Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 071039

Area Forecast Discussion
National Weather Service Louisville KY
639 AM 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 (12Z TAF Update)...
Issued at 635 AM EDT Wed Oct 7 2015

BWG has fogged this morning, with vis dropping into IFR.
Initialization will be a last-minute call, but the lack of any
significant fog on nearby webcams suggest that it won`t last long
after sunrise. Should be VFR across the board by 14Z, with light NE
winds and only a few diurnal cu to deal with.

Morning fog will be a potential concern yet again on Thursday, but
will not include in the TAFs yet this far ahead of time.


.LMK Watches/Warnings/Advisories...


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