Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 071723

Area Forecast Discussion
National Weather Service Louisville KY
123 PM EDT WED OCT 7 2015

...Updated Aviation Discussion...

.SHORT TERM (Now through Thursday)...
Issued at 300 AM EDT Wed Oct 7 2015

Weak and fairly flat ridging aloft, but a fairly stout surface high
will nose into the Ohio Valley as its center moves east across the
Great Lakes today. Dry and unseasonably warm pattern will continue
through Thursday. Even with partly cloudy skies, expect daytime
temps to continue to overachieve as they have for the last 3 days,
and in quiet weather back in September. Therefore the temp forecast
reflects the high end of guidance by day, and stays close to
consensus by night. Next wave will reach the Upper Peninsula of
Michigan by late Thursday, but any precip associated with the cold
front will hold off until later Thursday night.

.LONG TERM (Thursday night through Tuesday)...
Issued at 313 AM EDT Wed Oct 7 2015

Thursday Night - Friday Night...

The upper pattern will feature a shortwave diving into the Ohio
River Valley early Friday, passing east Friday night. Deeper
moisture is expected to pool along and ahead of this upper feature
and its associated surface front. This will allow for shower and iso
T chances across southern IN and northern Kentucky by dawn on
Friday. Best combination of forcing/moisture arrives during the
daylight hours where likely/categorical pops are warranted,
especially across the northern half of the CWA. Overall timing
continues to trend slightly slower as models are slightly more
amplified with the upper features, however still not impressed with
potential to destabilize much ahead of the precipitation. Given the
lack of expected instability and marginal deep layer shear values,
will continue to downplay thunder coverage and chances for organized
convection. Will stick with iso T mention.

Expecting a mild Thursday night as warm advection and increasing
clouds combine to only allow temps dropping into the low and mid
60s. Small diurnal trend on Friday as cloud cover/precip limit
heating. Look for highs in the 70s before temps drop off behind
frontal passage. Precipitation diminishes Friday night from West to
East with temps falling. Expect lows in the upper 40s to low 50s in
most spots.

Saturday - Tuesday...

Surface high pressure builds in to end the weekend and start the new
week. Meanwhile, upper ridging from the SW CONUS will build into the
Ohio River Valley, keeping any northern stream activity to the
north. Saturday/Saturday night will be the coolest of the period as
highs don`t make it out of the 60s and lows drop into the mid 40s.
Some low 40s are possible in the cool valleys. Expecting to warm
back into the 70s by Sunday, with temps well into the 70s
Monday/Tuesday. A few 80s will be possible west, closer to the upper

Some data suggests that a potent northern stream shortwave will be
able to dig enough across the Great Lakes region Monday night to
potentially bring some light precip to our area. However, with the
dry air in place, and upper ridge influence will lean toward a dry
forecast until models get a better handle.


.AVIATION (18Z TAF Update)...
Issued at 120 PM EDT Wed Oct 7 2015

Weak upper level ridging and sfc high pressure will continue this
TAF period.  Overall think that we`ll see the same fog concerns as
this morning tomorrow morning.  MOS guidance generally agrees with
this thinking with mainly light br forming late tonight into
tomorrow morning under almost clear skies, nearly calm winds, anda
good inversion.  Thus, went ahead and took BWG down to IFR minimum
although they may need a flight restriction lower than that. Took
SDF/LEX down to MVFR toward morning.  All TAF sites should improve
to VFR by 13-15Z tomorrow.  Winds will become more southerly
tomorrow ahead of a cold front which will approach the area just
beyond this TAF period.


.LMK Watches/Warnings/Advisories...


Short Term........RAS
Long Term.........BJS
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