Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 300712
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
312 AM EDT Mon Mar 30 2015

.SHORT TERM (Now through Tuesday)...
Issued at 245 AM EDT Mon Mar 30 2015

Weak cold front moving through the region this hour, with showers
out ahead of it and east of the forecast area. High pressure behind
this front will move into the Tennessee Valley by this evening. Then
another front will move through the region Tuesday, as a surface low
crosses well to our north. This front will be even more starved for
moisture than the one going through us now. Will continue
advertising a dry passage.

Despite this morning`s frontal passage, temperatures look to be a
little warmer today than Sunday. Stronger southwesterly flow ahead
of Tuesday`s front should make that day warmer still, with highs
generally around 70.

.LONG TERM (Tuesday Night through Sunday)...
Issued at 310 AM EDT Mon Mar 30 2015

Tuesday Night - Wednesday...

Surface high pressure and a progressive upper ridge will dominate
the pattern as we enter mid week. This will lead to dry conditions
and pleasant high temperatures on Wednesday just above normal
ranging from 65 to 70 in most spots. Lows Tuesday night/Wednesday
morning will be in the upper 30s north to low and mid 40s elsewhere.

Wednesday Night - Friday Night...

As we move through the end of the week, the pattern will become much
more active. Upper flow will flatten out or will take on a shallow
SW component. Meanwhile, the surface pressure gradient will tighten
over the Ohio River Valley in response to a passing low over the
northern Great Lakes and our departed high off the mid Atlantic
Coast. By Wednesday night, some isolated or widely scattered rain
showers will be possible in response to the southerly flow/weak
isentropic lift. Expect milder lows in the 50s. A cold front
trailing from the aforementioned system over the northern Great
Lakes will begin to approach on Thursday, laying out nearly parallel
to the upper flow along or just north of our CWA. There is some
question/ disagreement in timing placement of this boundary which
will ultimately decide how much coverage of showers and
thunderstorms we get. Confidence is higher that we will stay on the
warm side of the boundary on Thursday which will allow for temps in
the low and mid 70s. For now, will call for a chance of
showers/storms.

Shower and storm chances are expected to then persist into Thursday
night and Friday as the nearly stalled frontal boundary hangs near
the area and waves of energy eject out of the western CONUS trough
over our region. The trough axis looks to finally swing through
sometime Friday night, ending our precipitation chances from west to
east.

Will continue to keep an eye on chances for stronger storms Thursday
through Friday as details become more clear. The previous forecast
discussed the scenario where more instability looks likely on Thursday
with less shear. Meanwhile, Friday has better shear with less in the
way of instability. These scenarios still look reasonable, but won`t
get much more specific until details on timing/placement of the
boundary and individual waves become more clear. Temperatures will
be mild during this time on the warm side of the boundary.

Saturday - Sunday...

Cooler and dry conditions return for the weekend as Canadian high
pressure settles over the area. Highs will only be in the 50s on
Saturday with lows back in the upper 30s. Temperatures will quickly
modify back into the 60s by Sunday.

&&

.AVIATION (06Z TAF Update)...
Issued at 110 AM EDT Mon Mar 30 2015

Narrow band of light rain showers already past the SDF terminal and
soon will be past BWG/LEX as well. Front is not too far behind, with
wind shift to northwesterly. Model forecasts continue to be
optimistic on clearing out these clouds, which are VFR-based anyway,
soon after frontal passage. Satellite imagery agrees with this
thinking as well. Winds will become more variable by late this
afternoon and overnight as high pressure builds into the Tennessee
Valley.

&&

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

$$

Short Term........RJS
Long Term.........BJS
Aviation..........RJS




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