderstorms will pivot north ahead of northward
advancing warm front this morning. Due to limited coverage have
only a mention of vcsh.

Showers and thunderstorm will develop in the warm and moist
environment to our west ahead of surface wave tracking into
central Illinois. These storms to push into the western taf sites
toward evening. Have prevailing thunderstorms overspreading
all taf sites associated with a pre-frontal surface trof, with
MVFR conditions developing. Brief IFR conditions will be
possible in thunderstorms in heavy rain this evening.

Eventually expect IFR ceilings to develop later tonight in showers
with thunder diminishing with cold front passage early Friday.

East winds at 10 to 15 kts will veer to the south and increase
to around 15 kts today. Given a tightening pressure gradient
some wind gusts up to 25 knots will be possible this afternoon.

Outlook...MVFR ceilings and visibilities likely into Friday
evening. MVFR to IFR ceilings likely Friday night into
Saturday.

&&

Iln watches/warnings/advisories...
Ohio...none.
Kentucky...none.
In...none.

&&

$$

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