Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 010519
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
119 AM EDT Fri Aug 1 2014
...Updated Aviation Discussion...
.SHORT TERM (Now through Friday Night)...
Issued at 307 PM EDT Thu Jul 31 2014
The synoptic pattern early this afternoon features an abnormally
amplified regime for late July, as an eastern trough/western ridge
pattern continues. This general pattern will continue through the
short term period.
A few vertical cumulus clouds are showing up on the latest visible
imagery this afternoon, especially down across southern KY near the
Bowling Green area. While a stray shower or sprinkle is possible
from these clouds, coverage does not appear high enough to warrant a
mention in the forecast for the remainder of the afternoon. Highs
look to top out in the middle 80s.
Clouds will dissipate tonight with the setting sun. While there may
be some more mid and high level clouds pushing into portions of
southern and southeastern KY, still think most locations will remain
partly cloudy to mostly clear. Therefore, expect another cool night
as lows fall into the upper 50s and lower 60s.
On Friday, some guidance continues to try and hint at some
precipitation potential. However, looking at PWATs, there appears
to be a pocket of dry air that remains in place across north-central
KY and southern IN, which will likely help limit coverage. Think
the best potential of showers/isolated storms will be across the far
western CWA where an incoming PV anomaly will help provide lift and
in the far eastern CWA where deeper moisture will reside. Was not
confident enough to take precipitation completely out of the
forecast for central regions of the CWA (including the Louisville
metro), but suspect these areas will remain dry given limited
forcing and moisture (hi-res WRF-ARW supports this thinking).
Deep moisture will increase somewhat (PWATs go to 1.5 inches) on
Friday night ahead of a PV anomaly diving through the mean trough.
However, given the tendency for cold core showers to be diurnally
driven, still think most will remain dry. Will once again only
leave in very slim chances for Friday night. Overnight lows will be
in the low to mid 60s.
.LONG TERM (Saturday through Thursday)...
Issued at 329 PM EDT Thu Jul 31 2014
Upper trough looks to dominate throughout the early half of the
long-term period. With vort maxes rotating through, the Ohio Valley
will be left in an unsettled pattern through the weekend. The focus
for thunderstorms will be over much of the forecast area on
Saturday, primarily during the peak heating of the day but slight
chances in the night period (primarily evening hours) cannot be
ruled out. For Sunday, the eastern half of the forecast area could
see some slight thunderstorm chances. Only slight chance because the
trough axis, vort max, and moisture will be moving eastward. Sunday
night through Wednesday looks to be dry as the pattern transitions
to zonal flow aloft and high pressure at the surface fights for
High pressure will be getting pushed out as deterministic models
indicate a low ejecting out of the Rockies and into the Midwest.
Both the 12Z GFS and 12Z ECMWF have come into some agreement with
the placement of the low, having it remain well to the north of this
forecast area, tracking through the Great Lakes toward the end of
this forecast period. A frontal boundary will accompany this low and
provide a focus for additional thunderstorm chances. Details this
far out are somewhat unreliable but PoPs currently look to enter in
from the NW late Wednesday with more widespread chances Thursday.
Temperatures will attempt to return to near normal for this time of
year early next week. Highs on Saturday and Sunday will vie to be
some of the lowest of the period, ranging in the low to mid 80s.
Highs on Monday through Wednesday will be close to or exceeding 90
degrees. Thursday currently looks to be somewhere in between with
highs in the mid to upper 80s but will likely be dependent on cloud
cover/precip and placement of the front. Lows shouldn`t fluctuate
too much, generally in the 60s throughout the long-term.
.AVIATION (06Z TAF Update)...
Issued at 118 AM EDT Fri Aug 1 2014
VFR conditions are expected at the TAF sites through the upcoming
forecast period. Some mid-high level cloudiness will continue to
stream eastward across mainly southern KY overnight. Some light fog
may be possible out toward the KLEX terminal. However, the overall
threat looks fairly low at this time. Light and variable winds are
expected overnight. Winds look to be out of the NE to ENE during
the day on Friday at the terminals.