Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 191903

National Weather Service Jackson KY
203 PM EST Thu Jan 19 2017

Issued at 203 PM EST THU JAN 19 2017

Temps are still slow to climb. Showers are also moving in a little
bit faster than what was expected. In light of this have moved
isolated/scattered showers northeast a bit faster, and have
knocked a couple degrees off the forecast max temp.

UPDATE Issued at 1012 AM EST THU JAN 19 2017

Temps and dew points have been a little slow to rise this
morning compared to the inherited forecast, and have updated the
temperature curve in the forecast grids. Left the forecast highs
alone at this point, to see if we catch up during the day. |

UPDATE Issued at 700 AM EST THU JAN 19 2017

Issued a fresh set of grids mainly to remove the fog this morning
and also to fine tune the T and Td grids per the latest obs and
trends. These have been sent to the NDFD and web servers - along
with an updated set of zones.


.SHORT TERM...(Today through Friday)
Issued at 355 AM EST THU JAN 19 2017

08z sfc analysis shows an area of high pressure moving through
the Ohio Valley while a warm front is moving northeast toward the
area from the Lower Mississippi Valley. High clouds have spread
into the area ahead of this front. These clouds have had varying
thickness as they moved overhead this night and during the
thinner times the eastern valleys have managed to get colder than
the rest of the area. As such, readings range from the lower 40s
in the far south to the lower 30s in those colder spots.
Meanwhile, dewpoints are nearly matching temperatures keeping the
RH high this night while winds are light. So far, though, the fog
has not been too bad out there per web cams and observations.

The models are in pretty good agreement aloft through the short
term portion of the forecast leading to above average confidence
in their blended solution. They all depict a sharp ridge moving
quickly through the region ahead of a closed low strengthening
over the High Plains today. This places eastern Kentucky in deep
and persistent southwest flow with energy packets passing over the
state ahead of the core batch that pivots through around 12z
Friday. Heights then rise further over Kentucky through the day
Friday while troughing remains dominant over the Plains and
western portion of the country and strong ridging resumes through
the Southeast. Given the fairly small model spread during the
short term will favor a general blend along with a lean toward
the HRRR in the near term.

Sensible weather will feature another mild January day as the warm
front lifts into the area. The showers that will accompany this
gradually work east into this part of the state through the late
afternoon and early evening hours. This will lead to soaking
rains for most of the area tonight with amounts generally between
a half and three quarters of an inch - though places in the far
east may see little more than a quarter of an inch total. Will
keep thunder out of the forecast for now on account of the lack
of instability, though cannot completely rule it out given the
strengthening of the upper level system. Another very warm
January day can be expected Friday as the low`s track will keep
winds southerly and prevent any cold air from moving into the
state even as the showers depart to the northeast and we start to
dry out. Record temperatures will be within reach Friday - 66
degrees at both JKL and LOZ.

Used the CONSShort and ShortBlend as the starting point for most
elements through the short term portion of the forecast - making
only minor adjustments to raise temperatures today and Friday.
Also, adjusted PoPs in the near term to allow the pcpn chances to
spread in a tad quicker this afternoon nearer the Tennessee and
Virginia border.

.LONG TERM...(Friday night through Wednesday)
Issued at 255 AM EST THU JAN 19 2017

The overall large scale pattern in the extended remains basically
the same. A strong low pressure system aloft is forecast to move
across the Ohio and Tennessee valley regions from this weekend
through the beginning of next week. This strong system still will
affect eastern Kentucky Saturday through Monday. There will be the
potential for locally heavy rainfall Saturday night through Sunday
night, as a strong area of low pressures move across the lower
Tennessee valley. This system will keep rainfall in our area through
the day on Tuesday, as it continues to strengthen and slow down
during its trek towards the Mid Atlantic region. After this system
passes by, a ridge of high pressure will settle over the area
Tuesday night, bringing a brief period of dry weather to eastern
Kentucky. A fast moving, albeit weak, disturbance aloft is forecast
to move across the lower Great Lakes region on Wednesday. The weak
surface boundary associated with this system may bring isolated rain
showers to the area on Wednesday and Wednesday night, but these
should be few and far between and should be out of the area by
around dawn on Thursday.

We are still expecting above normal temperatures through out the
period. Especially on Saturday and Sunday, when the mercury could
climb into the upper 60s on Saturday and the low to mid 60s on
Sunday. Persistent southerly flow will be the cause of this jump in
temperatures. The warmth will last through Wednesday, with daily
highs in the 50s expected. Nightly lows will generally be in the 40s
and 50s through Monday, and will be slightly cooler from Tuesday
onward, as slightly cooler air filters in the area behind our
departed weather system. Lows from Tuesday morning onward should
bottom out around 40 each day.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)

Showers have started to move into the region from the southwest,
and have resulted in localized mvfr visibility near the TN border
at the start of the period. Elsewhere, conditions were VFR, but
ceilings were showing an overall lowering trend. The increasing
clouds and showers were due to a warm front approaching.

Showers will overspread the rest of the region this afternoon and
tonight. MVFR conditions (and perhaps some IFR in the west) will
also spread northeast over more of the JKL forecast area, but the
advance will be slowed over the far eastern part of Kentucky due
to low level downslope wind flow. Showers will taper off with
passage of the warm front from southwest to northeast overnight
and early Friday morning. However, downslope flow in the east will
also be lost with passage of the front, and all areas can expect
MVFR conditions on Friday morning.




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