Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 291114
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
714 AM EDT Sat Apr 29 2017

.UPDATE...
Issued at 714 AM EDT SAT APR 29 2017

Updated the forecast package for lingering showers in our east
which were generated by an outflow boundary that is beginning to
stall out across the heart of the area. Interestingly there are a
few feint echoes further south which suggests the cap in place
across the area may not be as strong as forecast soundings
suggested. Should the cap not be strong enough to keep convection
in check later today, the convective outflow boundary could play a
role in the refiring of afternoon showers and thunderstorms. The
HRRR did pick up on this activity to our south but suggest
convection will still be at a minimum this afternoon.

&&

.SHORT TERM...(Today through Sunday)
Issued at 505 AM EDT SAT APR 29 2017

A stationary front stretches west to east roughly along the Ohio
River this morning. Convection has been firing along this boundary
all night and has taken a small southward drift with time. At
present showers and thunderstorms are affecting locations mainly
along and north of I-64. Based on Kentucky mesonet observations
these storms have been producing outflows generally at or below 30
mph across our area. The Kentucky Mesonet has also shown some
decent rainfall rates, upwards of about an inch per hour in the
strongest thunderstorms. But storms have had some good motion and
are not laying down a tremendous amount of rainfall. However
there has been a considerable amount of training which has allowed
totals to add up rather quickly in spots.

Most recent regional IR loop has begun to show warming tops. In
addition current radar is showing a decreasing trend in higher
echos within these storms and a drop in rainfall rates as well.
Based on JKL VAD wind profile expect the weakening trend to
continue through sunrise this morning as our overnight LLJ of
30-50 kts has weakened considerably over the last few hours. Just
the same felt it would be prudent to mention the possibility of
locally heavy rainfall with thunderstorms this morning in the HWO
along with a potential of some minor nuisance type flooding where
storms tend to pass repeatedly over the same location.

Showers and thunderstorms will gradually come to an end today. Am
curious about the convective outflow boundary being produced
across the heart of the CWA. Cap appears just strong enough to
keep convection in check today. But if forecast soundings are off
and some convection should fire, this residual outflow boundary
would add another element to the picture. This will have to be
monitored closely.

The remainder of the short term is pretty much a temperature
forecast. Highs today still look on track to threaten records.
With moisture in the area, dew points in the lower to mid 60s and
highs climbing to near 90 this afternoon, it is sure to feel a
bit more like a summer out there.

.LONG TERM...(Sunday night through Friday)
Issued at 326 AM EDT SAT APR 29 2017

An area of low pressure will become cut off over the western great
lakes at the start of the period with an occluded front pushing
east across the Ohio river valley. Subsidence just ahead of this
front should keep the weather dry through Sunday evening across
eastern Kentucky. The front will then push across the area late
Sunday night through Monday morning, bringing a round of showers
and perhaps a few storms to the area. The more significant impact
will be the winds associated with the frontal passage. Winds will
likely pick up late Sunday night out of the south ahead of the
boundary and could gust up to 30 mph at times. If we can generate
some instability Monday morning, we could see some convective wind
gusts much higher. 00z NAM shows some limited instability, while
the 00z GFS has virtually none. Thus, right now, cannot rule out
some convective gusts as the activity pushes through Monday. In
the wake of the front, winds will remain gusty and likely even
stronger with gusts up to 40 mph likely. Its possible we may need
a wind advisory for Monday, but much too early to issue one. Winds
will remain up Monday night, but should drop back a bit in
strength.

Cooler air will filter in behind the front Monday afternoon
through Monday night. This will bring an end to our milder
weather. Zonal flow takes hold into the middle of the week, with
dry weather expected across the area. Temperatures will slowly
rebound into the middle of the week. Our next storm system will
take aim on the area by late Wednesday, with a warm front lifting
north across the area on Wednesday, followed by an area of low
pressure tracking across the Ohio river valley. This will bring
increasing rain chances to the area from Wednesday into Thursday.
Thursday and Friday are looking to be very damp days with
persistent rains along with cool conditions. We may see lows in
the 40s by weeks end with highs only in the 50s. Looks like the
first week of May may come in on the cool and damp side.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 714 AM EDT SAT APR 29 2017

VFR flight conditions expected through the forecast period. There
is considerable amount of debris cloud cover across the area from
lingering convection. However, showers and thunderstorms are
coming to an end across the area this morning. May see some
isolated convection refire later today, especially north closer to
a frontal boundary and over the higher terrain along the Kentucky
and Virginia state line. Otherwise winds will increase from the
south-southwest through the day to around 10kts with some higher
gusts.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

UPDATE...RAY
SHORT TERM...RAY
LONG TERM...KAS
AVIATION...RAY


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