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Office: JKL

FXUS63 KJKL 200025 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
825 PM EDT Sun Aug 19 2018

.UPDATE...
Issued at 745 PM EDT SUN AUG 19 2018

23z sfc analysis shows a washed out frontal boundary across the
area with little in the way of dry air brought into this part of
the state. A few pinprick showers remain along and south of this
front but the threat for thunder has ended. For this reason have
taken it out of the forecast for the rest of the evening as well
as lowering the PoPs. Currently temperatures are running in the
mid to upper 70s with dewpoints mainly in the low to mid 70s. The
small dewpoint depression has the potential to lead to more fog
later tonight as some radiational cooling takes place. However,
most of the near term models show only limited visibility
restrictions, likely the result of increasing mid and high clouds
inbound from the west. Accordingly, have limited the dense fog to
the usual river valleys and kept it off the ridges - unlike last
night when the stratus built down. Winds will be light and
variable through the night. Have also added in the latest T and Td
obs/trends to the grids. These updated grids have been sent to
the NDFD and web servers along with a freshened set of zones and
HWO.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 422 PM EDT SUN AUG 19 2018

Looking at generally isolated convection across the area this
afternoon. Locations to the south and along the higher terrain
appear to be closer to widely scattered and may be scattered at
times through the late afternoon. Convection should die off
through the early evening with sunset and loss of daytime heating.
At present there is a boundary across the area but it is nearly
indistinguishable and has all but washed out.

Models are in good agreement and advertise the passage of a short
wave ridge aloft through the overnight period. But another low
pressure system and trough will encroach on the Ohio Valley
through the short term, making it as far as the western portions
of the Commonwealth by late Monday night or early Tuesday morning.
The corresponding surface low will move from eastern KS tonight
to Lake Michigan by Tuesday morning. This system will pull a
surface boundary eastward into the Ohio Valley by early Tuesday
morning, stretching roughly from Chicago to Indianapolis to
Nashville before turning back to the southwest.

Sensible weather portends the continuation of stormy weather that
we have become accustomed to over the past couple of weeks. At
present severe weather parameters appear to be lacking. There is
ample instability for thunderstorms but mid level lapse rates and
overall shear are not impressive. There is a window of impressive
PWATs (1.8 to 2.0 in) passing through the region leading into
Tuesday. But it is a short window and storm motions are relative
fast at 15-25 kts. Actually this system appear more progressive
and stronger than we have seen more recently. Consequently feel
overall threats will continue to be similar to the past week or
so. The potential for a few strong storms exists...it is summer,
and possibly even an isolated severe storm could not be ruled out
should a cell or two manage to over perform. Potential flooding
looks to be a greater possibility but even then would be limited
to training due to the higher storm motions and probably isolated
in nature.

.LONG TERM...(Tuesday through Sunday)
Issued at 422 PM EDT SUN AUG 19 2018

A cold front, associated with a low pressure system moving into
Michigan, will progress through western Kentucky to start the long
term. This front will move quickly out of the Commonwealth later
Tuesday evening with the progression of the low pressure system from
the Great Lakes to the northeast. This will bring increased showers
and thunderstorms through Tuesday. The ECMWF shows a bit more QPF
during FROPA than the GFS. Adjusted PoPs slightly higher for this
based on the dynamic pattern and ample moisture.

Surface high pressure will then take hold for midweek until shifting
eastward by the weekend. Increased upper level forcing over the Ohio
Valley as well as warm, moist air from southerly flow will bring
showers back to the forecast this weekend for eastern Kentucky.
However, the models are not in good agreement with the strength of
this upper level forcing. The GFS shows a more amplified wave as
opposed to the ECMWF. Therefore, confidence is low and future model
runs will be needed to assess development of this system.

