Air Resources Laboratory banner image
Air Resources Laboratory web site National Oceanic and Atmospheric Administration (NOAA)

ky discuss

Office: JKL

FXUS63 KJKL 211737

National Weather Service Jackson KY
1237 PM EST Wed Nov 21 2018

Issued at 1020 AM EST WED NOV 21 2018

Issued an update to the forecast to input the latest observations
and trend them through the midday hours. Also adjusted the cloud
cover to hang around d a bit longer into the noon to 1pm
timeframe before giving way to sunny skies. With this, temps
should rebound into the upper 40s once the cloud cover clears out.

UPDATE Issued at 654 AM EST WED NOV 21 2018

A deck of clouds are remaining intact across much of eastern KY
early this morning, so adjusted the sky over the next couple of
hours to account for this. Once the sun rises, drier air aloft
will be able to mix down, and cloud cover should quickly
dissipate. Meanwhile, there has been several reports of light fog
despite the cloud cover, but with VIS generally 6 miles and being
so close to sunrise, expect this fog to also quickly dissipate
over the next hour. Loaded in the latest observations to make sure
the near term forecasts for temps, dew points, and winds are on
track with the current conditions. All updates have been published
and sent to NDFD/web. No updates to the forecast package are
needed at this time.


.SHORT TERM...(Today through Thursday)
Issued at 350 AM EST WED NOV 21 2018

Despite drier NW flow working across the region, a strong llvl
inversion is keeping some moisture trapped near the surface and
producing several areas of clouds across the CWA as of 8Z. As the
sun rises this morning, better mixing will ensue, and drier air will
work into these low levels, quickly cutting off this ongoing cloud

A large area of high pressure to our SW will continue to have hold
across the region today. However, there will be little eastward
progression of this system as a weak cold front drops southward
towards the Ohio River during the afternoon, then becomes stalled
across the northern portion of the CWA into the overnight. This
front is expected to be weak and dry, with the only associated
moisture resulting in some cloud cover to the northern CWA during
this time. Winds will shift to a northerly direction along and
behind the front, but considering winds should be light across the
CWA during the period anyways, even this will be of little

The front will finally progress southwestward across the remainder
of the CWA Thursday afternoon. Once again, with strong areas of high
pressure on each side of this front, this will pose little concern.
In fact, it will continue to lose moisture during this time, so we
may not even notice an increase in clouds as it progresses SW on
Thursday afternoon.

As for temperatures, strong W to NW flow aloft will continue to
advect cooler and well below normal temps into the CWA. Despite
mostly clear skies across much of the CWA today, temperatures will
only rise into the mid 40s. Overnight, maximum radiational cooling
and light winds will produce temperatures similar to early this
morning, generally upper 20s to around 30 degrees for lows. Coldest
temps will be in the valleys. Temperatures Thursday will range from
the lower to mid 40s in the north (where easterly winds and enhanced
cloud cover will be in place throughout the morning), and in the low
50s in the south where the driest airmass will be in place through
much of the day.

.LONG TERM...(Thursday night through Tuesday)
Issued at 434 AM EST WED NOV 21 2018

The period will start with surface high pressure to our northeast
slowly drifting offshore and providing southerly local flow, and
transient mid/upper level ridging moving east over our area. Our
resulting weather will be seasonably mild and dry through Friday.

The first of two systems to affect us during the period will be
moving through as the weekend starts. Its roots lie with the
mid/upper level trough currently off the west coast. Its associated
surface boundary will move east over the plains Thursday night and
Friday. Moisture aloft from the Gulf of Mexico will stream northward
ahead of it. The surface boundary for the gulf air will remain near
the Gulf Coast, and the boundary heading east across the Mississippi
Valley on Friday night would appear to be a warm occlusion, with
warmer air present behind the boundary. This will bring rain for our
area Friday night, and probably into Saturday in our eastern
counties. The boundary will be weakening as it approaches, and
should dissolve as it arrives Saturday. It will be replaced by high
pressure over the southern Appalachians to bring us dry and warmer
conditions Saturday night into Sunday.

