NWS Area Weather Forecast Discussion
Louisville, KY

FXUS63 KLMK 191059

Area Forecast Discussion
National Weather Service Louisville KY
659 AM EDT Fri Apr 19 2019

...Updated Aviation Discussion...

.Short Term...(Today and tonight)
Issued at 330 AM EDT Fri Apr 19 2019

A cold front continues to move east through eastern Kentucky. Winds
across southern Indiana and central Kentucky have already shifted to
the northwest. This is advecting cooler air into the Ohio Valley. By
sunrise parts of the far eastern Bluegrass will be in the low 60s
while areas northwest of Louisville will be in the low 40s.

Just behind the cold front a deep upper trough continues to contain
strong flow at the mid and upper levels. This divergence is taking
advantage of the strong Gulf moisture feed and will provide
scattered rain showers throughout the day.

As Friday night approaches, the upper trough moves east over
southern Tennessee increasing rain showers across the region. This
is when things could get more interesting. As the upper low nears
the slower moving surface low, the system will advect cold air from
the northwest by means of gusty winds in the 25 to 30 mph range. If
the temperature drops enough, an area of snow is likely to fall over
a narrow area running northwest to southeast across the CWA. Any
snowfall shouldn`t cause problems with higher ground temperatures
and lots of rain around, but elevated areas cold see a little bit of
the white stuff.

.Long Term...(Saturday through Thursday)
Issued at 312 AM EDT Fri Apr 19 2019

The extended starts off cold and wet Saturday morning as wrap-around
showers linger in the deformation zone of the upper closed low
slowly riding north along the Appalachians.  With the now nearly
stacked low so close by, northerly flow will occur from the surface
through the tropopause, preventing any hope of warming, especially
with clouds and showers only starting to clear from west to east in
the afternoon. A few ice pellets or snow flakes could mix in with
the showers, as the freezing level will be just a few thousand feet
AGL. The heaviest rainfall will have already occurred by Saturday
morning, with the remaining showers not expected to exceed a quarter
of an inch on Saturday.

Temperature-wise, highs will only range from the mid 40s in the
Bluegrass region to the lower 50s in our far western counties
- just at or slightly above climatological LOWS for the date.  With
a slightly earlier departure of the clouds as the system shifts
northeast, the far west could warm up a bit more, but it`s pretty
much a guarantee that Saturday will be gray and blustery east of a
line from the Hoosier National Forest to the Tennessee border south
of Bowling Green.

As dreary as Saturday will be for most of the area, Sunday promises
to be just the opposite. While it will again start out on the cool
side, with morning lows in the upper 30s to lower 40s, sunshine will
be abundant as short term ridging moves through for Easter Sunday
and Monday. Highs will rebound into the lower to mid 70s Sunday for
all but the I-75 corridor, which will top out in the upper 60s.
After seasonal lows a few degrees either side of 50 Monday morning,
temperatures will top out in the mid to upper 70s in the afternoon
as cirrus associated with a short wave flowing through the upper
ridge moves through north of the Ohio Valley.

Model guidance starts to diverge beyond Monday as the GFS and FV3
build upon the aforementioned short wave to start breaking down the
upper ridge, resulting in a positively tilted trof stretching from
the Great Lakes to the desert southwest.  The Euro keeps the ridge
intact but weakened, with a closed 50H low over the southwest U.S.
Regardless of the details with this developing system, all guidance
provide enough dynamics and moisture to show precip by Tuesday from
New England to the southern plains, cutting right through the Ohio
Valley.  When this exits the region is less certain though, so will
include POPs for the later periods of the forecast, but trim them
due to the uncertainty.

Temperatures should remain seasonably mild through the rest of the
week with highs in the 70s and lows in the 50s.


.Aviation...(12Z TAF Issuance)
Updated at 655 AM EDT Fri Apr 19 2019

As a strong low pressure system spins above the region, a chance of
rain remains. This chance will increase later this evening into
tonight. Count on IFR ceilings remaining for most of the forecast
period. Winds are going to increase as the day goes on, and near
sunset winds at SDF, LEX, and HNB will likely gust to near 30 knots.
BWG will likely be around 10 knots less.




Short Term...KDW
Long Term...JBS

Forecast Discussion from:
Script developed by: El Dorado Weather
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