High temperatures will be around 80 degrees Tuesday afternoon, but
then cool down to be in the mid to upper 70s Wednesday due to FROPA.
Temperatures will gradually be on the rise through the week,
reaching the mid 80s again this weekend. Lows will follow a similar
pattern, starting out in the mid 60s Wednesday morning before
dropping into the mid 50s Thursday morning. Lows will return to
be in the mid 60s Saturday morning.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 825 PM EDT SUN AUG 19 2018

A boundary has stalled over the area, but only a few pinprick
showers are noted. Expect these to fad out shortly with a quiet
night on tap. The main concern through the night will be the
potential for river valley fog to affect the TAF sites.
Indications are that there will be enough mid and high level
clouds around to keep the fog in check. SYM and SME will have the
best potential for seeing some MVFR fog for a time late tonight
but have left that out of the TAFs for now. On Monday, scattered
showers and storms will be possible by afternoon ahead of the next
system moving toward the region, though chances are too low to
include as prevailing in any TAF at this point so mention was
limited to VCTS. Winds will be generally light from the south on
Monday after being light and variable overnight.

&&

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

$$

UPDATE...GREIF
SHORT TERM...RAY
LONG TERM...CGAL
AVIATION...GREIF



Office: LMK FXUS63 KLMK 192337 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 737 PM EDT Sun Aug 19 2018 ...Updated Aviation Discussion... .Short Term...(This evening through Monday) Issued at 313 PM EDT Sun Aug 19 2018 Temps have warmed well into the 80s this afternoon, with even some upper 80s noted in spots. We've reached convective temps down across southern and eastern KY where very isolated showers have popped. Expect some brief heavy rainfall with any shower, and perhaps a lightning strike, although have not observed any yet. Could also get a brief wind gust with any shower as visible satellite imagery appears to show cold outflow extending out from some showers. Haven't seen any observed gusts yet, but with DCAPE values around 1000 J/Kg and the satellite evidence think we are seeing 30 mph gusts with the stronger showers. It's also interesting to note that visible satellite shows a more healthy cu field across the southern and eastern CWA, and is coincident with the highest Td's and low level moisture. Farther north, we've mixed out into the upper 60s and think think this will limit fog potential in that area overnight. However, do expect we could see some fog in the south and east part of the CWA, before the warm front and thicker cloud cover take hold later Monday morning. Also will have to keep an eye on near surface winds across southern KY as they become a bit stronger/mixier toward dawn and could mitigate fog formation just in time. Overall, best fog chance in our eastern CWA and have included mention there. Lows tonight should drop into the upper 60s to around 70. An unseasonably strong low pressure system will move from the lower Missouri River Valley into the mid Mississippi River Valley on Monday. As this occurs, the washed out frontal boundary that sank to our south yesterday will reinvent itself as a warm front and lift north through the day. Given increasing low level jetting and good warm advection lift with the front, expect scattered to numerous showers starting in the morning in our SW and moving NE through early afternoon. The main concern with any of these showers/storms will be heavy rain, especially over areas that saw a lot of rain late last week. Suppose a stronger storm or two could occur with the warm front activity, but not overly concerned at this point. The warm sector gets firmly established over our area by late afternoon into the early evening as the best forcing and the cold front still lag back to the west. Think we'll see a relative lull during this time, with a few breaks in the clouds and pockets of heating/destabilization possibly occurring. Don't think it will be enough to trigger much additional convection in the warm sector, but will keep at least small pops in during this time as the upper forcing will quickly be moving in around sunset or after. The long term portion of this discussion discusses shower and storm potential into Monday night with the cold front and better forcing. Highs Monday should reach the low and mid 80s. .Long Term...(Monday night through Sunday) Issued at 221 PM EDT Sun Aug 19 2018 Thunderstorms from earlier in the day just to our west will push through southern Indiana and central Kentucky Monday night. As they move east and we get further into the evening, instability will decrease and thunderstorms will become slightly elevated. With unidirectional shear and a low level jet up around 35kt, could still see some gusty winds make it to the surface with the stronger cores. Speaking of which, precipitable water values will be around two inches with a deep warm cloud depth and surface dew points in the lower 70s, so locally torrential downpours will be possible. Fortunately the storms will be moving along around 25-30mph so hopefully they won't stay over one spot for too long. Also, the storms will be moving ENE as part of a north-south band of showers/storms