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Area forecast discussion 
National Weather Service Louisville Kentucky
638 am EDT Sat Jul 4 2015

..updated aviation discussion...

Short term (now through sunday)...
issued at 300 am EDT Sat Jul 4 2015

The synoptic pattern this morning features a general trough across
the eastern Continental U.S. Due to a large upstream ridge across the West
Coast. This pattern will slowly deamplify through the short term
period, but chances for showers/storms will continue, mainly across
southern and eastern Kentucky.

The radar is finally quiet early this morning as a mid-level trough
pushing through the area has shunted the better moisture transport
off to the east/southeast. Expect this general trend to continue
today, with pwats of just over an inch entering the northern County Warning Area by
this afternoon. A frontal boundary currently draped across central
Kentucky will only slowly sag south today, likely stalling somewhere in
the vicinity of the Kentucky/Tennessee border. Therefore, while the main slug of
deep moisture transport will be shunted off the east/southeast,
still think we will see some scattered storm development along/near
the boundary this afternoon into early this evening. Given
generally unfavorable upper-level support and the aforementioned
moisture transport being shunted to the southeast of the region,
will cautiously allow the Flash Flood Watch to expire. Am a bit
concerned that coverage right along the boundary may be enough to
warrant perhaps an isolated flooding issue or two today across
southern Kentucky as storms will once again be slow-moving, but think the
widespread threat has ended so will go ahead and let the headline
expire.

By tonight, an upper-level low will slowly push into TN, crossing
through Kentucky during the day on Sunday. Moisture transport and ascent
will once again ramp up mainly on the eastern side of this system,
thus have upped pops into the likely category for Sunday across
portions of southern and eastern Kentucky. Coverage will be substantially
less across northern Kentucky and southern in. Will have to watch this
system closely as soundings out of klex show pwats of 1.75+ inches
and a skinny cape profile. In addition, showers/storms will be
slow-movers given the weak tropospheric flow. Therefore, we may
once again be dealing with some Hydro issues as this system pushes
through.

Temperatures will be dependent on convection, but highs today and
tomorrow should climb into the low to mid 80s, with overnight lows
tonight in the mid to upper 60s.

Long term (sunday night through friday)...
issued at 300 am EDT Sat Jul 4 2015

Still expecting a lull in an otherwise wet pattern to be ongoing
Sunday night and Monday, with weak surface and upper ridging to our
north and east. Limiting factor in forecast confidence is the
eventual behavior of a disturbance that is progged to move through
the Tennessee Valley. NAM/European model (ecmwf) are fairly bullish with this
impulse, and if this solution verifies it could remain wet in our
southern and eastern zones, particularly along the Cumberland
Escarpment. Will still dry things out by late Sunday evening, and
limit Monday pop to a 20-30% chance in the heat of the day, which
may be too generous north of the parkways but too conservative
farther south and east. Temps actually back near climo for this part
of the week, as cloud cover should not be that extensive.

By Monday night/Tuesday pops will ramp up from the west as low
pressure swings through the upper Great Lakes, and drags a cold
front into the Ohio Valley. This front will hang up somewhere in or
near the forecast area, and focus showers and storms for much of the
rest of the work week. Impulses riding along the front will be
difficult to time, but also have the potential to disrupt the
otherwise diurnal pop trend. Best chance for any strong storms would
be Thu night/Fri as a better-defined upper shortwave scoots across
the Great Lakes and strengthens the westerlies. Temps near normal or
just a bit cooler by day, but just above climo by night as clouds
and abundant moisture limit diurnal ranges.

&&

Aviation (12z taf update)...
issued at 638 am EDT Sat Jul 4 2015

IFR conditions at kbwg and klex continue this morning, with MVFR
cigs at ksdf. Expect conditions to slowly improve through the
mid-morning hours as daytime mixing commences and drier air slowly
works in. Can't completely rule out a shower or storm today at klex
or kbwg, but the limited expected coverage precludes any mention at
this time.

By tonight, an upper-level low will return moisture back into kbwg
and klex likely resulting in renewed showers/storms and lowered cigs
towards the end of the period. Will introduce MVFR cigs with this
package. Ksdf should remain in the drier air, so restrictions
aren't expected there.

&&

Lmk watches/warnings/advisories...
Kentucky...none.
In...none.
&&

$$

Short term........kjd
long term.........Ras
aviation..........kjd

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