Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 261720
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
120 PM EDT Sun Oct 26 2014
...Updated Aviation Discussion...
Issued at 1114 AM EDT Sun Oct 26 2014
Area webcams and surface observations have shown improvement in
visibilities over the past hour. Have allowed the Dense Fog Advisory
to expire at 11 AM. A few lingering patches of fog will persist
through midday, but overall conditions have improved enough to let
the headline go.
Otherwise, a pleasant and sunny day is in store.
.SHORT TERM (Now through Monday)...
Issued at 310 AM EDT Sun Oct 25 2014
...Dense Fog This Morning...Near Record Warmth Monday...
The near term forecast focus has been on locally dense fog that has
developed across southern Kentucky this morning thanks to
light/variable surface winds and a relatively moist air mass.
Dewpoints range from the middle to upper 50s ahead of a weak surface
boundary that lies to the north. Until this boundary pushes through
the area later this morning, conditions will be ideal for radiation
fog. The HRRR model has been capturing the fog very well and shows
it lingering through mid morning before burning off. As such, a
dense fog advisory has been issued for the southern part of the
forecast area through mid morning to account for the expected
impacts due to locally 1/4 mile visibilities or less.
Once morning fog burns off, plan on a very pleasant day as high
pressure will be the dominant weather feature. Sunny skies, light
winds and above normal temperatures will be the rule. Compared to
yesterday, highs will be a few degrees lower, thanks to some cooler
air aloft that will work in from the northeast. Highs should still
top out around 70 across the northeast forecast area to middle 70s
in the southwest.
The upper level pattern will then transition from zonal to
southwesterly, paving the way for near record warmth for much of the
Ohio River valley Monday. 26.00z model guidance remains very
consistent with past model cycles showing that as a strong shortwave
trough advances across the northern Plains, the ensuing
southwesterly flow will bring a surge of +16 to +17C 850 mb air
across the region. Soundings show mixing up to around 850 mb, so
this supports highs in the lower to middle 80s. With near full
sunshine, kept forecast highs on the warm side of guidance. 26.00z
850 mb temperature standardized anomalies vary from +2 to nearly
+2.5 SD, which increases confidence in approaching records for
Monday. It will also be a breezy day with winds gusting to 30 mph at
times across much of the area.
Below are the records for Monday and Monday night.
Record Max Oct 27 Record Warm Low Oct 28
Louisville 84 (1940) 64 (1991 and 1984)
Lexington 87 (1940) 64 (1984)
Bowling Green 87 (1919) 65 (1984)
Frankfort 89 (1940) 61 (1899)
.LONG TERM (Monday Night through Saturday)...
Issued at 315 AM EDT Sun Oct 26 2014
After a warm and breezy night Monday night with lows generally in
the 58-63 degree range, a cold front will advance into the region on
Tuesday. Widespread showers and scattered thunderstorms will
accompany the front, with just about everybody standing a chance at
getting some rain. The front will be losing some of its punch as it
enters the Ohio Valley and the best dynamics will be to our north
across IN/OH, but we`ll still have a chance at some thunder here
coincident with a narrow band of surface based instability around
mid day. High temperatures should be in the 70s with winds gusting
to around 20 or 25 mph (maybe some higher gusts in thunderstorms).
Tuesday night the front will push off to the east and our showers
will taper off from northwest to southeast. There could still be a
few left over rumbles of thunder in the Lake Cumberland region
during the evening hours. General rainfall totals are progged in
the quarter to half inch range, though amounts will vary with the
convective nature of the precipitation. Overnight lows behind the
front will be in the 40s.
During the remainder of the week several waves will pass overhead in
progressive WNW flow, but a lack of deep moisture for these waves to
work with will lead to a mostly dry forecast for now. Daily highs
will decrease from around 60 on Wednesday to around 50 (probably 40s
in the Blue Grass) on Saturday as Canadian high pressure dives SSE
right into the Ohio Valley by the weekend. Morning lows on Saturday
should be around the freezing mark, and below freezing Saturday
.AVIATION (18Z TAF Update)...
Updated at 120 PM EDT Sun Oct 26 2014
VFR conditions will prevail the remainder of this afternoon and
evening with light and variable winds as surface high pressure
slides across the region.
Tricky forecast for the overnight period as a warm front lifts back
north across the area. Expect to see deteriorating conditions after
Midnight at BWG as most likely scenario will be low stratus. Data
suggest ceilings could go down around minimums. Some data suggests
fog, however think that stronger low level jetting will be more
conducive to low stratus than fog. Also a bit concerned about low
level wind shear potential at the interface of the warm front where
nearly calm surface winds will be below a veering and strengthening
low level jet around 30 knots. At this point, think it will be too
marginal, however will continue to monitor with future forecasts.
SDF can expect the low stratus to begin sometime in the pre-dawn
hours, generally aroun 4 AM EDT, with LEX a couple hours later.
Conditions will scatter out by late morning and early afternoon,
with a strong SW gradient taking over. Gusts to 30 mph will be