so training may not be a significant threat. Nevertheless, locations that have received heavy rain over the past few days will want to keep an eye on this system. The upper trough associated with this weather will pass overhead Tuesday as the surface low crosses the Great Lakes and its trailing cold front extends down to the Gulf Coast States. Lingering showers and a few storms can be expected Tuesday as this system makes its way through the region. For the rest of the week high pressure will mosey from the Great Plains...though the Ohio Valley Thursday...to the Northeast Friday and then possibly build southwestward into the southeast United States this weekend. As a result we should have mostly dry and pleasant weather mid-late week. Some low chance PoPs will creep back into the forecast this weekend as we get into some return flow. && .Aviation...(00Z TAF Issuance) Issued at 735 PM EDT Sun Aug 19 2018 A surface warm front will lift northward toward the region tonight ahead of a developing low pressure system over the eastern Plains. Late tonight as the front approaches, we could see some lowering of ceilings with scattered showers and storms developing north of the warm front. This would be around sunrise at KBWG and in the mid- late morning hours at KHNB/KSDF/KLEX. Winds will start off light and variable and then become southeasterly overnight, shifting to the south by Monday afternoon. Still think we could see a little bit of fog at KBWG and KLEX prior to the front getting here. For now, have still kept things at MVFR, but there is a possibility that we could drop to IFR briefly if fog become more extensive than forecast. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Short Term...BJS Long Term....13 Aviation.....MJ
Office: PAH FXUS63 KPAH 192255 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 555 PM CDT Sun Aug 19 2018 .SHORT TERM...(This afternoon through Tuesday night) Issued at 1000 AM CDT Sun Aug 19 2018 Confidence is high in the short term with models in good agreement for several days now. Weak upper level ridging should keep us dry through the day. Tonight however a closed upper level low will make its way into the region as surface warm front lifts north through the region. This will result in storms and showers across the region. There will be a cold front in its wake but we will be in the warm sector at least through Tuesday morning allowing for additional convection. As the upper level closed low moves over us in appears to open up which usually indicates it will speed up it eastward progress. We will also be in a very soupy air mass with dew points well into the 70s. SPC has already upgraded to a slight risk of severe storms. The models are placing us in an area of CAPE's 1500 to 2k j/kg2 and LI's of negative 5. This could possibly elevate us into a slight risk. In contrast...cloud cover and a worked over atmosphere could inhibit this escalation. Winds have some strength but they are unidirectional. The freezing level will under 15k feet slightly so hail can not be ruled out but damaging wind will likely be the main threat with any strong or severe storms. Temperatures will fall well below normal after the cold front passage starting Tuesday and last through the week. .LONG TERM...(Wednesday through Saturday) Issued at 1000 AM CDT Sun Aug 19 2018 Much improved confidence in the extended with models starting to look much more in sync. High pressure over the southwest will try to build into the region in the extended. We will have surface high pressure in place over the area. This should inhibit convection. However aloft the high never really makes it into the area and places us in a northwest flow aloft. Any perturbation that gets caught up in this flow could result in at least slight chances of storms. Especially if its combined with peak heating. On the good side severe weather is not anticipated at this time. Most of the area should remain dry through the week after Tuesday. There is a weak disturbance aloft next weekend but the upper high over the southwest should make its way east and be centered over the gulf states by then. This again will inhibit convection. This weekend however temperatures will increase to at least normal with both a surface high over the area and an upper level high centered just south of the region. Until then enjoy the below normal temperatures this week. && .AVIATION... Issued at 555 PM CDT Sun Aug 19 2018 First couple arched band of clouds associated with closed low over northeast KS/northwest MO (northwest of Kansas City at 23z) moving through southeast Missouri, southern IL/west Kentucky should remain VFR through the late evening hours. The more significant line of convective activity should move into the KCGI and KPAH TAF locations between 04z-08z Monday, working toward KEVV and KOWB around 12z Monday. There may be a 1-2 hour delay depending on any changes of the speed of the convective rain bands. Kept ceilings in VFR category with a slight intrusion of MVFR visibilities with thunderstorms. Not enough confidence on timing and intensity of any renewed convection Monday afternoon, so left out any significant mention of ceilings below VFR and mention of thunderstorms over most TAF locations. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ SHORT TERM...KH LONG TERM...KH AVIATION...Smith