By Sunday, our next weathermaker will already be churning over the
middle of the CONUS. Its roots trace to the mid/upper low currently
over AK. As the upper level system moves southeast and then east
over the CONUS, it should prompt rapid deepening of a strong surface
low moving from the TX/OK panhandles region on Saturday, east
northeast over the Midwest on Sunday. Its cold front (or cold
occlusion) spiraling around it is expected to cross our area on
Sunday night with a band of showers. Chillier air arrives behind
this front to start the work week.


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

With high pressure slowly nosing into the area, skies have cleared
out and mostly sunny conditions have set up. Thus will expect VFR
conditions into tonight. The clear skies overnight will lead to
some fog development as the winds decouple late tonight. Mainly
the ridge top TAF sites will avoid the field mins but the valleys
will see some dense fog develop. The other limiting factor will be
the cloud cover nudging into the northern kentucky locations. This
will be enough to make it into SYM and hinder fog development.
LOZ and SME will have the best chance to see fog development late
tonight. Fog will begin to lift by 14z tomorrow morning. Winds
will be light and variable overnight.





Office: LMK FXUS63 KLMK 211727 AFDLMK Area Forecast Discussion National Weather Service Louisville KY 1227 PM EST Wed Nov 21 2018 ...Updated Aviation Discussion... .Short Term...(Today and tonight) Issued at 230 AM EST Wed Nov 21 2018 Early this morning, any remaining clouds across central Kentucky will dissipate and sunshine will prevail through the rest of the day. An upper ridge covering the central United States is moving east towards the CWA. The Ohio River Valley will continue to see more surface high pressure moving in from the Mississippi River Valley. This will promote clear skies and a southwest wind. Highs today will top out in the mid 40s to low 50s. Tonight, skies will remain clear and winds will go near calm. Lows will drop to the upper 20s to lower 30s by Thursday morning. .Long Term...(Thursday through Tuesday) Issued at 230 AM EST Wed Nov 21 2018 Quiet and seasonable weather is expected for Thanksgiving and most of Black Friday with a strong surface high over the mid-Atlantic states and shortwave ridging aloft over the Ohio Valley. A surface ridge axis extending SW across the Ohio and Tennessee Valleys Thu morning will give us a chilly start for pre-turkey activities, and could limit the afternoon warmup a bit, but plenty of sunshine and light winds will make for a fairly pleasant late fall day. By Friday the southerly gradient starts to tighten up and the flow aloft starts to back ahead of a progressive trof. Expect breezy and increasingly cloudy conditions, but the warm advection pattern should be strong enough to boost max temps well into the 50s. If we get more sunshine than expected we could easily push 60. WIdespread showers expected Friday night into Saturday as the northern and southern streams phase enough to get a decent Gulf moisture tap and deep S-SW flow. QPF will likely end up just over a half inch in most places. Not enough instability to support thunder, but a decent low-level jet will allow some gusty winds to mix down with the rain. Temps through the weekend will run slightly above normal with shortwave ridging aloft and a Pacific air mass. Another sharp but progressive wave will develop a closed upper low over the Plains Sat night, and push through the Ohio Valley Sunday afernoon and evening. Still some question on the exact timing of this system, so will limit POPs in either period to likely even though rain at some point is a near certainty. Broad eastern CONUS trofiness will maintain a deep NW flow into the Ohio Valley early next week. Precip chances taper down early in the day on Monday, and while temps should still be cleanly above freezing we can't rule out a few flurries as the cold air chases the moisture out. Otherwise expect December temps to settle in a few days early. && .Aviation...(18Z TAF Issuance) Updated at 1225 PM EST Wed Nov 21 2018 VFR conditions expected through most of the period. Patchy fog may be possible at some TAF sites early tomorrow morning, which will result in reduced visibilities. The fog should burn off by mid morning. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Short Term...KDW Long Term...RAS Aviation...DM
