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Area forecast discussion 
National Weather Service Jackson Kentucky
132 PM EDT Thursday Jul 2 2015

issued at 1226 PM EDT Thursday Jul 2 2015

WSR-88D continues to show an area of showers and embedded storms
continuing east across the region early this afternoon. Given that
ffg guidance continues to decrease across the area and frontal
boundary draped along and near the Ohio River...did opt to extend
the Flash Flood Watch for the entire area. Also added heavy
rainfall wording to the zones. Otherwise just some minor changes
and updates to latest obs/trends.

Update issued at 1024 am EDT Thursday Jul 2 2015

WSR-88D radar and lightning data shows area of rain and embedded
thunderstorms moving across much of eastern Kentucky this morning.
Some areas could see locally heavy rainfall with strong storms.
Based on cams and boundary just to our north along the Ohio this
morning would expect showers and storms across the region much of
the day with perhaps some small breaks in between bands. Updated
with latest observation and trends. Otherwise no major changes needed for
this update.

Update issued at 642 am EDT Thursday Jul 2 2015

A decent rain shield is currently moving into the western portion
of the County Warning Area. Updated probability of precipitation to better reflect ongoing conditions and
likely trends through the morning hours. This will include
widespread rain across much of the southwestern County Warning Area...which has
already received a large amount of rain over the last couple days.
Given the already saturated soils...and one hour flash flood
guidance an inch or less in some locations...went ahead and
issued an hour Urban and Small Stream advisory for any rains that
impact this area over the next few hours. seems as
though this first line of showers is weakening as it moves into
the area...but expect them to start intensifying as the sun starts
warming things up this morning. Also updated the near-term
forecast for temperatures...dew points...and winds with the latest
observational data.


Short term...(today through friday)
issued at 323 am EDT Thursday Jul 2 2015

As of 3 am...lingering evening convection over the County Warning Area is continuing
to dissipate as best energy turns its attention to the mesoscale convective system still
over Missouri...which is now generating scattered showers and
thunderstorms out ahead of it. These showers and thunderstorms are
currently making it into western and central Kentucky/Tennessee and will
likely make it into our southern County Warning Area over the next hour or so.
Given the high amount of rain this area of our County Warning Area has seen over
the last couple of days...and the very low ffg as of 0z
7/02...expect that flooding concerns will likely start arising in
this area just before dawn and continue through the morning...and
even through much of the day. An upper level shortwave will
continue to shift east-southeast today...pulling the mesoscale convective system with it. Expect The
Heart of the mesoscale convective system to be over western Kentucky and southern Illinois by 12z
today...with a cold pool driven outflow pulling heightened chances
for showers and thunderstorms into eastern Kentucky. The mesoscale convective system will
continue to shift across the state through the day following an
shortwave as it rounds an upper level longwave trough. As it
shifts will become more cold pool driven once more
with multiple outflows likely creating their own means for
multiple areas of convection.

Despite widespread heavy rain through the day and into the
overnight hours...wpc and other models are still pegging the
southern half of the County Warning Area with the highest quantitative precipitation forecast amounts. As
mentioned above...this is the same area that has already been hard expect an active day and overnight period as any rain
that occurs will likely result in runoff. Will keep with current
Flash Flood this seems to line up well with latest guidance and
wpc quantitative precipitation forecast forecast.

There is some discrepancies in the European model (ecmwf) and the nam12 late tonight
as the mesoscale convective system reaches the far eastern extent of the County Warning Area. The NAM shows a
broader surface low pressure system forming and keeps multiple
heavier waves of precipitation over southern and eastern Kentucky through 12z
Friday. Meanwhile...the European model (ecmwf) has a slightly weaker but more
centralized low...and pulls most of the moisture out of the state
with the exception of far eastern Kentucky by this same time.
Regardless...expect there will be some degree of rain potential
centered over our County Warning Area...which warranted keeping likely and above
probability of precipitation across much of the County Warning Area through the night.

For Friday...any lingering moisture across the state will likely
result in a resparking of scattered to numerous showers and thunderstorms
during the daytime hours due to peak heating and interaction with a
stalled frontal boundary passing through the state /attached to
the departing low/. While convection will generally be in and
around the area of the boundary...expect coverage to include a
wide area across most of the state and areas southeast. One thing to that model soundings are showing a large
influx of dry air in the middle and upper levels after the
shortwave/MCS/and surface Low Pass through. This will keep most
moisture confined to a shallow low level layer. Latest nam12 forecast
soundings are also showing an inversion at all taf sites just
above this moist layer. With this in mind...expect strong to
severe storm potential to be very limited with this inversion in
place...and any showers to be much lighter in nature with lower
quantitative precipitation forecast values. This correlates well with the end of the watch period
as well.

Long term...(friday night through wednesday)
issued at 455 am EDT Thursday Jul 2 2015

An wavering frontal boundary is expected to sink slowly southward
from the region during the period. Its proximity will support a
continuing possibility of showers and thunderstorms. However...
enough drier air may make it into the region to lower the pop
Sunday through Monday...before another weakening cold front moving
in from the northwest brings an increase in the pop Tuesday and


Aviation...(for the 18z tafs through 18z Friday afternoon)
issued at 132 PM EDT Thursday Jul 2 2015

15z surface analysis shows frontal boundary draped near and
across the Ohio River this afternoon with surface lows along the
front. This will lead to a stormy taf period overall. This
afternoon many of the northern and eastern sites are seeing LIFR
to MVFR ceilings and visible. We are seeing some clearing across the
southern sites...however any clearing could lead to increased
instability. Given that shower and storm activity continues to
develop upstream the concern would be additional development would
be possible. Although do expect development the exact locations of
this are still uncertain. Therefore did keep tafs this afternoon
and overnight thunderstorms in the vicinity/vcsh at this point. Also seem reasonable that
fog and lower ceiling would have the potential to develop
overnight once again leading to LIFR/IFR conditions. Otherwise
overall winds are expected to be light in nature...except perhaps
with storm activity.


Jkl watches/warnings/advisories...
Flash Flood Watch through Friday morning for kyz044-050>052-


short term...jmw
long term...hal

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