Area Forecast Discussion
Issued by NWS Louisville, KY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KLMK 201914
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
314 PM EDT Sun Apr 20 2014

.SHORT TERM (Now through Monday Night)...
Issued at 312 PM EDT Sun Apr 20 2014

An upper level ridge is in place across the region today with mostly
sunny skies and light and variable winds. Temperatures are currently
ranging in the low and mid 70s, on their way to the upper 70s to
around 80 for highs. Drier air is mixing down this afternoon, mostly
ranging from 36-41 at this hour. This process is occurring slower
than yesterday due to less mechanical mixing from lighter winds
today. RH values will hover in the 20-30% range for many hours this
afternoon, however winds are light enough that an elevated wildfire
threat is not a concern at this time.

The upper level ridge axis will begin to slide East overnight as a
shortwave approaches from the west. This will allow more mid and
upper level clouds to stream into the area, along with a slight
uptick in southerly winds. Previous forecast mentioned slightly
milder overnight lows for these reasons and will continue this
thought. Will call for lows mostly in the upper 40s and low 50s,
however dip bump a few of the cooler valleys down to the mid 40s
since we saw valleys in the upper 30s last night under similar
conditions.

The majority of Monday will be dry, although will continue mention
of isolated to widely scattered showers and a t-storm along and west
of I-65 by mid to late afternoon. These chances will be due to an
isentropic ascent component combined with some weak instability, and
what appears to be an uncapped environment. Not too impressed if you
look at moisture profiles from a time height perspective as moisture
looks pretty limited. The main precipitation chances will come
overnight on Monday. Upper level clouds will limit heating just a
bit on Monday, although still expect solid upper 70s as we do pick
up a more steady SW wind and still see some peaks at the sun. If
there are any Fire Weather concerns tomorrow, it would be along the
I-75 corridor.

Deeper moisture will arrive Monday night ahead of the upper level
trough axis and along the weak cold front trailing from a surface
low over the eastern Great Lakes. Mention of scattered to numerous
showers and scattered thunderstorms still seems reasonable. Areas
that do see rain should expect between a tenth and a quarter of an
inch, with up to an half an inch possible in the wettest spots.
Overnight lows will obviously be milder just ahead of the front,
ranging in the upper 50s to around 60.

.LONG TERM (Tuesday through Sunday)...
Issued at 310 PM EDT Sun Apr 20 2014

A cold front will be right over our forecast area at the start of
the period, with the chance for rain out ahead of it mainly in the
morning hours. The next chance for rain holds off until either late
Thursday afternoon or Thursday night, as another cold front
approaches the area. This front will be followed by another one
Friday night. The Thursday night system has the most moisture
available with it, and may set up with a line of storms developing
to our west and moving through the area as they weaken. The Friday
night front will not as much moisture to work with, so will keep
forecast dry for now.

By Sunday, the 00Z ECMWF allows the warm front behind these systems
to lift over us quicker than the new GFS, bringing rain chances back
to the region for Sunday. The GEFS lends credence to the pattern
over us, but the spread is high for the placement of a low pressure
center over the Central Plains, which if on the north end would give
us a better chance for the front to be farther north. Given the
differences here, will keep rain chances low for the end of this
period.

Wednesday still looks to be the coolest day this period, with
temperatures in the morning in the low 40s and possibly some upper
30s in our cold spots. Winds still look to stay up Tuesday evening,
keeping us from the best chance for a quick cool down. Then on
Thursday and Friday temperatures bounce back above normal before
dipping back to normal for the weekend.

&&

.AVIATION (18Z TAF Update)...
Issued at 1259 PM EDT Sun Apr 20 2014

VFR conditions will prevail through the period. High pressure will
remain in control over the Ohio Valley through the next 24 hours.
Any noticeable gradient wind will be light out of the south today,
with only a few passing cirrus or diurnal cu. This cirrus shield may
increase a bit toward this evening and overnight, but it will be of
no impact to aviation operations. A light SW wind become more
established after sunrise on Monday with steadily increasing upper
level clouds and scattered Cu around 4-5 K feet. A shower may be
possible at SDF early Monday evening.

&&

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

$$

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





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.