Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 262358
AFDJKL

Area Forecast Discussion
National Weather Service Jackson KY
758 PM EDT SUN JUN 26 2016

.UPDATE...
Issued at 758 PM EDT SUN JUN 26 2016

Outside of a few rogue storms popping up to our southeast and
west, the evening is shaping up to be quiet. Earlier activity
across central Kentucky has died off just before it worked into
our forecast area. Watching convection to our northwest. HRRR
continues to show this line weakening as it loses the instability
overnight. Thus, not expecting the line in its current form to
make it this far south. Thus, trimmed back pops a bit through the
overnight hours. As the front pushes south tomorrow morning,
instability should build ahead of the boundary with more robust
convection developing after daybreak Monday. As far as cloud
cover, cut back on it overnight as well with the lack of organized
features. Should see plenty of clearing tonight allowing for a
small ridge valley split.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 330 PM EDT SUN JUN 26 2016

WSR-88D radar is picking up on a area of slow moving showers and
thunderstorms west of I-75 as expected this afternoon. None of
the meso models have had a great handle on the timing of the
convection overall, but the SPC SSEO page was indicating the
higher chance across this area this afternoon. This all seems
reasonable given the better moisture return in this area with
PWATS running 1.5 to 1.7 inches and generally dryer as you move
east of I-75. These storms will be capable of producing locally
heavy rainfall with dual pol estimates of around a inch per hour
in some of these storms. Also radar indicating many of these
storms are low centroid and are slow moving given little steering
flow. Most of the data including the SSEO would suggest a lull in
precip in the early evening ahead of the boundary that will aid in
firing off additional convection later tonight. However the SSEO
has much less of a signal overall at this time, so went no more
than scattered activity overnight. It is expected to be a muggy
night given the moisture return with dewpoints in the upper 60s to
70.

Now front is progged to progress across the region through the day
into Monday. This should be enough forcing to lead to more
numerous showers and storms. Right now the better chance looks
like it will reside across the southeastern half of the region,
but again kept with most spots seeing numerous showers and storms.
We will have sufficient lift along the front, MUCAPE on the order
of 1000 to 2000 J/kg, and PWAT values nearing the 2 inch, but we
will lack severely in the shear side given bulk shear values are
expected to run 20 knots at best. That said SPC does have the far
SE in a marginal severe risk but agree with them that this will
be more pulse like storm situation. The bigger threat overall will
be the potential for isolated flash flooding, given the PWATS are
running upwards of 2 inches and weak steering flow aloft. The FFG
has had time to recover from past weeks storms about 3 days ago.
Did opt to hold off on a flash flood watch given the higher
guidance and uncertainty on afternoon and overnight convection.
However have opted to continue to highlight this threat in the HWO
product. Monday night we will see a overall clearing trend as
front dives SE across the region, with isolated coverage as we
move through the night.

.LONG TERM...(Tuesday through Sunday)
Issued at 454 PM EDT SUN JUN 26 2016

The initial cold front of the short term period should be to our
southeast by Tuesday morning, along with its precip. A secondary
cold front dropping southeast through the Midwest is expected to
move through our local area on Tuesday and Tuesday evening.
However, forecast models disagree on the extent of drying which
will occur with the first front. The GFS and ECMWF both show the
most significant drop in dew points occurring with the first
front, while the NAM holds onto much more low level moisture until
the second front passes. That being the case, the NAM develops
substantial instability ahead of the second front on Tuesday, with
scattered thunderstorms occurring. Although the NAM is generally
not favored at longer range, it sometimes can do a better job
picking up details near the surface, and it will not be completely
discounted at this point. Have included a slight chance of
showers/thunderstorms over the southern and southeastern portions
of the forecast area ahead of the front on Tuesday afternoon and
evening.

Even the NAM has lower dew points eventually arriving behind the
second front (but still not as dry as the GFS and ECMWF), and a
dry forecast has been used beginning late Tuesday night. Sprawling
surface high pressure will pass by to our north underneath an
upper level trough at midweek. This will result in pleasant
conditions by summertime standards. In fact, forecast soundings
from both the GFS and ECMWF suggest surface dew points falling to
near 50 deg F or lower Wednesday into Friday. This would allow for
cool morning lows, especially in valleys. Sunshine would also
result in warm afternoons and large diurnal ranges.

The persisting eastern CONUS upper trough allows yet another cold
front to drop southeast into the area next weekend, but it`s
unclear how quickly it will exit. Moisture return is indicated
along the front, and it is shown lingering longest over our
southern counties. Precip has been included areawide Friday night
into Sunday, with the highest POP in the south. Even so, the POP
is held to no higher than chance category at this point.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 758 PM EDT SUN JUN 26 2016

VFR conditions will dominate through the overnight hours. A cold
front will bring increasing shower/storm chances by mid to late
Monday morning for all of eastern Kentucky. Torrential rain is
likely with the storms, reducing visibilities. Showers and storms
will continue for much of the area into the early to mid afternoon
hours before exiting south. Thus, expect convection to gradually
decrease from north to south through Monday evening, with VFR
conditions returning.

&&

.JKL Watches/Warnings/Advisories...
None.
&&

$$

UPDATE...KAS
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...KAS


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