Office: PAH FXUS63 KPAH 211105 AFDPAH Area Forecast Discussion National Weather Service Paducah KY 505 AM CST Wed Nov 21 2018 .SHORT TERM...(Today through Friday night) Issued at 336 AM CST Wed Nov 21 2018 This morning should be the coldest morning of the holiday week, as synoptic scale ridge axis moves east toward the WFO PAH forecast area through Thanksgiving day, generating an increase in thicknesses and warm advection into the region. With a slight southerly flow over the area this morning, seeing some very weak low level mixing and condensation within the boundary layer, supporting some fog, generally between three and five miles in visibility. A few protected locations may see fog dipping below a mile. With temperatures well into the 20s, some deposition of the fog droplets on untreated and elevated surfaces may generate some black ice. A Special Weather Statement was issued for part of the WFO PAH forecast area through daybreak to account for potential travel concerns. Weather continues to look benign today, Thanksgiving day, and even into early Friday, when the ridge axis aloft currently off the WA/OR/northern CA coastline will move east into the middle Mississippi valley by 6am Friday. Decent warm advection from the Gulf of Mexico and faster winds aloft ahead of trough of low pressure will advect sufficient moisture into western section of southeast Missouri during the late afternoon on Friday to support some shower activity. The overall layer relative humidity will become more efficient into Friday evening to produce more widespread rainfall across the region. Previous forecasts have indicated a high PoP for Friday night, and the signal continues to be on target for this time period. The 12km NAM-WRF and GFS Ensembles initialized well with this feature and its progression toward the WFO PAH forecast area, although the majority of the numerical guidance suite did a good job of tracking this system. Made some subtle adjustment to temperatures and dewpoints early on, as only the high resolution RAP/NAM-WRF numerical guidance families were responsive to larger swings in temperatures through Thanksgiving Day. .LONG TERM...(Saturday through Tuesday) Issued at 336 AM CST Wed Nov 21 2018 Fairly good confidence at the start of the extended but falls off sharply by the end of of the weekend. Models are in good agreement with the system departing early Saturday morning with only slight chances of rain in the far east early. So most of Saturday will be dry for most areas. So most of Saturday and Saturday night will be dry. Sunday however we will have an occluded front move through bringing good chances of rain to the region as warm sector for a short period. However thunder does not appear likely...especially anything surface based as we keep a strong surface inversion at the surface. Even the K index values are dropping from previous runs to around 20. From looking at the forecast soundings moisture will be very limited...thus that is why the uncertainty begins. A cold front will finally move through Sunday night bringing an end to any rain chances. It also may mix with or change over to snow as it ends...mainly north of the Ohio River. This should have little if any impact as temperatures will remain above freezing at that time. After that high pressure will build in over the gulf states. Temperatures will above normal at the start of the extended but by early next week they will plummet in the wake of Sundays cold front. One thing we can expect is windy conditions with both systems both Friday and Sunday into Monday. Temperatures will go from around 5 degrees above normal to 10 degrees below normal. Lows will fall to around 5 degrees below normal for the start of next week. For now we are forecast to go below freezing next week for lows. In summary...high confidence in the Friday and Friday night system. Not so much with the Sunday system with limited moisture and possibly a farther northerly track with the vertically stacked low. && .AVIATION... Issued at 505 AM CST Wed Nov 21 2018 MVFR Visibilities due to freezing fog may linger into the first hour of the 12z Wednesday WFO PAH TAF issuance at KCGI and KPAH. Otherwise unrestricted ceilings and visibilities will be the rule for all of the WFO PAH 12z TAF time period. TAF periods were separated primary for key adjustments to the mean wind direction throughout today and tonight. Weather impacts on aviation should be minimal. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ SHORT TERM...Smith LONG TERM...KH AVIATION...Smith