Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 201710
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
110 PM EDT Mon Oct 20 2014

...Updated Aviation Discussion...

...Forecast Update...
Issued at 1135 AM EDT Mon Oct 20 2014

The area of rain associated with this morning`s PV anomaly continues
to slowly shift to the east. Coverage of showers across south
central Kentucky is a bit higher late this morning than previously
anticipated so have bumped up pops for the next few hours. Isolated
to scattered showers will continue to be possible this afternoon and
into the evening hours as a front approaches and moves into the
area.

Issued at 928 AM EDT Mon Oct 20 2014

The narrow line of showers continues to slowly move east across the
area. In addition, a few showers have popped up both north and south
of this line. In general the forecast is in pretty good shape. The
pop grids were updated to include a slight chance for precipitation
across south central KY where the forecast was dry before. Also
brought grids in line with current observations.

Issued at 615 AM EDT Mon Oct 20 2014

A narrow line of showers has developed over southern Indiana ahead
of an approaching PV anomaly from the NW. These light showers will
continue to push east across the northern half of the CWA through
the morning. Have increased chances to likely (60-70% coverage)
along a narrow axis in southern IN and northern KY to account. The
highest pops will roughly be along and several miles either side of
the I-64 corridor. Areas north and south of this region can expect
isolated to widely scattered light rain showers through the morning
and early afternoon.

Refer to the 20/00z or 20/06z NAM or recent runs of the HRRR as they
appear to have a good handle on what will transpire with light rain
today.

.SHORT TERM (Now through Tuesday)...
Issued at 305 AM EDT Mon Oct 20 2014

Things are quiet across the CWA at this hour, with only some mid and
upper level sky cover in place, and temperatures running in the low
and mid 40s. Will watch chances for isolated to scattered rain
showers increase over the next few hours ahead of a PV anomaly
diving in from the upper Midwest. Light rain showers have already
begun to organize from NW Indiana through southern Missouri ahead of
this feature, and expect a cluster of these showers to mainly focus
over southern Indiana and northern Kentucky later this morning. Less
impressed with measurable rain chances across south central KY where
there will be less moisture and more displaced from the best
forcing. Can`t rule out an isolated sprinkle, but think measurable
rain will be hard to come by. Will see temperatures warm to the mid
and upper 60s today on a steady SW wind, despite the lack of strong
solar insolation.

Will keep an chances for an isolated shower in across the far NE
into the late evening hours where deep moisture will be most
impressive. Things should dry out after Midnight. Will see milder
lows tonight under cloud cover and a somewhat mixy near-surface
environment.

Will have one more shot at isolated light rain showers across our NE
on Tuesday morning as another wave dives into the mean trough over
the eastern CONUS, and combines with the lingering low level
moisture. Most spots will stay dry this day with a fairly sizable
temperature gradient across the CWA. Look for upper 50s NE to mid to
upper 60s SW.

.LONG TERM (Tuesday Night through Sunday)...
Issued at 300 AM EDT Mon Oct 20 2014

An extended period of tranquil fall weather is on the way, with no
precip chances in the forecast through Sunday. The middle of the
week will feature shortwave ridging aloft, but Canadian surface high
pressure will be drawn southward behind a slowly departing East
Coast low. This will keep out temps below normal for most of the
work week. Coldest mornings will be Thursday with the surface ridge
axis directly over the Ohio Valley, and Friday as favorable
radiational cooling conditions persist. More sheltered/rural
locations could see lows in the 30s, and frost can`t be ruled out
either.

By the weekend, the next upper shortwave trof will weaken as it
heads into the Great Lakes, and with precipitable water values
barely touching climo, the only sensible weather impact will likely
be an increase in cloud cover. Temps will recover to near or above
climo as upper ridge starts to build from the SW, but that could be
limited by N-NE low-level flow depending on how strongly the surface
high is reinforced by the weakening upper impulse. Current forecast
is more in line with the raw model consensus, but if the upper
ridging wins out extended GFS MOS highs in the 70s could be the way
to go.

&&

.AVIATION (18Z TAF Update)...
Updated at 105 PM EDT Mon Oct 20 2014

Isolated showers will continue this afternoon as another disturbance
nears the area. However, the chances of any one of them affecting
the terminals are low so will leave mention of them out of the TAFs.
VFR conditions are expected to continue for the remainder of the
afternoon at all sites. Some breaks in the clouds are expected
through the afternoon.

For tonight a cold front will move through the area. Clouds will
build back in, particularly at LEX and SDF. This will shift winds to
the northwest by tomorrow morning with speeds increasing to 8-10
knots. Some light fog will be possible at LEX early tomorrow
morning. This should improve shortly after sunrise.

&&

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

$$

Update.........EER/BJS
Short Term.....BJS
Long Term......RAS
Aviation.......EER





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