River Flood Advisory 13, NWS Louisville, KY

Area Forecast Discussion
National Weather Service Louisville KY
647 AM EST Sat Dec 15 2018

...Updated Aviation Discussion...

.Short Term...(Today and tonight)
Issued at 305 AM EST Sat Dec 15 2018

Another wet day is in store for southern Indiana and central
Kentucky. A large 500mb low is centered over Mississippi with a
moisture feed from the Gulf moving over Florida, Georgia, and the
CWA as it wraps cyclonically towards the low pressure center. Dry
air is filling in from west and wrapping around the low keeping
Alabama and parts of southern Tennessee mostly dry. Looking at water
vapor imagery, A clearly defined deformation zone is observed.

The linear setup will focus areas of heaviest rainfall. During the
pre-dawn hours, the northern half of the CWA, near the north end of
Hart county, will likely experience heavier precipitation than areas
south of that location. From sunrise until the afternoon the focus
will be north of Interstate-64 to south of Indianapolis with amounts
tailing off to the south. Starting this evening into tonight showers
will start winding down over the area as they move east.

With more rain focused in the northern half of the CWA, expect 1-
1.5" of more rainfall with this system in that area. Totals will
drop off to the south. Those along the Tennessee border likely
seeing 0.25 to 0.50" of additional rainfall.

As the upper low moves east just south of Kentucky the surface low
will likely move across Kentucky. This will cause the wind to change
directions as the cyclonic flow moves past the area. A small amount
of warm air advection is expected in south central Kentucky to help
south central Kentucky reach the mid 50s for highs. Southern Indiana
and north central Kentucky will likely top out in the low 50s.

Tonight, with the passing of the low, cool air will start flowing
into the region from the north. This will cause lows Sunday morning
to cool to the upper 30s and lower 40s. This is a little cooler than
the last couple of nights.

.Long Term...(Sunday through Friday)
Issued at 255 AM EST Sat Dec 15 2018

Last few showers should be departing the Bluegrass and Lake
Cumberland areas on Sunday morning, as lingering cyclonic flow gives
way to ridging from the Great Plains. The sfc and upper ridge will
dominate the pattern through Wednesday, resulting in a period of
quiet weather. Temps will run near mid-December normals through
Tuesday, then trend a bit milder in the developing return flow on
Wednesday.

Forecast confidence beyond Wednesday is still only moderate at best,
but we are finally starting to see some model agreement. Latest GFS
run seems to be getting on board with the more phased ECMWF
solution, but there is still plenty to sort out in the details. Both
develop a closed southern stream low by Friday, but the ECMWF is
dominated by that low while the GFS has a stronger northern stream
low to help eject the southern low more quickly NE. Bottom line is
wet weather and above normal temps for Thursday and Friday, and
accordingly POPs have been increased to likely.

Depending on which solution works out, we could have enough cold air
in the wraparound for precip type issues as the system departs.
However that remains beyond the scope of the 7-day forecast, and we
can address it when forecast confidence will be higher.

&&

.Aviation...(12Z TAF Issuance)
Updated at 645 AM EST Sat Dec 15 2018

As the low pressure system moves east through Tennessee today, the
day will start with less rainfall in the area surrounding BWG. HNB
is expected to see steady rainfall most of the day, and SDF and LEX
are somewhere in the middle. Ceilings are expected to be fairly
constant while visibilities will change based on area precipitation.

Guidance has been slightly pessimistic several hours out, so TAFs
have been bumped more in the optimistic direction.

The most noticeable change today will be wind direction. The low
system comes with cyclonic flow that will change wind direction as
it passes, and with the system being so close, some sites will see
much more changes than others.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

Short Term...KDW
Long Term...RAS
Aviation...KDW

Hazardous Weather Outlook
National Weather Service Louisville KY
311 AM EST Sat Dec 15 2018

INZ076>079-083-084-089>092-KYZ023>043-045>049-053>057-061>067-
070>078-081-082-160815-
Orange-Washington-Scott-Jefferson-Dubois-Crawford-Perry-Harrison-
Floyd-Clark-Hancock-Breckinridge-Meade-Ohio-Grayson-Hardin-Bullitt-
Oldham-Trimble-Henry-Shelby-Franklin-Spencer-Anderson-Woodford-
Fayette-Bourbon-Nicholas-Nelson-Mercer-Jessamine-Larue-Marion-Boyle-
Garrard-Madison-Butler-Edmonson-Hart-Green-Taylor-Casey-Lincoln-
Logan-Warren-Simpson-Allen-Barren-Monroe-Metcalfe-Adair-Russell-
Cumberland-Clinton-
Including the cities of Paoli, Salem, Scottsburg, Madison, Jasper,
English, Tell City, Corydon, New Albany, Jeffersonville, Lewisport,
Hawesville, Hardinsburg, Brandenburg, Hartford, Leitchfield,
Elizabethtown, Shepherdsville, Louisville, La Grange, Bedford,
Milton, New Castle, Shelbyville, Frankfort, Georgetown, Cynthiana,
Taylorsville, Lawrenceburg, Versailles, Lexington, Paris, Carlisle,
Bardstown, Springfield, Harrodsburg, Nicholasville, Winchester,
Hodgenville, Lebanon, Danville, Lancaster, Richmond, Morgantown,
Brownsville, Horse Cave, Greensburg, Campbellsville, Liberty,
Stanford, Russellville, Bowling Green, Franklin, Providence,
Scottsville, Glasgow, Tompkinsville, Edmonton, Columbia, Jamestown,
Burkesville, and Albany
311 AM EST Sat Dec 15 2018 /211 AM CST Sat Dec 15 2018/

This hazardous weather outlook is for portions of south central
Indiana and Central Kentucky.

.DAY ONE...Today and Tonight.

Bands of moderate rain will bring reduced visibilities and ponding
of water during the most intense rainfall.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

KDW